A 21-year-old woman comes to the university health clinic complaining of a 2week history of fatigue, lethargy, and fever. She has also noticed a mild sore
throat. Her past medical history is otherwise unremarkable and she takes
only oral contraceptive pills for birth control and acne. Her temperature is
39.0 C (100.4 F), blood pressure is 120/75 mm Hg, pulse is 82/min, and
respirations are 18/min. She appears somewhat ill, but in no clear distress.
Her pharynx appears erythematous and she has mild splenomegaly.
Supportive therapy and avoidance of contact sports is the appropriate
treatment if laboratory studies show
A. leukopenia with atypical leukocytosis
B. positive culture for group A beta-hemolytic Streptococcus
C. positive Mycoplasma PCR
D. positive RNA p24 antigen PCR
E. positive serum HSV PCR
Explanation:
The correct answer is A. This patient has infectious mononucleosis caused
by the Epstein-Barr virus. This disease can present in a very similar manner
to infectious pharyngitis caused by the group A beta hemolytic
streptococcus. These patients typically present with more mild symptoms of
fever and sore throat and in many cases have splenomegaly. The classic
laboratory finding is leukopenia with atypical leukocytosis. The treatment of
mono typically includes supportive therapy with avoidance of contact sports
(to avoid splenic rupture).
A positive culture for group A beta-hemolytic Streptococcus (choice B) would
represent infection with a bacteria that causes bacterial pharyngitis, not
mononucleosis. Although the presentations of the 2 diseases may be
similar, their causative agents are quite dissimilar. Antibiotics are used to
group A beta-hemolytic Streptococcus.
A positive mycoplasma PCR (choice C) represents infection with
Mycoplasma pneumonia, a common cause of atypical community acquired
pneumonia in this age group. Antibiotics are used to treat this infection.
A positive RNA p24 antigen PCR (choice D) would represent evidence of
infection with the HIV virus. Antiviral therapy is used to treat HIV.
A positive serum HSV PCR (choice E) indicates active herpes virus
infection. These agents are responsible for a number of human diseases,
including pharyngitis, but the symptoms are much milder. Herpes virus
infection does not cause infectious mono. Antiviral therapy is used to treat
HSV.
A 3-year-old girl is brought to the office by her father because a boy in her daycare
center was diagnosed with group A meningococcal meningitis. You care for the boy that
1
they are referring to so you know that this information is accurate. Even though this girl
is asymptomatic, the father is very concerned about her health. Her physical
examination is completely unremarkable. The most appropriate next step in
management is to
A. administer a serogroup-specific quadrivalent meningococcal vaccine
B. administer a single dose of ceftriaxone, intramuscularly
C. admit her to the hospital for careful observation
D. obtain throat and nasopharyngeal culture to decide if treatment is indicated
E. recommend careful observation and schedule a follow-up visit in 1 week
Explanation:
The correct answer is B. The risk of contracting meningococcal disease among
household members and childcare and nursery school contacts is considered high
enough to warrant chemoprophylaxis. Rifampin, ceftriaxone, and ciprofloxacin are the 3
recommended agents used as chemoprophylaxis for invasive meningococcal disease.
A serogroup-specific quadrivalent meningococcal vaccine (choice A) is used to prevent
cases of invasive meningococcal disease. It is given routinely to all military recruits and
recommended for children with asplenia and other immunodeficiencies. Some groups
also advise college students to receive this vaccine. The vaccine may be useful as an
adjunct to chemoprophylaxis during an outbreak, but it is not routinely recommended,
as chemoprophylaxis is.
It is unnecessary to admit her to the hospital for careful observation (choice C). This
patient should be given chemoprophylaxis and her father should be advised to observe
her carefully for the development of a febrile illness. Medical evaluation should be
sought immediately if an illness occurs, but hospitalization at this time in this
asymptomatic patient is not indicated.
Throat and nasopharyngeal culture to decide if treatment is indicated (choice D) is
incorrect. Throat and nasopharyngeal cultures are not useful in determining the risk of
contracting this disease. Chemoprophylaxis for invasive meningococcal disease is
indicated for this high-risk contact.
It is inappropriate to recommend careful observation and schedule a follow-up visit in 1
week (choice E). This patient is a high-risk contact and therefore requires
chemoprophylaxis. Careful observation is important too.
A 72-year-old man with non-Hodgkin's lymphoma, who is 10 days post chemotherapy,
has persistent fevers. Of note, 3 days after his chemotherapy finished, he had a
temperature of 38.5 C (101.3 F). He was started on ceftazadime and tobramycin. His
fever resolved initially. However, now it is 7 days later and he again has similar
temperature elevations. He has also developed some minimal hemoptysis. His blood
pressure is 115/85 mm Hg, pulse 82/min, and respirations 20/min. Heart has a regular
rhythm with no murmurs, lungs have some dry basilar crackles, abdomen is benign, and
extremities have 1+ edema, but no erythema. Laboratory studies show a leukocyte count
2
of 3,200mm3, hematocrit 28%, and platelets 18,000mm3. A chest x-ray shows
development of some bilateral nodular densities. A CT scan of the lungs confirms
multiple lung nodules, many of which have small hazy borders consistent with minimal
perinodular hemorrhage. The most appropriate next step in management is to
A. add amphotericin B intravenous therapy to his current therapy
B. change the chemotherapy regimen due to treatment failure
C. continue the ceftazidime and tobramycin and give it time to work
D. refer the patient to radiation oncology for emergent bilateral lung radiation
E. send him for a transesophageal echocardiogram
Explanation:
The correct answer is A. In any post chemotherapy patient who has persistent fever
despite appropriate broad-spectrum antibiotic coverage, fungal and resistant Grampositive organisms need to be considered. This patient also has a chest CT scan
showing multiple bilateral lung nodules with surrounding hemorrhage which is classic
for invasive aspergillosis. The most effective current therapy is with amphotericin B.
Continuing the ceftazadime and tobramycin (choice C) alone would not address the
current problem.
The patient is presenting with an acute infectious process related to chemotherapy
induced immune suppression. Although a lymphoma can involve the lung directly, it is
not particularly common and does not fit this clinical scenario. This makes a treatment
failure (choice B) incorrect. Bilateral lung irradiation is not something that is typically
done in non-Hodgkin's lymphoma and certainly would not be an emergent procedure
(choice D).
A transesophageal echocardiogram (choice E) can be used to look at vegetations on
heart valves seen in endocarditis. If the vegetations are on the tricuspid or pulmonary
valves, they can give off septic emboli to the lungs. This too can cause multiple lung
nodules. However, they are often cavitary and do not show the perinodular hemorrhage
that is classic for invasive aspergillosis.
A 72-year-old man with non-Hodgkin's lymphoma, who is 10 days post chemotherapy,
has persistent fevers. Of note, 3 days after his chemotherapy finished, he had a
temperature of 38.5 C (101.3 F). He was started on ceftazadime and tobramycin. His
fever resolved initially. However, now it is 7 days later and he again has similar
temperature elevations. He has also developed some minimal hemoptysis. His blood
pressure is 115/85 mm Hg, pulse 82/min, and respirations 20/min. Heart has a regular
rhythm with no murmurs, lungs have some dry basilar crackles, abdomen is benign, and
extremities have 1+ edema, but no erythema. Laboratory studies show a leukocyte count
of 3,200mm3, hematocrit 28%, and platelets 18,000mm3. A chest x-ray shows
development of some bilateral nodular densities. A CT scan of the lungs confirms
multiple lung nodules, many of which have small hazy borders consistent with minimal
perinodular hemorrhage. The most appropriate next step in management is to
3
A. add amphotericin B intravenous therapy to his current therapy
B. change the chemotherapy regimen due to treatment failure
C. continue the ceftazidime and tobramycin and give it time to work
D. refer the patient to radiation oncology for emergent bilateral lung radiation
E. send him for a transesophageal echocardiogram
Explanation:
The correct answer is A. In any post chemotherapy patient who has persistent fever
despite appropriate broad-spectrum antibiotic coverage, fungal and resistant Grampositive organisms need to be considered. This patient also has a chest CT scan
showing multiple bilateral lung nodules with surrounding hemorrhage which is classic
for invasive aspergillosis. The most effective current therapy is with amphotericin B.
Continuing the ceftazadime and tobramycin (choice C) alone would not address the
current problem.
The patient is presenting with an acute infectious process related to chemotherapy
induced immune suppression. Although a lymphoma can involve the lung directly, it is
not particularly common and does not fit this clinical scenario. This makes a treatment
failure (choice B) incorrect. Bilateral lung irradiation is not something that is typically
done in non-Hodgkin's lymphoma and certainly would not be an emergent procedure
(choice D).
A transesophageal echocardiogram (choice E) can be used to look at vegetations on
heart valves seen in endocarditis. If the vegetations are on the tricuspid or pulmonary
valves, they can give off septic emboli to the lungs. This too can cause multiple lung
nodules. However, they are often cavitary and do not show the perinodular hemorrhage
that is classic for invasive aspergillosis.
Two separate tests for the detection of anthrax exposure have recently been
developed, a general screening test and a confirmatory diagnostic test. The
screening test is used in the general population, while the diagnostic test is
used to confirm suspected cases already identified by other means. Nonphysician field personnel administer the screening test, while physicians or
technicians under physician supervision administer the diagnostic test. The
screening test is much cheaper than the diagnostic test, costing only 1/10 as
much. Although both have the same level of sensitivity, over the course of
their use, the diagnostic test is discovered to have a substantially higher
positive predictive value. This difference between the two tests is most likely
accounted for by the
A. care of the laboratory technicians
B. differences in specificity between the tests
C. expense of the test
4
D. length of time the tests have been used
E. prevalence within the sample tested
F. training of the personnel administering each test.
G. uncategorized error variance
Explanation:
The correct answer is E. The prevalence of exposure in the general
population is almost certainly much less than the prevalence in the
population to which the diagnostic test was applied. Higher prevalence
enhances positive predictive value. Simply put, if more people actually have
the disease, then a positive test result has a higher probability of being true.
Note that for the reasons described here, diagnostic tests always have a
higher positive predictive value than screening tests.
Although the care and skill of laboratory technicians (choice A) varies, there
is no evidence that this is a key issue here.
If the diagnostic test has better specificity (choice B) than the screening test,
we would expect a higher positive predictive value. However, while this is
possible, the different sample prevalence is almost a certainty making that
the better answer.
More expensive (choice C) does not, by itself, mean better.
The question gives no information about the length of time (choice D) that
either test has been used.
The assumption that non-physicians (choice F) provide less accurate test
results is supported by neither the question content nor real life experience.
Every test result has error as a part of the measurement it provides, but that
is not what accounts for the differences reported here. The difference in
results here are the result, not of uncategorized error (choice G), but error
rates linked directly to the different prevalences on which the tests were
conducted.
A 5-year-old boy is brought to the clinic by his mother because of the new
onset of a flaky scalp and patches of hair loss. He just started preschool 2
months ago and his teacher noted the alopecia during a nap break. His past
medical and birth history are insignificant, and he is not on any medications at
this time. He has 1 cat and 1 dog at home. On examination, there are multiple
circular patches of alopecia studded with black dots on the surface of the
scalp. After examining the boy, the mother shows you lesions on her right
shoulder. There is an annular erythematous plague with central clearing. The
edge is slightly raised and there are tiny vesicles and a fine scale. There is
mild lymphadenopathy appreciated. The best next diagnostic step is to
5
A. exam the boy's hair microscopically with potassium hydroxide
B. inquire about autoimmune diseases in the family and obtain a
thyroid function test
C. perform a punch biopsy of the boy's scalp
D. perform a Wood's light exam of the boy's scalp
E. refer him to psychiatry for trichotillomania
Explanation:
The correct answer is A. Examining the hair microscopically with potassium
hydroxide (KOH) is correct because this child has tinea capitis secondary to
his mother's tinea corporis. Tinea capitis commonly presents as areas of
alopecia with studded black dots representing infected hairs broken off at or
below the surface of the scalp. Different species of fungus can cause either
inflammatory or non-inflammatory lesions. Trichophyton mentagrophytes,
the species responsible for both inflammatory tinea capitis and tinea
corporis, can result in pain and regional lymphadenopathy. Most commonly,
the mode of transmission is child to child in school age children. The fact
that this child's mom has classic "ringworm" on her left shoulder, which is
usually described as concentric erythematous plaque with central clearing
and superficial scales points the differential diagnosis toward a fungal
infection. Diagnosis of tinea capitis is usually confirmed with microscopic
exam of the hair and looking for ectothrix or endothrix spores.
Inquiring about autoimmune disease (choice B) is incorrect because
autoimmune processes are usually associated with alopecia areata, not
tinea capitis. Alopecia areata is not usually associated with
lymphadenopathy or "black dots" of broken hair.
Punch biopsy of the scalp (choice C) is incorrect because if tinea capitis is
suspected, the first step toward diagnosis includes KOH of hair and a fungal
culture of the scalp.
Wood's light exam of the scalp (choice D) is incorrect because only ectothrix
species fluoresce with Wood's light but not endothrix types. Therefore, this is
not the best diagnostic method to confirm tinea capitis
Referral to psychiatry for trichotillomania (choice E) is incorrect, because this
type of alopecia should not have associated lymphadenopathy.
A 62-year-old man underwent coronary artery bypass surgery 12 weeks ago. His
postoperative course is complicated by bleeding and cardiac tamponade, for which he
had an emergency sternotomy. One week later he developed a sternal wound infection
for which debridement and a pectoralis muscle flap procedure is performed. During
these surgeries he receives multiple blood transfusions. At his 3-month followup he
reports dark urine, fatigue, and anorexia. On examination, he is not jaundiced. There is
mild, tender hepatomegaly on palpation of the abdomen. Laboratory studies show:
6
The most likely explanation for the patient's clinical condition is
A. acute viral hepatitis A
B. acute viral hepatitis B
C. acute viral hepatitis C
D. acute viral hepatitis D
E. acute viral hepatitis E
Explanation:
The correct answer is C. Post transfusion non-A, non-B hepatitis is mostly the result of
hepatitis C infection. The incubation period is usually 5-10 weeks and the mean peak
aminotransferase levels are 500-1000 IU/L. Anti-HCV antibody is commonly not
detectable until 18 weeks after illness onset. Approximately 70% of patients with acute
hepatitis C progress to chronic hepatitis and potentially cirrhosis.
Negative hepatitis A (choice A) antibody rules out hepatitis A infection.
Negative serology for hepatitis B (choice B) rules out hepatitis B infection.
Hepatitis D (delta) virus (choice D) is capable of infecting only patients who also have
HBsAg, because HDV is an incomplete RNA virus.
Hepatitis E virus (choice E) is rare, except in association with water-borne epidemics in
India, the Middle East, and South America.
An 8-year-old boy with asthma is admitted to the hospital with shortness of breath. The
mother tells you that he is usually well controlled with bronchodilator inhalers. However,
for the past 2 days he has had rhinorrhea, a low-grade fever, and myalgias. She also
reports that the child has a non-productive cough. Bronchodilators temporarily improved
the child's breathing at home, but it once again worsened and they became worried. On
admission, this child is given droplet precautions. Nebulized bronchodilator treatments
are initiated. Oxygen supplementation is given by nasal cannula and he is given aspirin
for the relief of fever. For prophylaxis of influenza, amantadine is administered because
of a recent influenza outbreak in the community. Of all of the therapies initiated in this
patient, the one that is not indicated in this case is
7
A. amantadine
B. aspirin
C. droplet precautions
D. nebulized bronchodilators
E. oxygen
Explanation:
The correct answer is B. Although aspirin is appropriate for the relief of fever, this
patient is an 8-year-old child. The use of aspirin in a child with influenza is
contraindicated, due to the association of aspirin usage in children with influenza and
the development of Reye's syndrome. Reye's syndrome is more common with influenza
B, but outbreaks have been found to be associated with influenza A. Hence, during an
outbreak of influenza, aspirin is contraindicated in children with respiratory symptoms or
fever.
Amantadine until 48 hours after the symptoms have resolved (choice A) is a therapy for
the prophylaxis of influenza.
Placing the child on droplet precautions is essential for the prevention of spread of
respiratory infections during an influenza outbreak (choice C).
Nebulized bronchodilators (choice D) are essential for preventing bronchospasm and
for better oxygenation in children with respiratory symptoms.
Supplementation of oxygen, if oxygen saturation is low (choice E), is an essential
therapeutic maneuver in children with respiratory symptoms.
A 71-year-old woman comes to the emergency department because of severe shortness
of breath, retrosternal chest pain, a fever, and a dry cough that has worsened over the
past three weeks. She says that she is rarely sick and she prides herself on being the
"healthiest and most active grandmother in the northeast." She swims everyday and
goes out with friends four nights a week since her husband passed away five years ago.
She blushes as she admits that she has many male "suitors". She does not smoke
cigarettes. However, she drinks a "moderate" amount of alcohol each day. She recalls
having an episode of fever, headaches, joint pain, a loss of appetite, and a mild sore
throat a few months ago that she did not seek medical attention for because she
assumed it was a "virus". Her temperature is 38.8 C (101.8 F) and respirations are
35/min. She has bibasilar rales and significant cervical, axillary, and inguinal
lymphadenopathy. A chest x-ray shows bilateral patchy alveolar infiltrates. Histologic
evaluation of a sputum sample obtained by bronchoalveolar lavage shows round
structures when stained with methenamine silver. An important question to ask at this
time is:
A. "Did you or your late husband ever install insulation or brake lining, do
construction work, or work in a shipyard?"
B. "Do you engage in unprotected sexual intercourse at the present time or at any
8
other time in the past?"
C. "Have you ever been involved in a homosexual relationship?"
D. "Have you ever had a morning drink to get started (an "eyeopener")?"
E. "Have you ever had a positive PPD or been exposed to anyone with
tuberculosis?"
Explanation:
The correct answer is B. This patient most likely has Pneumocystis carinii pneumonia
(PCP), and she is probably infected with the human immunodeficiency virus (HIV), in
her case, most likely due to unprotected sexual intercourse with an infected individual. It
is important to recognize that elderly patients may be sexually active, even if their
spouse is no longer around. They are at risk for HIV and other sexually transmitted
diseases because they may not think to use a condom because they are not worried
about getting pregnant. PCP is characterized dyspnea, fever, a nonproductive cough,
retrosternal chest pain, tachypnea, tachycardia, few abnormalities on auscultation,
bilateral patchy alveolar infiltrates on chest x-ray, and round cysts found under light
microscopy when stained with methenamine silver. The treatment is trimethoprimsulfamethoxazole. The "episode of fever, headaches, joint pain, a loss of appetite, and
mild sore throat" that she describes having a few months earlier is consistent with the
acute HIV syndrome which affects many patients with HIV, approximately three to six
weeks after the primary infection. This syndrome coincides with plasma viremia (wide
dissemination of the virus). The symptoms gradually subside over a few weeks.
"Did you or your late husband ever install insulation or brake lining, do construction
work, or work in a shipyard?" (choice A) is an important question if an asbestos-related
disease is suspected, but this case is more consistent with Pneumocystis carinii
pneumonia than asbestosis or malignant mesothelioma. Asbestosis is characterized by
dyspnea, a nonproductive cough, basilar crackles or rales, clubbing, linear streaking
and pleural thickening seen on chest x-ray, and ferruginous bodies seen on microscopic
examination of lung tissue (rod-shaped bodies with clubbed ends). Malignant
mesothelioma is a tumor of the pleura that is characterized by chest pain, dyspnea, a
cough, a chest x-ray showing pleural fluid, irregular pleural thickening, and a biopsy
demonstrating the malignant cells.
"Have you ever been involved in a homosexual relationship?" (choice C) is not a vital
question at this time because it is very unlikely that this woman contracted HIV and
AIDS from unprotected sexual intercourse with another woman. It is more likely that she
contracted the infection from unprotected sexual intercourse with a man. Also, if you
wanted to know if a patient has homosexual relationships, it is better to ask in a
nonjudgmental way, such as, "Do you have sex with men, women, or both?"
"Have you ever had drink in the morning to get started (an "Eyeopener")?" (choice D) is
a part of a four question screening test to detect problem drinking called the CAGE
questionnaire. The other three questions that make up the CAGE questionnaire include:
“Have you ever felt the need to Cut down on your drinking?”, “Have you ever felt
Annoyed by criticisms of your drinking?”, and “Have you ever had Guilty feelings about
drinking?”. Two positive responses indicate that a problem is likely. These questions
may be important, but the immediate concern in this case is this patient's Pneumocystis
carinii pneumonia and whether she has been infected with the HIV virus. Questions
9
related to her sexual practices may help to identify the source of infection.
"Have you ever had a positive PPD or been exposed to anyone with tuberculosis?"
(choice E) is a question that is important if tuberculosis or an aspergilloma is suspected.
However, this case is more consistent with Pneumocystis carinii pneumonia. Primary
tuberculosis (TB) is characterized by systemic symptoms, a cough, sputum production,
hemoptysis, lower lobe infiltrates, hilar node enlargement, pleural involvement, and the
presence of acid-fast bacilli. Reactivation TB is characterized by infiltrates with
cavitation in the apices. An aspergilloma is a "fungus ball"' that typically forms within a
preexisting cavity (from TB or sarcoidosis) in the pulmonary parenchyma. The patients
may be asymptomatic or present with hemoptysis. A culture shows fungal mycelia,
which appear as branching hyphae. In this case, microscopic evaluation shows round
structures, not acid-fast bacilli or hyphae.
A 31-year-old alcoholic homeless man with a history of type 1 diabetes
comes to the urgent care clinic with a left foot ulcer. The ulcer has been
present for 4 months, but has been sore for the past 2 weeks. There is no
other medical history. His blood pressure is 92/54 mm Hg and pulse is
170/min. Physical examination shows an eschar extending to the bone with
necrotic sides on the dorsal aspect of the hallux just distal to the
interphalangeal joint. Laboratory studies reveal a leukocyte count of
33,000/mm3. Fingerstick glucose is 210 mg/dL. Urinalysis, complete blood
count, chest radiograph, and blood cultures are pending. An
electrocardiogram shows a sinus tachycardia at a rate of 180/min. The most
appropriate first-line therapy for this patient's tachycardia is
A. atenolol
B. intravenous imipenem
C. intravenous 0.9% normal saline and broad spectrum antibiotics
D. metoprolol
E. packed red blood cell transfusion
Explanation:
The correct answer is C. This patient is at risk for Gram-negative cellulitis
because he is diabetic. Clinically, this patient is most likely having sepsis
from a cellulitis. He is exhibiting the signs of septic shock, which include
tachycardia and hypotension due to decreased vascular tone secondary to
circulating toxins. The treatment is intravenous fluids, preferably a 0.9%
normal saline which remains in the vasculature longer than a 0.5% normal
saline or dextrose in water intravenous solutions. Intravenous fluid will
address the issue of septic shock immediately, and broad-spectrum
antibiotics are critical to stopping the proliferating infection.
β-blockers, such as atenolol (choice A) will stop the tachycardia, but this
patient is most likely tachycardic as a normal response to hypotension.
Clinically, this patient is most likely having sepsis from a cellulitis. He is
10
exhibiting the signs of septic shock which include tachycardia and
hypotension due to decreased vascular tone secondary to circulating toxins.
The treatment is intravenous fluids, preferably a 0.9% normal saline which
remains in the vasculature longer than a 0.5% normal saline or dextrose in
water intravenous solutions. Since this patient most likely has septic shock,
intravenous fluids and antibiotics are the most appropriate therapy.
Intravenous fluids will address the issue of septic shock immediately and
broad-spectrum antibiotics are critical to stopping the proliferating infection.
Antibiotics (choice B) are necessary for the treatment of this infection, but
they do not work quickly enough to prevent the impending septic shock.
Intravenous fluids will address the issue of septic shock immediately and
broad-spectrum antibiotics are critical to stopping the proliferating infection.
β-blockers, such as metoprolol (choice D) will stop the tachycardia, but this
patient is most likely tachycardic as a normal response to hypotension, so
intravenous fluids are the most appropriate first line therapy.
Packed red blood cell transfusion (choice E) may be necessary if there is a
severe anemia, but saline is the first choice to rehydrate an unstable
intravascular volume in a depleted patient.
A 21-year-old woman comes to the university health clinic complaining of a 2week history of fatigue, lethargy, and fever. She has also noticed a mild sore
throat. Her past medical history is otherwise unremarkable and she takes
only oral contraceptive pills for birth control and acne. Her temperature is
39.0 C (100.4 F), blood pressure is 120/75 mm Hg, pulse is 82/min, and
respirations are 18/min. She appears somewhat ill, but in no clear distress.
Her pharynx appears erythematous and she has mild splenomegaly.
Supportive therapy and avoidance of contact sports is the appropriate
treatment if laboratory studies show
A. leukopenia with atypical leukocytosis
B. positive culture for group A beta-hemolytic Streptococcus
C. positive Mycoplasma PCR
D. positive RNA p24 antigen PCR
E. positive serum HSV PCR
Explanation:
The correct answer is A. This patient has infectious mononucleosis caused
by the Epstein-Barr virus. This disease can present in a very similar manner
to infectious pharyngitis caused by the group A beta hemolytic
streptococcus. These patients typically present with more mild symptoms of
fever and sore throat and in many cases have splenomegaly. The classic
laboratory finding is leukopenia with atypical leukocytosis. The treatment of
mono typically includes supportive therapy with avoidance of contact sports
11
(to avoid splenic rupture).
A positive culture for group A beta-hemolytic Streptococcus (choice B) would
represent infection with a bacteria that causes bacterial pharyngitis, not
mononucleosis. Although the presentations of the 2 diseases may be
similar, their causative agents are quite dissimilar. Antibiotics are used to
group A beta-hemolytic Streptococcus.
A positive mycoplasma PCR (choice C) represents infection with
Mycoplasma pneumonia, a common cause of atypical community acquired
pneumonia in this age group. Antibiotics are used to treat this infection.
A positive RNA p24 antigen PCR (choice D) would represent evidence of
infection with the HIV virus. Antiviral therapy is used to treat HIV.
A positive serum HSV PCR (choice E) indicates active herpes virus
infection. These agents are responsible for a number of human diseases,
including pharyngitis, but the symptoms are much milder. Herpes virus
infection does not cause infectious mono. Antiviral therapy is used to treat
HSV.
A 43-year-old woman comes to the emergency department because of fever and
abdominal pain. She has a history of cirrhosis and long standing alcohol abuse. She
takes no medications except for the occasional acetaminophen for a headache. She
reports that 5 days ago, she had fever of 38.6 C (101.5 F) and the gradual onset of
diffuse abdominal pain. Her blood pressure is 95/40 mm Hg and pulse is 104/min and
regular. Physical examination shows clear lungs, numerous spider angiomata on her
thorax and back, and a massively distended abdomen with shifting dullness by
percussion. An abdominal paracentesis is performed and the results are as follows:
Laboratory studies show:
The most appropriate pharmacotherapy is
12
A. ampicillin, intravenously
B. azithromycin, intravenously
C. cefotaxime, intravenously
D. penicillin G, intravenously
E. vancomycin, intravenously
Explanation:
The correct answer is C. The prevalence of infection of ascites fluid, so called
spontaneous bacterial peritonitis (SBP), has an estimated prevalence of 50% in
hospitalized cirrhotics. ALL febrile patients admitted with ascites must have an
abdominal paracentesis performed to both determine the cause for the ascites and rule
out infection of the ascites. The diagnosis of SBP is made when there is an elevated
ascitic fluid absolute neutrophil count (>250 cells/mm3) without an evident
intraabdominal or surgically treatable cause for the infection. SBP most often occurs
with portal hypertensive ascites. The most sensitive marker available for such ascites is
a serum/ascites albumin gradient >1.0 mg/dL. Traditionally, the empiric treatment for
SBP is ampicillin (choice A) plus an aminoglycoside. However, owing to the
nephrotoxicity of that regimen in the setting of patients who may require liver transplant,
monotherapy with a third-generation cephalosporin is now the treatment of choice. The
duration of therapy is 5 days. An alternative regimen is amoxicillin-clavulanic acid.
Azithromycin (choice B) is often used to treat respiratory infections and nongonococcal
urethritis and cervicitis. It is not used in SBP.
Penicillin G (choice D) is used to treat syphilis and streptococcal infections. It is not
used to treat SBP, which is often caused by a mixture of Gram-positive and Gramnegative bacteria.
Vancomycin (choice E) is used for pseudomembranous colitis and staphylococcal
infections. It is not used to treat SBP, which is often due to Gram-negative and -positive
bacteria.
A 25-year-old man comes to the clinic complaining of an itchy rash for 2-3 weeks on his
chest and upper back. He is otherwise healthy and is not taking any medications. On
physical examination, there are numerous hypopigmented macules, some coalescing
into patches on his chest wall, upper back, and proximal arms bilaterally. There is
superficial scaling on some of the lesions, but no erythema or violaceous borders.
Wood's lamp on the lesions revealed yellow-white fluorescence. A scraping of the skin
with potassium hydroxide, under the microscope, reveals short hyphae with numerous
round spores. The correct diagnosis and treatment for this patient is
A. erythrasma and topical cleomycin
B. erythrasma and topical ketoconazole
C. tinea corporis and topical terbinafine
13
D. tinea versicolor and topical cleomycin
E. tinea versicolor and topical ketoconazole
Explanation:
The correct answer is E.Tinea versicolor and topical ketoconazole is the correct answer
because this is a common skin disorder caused by Malassezia furfur (also known as
Pityrosporum ovale). The disease may occur at any age, but it is much more common
during the years of higher sebaceous activity (i.e., adolescence and young adulthood).
Some individuals, especially those with oily skin, may be more susceptible. The lesions
begin as multiple small, circular macules of various colors (white, pink, or brown) that
enlarge radially. The hypopigmented lesions are caused by alterations in melanosome
formation and transfer to keratinocytes. The upper trunk is most commonly affected, but
it is not unusual for lesions to spread to the upper arms, neck, and abdomen. Diagnosis
is confirmed by potassium hydroxide examination of the scale which shows numerous
hyphae that tend to break into short, rod-shaped fragments intermixed with round
spores in grapelike clusters, giving the so-called "spaghetti and meatballs" pattern.
Wood's light examination shows irregular, pale, yellow-to-white fluorescence that fades
with improvement. Treatment includes a a topical selenium sulfide suspension,
ketoconazole, zinc pyrithione shampoo, or oral ketoconazole, itraconazole, or
fluconazole. A topical antibiotic such as cleomycin (choice D) is the incorrect choice of
treatment for these patients.
Erythrasma with topical cleomycin (choice A) and erythrasma with topical ketoconazole
(choice B) are both incorrect because erythrasma is caused by Corynebacterium
species. Therefore, it should not have any hyphae on scraping. It is a disorder
characterized by red to brown scaling patches affecting the intertriginous areas such as
the groin, submammary regions, axillae, and toe webs. The correct treatment for
erythrasma is either topical erythromycin or cleomycin
Tinea corporis(choice C) is incorrect because tinea corporis lesions, also known as ring
worm, tend to be round with elevated erythematous borders that have a central clearing
and superficial scales. In addition, tinea corporis is usually caused by the Trichophyton
species which do not fluoresce with wood's lamp examination.
A 28-year-old woman comes to the office because of a 3-hour history of
severe nausea, vomiting, abdominal cramps, and diarrhea. She ate lettuce
with salad dressing, custard, and pastries and drank stream water at a family
picnic at a local park 2 hours before the onset of the symptoms. She is
unsure whether anyone got sick. She was "absolutely fine" before she went
to the picnic. She does not take any medications. Her temperature is 36.7 C
(98.0 F), blood pressure is 110/70 mm Hg, pulse is 65/min, and respirations
are 14/min. Physical examination shows mild abdominal tenderness. A stool
sample shows large numbers of Gram-positive cocci in clusters. At this time
the most correct statement about her condition is:
A. An antibiotic is indicated to treat her infection
B. Colonoscopy will show pseudomembranes and friable mucosa
14
C. Contaminated stream water at the picnic caused these symptoms
D. Her symptoms are due to an enterotoxin produced by the organism
E. It is unlikely that the organism was transmitted from an individual
with purulent lesions on the hands, nose, and face
Explanation:
The correct answer is D. This patient most likely has staphylococcal food
poisoning, which typically presents with nausea, vomiting, abdominal
cramps, and diarrhea within hours of consuming the contaminated food. The
contaminated foods have usually come into contact with food handlers or
contaminated preparation equipment. These food handlers are infected
carriers who may have abscesses, boils, and purulent lesions on their
bodies. The staphylococcal infection is usually due to an enterotoxin
producing Staphylococcus aureus strain. Large amounts of S. aureus are
found in the vomitus and the stool of infected patients. The treatment is
supportive. Antimicrobials are not indicated.
Even though this patient most likely has staphylococcal food poisoning, an
antibiotic is NOT indicated to treat her infection (choice A). This condition is
usually self-limited.
Colonoscopy will show pseudomembranes and friable mucosa (choice B) in
pseudomembranous colitis, which is usually associated with Clostridium
difficile infection. C. difficile typically occurs in patients taking antibiotics and
usually presents with fever and large amounts of watery diarrhea.
If this patient had giardiasis, contaminated stream water at the picnic would
have caused these symptoms (choice C). However the incubation period for
this patient's symptoms was hours and is therefore more consistent with
staphylococcal food poisoning than with giardiasis. Giardiasis typically has
an incubation period of days to weeks.
It is unlikely that the organism was transmitted from an individual with
purulent lesions on the hands, nose, and face (choice E) is incorrect. This
patient most likely has staphylococcal food poisoning, which is often
associated with food handlers that have abscesses, boils, and purulent
lesions on their bodies.
A 43-year-old man with acquired immunodeficiency syndrome (AIDS) is in the
hospital for pneumonia. On his second hospital day, he reports difficulty
swallowing his meals. He says that for the last month he has had difficulty
swallowing food and medications. He also occasionally feels a burning pain in
his upper chest when swallowing. He denies abdominal pain, nausea, or
vomiting. Vital signs are: 37.0 C (98.6 F), blood pressure 129/88 mm Hg,
pulse 80/min. Examination of his mouth reveals pink oral mucosa and a
normal tongue. He has no significant cervical lymphadenopathy. Abdominal
examination is normal. The patient's last CD4 count was performed 5 months
ago and at that time was 190/mm3. The most appropriate next step in the
15
management of this patient is to
A. order esophagogastroduodenoscopy (EGD)
B. order a Helicobacter pylori antibody test
C. prescribe a trial of antacids and schedule a follow-up appointment
D. prescribe oral acyclovir
E. prescribe oral fluconazole
Explanation:
The correct answer is A. The symptoms of dysphagia and odynophagia in a
patient with AIDS are highly suspicious for esophagitis. The causes of
esophagitis in the setting of AIDS or other immunocompromised states
include Candida albicans, cytomegalovirus (CMV), and herpes simplex virus
(HSV). The most frequent cause is C. albicans, which accounts for 50-70%
of all cases. Esophagogastroduodenoscopy (EGD) is the best way to
diagnose the etiology of esophagitis by providing both direct visualization of
the esophageal lesions and the ability to obtain biopsies. If the patient has
oral thrush and symptoms of esophagitis, the most likely etiology is C.
albicans and treatment with fluconazole can be initiated empirically. This
patient, however, has normal oral mucosa and needs an EGD prior to
treatment.
The Helicobacter pylori antibody test (choice B) is used to determine the
etiology of gastric ulcers. This test is not indicated in this patient because he
does not have symptoms of ulcer disease. The symptoms of dysphagia and
odynophagia in a patient with AIDS are highly suspicious for a fungal or viral
esophagitis.
A trial of antacids (choice C) is inappropriate for this patient. The symptoms
of dysphagia and odynophagia in a patient with AIDS are highly suspicious
for fungal or viral esophagitis. Antacids are used primarily for
gastroesophageal reflux disease and will not help in this case. A follow-up
appointment is important, however, after the patient has an
esophagogastroduodenoscopy (EGD) and is started on appropriate
medications.
Treatment with acyclovir (choice D) is premature at this time. There are
multiple causes of esophagitis in patients with AIDS and an
esophagogastroduodenoscopy (EGD) should be performed to evaluate the
esophageal lesions as well as to obtain biopsies. If the esophagitis is caused
by herpes simplex virus (HSV), acyclovir is the anti-viral medication of
choice.
Treatment with fluconazole (choice E) is premature at this time. There are
multiple causes of esophagitis in patients with AIDS and
esophagogastroduodenoscopy (EGD) should be performed to evaluate the
esophageal lesions as well as to obtain biopsies. If the esophagitis is caused
by Candida albicans, fluconazole is the anti-fungal medication of choice.
16
A 57-year old woman comes to the emergency department because of a
"very high fever." She has diabetes mellitus and hemodialysis-dependent
renal failure. She also has hypertension and is status-post total abdominal
hysterectomy. She is frail appearing and diaphoretic. Her blood pressure is
170/90 mm Hg and temperature is 38.3 C (101.0 F). Her neck is supple
without any specific meningismus. She has a Tesio catheter in her left
subclavian vein. Her lungs are clear and she has no costovertebral angle
tenderness. Her laboratory studies show a white blood cell count of
23,000/mm3 and a hematocrit of 31%. Her urinalysis is dipstick negative for
white blood cells. The most appropriate next step in management is to
A. begin antibiotic therapy with gentamycin
B. begin antibiotic therapy with vancomycin and gentamycin
C. order urinalysis analysis and culture
D. perform a lumbar puncture and send CSF for analysis and culture
E. schedule emergent surgical removal of her Tesio catheter
Explanation:
The correct answer is B. Infection is the most common cause of death in
patients with chronic renal failure. This is followed closely by cardiovascular
events. The etiology of increased risk of infection is multifactorial and
involves a complex interplay of decreased immune response and
complement activation by dialysis membranes all coupled with long-term
indwelling components such as catheters. When a dialysis patient presents
with infection, the first step in their management is to initiate broad antibiotic
coverage based upon the likely causative organisms. This patient has an
indwelling catheter and therefore has an increased risk of infection with both
coagulase-positive and coagulase-negative Gram-positive cocci. Given the
large percentage (25% at most centers) of methicillin resistant
Staphylococcus aureus (MRSA), vancomycin is usually initiated until
sensitivity data is available. An aminoglycoside is usually added to cover for
very common Gram-negative infections.
Begin antibiotic therapy with gentamicin (choice A) is inadequate since the
majority of infections in patients such as these will not be covered by an
aminoglycoside alone.
Sending her urine for analysis and culture (choice C), although prudent, to
perform this with a negative urine dipstick for WBCs, will not change your
initial management and decision to cover the patient with broad spectrum
antibiotics.
Performing a lumbar puncture and sending a CSF for analysis and culture
(choice D) implies meningitis as a cause for the fevers. Meningitis is a rare
cause of fevers generally. And although dialysis patients are at mildly
increased risk of meningeal infections, in the absence of localized signs and
17
symptoms, the likelihood of meningitis is very low and therefore the risk of
an LP is not warranted.
Schedule emergent surgical removal of her Tesio catheter (choice E) is not
an appropriate initial management step in a febrile patient. This may be
indicated later in the course of care, but concern over removal before
antibiotics have begun, is not appropriate.
A 24-year-old man comes to the clinic because of 2 "bumps" on his penis and
scrotum. The lesions have been there for approximately 7 months and have
been getting progressively larger. They are not painful. He is sexually active
with 2 female partners, who are both on oral contraceptive pills and so they
do not use barrier contraception. He had chlamydial urethritis last year. His
temperature is 37.0 C (98.6 F). Physical examination shows a 3 mm fleshcolored, non-tender, lesion with a "heaped-up" appearance on the shaft of the
penis and a 4 mm lesion with a similar appearance on his scrotum. The
remainder of the examination is unremarkable. A rapid plasma regain (RPR),
VDRL, and fluorescent treponemal antibody absorption (FTA-ABS) test are
all nonreactive. In addition to providing the appropriate treatment, he should
be told that:
A. Condoms will prevent the spread of this disease to future sexual
partners
B. His sexual partners should be evaluated because they may be at
an increased risk for cervical cancer
C. Oral suppressive therapy will decrease the frequency of
recurrences
D. The state health department will be contacted because this is a
notifiable infectious disease
E. Treatment will eradicate the infection
Explanation:
The correct answer is B. This patient has an anogenital human
papillomavirus (HPV) infection (also known as genital warts). These lesions
may be confused with condyloma lata (secondary syphilis). However, the
"heaped-up" appearance of the flesh colored lesions are more characteristic
of HPV and the serology for syphilis is negative. The treatment options for
HPV include podophyllin application, cryotherapy, trichloroacetic acid,
imiquimod, electrocautery, laser surgery, or surgical excision. This patient
needs to tell his sexual partners to be evaluated because HPV infection is
associated with cervical cancer.
Condoms may help to decrease the spread of this disease to future sexual
partners, but it will not prevent it (choice A) because the treatment does not
eradicate the infection from the surrounding tissues. He still should be
advised to use condoms.
If this patient had a herpes infection (vesicles and ulcers), oral suppressive
18
therapy would decrease the frequency of recurrences. However, he has an
HPV infection, which is not usually treated with oral suppressive therapy
(choice C).
It is incorrect to tell him that the state health department will be contacted
because this is not a notifiable infectious disease (choice D). Notifiable
sexually transmitted diseases are syphilis, chlamydia, gonorrhea, and AIDS.
It is incorrect to tell him that treatment will eradicate the infection (choice E)
because while treatment may initially remove the wart, it does not eradicate
the HPV from the surrounding tissues.
A 37-year-old man comes to the clinic because of painful ulcers on his penis. He has no
other symptoms, but he is very concerned because he recently returned from a business
trip where he had sexual intercourse with a prostitute and he "obviously" does not want
his wife to find out. He "needs" you to do something for him "fast". He admits to having
other sexually transmitted diseases including chlamydia and gonorrhea before he was
married. He denies ever having "sores" on his penis or anus in the past. Physical
examination shows painful, shallow ulcers on the penis and the perineum. A Tzanck
preparation made from a scraping taken from the base of the lesion shows
multinucleated giant cells. The results of a tissue culture, which return 5 days later, show
herpes simplex virus-2. You prescribe a 10-day course of oral acyclovir. He should be
told that:
A. Chronic daily suppressive therapy with acyclovir does not reduce the
frequency of reactivation
B. He needs to use condoms with his wife only when lesions are present
C. Herpes simplex virus-2 usually becomes a life-long latent infection in the
epithelial cells
D. The recurrence rates for herpes simplex virus-1 are higher than that of herpes
simplex virus-2
E. Vaccination against the hepatitis B virus is recommended at this time
Explanation:
The correct answer is E. This patient has herpes simplex virus-2, which is a very
common sexually transmitted disease in the United States. It is estimated that 22% of
the adult population has antibodies to the virus, even though only a small percentage of
this group ever reports symptoms. Unfortunately, approximately 90% of those who
report symptoms will have a recurrence. Transmission is possible during asymptomatic
periods and subclinical shedding of the virus is well documented. Herpes simplex virus2 can be transmitted by skin-to-skin contact when lesions are present, even when a
condom is used. Acyclovir, an antiviral agent that inhibits viral DNA polymerase,
shortens the duration of symptoms and the viral excretion time. Individuals who have
recently acquired a sexually transmitted disease that have not been vaccinated against
the Hepatitis B virus should be offered the Hepatitis B vaccine.
Many patients with frequent reactivation of herpes simplex virus-2 require chronic daily
suppressive therapy with acyclovir to reduce the frequency of reactivation. It is incorrect
19
to say that chronic daily suppressive therapy with acyclovir does not reduce the
frequency of reactivation (choice A).
Transmission of HSV-2 is possible even during asymptomatic periods and subclinical
shedding of the virus is well documented. Therefore he needs to use barrier protection
all of the time, even when lesions are not present, to decrease the likelihood of
transmission. He needs to use condoms with his wife only when lesions are present
(choice B) is incorrect
Herpes simplex virus-2 usually becomes a life-long latent infection in the sensory
ganglion cells, not epithelial cells (choice C). Once stressors such as trauma, fever, UV
light, sexual intercourse, or immunodeficiency reactivate the virus in the neural tissue,
HSV is transported back to the epithelium and another episode occurs.
The recurrence rate for herpes simplex virus-1are approximately 55% and 90% for
herpes simplex virus-2. Therefore, recurrence rates for herpes simplex virus-1 are
higher than that of herpes simplex virus-2 (choice D) is incorrect.
A 29-year-old man comes to the office because of a recurrent rash that worsens in the
summer season and recurs more frequently with humid weather. Usually the rash
involves his upper back and occasion spreads to the shoulders and proximal arms. It is
occasionally pruritic. Physical examination shows multiple hypopigmented oval macules
and patches on his upper back. His hands and feet are not involved and all nails appear
normal. You examine scrapings of the scale with potassium hydroxide under the
microscope and find numerous short hyphae with multiple round spores in clumps. You
should tell the patient that he has
A. tinea corporis and should be treated with oral terbinafine
B. tinea corporis and should be treated with topical ketoconazole
C. tinea corporis and should be treated with topical terbinafine
D. tinea versicolor and should be treated with oral terbinafine
E. tinea versicolor and should use ketoconazole shampoo
Explanation:
The correct answer is E. This patient has tinea versicolor and he should be treated with
ketoconazole shampoo. Tinea versicolor, also known as pityriasis versicolor, usually
presents on the upper trunk and extends onto the upper arms, finely scaling, guttate, or
nummular patches appear, particularly on young adults who perspire freely. The
individual patches are yellowish or brownish macules in pale skin or hypopigmented
macules in dark skin, with delicate scaling. Mild itching and inflammation may be
present. This common disease is most prevalent in the tropics, where there is high
humidity, high temperatures and frequent exposure to sunlight. The fungus is easily
demonstrated in scrapings of the scales. Microscopically, there are short, thick fungal
hyphae and large numbers of variously sized spores. This combination is commonly
referred to as "spaghetti and meatballs". Treatment is accomplished with topical
imidazoles, oral ketoconazole, or itraconazole. Oral terbinafine (choice D) has been
20
shown to be ineffective.
Tinea corporis (choices A, B, C) are all incorrect, because the lesions described on this
young man are not consistent with tinea corporis. Typical tinea corporis lesions (also
known as ring worm) are round, erythematous borders with central clearing and
superficial scales. The borders tend to be elevated rather than flat.
A 37-year-old woman with a history of intravenous drug use, hepatitis B,
asthma, and acquired immunodeficiency syndrome (AIDS) is admitted to the
hospital because of fever, night sweats, and malaise. Her last CD4 count was
1 month ago and measured 180/mm3. Vital signs are: temperature 38.5 C
(101.3 F), blood pressure 145/76 mm Hg, and pulse 90/min. Physical
examination is significant for a soft diastolic murmur heard best at the lower
left sternal border. Auscultation of the lungs reveals diffuse rhonchi. The
abdominal and neurologic exams are unremarkable. The next step in
managing this patient is
A. analysis and culture of spinal fluid
B. a blood culture
C. a CT of the head
D. a urinalysis
E. an x-ray of the chest
F. an x-ray of the abdomen
Explanation:
The correct answer is E. A chest x-ray is essential because of the rhonchi
heard on lung exam. A patient with AIDS is at risk for an opportunistic
infection and the risk increases greatly as the CD4 lymphocyte count drops.
An echocardiogram should also be obtained because of the cardiac murmur
which is suspicious for endocarditis. Intravenous drug users are at particular
risk for right-sided endocarditis. Statistically, however, community acquired
pneumonia is still more probable than endocarditis even with these clinical
findings.
The patient has no mental status changes, neurological deficits, or
symptoms of headache to suggest meningitis as the cause of fever. Hence,
an analysis and culture of spinal fluid (choice A) is not necessary at this
time. A chest x-ray is essential because of the rhonchi heard during the lung
exam. A patient with AIDS is at risk for opportunistic infections and the risk
increases greatly as the CD4 lymphocyte count drops. An echocardiogram
must also be obtained because of the cardiac murmur which is suspicious
for endocarditis. Intravenous drug users are at particular risk for right-sided
endocarditis.
Obtaining blood cultures (choice B) is not the most appropriate next step. A
chest x-ray is essential because of the rhonchi heard on lung exam. If the
21
suspicion for endocarditis is still high after the chest x-ray, blood cultures
should be obtained.
A CT of the head (choice C) is not indicated because the patient does not
have mental status changes, neurologic deficits, or symptoms of headache.
A chest x-ray is essential because of the rhonchi heard on lung exam.
A urinalysis (choice D) is not necessary at this time because the patient
does not have urinary symptoms such as dysuria or increased frequency.
An x-ray of the abdomen (choice F) is not necessary at this time because
the patient has a normal abdomen on examination and no abdominal
symptoms.
A 64-year-old woman comes to the emergency department because of a nonhealing ulcer in the right foot. She is a known insulin-dependent diabetic, is
hypertensive, and is on dialysis for chronic renal failure. She noticed an ulcer
in the plantar aspect of her foot a week ago following a hike on marshy
grounds. She started taking oral antibiotics that she had at home from a past
illness. However, since yesterday, she has noticed a foul smelling discharge
from the ulcer, along with foot swelling and fever. Her temperature is 39.1 C
(102.4 F), blood pressure 140/68 mm Hg, and pulse 88/min. Local
examination of the right lower extremity shows swelling of the lower leg and
foot with crepitus. A 3x2 cm. ulcer at the base of the great toe is noticed on
the plantar aspect with foul smelling serous brownish discharge. Lower
extremity pulses are diminished bilaterally. Laboratory studies show:
The most appropriate next step in management to limit disability is to
A. administer insulin and send her home with oral antibiotics
B. order foot and leg x-rays
C. perform incision and drainage of the ulcerated area
D. provide intravenous antibiotics
E. repeat serum potassium level
Explanation:
The correct answer is B. Diabetic foot ulcers, when inadequately treated,
can result in wet gangrene and necrotizing infections. Serous brownish
discharge, swelling of foot and leg with crepitus, fever, and high leukocyte
counts, are hallmarks of a necrotizing infection in a diabetic foot. Immediate
22
foot and leg x-rays are essential to diagnose subcutaneous air and to
delineate the level of spread. Following this, the patient should be taken to
the operating room for a wide debridement or even an amputation
depending upon the extent of necrosis of the tissues.
Control of blood sugar is essential for proper wound healing in a diabetic,
but the removal of the source of infection is important in preventing further
complications of infection (choice A). In this patient, administering insulin
and antibiotics are essential, but surgical debridement is more important in
limiting the disability. She requires further evaluation and treatment and
should not be sent home.
Simple incision and drainage (choice C) is not adequate in treating a
necrotizing infection.
This patient is already taking antibiotics at home. Although she needs
intravenous antibiotics (choice D) for better control of the infection, surgical
debridement of the foot is the first essential step to control the damage and
limit disability.
High serum potassium level is a consequence of her chronic renal failure
and increased cellular lysis in this necrotizing infection. Without controlling
further spread of infection, serum potassium level is bound to increase and
can cause cardiac dysrhythmias. To limit the disability, removal of the
source of high potassium level is essential rather than repeating potassium
level (choice E).
A 64-year-old woman comes to the emergency department because
of a non- healing ulcer in the right foot. She is a known insulindependent diabetic, is hypertensive, and is on dialysis for chronic
renal failure. She noticed an ulcer in the plantar aspect of her foot a
week ago following a hike on marshy grounds. She started taking
oral antibiotics that she had at home from a past illness. However,
since yesterday, she has noticed a foul smelling discharge from the
ulcer, along with foot swelling and fever. Her temperature is 39.1 C
(102.4 F), blood pressure 140/68 mm Hg, and pulse 88/min. Local
examination of the right lower extremity shows swelling of the lower
leg and foot with crepitus. A 3x2 cm. ulcer at the base of the great
toe is noticed on the plantar aspect with foul smelling serous
brownish discharge. Lower extremity pulses are diminished
bilaterally. Laboratory studies show:
The most appropriate next step in management to limit disability is
23
to
A. administer insulin and send her home with oral antibiotics
B. order foot and leg x-rays
C. perform incision and drainage of the ulcerated area
D. provide intravenous antibiotics
E. repeat serum potassium level
Explanation:
The correct answer is B. Diabetic foot ulcers, when inadequately
treated, can result in wet gangrene and necrotizing infections.
Serous brownish discharge, swelling of foot and leg with crepitus,
fever, and high leukocyte counts, are hallmarks of a necrotizing
infection in a diabetic foot. Immediate foot and leg x-rays are
essential to diagnose subcutaneous air and to delineate the level of
spread. Following this, the patient should be taken to the operating
room for a wide debridement or even an amputation depending
upon the extent of necrosis of the tissues.
Control of blood sugar is essential for proper wound healing in a
diabetic, but the removal of the source of infection is important in
preventing further complications of infection (choice A). In this
patient, administering insulin and antibiotics are essential, but
surgical debridement is more important in limiting the disability. She
requires further evaluation and treatment and should not be sent
home.
Simple incision and drainage (choice C) is not adequate in treating
a necrotizing infection.
This patient is already taking antibiotics at home. Although she
needs intravenous antibiotics (choice D) for better control of the
infection, surgical debridement of the foot is the first essential step
to control the damage and limit disability.
High serum potassium level is a consequence of her chronic renal
failure and increased cellular lysis in this necrotizing infection.
Without controlling further spread of infection, serum potassium
level is bound to increase and can cause cardiac dysrhythmias. To
limit the disability, removal of the source of high potassium level is
essential rather than repeating potassium level (choice E).
A 2-week-old previously healthy baby boy who was born
full term without any complications is brought to the
emergency department by his mother for a fever. The
baby appears well, but his temperature is found to be 38.9
C (102.0 F). After the appropriate blood work and cultures
are done, you decide to start this baby on antibiotics. The
24
most appropriate pharmacotherapy at this time is
A. ampicillin and cefazolin
B. ampicillin and cefotaxime
C. ceftriaxone alone
D. vancomycin and cefotaxime
E. vancomycin and cefuroxime
Explanation:
The correct answer is B. The organisms most responsible
for bacteremia in a baby less than 4 weeks of age are
Group B Streptococcus, E. coli, and Listeria; i.e., vaginal
flora. Other less common organisms are anaerobes,
Pneumococcus, and other Gram-negative enterics.
Therefore, the antibiotics of choice are ampicillin (to
cover for Listeria and other Gram-positive organisms) and
a third-generation cephalosporin. Traditionally,
cefotaxime is the third generation cephalosporin of
choice.
A first-generation cephalosporin, such as cefazolin, in
addition to ampicillin (choice A) would give good Grampositive coverage, but would not effectively cover Gramnegative organisms. In a baby this age, you have to
worry about infections with vaginal organisms such as E.
coli and other Gram-negatives, therefore a thirdgeneration cephalosporin or an aminoglycoside is a more
appropriate choice as an addition to the ampicillin.
Ceftriaxone (choice C) is a third-generation
cephalosporin with very good central nervous system
penetration. Unfortunately, ceftriaxone increases the risk
for hyperbilirubinemia and does not cover Listeria
sufficiently. Therefore, it is not the treatment of choice for
a 2-week-old with possible sepsis.
Although vancomycin and cefotaxime (choice D) would
cover the appropriate organisms, vancomycin would be
"overkill" in this previously healthy baby with no history of
any in-dwelling lines or hardware. Also, there are certain
strains of Listeria that are not susceptible to vancomycin.
If this baby had a history of prematurity, had a prolonged
hospital stay and therefore at increased risk of
nosocomial infection, or had any in-dwelling catheter that
put him at increased risk for Staphylococcus aureus, then
vancomycin would be an appropriate addition to the
regimen. As you are given a history of a healthy baby,
ampicillin and cefotaxime are the appropriate regimen
25
while awaiting culture growth and organism sensitivity.
Vancomycin and cefuroxime (choice E) is also not an
appropriate choice. As above, vancomycin is not
indicated nor sufficient in this patient and unnecessarily
exposes this child to side effects such as red man's
syndrome and ototoxicity. Cefuroxime is not a good
choice because it is a second-generation cephalosporin,
and therefore does not cover the Gram-negative
organisms such as E. coli as well as a third-generation
cephalosporin like cefotaxime would.
A 38-year-old man comes to the clinic complaining of a 2-week history of an itchy, scaly,
red rash on his left upper chest. He initially treated it with an over-the-counter antibiotic
cream. After 5 days with no apparent improvement, he switched to a hydrocortisone
cream, which he has been using for the past 9 days. This decreased the redness and
itch, but since switching to the steroid, the area of involvement has been growing
steadily. He is a school bus driver and he enjoys gardening. He says that he was
spending excessive time outside in the sun working in his garden for several weeks
leading up to the appearance of the rash. He has been told he has "borderline" diabetes
and is currently on a 6-month trial of dietary modification and exercise to see if he can
avoid oral hypoglycemic agents. Physical examination reveals an overweight Caucasian
man with a scaly, slightly erythematous, 6 by 10 cm plaque which is slightly indurated at
the periphery. No other significant lesions are seen. The most appropriate next
diagnostic step is to
A. check an antinuclear antibody titer
B. check the patient's thyroid stimulating hormone
C. obtain a skin biopsy
D. perform a KOH preparation of the scale
E. test the patient for the presence HIV antibody
Explanation:
The correct answer is D. This is an excellent history and physical exam for tinea
corporis, a fungal infection of the skin. A scaly, erythematous plaque which is
accentuated or indurated at the periphery, must always be checked for fungal hyphae
with a KOH preparation. The dermatologic adage, "if there is scale, scrape it" [to check
for fungus] is very sound advice. The application of topical steroids to tinea corporis will
generally help decrease the erythema, but will allow the fungus to grow unchecked and
the involved area to enlarge. A scaly area that is worsened by topical steroids should be
considered tinea until proven otherwise. Tinea in adults is generally acquired by contact
with children, pets, or soil. Tinea is also much more common in patients with diabetes.
Checking an antinuclear antibody titer (choice A) can be useful if one is concerned
26
about autoimmune or rheumatologic disorders such as lupus erythematosus. Several of
the criteria for the diagnosis of lupus erythematosus are dermatologic manifestations
including the presence of a malar rash, discoid lesions, and oral ulcerations. Sun
exposure is a known trigger and will exacerbate the cutaneous manifestations of lupus
erythematosus. Discoid lesions of lupus erythematosus (clinically appearing as circular,
atrophic, hypopigmented plaques occasionally with scale) can sometimes be confused
with fungal infections, but are generally confined to the head and neck. Discoid lupus
would also be helped by topical steroids, not exacerbated by them.
Checking a TSH level (choice B) is a sensitive and specific way for detecting hypo- and
hyperthyroidism. Weight gain can be a sign of hypothyroidism; however the vast
majority of obese individuals are euthyroid. The dermatologic manifestations of
hypothyroidism include rough and dry skin, coarse hair, and brittle nails. Scaly plaques
are not a sign of thyroid disease.
A skin biopsy (choice C) is an excellent method to diagnose skin disorders and if
diagnostic dilemmas occur, it can be used to differentiate between various rashes.
Before you put the patient through the discomfort, scarring, and expense of a skin
biopsy however, tests you can perform and evaluate right in your office, such as a KOH
preparation, are preferable.
Checking for the presence of HIV antibody (choice E) may be indicated in patients who
present with widespread fungal infections without any known predisposing factor such
as diabetes mellitus or other immunocompromising condition.
A 4-year-old boy is brought to the office because he has refused to walk for the past 24
hours. He was well until yesterday afternoon when he woke from a nap complaining of
feeling "wobbly". When his parents got him up to walk he was extremely unsteady and
they needed to hold him to keep him from falling over. He has not improved at all over
the last day. His unsteadiness persists when he is sitting down. His temperature is 37.0
C (98.6 F), pulse is 100/min, and respirations are 24/min. He has horizontal nystagmus,
which is worse at the extremes of gaze. He appears markedly ataxic and his gait is
broad based. He has no papilledema. If obtained, the information that would be most
pertinent to his current condition is
A. concomitant diarrhea
B. a cousin with a brain tumor
C. a history of varicella infection 3 weeks ago
D. previous history of epilepsy in this patient
E. recent streptococcal pharyngitis
Explanation:
The correct answer is C. The history given above is a classic presentation of acute
post-infectious cerebellar ataxia. 25% of children with this disorder have a history of
varicella infection within 1 month prior to the onset of the disorder and 5% of children
have a previous history of varicella vaccination. The onset of acute cerebellar ataxia is
27
usually explosive, often with the child awakening from sleep with maximal symptoms of
ataxia and nystagmus. In any child with acute ataxia, it is important to obtain a drug
screen and a careful history of any possible toxic exposures since poisoning and acute
cerebellar ataxia account for most of the cases of acute ataxia in children. Resolution of
the symptoms occurs in most children over a period of weeks to months.
Concomitant diarrhea (choice A) is not relevant to this presentation. Although there are
forms of Guillain-Barre syndrome that have ataxia as a prominent component, this child
does not have the other symptoms associated with these variants of GBS
(ophthalmoplegia, depressed reflexes), and Campylobacter diarrhea usually precedes
the onset of GBS.
While an intracranial tumor is always of concern in a child with neurologic symptoms,
the history above is atypical for tumors, which usually present more indolently. The
history of a cousin with a brain tumor does not increase the likelihood that this child's
symptoms are due to an intracranial mass (choice B).
Pseudoataxia (choice D) is a syndrome of recurrent bouts of ataxia that are actually
atypical seizures on EEG. The attacks are similar in timing to seizures and there may
be a postictal state. They are not likely to persist over days as in this child.
Recent streptococcal pharyngitis (choice E) is of importance in movement disorders
associated with acute rheumatic fever, such as Sydenham chorea, but does not
predispose to any known form of ataxia.
You are called to see a 41-year-old man, who is 6 days post—transplant from an
allogenic bone marrow transplant, for a fever spike to 39.8 C (103.6 F). He was
diagnosed with acute myelogenous leukemia seven weeks prior. He underwent
induction with busulfan and cyclophosphamide and received an HLA-matched graft from
his sister. His current medications include trimethoprim-sulfamethoxazole three times
weekly, levofloxacin three times weekly, cyclosporine daily, and a beta blocker for his
hypertension. His most recent white cell count was 1300 cells/mm3 with an absolute
neutrophil count of less than 100. The patient has no indwelling central vascular
catheters of any type. The most appropriate antibiotic for this patient is
A. cefotetan, intravenously
B. ceftazidime, intravenously
C. imipenem/cilastatin, intravenously
D. piperacillin, intravenously
E. vancomycin, intravenously
Explanation:
The correct answer is B. This is an example of a patient with fever and neutropenia.
This is a common scenario encountered on ward services. Neutropenia is defined as a
count less than 500/microliter, and fever is defined as a single oral temperature greater
than 38.5 C (101.3 F). Standard therapy is empiric and consists of monotherapy with an
28
antipseudomonal third-generation cephalosporin or of an antipseudomonal penicillin
and an aminoglycoside.
Cefotetan (choice A) is a second-generation cephalosporin often used to treat bowel
infections. It has no activity against pseudomonas.
Imipenem/cilastatin (choice C) is a combination of a cell wall synthesis inhibitor
(Imipenem) and a beta lactamase inhibitor (cilastatin) that is very potent and
efficacious. However, like piperacillin, its broad use will encourage resistance and is
therefore not routinely used.
Piperacillin (choice D) is a new generation penicillin with very broad coverage of both
Gram-positive and Gram-negative organisms including pseudomonas. It is however not
generally indicated because of concerns about developing resistance.
Vancomycin (choice E) is used in febrile and neutropenic patients in addition to
ceftazidime when the patient has an indwelling central vascular catheter.
You are called to the emergency department to evaluate a 6-year-old girl who has
developed a rash on her distal extremities 2 days ago that has been progressing toward
her trunk. She has had a fever and arthralgias over the past 2 days for which she was
given acetaminophen. On further questioning, the patient's mother reports that the
patient was bitten by her pet rat a few days prior to onset of the fever and rash; however,
the site appears to be healing well. Her mother reports that the girl has a normal past
medical history without any significant health problems. Laboratory studies show
leukocytosis with an elevated neutrophil count. Blood culture results are pending. At this
time the most correct statement about this patient's condition is:
A. Her rash is classic for Rocky Mountain Spotted Fever and she should be
started on antibiotics for rickettsial organisms
B. Meningitis can be ruled out because the rash usually starts on the trunk and
extends peripherally
C. The patient should be admitted and started on broad-spectrum antibiotics to
cover Streptobacillus moniliformis and Spirillum minor
D. This is a drug eruption secondary to acetaminophen and you should advise
the patient's mother to stop acetaminophen and give ibuprofen instead
E. This is most likely a viral exanthem and will resolve spontaneously in 1-2
weeks
Explanation:
The correct answer is C. Rat bite fever is an acute febrile illness that is usually
accompanied by a skin rash. It is caused by either Streptobacillus moniliformis or
Spirillum minor which are the bacteria that generally infect humans as a result of the
bite of a rat, mouse, or other rodents. Following a rat bite, there is minimal local
inflammation with prompt healing of the wound. If the infection is not halted, bacteremia
ensues and lesions distant from the bite appear 1-3 days after the bite. Manifestations
include fever, rigors, headaches, malaise, and arthritis. Treatment of choice is penicillin
G or tetracycline for patients allergic to penicillins. Occasionally the course is
complicated by endocarditis, meningitis, myositis, abscesses, splenic or renal infarction,
29
brain abscess, and sepsis.
Rocky mountain spotted fever (choice A) is incorrect because there is no history of tick
bite reported. In addition, in a child of this age group, fever accompanied by an
extremity rash should alert physicians to treat and cover meningitis organisms until
blood culture results become available. Therefore, since meningitis cannot be
definitively ruled out at this time, (choice B) is also incorrect.
Drug eruption (choice D) is incorrect for two reasons. First, drug eruptions typically start
on the trunk and extend peripherally. Second, fever and arthritis usually do not
accompany typical drug eruptions.
Viral exanthem (choice E) is incorrect at this stage of evaluation. One should rule out
more urgent causes of fever and rash before concluding that it is viral exanthem.
A 66-year-old woman comes to the clinic complaining of severe pain across
her chest and abdomen. You treated the patient for shingles 5 months ago
and at that time she had a shingles band at the right T8 level. The current
pain is in the same region where she had her shingles. She states that she
cannot stand to have her clothes touch the area and that even shower water
hurts. She has hypertension and glaucoma for which she takes beta blocker
eye drops and lisinopril. At the level of her T8 dermatome on the right, she
has marked allodynia, primary and secondary hyperalgesia. The area is
exceptionally tender to palpation. The most appropriate therapy is at this time
is
A. acyclovir
B. amantadine
C. amitriptyline
D. lidocaine cream
E. oxycodone, sustained release
Explanation:
The correct answer is C. This patient has established postherpetic neuralgia.
She has all of the classical signs of neuropathic pain including, allodynia
(nonpainful stimuli eliciting pain), primary hyperalgesia (pain increasing in
intensity with stimulation), and secondary hyperalgesia (surrounding tissue
having pain). This entity often follows the varicella zoster reactivation
disease shingles and it follows the distribution of the original infection. The
main risk factor for the neuralgia is increasing age. There is excellent clinical
data showing dramatic pain relief from the use of tricyclic antidepressants.
The mechanism of action is unknown.
The use of acyclovir (choice A) is indicated for the prevention of postherpetic
neuralgia and hastening the resolution of the zoster infection. These antiretroviral agents have no efficacy in pain control for established postherpetic
30
pain.
There is no benefit to the use of amantadine (choice B). This class of drugs
has benefit in decreasing infectivity from influenza virus by inhibiting early
stages of the infection process.
There is some evidence that topical lidocaine cream (choice D) offers some
pain relief from neuropathic pain, but compared to tricyclic therapy, the
benefits are minimal.
Narcotic drugs such as oxycodone (choice E) are actually very ineffective at
controlling neuropathic pain. In fact, they have no recommended role in the
management of this type of pain. Oxycodone, sustained release, is an oral
sustained release formulation of morphine and is used for the treatment of
chronic, nonneuropathic pain conditions. Sustained release formulation are
not to be used for the management of acute pain.
A 29-year-old man comes to the office because one of his 3 sexual
partners recently had a Pap smear that showed dysplasia and
koilocytic changes. Her physician recommended that all of her
sexual partners be evaluated. He has always been healthy and has
never had any sexually transmitted diseases. All of his partners are
"on the pill" so they do not use condoms. Physical examination is
completely unremarkable. There are no visible lesions on his
anogenital region. He is still very concerned that he has an infection
that you cannot see. The most appropriate next step is to
A. advise him to return if he develops any lesions
B. apply vinegar to his penis and scrotum
C. recommend that he use condoms during all sexual activity
D. send for a fluorescent treponemal antibody absorption
(FTA-ABS) serology
E. take random biopsies of the penis
F. tell him that he is healthy
Explanation:
The correct answer is B. This patient's girlfriend most likely has
human papillomavirus (HPV) infection, which is associated with
dysplastic changes and cervical cancer. This patient should be
evaluated for an HPV infection, and if there are no visible lesions,
acetic acid (vinegar) should be applied to the anogenital region to
detect the presence of the virus. Invisible lesions typically turn white
when acetic acid is applied. This is thought to occur because the
acetic acid causes maceration and swelling of virally induced
epithelial hyperplasia, which usually has an increased glycogen
content and enhanced permeability. Even though this is not specific
31
for HPV and false-positives can occur, it may enhance the
detection of an HPV infection.
If no lesions are found when acetic acid is applied, you should
advise him to return if he develops any lesions (choice A) and
recommend that he use condoms during all sexual activity (choice
C). Condoms will probably not completely prevent the spread of
infection, but they should theoretically reduce transmission.
Since his sexual partner most likely has an HPV infection and he is
sexually active with many partners, syphilis screening may be
appropriate, but the VDRL (Venereal Disease Research
Laboratory) and RPR (rapid plasma reagin) tests are used for
screening, not the FTA-ABS (choice D). The FTA-ABS is more
specific, but it is usually not considered a screening test because it
is more expensive and remains reactive in patients with a prior,
treated syphilis infection.
Taking random biopsies of the penis (choice E) is completely
inappropriate, and it will make a patient very unhappy. Acetic acid
should be applied to help see invisible lesions and biopsies can be
taken from suspicious areas.
Since many patients infected with HPV have no visible signs and
symptoms, it is inappropriate to tell him that he is healthy (choice F)
before further evaluation (application of acetic acid).
A 13-year-old boy comes to the office because of an 8-day
history of a fever, sore throat, and extreme "tiredness". He also
complains of a "red rash" that he noticed 5 days ago. He had
been seen at a 24-hour clinic 6 days ago for a sore throat, and
even though no diagnostic test was performed, he was treated
with a 5-day course of ampicillin. He is usually very healthy and
has never had "strep throat" before. His temperature is 37.8 C
(100.0 F). Physical examination shows cervical adenopathy,
tonsillar enlargement with a pharyngeal exudate, and a macular
rash on his trunk. Laboratory studies show an elevated white
blood cell count with 40% atypical lymphocytes. The most
appropriate next step is to
A. obtain a rapid strep test
B. obtain a throat culture
C. order a heterophile test
D. order a Tzanck smear of a scraping from the rash
E. prescribe a 7-day course of prednisone
Explanation:
The correct answer is C. This patient most likely has infectious
32
mononucleosis (IM), which is a disease caused by the EpsteinBarr virus. The pharyngitis, fever, lymphadenopathy, fatigue,
and malaise are common findings early on in the disease. After
about 2 weeks, splenomegaly may be a prominent feature. The
heterophile test is used to diagnosis the infection. It is usually a
self-limited infection that only requires bed rest and analgesics.
Physical activity should be avoided for a month to avoid the risk
of splenic rupture. If it does occur, the symptoms may be
abdominal pain referred to the shoulder and shock. Infectious
mononucleosis is often associated with thrombocytopenia and a
morbilliform or papular rash. Complications of IM include
splenic rupture, airway obstruction from hypertrophied tonsils
and adenoids, encephalitis, meningitis, hepatitis, interstitial
nephritis, myocarditis, and pericarditis.
A rapid strep test (choice A) is 95% specific for streptococcal
pharyngitis when it is positive, however it is not cost effective in
this case because the laboratory studies show atypical
lymphocytes, which are often seen in infectious mononucleosis,
not in streptococcal infections. A heterophile test is used to
diagnose IM.
A throat culture (choice B) is often used to diagnose
streptococcal pharyngitis when the rapid strep test is negative
and the clinical suspicion is strong.
A Tzanck smear of a scraping from the rash (choice D) is
unnecessary because this patient most likely has infectious
mononucleosis, not chicken pox. A Tzanck smear of a vesicle
from a patient with chicken pox (varicella-zoster virus) will show
multinucleated giant cells. The rash of chicken pox is often
described as lesions in various stages of healing
(maculopapular, vesicular, crusting, etc.). This patient's rash is
most likely due to the ampicillin. The mechanism is unknown,
but patients with infectious mononucleosis that are treated with
ampicillin develop a macular rash.
A 7-day course of prednisone (choice E) is inappropriate at this
time in this patient with infectious mononucleosis (IM). Steroids
are sometimes necessary in patients with IM who have severe
thrombocytopenia and to prevent airway obstruction when
severe tonsillar hypertrophy is present. It is not recommended
in uncomplicated IM because it may increase the chance for the
development of a superinfection with a bacteria.
A 32-year-old HIV-positive intravenous drug abuser is admitted to the hospital
following a seizure. He was diagnosed as HIV positive a few years ago, and
is currently taking antiviral therapy. He has no previous history of seizures or
any other medical problems. He is awake, alert, and oriented. Neurological
examination is normal. A CT scan of the brain performed with intravenous
33
contrast shows 3 ring-enhancing lesions. The patient is started on
anticonvulsant medications. The most appropriate next step in management
is to
A. obtain CT scan of chest to rule out lymphoma
B. obtain viral titers
C. schedule a brain biopsy
D. start empiric treatment for toxoplasmosis
E. start empiric treatment for tuberculosis
Explanation:
The correct answer is D. HIV patients with focal brain lesions are treated
with 2-3 weeks of empiric treatment for toxoplasmosis followed by biopsy
(choice C) if the radiological or clinical condition deteriorates. Toxoplasma
gondii, the protozoan that causes toxoplasmosis, accounts for 50-70% of
focal brain lesions in these patients. 10-20% of focal lesions are CNS
lymphomas.
Primary CNS lymphoma (choice A) is a rare intracranial tumor, accounting
for 1.5% of all primary brain tumors. CNS lymphoma is still significantly more
common in HIV-positive patients, even compared to that in generally
immunosuppressed populations. When empiric therapy for toxoplasmosis
fails, CNS lymphoma should be ruled out.
Viral titers are of no value in this patient (choice B). Although opportunistic
infections such as progressive multifocal leukoencephalopathy caused by
papova virus JC, Cytomegalovirus, herpes, toxoplasmosis, and
cryptococcosis can cause HIV-related CNS diseases, incidence is low and
not of primary etiology.
Tuberculosis causing CNS symptoms is not common (choice E) in this
patient population.
A 22-year-old woman is brought to the emergency department by ambulance.
She is accompanied by her roommate who states that the patient developed
a fever and some confusion 3 hours before, and approximately 30 minutes
ago became unconscious. The roommate reports that the patient was
complaining of a stiff neck and headache a few hours before she became ill.
The roommate knows of no significant medical history but reports that the
patient is a volunteer at a local children's hospital. Initial examination shows
the patient to be non-responsive. Her temperature is 40.4 C (104.7 F), blood
pressure is 70/40 mm Hg, pulse is 140/min, and respirations are 32/min.
There are diffuse petechial and purpuric lesions across the hands, face, and
arms. After tracheal intubation, infusion of pressors fails to augment the blood
pressure and it remains at 65/35 mm Hg. The most appropriate next step in
this patient's care is to
34
A. begin heparin therapy only
B. give her high-dose corticosteroids, intravenously
C. initiate chest compressions
D. perform a lumbar puncture
E. transfer her to the intensive care unit
Explanation:
The correct answer is B. This patient almost certainly has meningococcal
sepsis and Waterhouse-Friderichsen syndrome (meningococcemia and
adrenal hemorrhage). These patients require exogenous steroids for acute
adrenal insufficiency, although they have not been shown to alter survival
outcomes. This is presumably due to the fact that these patients are critically
ill and are at grave risk for renal and pulmonary failure, massive
coagulopathy, and irreversible septic shock. She requires high doses of
intravenous corticosteroids and saline and antibiotics.
A characteristic of all sepsis syndromes is disseminated intravascular
coagulation (DIC), a consumptive coagulopathy. This patient also has
microangiopathic hemolysis secondary to massive small vessel clotting. The
correction of her coagulation disorder requires coagulation factors and
resolution of her sepsis. Heparin (choice A) may be necessary, but it should
only be used in combination with cryoprecipitate and platelets because it
may cause bleeding if given alone.
There is no need to initiate chest compressions (choice C) since the patient
has a blood pressure, albeit a very weak one. She is in profound septic
shock with concomitant adrenal insufficiency and requires catecholamines
and steroids.
There is no need for a lumbar puncture (choice D) since this patient has
disseminated disease and blood cultures will certainly reveal the presence of
the organism.
It is appropriate to transfer the patient to an intensive care unit (choice E)
once her condition is stabilized. Patients such as this must be stabilized
before being moved since transport through the hospital exposes the patient
to a situation where further decompensation is possible while in transit.
A 25-year-old athletic appearing man comes to the office with a recurrent
rash in his groin. He denies any significant medical history. He recalls that a
similar rash recurs each summer with associated mild pruritus. It usually
improves significantly in the winter and he has not been treated. He normally
wears tight jockey shorts. Physical examination shows a sharply marginated,
scaly, red eruption on the inner thighs that spares the testicles. No satellite
lesions are appreciated. The penoscrotal fold and the scrotal sac do not
appear to be involved. He also has hypertrophic, discolored, thickened
35
toenails involving only the first toe of both feet. The most appropriate
management is to
A. prescribe a topical erythromycin cream
B. recommend a topical steroid cream
C. recommend a topical anti-candidal treatment
D. recommend a topical antifungal agent
E. tell him that no treatment is indicated for this anxiety induced
dermatosis
Explanation:
The correct answer is D. Topical antifungal treatment is correct, because
tinea cruris occurs most frequently in men on the upper and inner surfaces
of the thighs, especially during the hot summer, if the humidity is high. It
begins as a small erythematous, scaling or vesicular and crusted patch, that
spreads peripherally and partly clears in the center. In contrast to candida
infection, the borders are well demarcated without satellite lesions. Heat and
humidity are the predisposing factors for the development of tinea cruris.
Tight jockey shorts, which prevent evaporation of the increased perspiration
produced during warm weather, may be an additional predisposing factor.
Treatment of tinea cruris usually includes methods to reduce perspiration,
keeping the area as dry as possible with antifungal powder. Additional
topical or oral antifungal agents may be necessary for some patients.
Topical erythromycin (choice A) is incorrect because this is used for treating
erythrasma. The crural region is not only a common site for tinea cruris, but
also for bacterial and candidal infections. Erythrasma is caused by
Cornynebacterium minutissimum. and typically treated with topical
erythromycin or clindamycin.
Topical steroids (choice B) is incorrect because fungus thrive in steroid-rich
environments and this can worsen the infection.
Topical anti-candidal treatment (choice C) is incorrect because, as stated
above, candidal infections usually have satellite lesions, and the color the
lesions are generally bright red.
Anxiety induced dermatosis (choice E) is incorrect because this patient's
history and exam point to a rash that's associated with heat and humidity,
and he has associated onychomycosis on his toenails.
A 23-year-old college student comes to the clinic because of odynophagia with solids
and liquids and dysphagia that is most severe when eating solid foods. The patient had
a past medical history of Shigella colitis last year while she was a Peace Corps volunteer
in Peru. She takes oral contraceptives and smokes 1 pack of cigarettes daily. She does
not drink alcohol. Vital signs are: temperature 37.8 C (100 F), blood pressure 100/70 mm
Hg, pulse 79/min, and respirations 8/min. Physical examination is normal.
36
Electrocardiogram reveals normal sinus rhythms with a rate of 85/min and a markedly
enlarged QRS complex in leads V3-V5. Chest x-ray reveals an enlarged cardiac
silhouette. A barium esophagram demonstrates a tapering of the distal esophagus that
eventually releases as the esophagus is distended. There is no evidence for extrinsic or
intrinsic compression of the distal esophagus or an esophageal mass. There is no reflux.
The test most likely to lead to a unifying diagnosis in this case is
A. an agglutination test for trypanosomes
B. a chest CT
C. an esophageal manometry
D. a liver biopsy
E. a myocardial biopsy
Explanation:
The correct answer is A. The findings of achalasia and cardiomyopathy in a patient with
history of travel to Central or South America support the diagnosis of Chagas disease.
This is caused by infection of Trypanosoma cruzi in the muscles of the heart,
esophagus, and colon. A serum agglutination test is a noninvasive means of testing for
this infection, and is highly sensitive. Left untreated, heart failure and megacolon could
develop.
A chest CT (choice B) would not reveal any specific findings of Chagas disease. Using
a CT to evaluate for an occult cancer causing esophageal narrowing is superfluous
given the findings on the barium esophagram, which is specific for achalasia.
An esophageal manometry (choice C) is a confirmatory test for achalasia. Given the
highly suggestive findings of achalasia on the barium esophagram, manometry would
not be necessary.
A liver biopsy (choice D) has no role in the evaluation of Chagas disease.
A myocardial biopsy (choice E) is not necessary to diagnose Chagas disease with the
availability of the serum agglutination test for trypanosomes. Invasive procedures
should be deferred until they are absolutely necessary.
A 29-year-old woman comes to the office because of a 4-day history of pain during
urination and increased urinary frequency. She states that her and her husband went
away for the weekend, and she developed these symptoms a couple of days after they
returned. He is asymptomatic. She had a similar episode on 1 previous occasion, 5
years ago. She does not take any medications and denies any other symptoms. Her
temperature is 37.2 C (99.0 F), blood pressure is 110/80 mm Hg, and pulse is 65/min.
Physical examination shows mild suprapubic tenderness. There is no costovertebral
angle tenderness present. Urinalysis shows:
Color
cloudy
Glucose negative
Protein negative
37
Bacteria present
Nitrites present
WBC
200/hpf
RBC
3/hpf
A urine culture and Gram stain is sent to the laboratory. The most appropriate next step
is to
A. do nothing until the urine culture and Gram stain return
B. order an intravenous pyelogram
C. order a renal ultrasound
D. prescribe a 7-day course of metronidazole
E. prescribe a 3-day course of trimethoprim-sulfamethoxazole
Explanation:
The correct answer is E. This patient most likely has an uncomplicated case of cystitis,
which is most likely caused by E. coli spread from the anus to the urethra and up into
the bladder. Acute cystitis is a very common infection in women, probably due to the
short distance between the anus and urethra. Intercourse and improper wiping
techniques (back to front) tend to increase the risk for cystitis in women. Urinalysis and
culture are usually obtained. However, treatment can begin based on the symptoms
and urinalysis results, even before the cultures are back. A 3-day course of
trimethoprim-sulfamethoxazole is the appropriate treatment for uncomplicated cystitis.
It is inappropriate to do nothing until the urine culture and Gram stain return (choice A).
You know that she has cystitis based on the history and urinalysis, and therefore an
antibiotic is necessary even before the cultures return. Most uncomplicated infections
are due to E. coli.
An intravenous pyelogram (choice B) and a renal ultrasound (choice C) are usually only
indicated in women with recurrent urinary tract infections (2 in 5 years is not considered
recurrent), and in men with urinary tract infections. These tests are done to rule out any
obstructions, stones, and renal abnormalities. They are completely unnecessary in a
single (the one 5 years ago was so long ago that it does not really count) uncomplicated
case of cystitis in a woman.
A 7-day course of metronidazole (choice D) is the treatment for bacterial vaginosis,
which is typically characterized by a malodorous vaginal discharge. This patient has
cystitis, which is a urinary tract infection, not vaginitis.
A 30-year-old previously healthy man is admitted to your medical service for
the management of acute renal failure. He had been vacationing in India a
week earlier and on arrival back to the United States he developed severe,
bloody diarrhea. He has no known sick contacts, is not on any medications,
and has no allergies. His temperature is 37.0 C (98.6 F), blood pressure is
38
100/67 mmHg, pulse is 103/min, and respirations are 23/min. Physical
examination is unremarkable. Laboratory studies show:
The most appropriate next diagnostic step is to send a stool culture for
A. Escherichia Coli O157:H7
B. Helicobacter pylori
C. Salmonella typhi
D. Staphylococcus aureus
E. Vibrio cholera
Explanation:
The correct answer is A. A history of acute renal failure, anemia (hemolytic),
and thrombocytopenia following bloody diarrhea is characteristic of the
hemolytic-uremic syndrome associated with Escherichia Coli O157:H7
infection.
Helicobacter pylori (choice B) is associated with ulcer disease at the gastric
antrum. It is not associated with bloody diarrhea, renal failure, anemia, or
thrombocytopenia.
Salmonella typhi (choice C) in its acute form can produce a bloody diarrhea.
However, it is not associated with renal failure, anemia, or
thrombocytopenia.
Staphylococcus aureus (choice D) is the most common cause of food
poisoning in the U.S. However, it is not associated with bloody diarrhea,
renal failure, anemia, or thrombocytopenia.
Vibrio cholera (choice E) is associated with massive watery diarrhea. It is not
associated with renal failure, anemia, or thrombocytopenia.
A 28-year-old man comes to the emergency department complaining of 3 days of nonradiating pain in his right upper quadrant, nausea, and 2 episodes of non-bloody, nonbilious emesis. He also reports that 2 days ago he turned "yellow". He has no past
medical history, has had no recent illnesses, and denies any alcohol or drug abuse. He
is married and has not had sexual intercourse with anyone besides his wife in 7 years.
His temperature is 37 C (98.6 F), blood pressure is 120/80 mm Hg, and pulse is 65/min.
Examination shows scleral icterus and mild jaundice of the skin. There is right upper
quadrant tenderness, but no palpable gallbladder or Murphy sign. The laboratory finding
39
most likely to establish the underlying cause of his current symptoms is
A. positive serum hepatitis A IgG titer
B. positive serum hepatitis A IgM titer
C. positive serum hepatitis B surface antibody titer
D. positive serum hepatitis C antibody
E. positive serum hepatitis C RNA level
Explanation:
The correct answer is B. This patient likely has acute hepatitis A infection. The
prodrome of this infection is very similar to this patient's presentation and within 10-14
days after infection, patients will manifest varying degrees of abdominal pain as well as
jaundice. The disease is self- limiting, usually transmitted by contaminated shellfish or
oral-anal contact with an infected person or their feces, and does not predispose
patients to the same long-term risks as infection with the other hepatitis viruses. In the
acute setting, blood titers may be positive for IgM antibody.
A positive serum hepatitis A IgG titer (choice A) would be seen months after the acute
infection has passed and is a marker for previous infection.
A positive serum hepatitis B surface antibody titer (choice C) is a marker for previous
hepatitis B exposure.
A positive serum hepatitis C antibody (choice D) is a marker for hepatitis C infection.
Although both B and C varieties can cause acute viral illnesses similar to this patient,
the epidemiology of their transmission is quite different from this patient's risk factors.
Both of these agents are transmitted via blood-to-blood contact and in our day, this is
primarily by intravenous drug abuse exposure to infected blood (e.g. healthcare workers
and needle sticks).
A positive serum hepatitis C RNA level (choice E) is a test ordered after initial exposure
to hepatitis C and in following the activity of disease over time. Unless we suspected
hepatitis C infection in this patient, this is not the appropriate test to order.
A 44-year-old man is admitted to the hospital from the clinic because of possible sepsis.
The patient came to clinic because of left cheek pain that has been increasing for the
past 3 days and is associated with rhinorrhea and cough. The patient is HIV positive and
takes many HIV medications, but cannot give a more detailed medication history. Vital
signs are: temperature 40 C (104 F), blood pressure 100/70 mm Hg, pulse 90/min, and
respirations 15/min. Oxygen saturation is 96% on room air. On physical examination,
there is tenderness with percussion of the left maxillary and frontal sinuses. The ears,
nose, and throat are normal. The lungs are clear. Neurologic examination is significant
for a mildly dilated and hyporeactive left pupil. A chest x-ray is normal. A complete blood
count, blood cultures, and a basic blood chemistry panel are pending. The next step in
the care of this patient is to
A. administer amoxicillin-clavulanate orally
40
B. administer ciprofloxacin, intravenously
C. administer phenylpropanolamine, orally
D. administer prednisone, orally
E. order a CT scan of the head and sinuses
Explanation:
The correct answer is E. This immunocompromised patient is at risk for fungal sinusitis.
Given the neurological findings, this patient needs imaging to evaluate the extent of
disease. This is in preparation for open or endoscopic debridement of the sinuses.
Typical causative agents are Aspergillus fumigatus and invasive mucormycosis.
Complications of fungal sinus infections include osteomyelitis, meningitis, and brain
abscesses.
This patient is at risk for fungal sinusitis, so antibiotics (choice A) would not be the first
step in treatment. Amoxicillin-clavulanate is the mainstay in the treatment of and
prophylaxis of pneumonia secondary to Pneumococcus carinii in patients with AIDS.
This patient is at risk for fungal sinusitis, so antibiotics such as ciprofloxacin (choice B)
would not be the first step in treatment.
An oral decongestant therapy such as phenylpropanolamine (choice C) is often useful
in chronic sinusitis, but has no real role in the acute treatment of fungal sinusitis.
Oral steroids (choice D) have no role in the treatment of a fungal infection. Infact, the
immunosuppressive properties of the steroid could make the infection worse.
A new mother brings her 7-month-old baby boy to the clinic because he has developed
"a rash" over his trunk and neck this morning. She states that the baby has had a high
fever for the last 4 days, reaching a maximum temperature of 39.5 C (103.1 F). Besides
the fever, he has been happy, feeding well, and has not attempted to scratch any of the
rash. His temperature is 37.0 C (98.6 F). Physical examination shows a well-developed,
well-nourished boy with 2-5 mm, rose-pink macules and papules on the trunk and neck.
He has a few small, palpable lymph nodes on his occipital region and moderate
erythema on the pharyngeal walls. Conjunctival mucosa is unaffected. The most
appropriate next step is to
A. admit the baby and start work up for Kawasaki
B. reassure the mother that the baby has mononucleosis and it will resolve on its
own
C. reassure the mother that a roseola rash usually resolves within a few days
D. tell the mother her baby has chicken pox and only needs supportive care
E. tell the mother her baby has hand-foot-mouth disease and only needs
supportive care
Explanation:
41
The correct answer is C. Roseola, also known as exanthem subitum, is a common, selflimited illness of infancy characterized by 3-5 days of high fever followed by an
exanthem after defervescence. Roseola typically develops in children 6 months to 3
years of age. Most infants appear to be well with mild lymphadenopathy. The rash is
characteristically flat with rose-pink macules distributed over trunk and neck.
Kawasaki patients (choice A) tend to present with fever longer than 5 days, associated
with edema of the hands, conjunctivitis, cervical lymphadenopathy, and morbilliform
exanthem with desquamation.
Infectious mononucleosis (choice B) is caused by the Epstein-Barr virus. The disorder
begins with headache and malaise with high fevers, which usually lasts 4-14 days.
Lymphadenopathy is generalized and the spleen is moderately enlarged in two-thirds of
cases. Exanthem of morbilliform type occurs between 4th and 6th day involving the
face, trunk, and extremities.
Chicken pox (choice D) is not typically associated with a high fever (mild fever is
common) and the exanthem tends to be classic "dew drops on a rose petal" (i.e.,
vesicles on an erythematous base), at various stages of progression.
Hand-foot-mouth disease (choice E) is characterized by prodrome of low fever,
anorexia, sore mouth, malaise, and abdominal pain which precedes the enanthem by 12 days. The exanthem occurs shortly after enanthem. The oral lesions tend to begin as
small red macules and evolve into small vesicles. One-fourth to two-thirds of affected
patients also have highly characteristic vesicular lesions on the hands and feet.
You get a call from the mother of a 5-year-old patient of yours saying that the
school nurse called to tell her that her daughter has head lice. The daughter
has been scratching her head quite a bit lately, but she thought that it was
due to the decreased frequency of shampooing and brushing since she has
insisted upon having small braids in her hair. The mother is concerned about
her daughter's health and wants to know what she should do right now
because her daughter is still in school. You should advise her that:
A. Head lice are not responsible for the spread of any disease
B. Her daughter should be sent home early from school and treated
C. In addition to infested family members, all members of the
household must be treated with a pediculicide
D. Infestations are influenced by length of hair and frequency of
shampooing and brushing
E. Since there is widespread resistance to permethrin in the United
States, lindane is the preferred method of treatment of head lice
Explanation:
The correct answer is A. This patient most likely has head lice, which is an
infestation caused by Pediculus humanus capitis. It is spread by direct
contact with hair of infected persons and sometimes by sharing hats, combs,
and hairbrushes. It is treated with permethrin and some believe that a
42
second treatment is advisable 7-10 days after the first. While head lice might
be a nuisance, it is not responsible for the spread of any disease
Even though lice is contagious, The American Academy of Pediatrics
recommends that children remain in school for the day and that their parents
are notified of their condition and properly treat them before sending them to
school the next day. Her daughter should be sent home early from school
and treated (choice B) is incorrect.
In addition to infested family members, all members of the household must
be treated with a pediculicide (choice C) is incorrect. Close contacts and
household members should be examined. Treatment is only necessary if the
individual is infested. But the bedmates should be treated prophylactically.
This is not the same as scabies, where it is recommended that the entire
household be treated prophylactically.
Infestations with head lice are NOT influenced by length of hair and
frequency of shampooing and brushing (choice D). Transmission occurs by
direct contact whether or not the individual has poor hygiene.
While there is some resistance to permethrin in the United States,
widespread resistance is found in other countries, and so permethrin is still
one of the preferred treatment methods. Lindane is not the preferred method
of treatment of head lice (choice E). Lindane is often used for individuals
who have not responded to other therapies.
A 17-year-old boy who is hospitalized for depression on the general psychiatric unit
complains of severe chest pain. The pain is worse on inspiration and has been present
for about 2 weeks. His past medical history is significant for depression with multiple
suicide gestures for the past 5 years and seasonal allergies. His only medication is
fluoxetine. He tells you that he is not sexually active and denies illicit drug use. Review
of systems is significant for a recent bronchitis. Vital signs are temperature 37.2 C (99
F), blood pressure 120/70 mm Hg, pulse 92/min, and respirations 10/min. The patient is
disheveled, but well developed. Cardiac examination reveals a leathery sound on systole
and diastole. There is a normal rate and rhythm, but no third or fourth heart sounds. The
lungs are clear. The lower extremities are normal. An electrocardiogram reveals normal
sinus rhythm at a rate of 95/min. Chest x-ray reveals moderate cardiomegaly. A prior
report from a chest x-ray taken 8 months ago states that the heart size was normal. The
next step in managing this patient would be to
A. begin therapy with ibuprofen
B. begin therapy with prednisone
C. obtain permission for an HIV test
D. order a cardiac perfusion scan
E. send cardiac enzymes to rule out a myocardial infarction
Explanation:
43
The correct answer is A. This patient is presenting with inspiratory chest pain, a
leathery rub on systole and diastole, and a newly enlarged heart. This is consistent with
postviral pericarditis, the most common form of pericarditis. Treatment includes
nonsteroidal antiinflammatory medication and in refractory cases, steroids. Other
causes of pericarditis not apropos to this case include myocardial infarction, connective
tissue disease such as rheumatoid arthritis and lupus, drugs such as procainamide,
hydralazine, and isoniazid, metastatic cancer such as lung and breast cancer, and renal
failure.
Steroid treatment such as prednisone (choice B) is prescribed only after an aggressive
course of antiinflammatory treatment has failed given the many side effects of steroid
medication.
An HIV test (choice C) is unnecessary given the low-risk social history of this patient.
Evaluation and treatment for pericarditis is the most appropriate next step.
A cardiac perfusion scan (choice D) would only be appropriate for a postmyocardial
infarction. Evaluation and treatment for pericarditis is the most appropriate next step.
Cardiac enzymes (choice E) are unnecessary given the patient's age and lack of
electrocardiographic findings to suggest a myocardial infarction. This patient is
presenting with inspiratory chest pain, a leathery rub on systole and diastole and a
newly enlarged heart. This is consistent with postviral pericarditis, the most common
cause of pericarditis.
A 35-year-old prisoner was recently stabbed in the left leg by another inmate. He is
brought to the emergency department by the county corrections officer because of high
fevers, swelling of the left thigh, and severe pain at the puncture wound site. His
temperature is 38.3 C (101.0 F), blood pressure is 90/50 mmHg, pulse is 120/min, and
respirations are 25/min. Although he is awake, he appears lethargic. The left thigh
appears pale and swollen around the puncture sight. There is notable crepitus on
palpation around the wound. X-rays of the left thigh show translucences in a feathery
pattern along the quadriceps. Laboratory studies show:
On exploration of the wound, serosanguinous discharge is noted. Blood cultures are
drawn and intravenous crystalloid fluids are instituted. A tetanus booster shot is
administered. The most appropriate additional therapy is
A. ceftriaxone and aztreonam
B. ciprofloxacin
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C. penicillin and clindamycin
D. ribavirin and interferon alpha
E. vancomycin and gentamicin
Explanation:
The correct answer is C. This patient most likely has gas gangrene and myonecrosis.
The causative organism is the Gram-positive anaerobic cocci, Clostridium perfringens.
The x-ray shows classic feathery gas pattern seen in gas gangrene. The triad of
management aside from fluid replacement includes antibiotics, surgical debridement,
and hyperbaric oxygen. Penicillin and clindamycin are the most active antibiotic
regimen against the Clostridia species.
Ceftriaxone (choice A) is an alternative antibiotic choice to penicillin and clindamycin,
but aztreonam lacks any significant activity against Gram-positive organisms.
Ciprofloxacin (choice B) and other fluoroquinolones (except levofloxacin) generally have
weak activity against the Clostridium species.
Ribavirin and interferon alpha (choice D) are anti-viral agents, not antibacterial agents.
Vancomycin (choice E) has sufficient coverage for C. perfringens. Gentamicin is an
aminoglycoside that requires oxygen-dependent transport into bacterial cells, and so it
is ineffective against anaerobic organisms.
You are asked to see a baby in the newborn nursery. The baby is small for
gestational age and has microcephaly. Physical examination shows
hepatomegaly, a widened pulse pressure, a "machinery" heart murmur, and a
purpuric skin rash. There is no red reflex in either eye. At this point, you are
suspicious that the baby has a congenital infection caused by
A. Cytomegalovirus
B. rubella virus
C. Toxoplasma gondii
D. Treponema pallidum
E. varicella-zoster virus
Explanation:
The correct answer is B. This baby most likely has congenital rubella. Some
of the most common anomalies associated with congenital rubella are
intrauterine growth retardation, microcephaly, microphthalmia, cataracts,
glaucoma, retinopathy, patent ductus arteriosus, hepatomegaly, jaundice,
thrombocytopenia, metaphyseal lucency, and a purpuric rash also known as
a "blueberry muffin" rash. Infants may be asymptomatic at birth, but the
earlier in pregnancy the mother is infected with the rubella virus, the more
likely the baby is to have defects. For example, if a mother is infected in the
45
first 8 weeks of pregnancy, the baby has an 85% chance of having a defect.
Congenital Cytomegalovirus (CMV) infection (choice A) is usually
asymptomatic at birth (approximately 85% of the time). Clinical manifestation
is found to be severe in approximately 5% of babies with congenital CMV.
Manifestations include: intrauterine growth retardation, chorioretinitis,
microcephaly, intracerebral calcifications, hepatosplenomegaly, jaundice,
thrombocytopenia, neutropenia, purpura, and pneumonia. Although the baby
in the question has many of the defects found in congenital CMV, congential
heart defects and cataracts are not associated with CMV.
Toxoplasma gondii(choice C) is another organism that can cause congenital
infection, but 70–90% of infants with congenital infection are asymptomatic
at birth. It is important to note that a large percentage of the infants that are
asymptomatic at birth will develop visual impairment, learning disabilities, or
mental retardation months to years later. Signs of congenital toxoplasmosis
include: hydrocephalus, microcephaly, cerebrospinal fluid abnormalities,
intracranial calcifications, chorioretinitis, hepatosplenomegaly, generalized
lymphadenopathy, and a maculopapular rash.
Treponema pallidum(choice D) is the organism responsible for syphilis
infection. Congenital syphilis is characterized by nonimmune hydrops,
prematurity, anemia, neutropenia, thrombocytopenia, pneumonia, and
hepatomegaly. Late onset syphilis, which may present up to two years of
age, is characterized by snuffles, rash, hepatosplenomegaly, condylomata
lata, osteochondritis, cerebrospinal fluid pleocytosis, lymphadenopathy, and
thrombocytopenia. Untreated infants may develop late manifestations
involving the central nervous system, teeth, eyes, skin, ears, bones, and
joints.
Varicella-zoster infection (choice E) in a mother causes different syndromes
in a baby depending on the time of the infection. If the mother is infected in
the first trimester or early in the second trimester, the baby may develop
varicella embryopathy which is characterized by microphthalmia, cataracts,
chorioretinitis, cutaneous and bony aplasia/atrophy, and scarring of the skin
of the extremity. If the mother is infected during the second 20 weeks of
pregnancy, the baby may show no clinical manifestations of varicella, but
may develop zoster later in life without ever having extrauterine infection. If
the mother develops varicella from 5 days before delivery until 2 days after
delivery, the child may develop severe infection, which may lead to death.
A 20-year-old man without a significant past medical history comes to the clinic
complaining of severe vomiting for the last 10 hours. He denies fevers and reports only 1
episode of small volume, non-bloody diarrhea. He lacks significant abdominal pain. The
symptoms reportedly began 6 hours after eating a hamburger and macaroni salad at a
neighborhood fast food restaurant. His temperature is 37 C (98.6 F), blood pressure is
105/70 mm Hg, pulse is 100/min, and his respirations are 17/min. He has slightly dry
mucous membranes, a non-tender abdomen with decreased bowel sounds, and guaiacnegative stool. The most likely etiology of his gastrointestinal complaints is
46
A. Bacillus cereus
B. Campylobacter jejuni
C. Clostridium perfringens
D. E. Coli (0157:H7)
E. Staphylococcus aureus
Explanation:
The correct answer is E. This patient has an illness which is caused by a preformed
toxin. S. aureus is a likely culprit in this patient. Staphylococcus produces a preformed
toxin, which is obtained from dairy products such as mayonnaise. The illness that
follows typically occurs 1-8 hours after ingestion of the toxin. Fever is usually absent
and vomiting is major feature of these illnesses. Diarrhea can occur but to a lesser
extent than the vomiting. The illness is self limiting and will resolve in 24-48 hours.
Treatment involves electrolyte and fluid resuscitation. Antibiotics are not indicated.
Bacillus cereus(choice A) presents in a similar fashion to S. aureus toxin. There is a
short incubation period followed by vomiting with a lack of fever. Treatment is identical.
The two are differentiated by the types of foods that they are associated with. Bacillus
Cereus is typically associated with reheated Chinese fried rice.
Campylobacter jejuni (choice B) causes bloody diarrhea and fevers. Flouroquinolones
are indicated in severe cases.
Clostridium perfringes (choice C) causes another toxin based "food poisoning" illness
but with different features. This organism is ingested and then produces its toxin while
in the gut, thereby causing a longer latent period of 8-16 hours before symptoms begin.
Symptoms typically include more abdominal cramping and diarrhea than S. aureus and
Bacillus cereus . Treatment is again supportive with resolution in 1-4 days.
Fast food restaurant questions on the USMLE should always make you think about E.
Coli 0157:H7 (choice D). This is a strain of E. coli obtained by eating undercooked
hamburger meat. There is typically a latent period between 24-72 hours followed by a
severe hemorrhagic colitis with fevers and abdominal pain. This patient's symptoms are
not consistent with this organism.
A 27-year-old HIV-positive man comes to the clinic for a periodic health
maintenance examination. He contracted the disease 5 years ago from a
former partner. He has been followed in the community health clinic since
that time. He has no other medical history and takes only diazepam orally for
anxiety. His last visit was 11 months ago. His temperature is 37.0 C (98.6 F),
blood pressure is 140/85 mm Hg, pulse is 78/min, and respirations are
12/min. He has clear lung fields bilaterally, his skin is free of rashes or
excoriations, and his abdomen is soft and nontender. Blood work drawn a few
weeks ago reveals a CD4 count of 98 cells/mm3 and a hematocrit of 34%
with an MCV of 95 fl. His last tuberculin skin test was 3 months ago and was
read as 4mm and flat. In addition to initiating vitamin B12 and folate therapy
47
for his patient, the most appropriate intervention at this time is
A. antibiotic prophylaxis for PCP pneumonia
B. antibiotic prophylaxis for tuberculosis
C. a skin test for tuberculosis
D. treatment for active tuberculosis infection
E. none is indicated based upon his CD4 count at this time
Explanation:
The correct answer is A. Opportunistic infections occur in people with HIV
and define many of the components of the clinical syndrome known as
AIDS. They are caused by a wide variety of pathogens and all have the
common etiology that the host is susceptible due to the immune destruction
brought on by the HIV virus. Prognosis depends on the type of infection and
often, even with appropriate therapy, morbidity and mortality is high. There
are means to prevent or reduce the likelihood of developing these infections.
For this patient, his CD4 count of less than 200 cells/mm3 indicates that he
should begin antibiotic prophylaxis, usually with TMP/SMX, for PCP
pneumonia.
Starting antibiotic prophylaxis for tuberculosis (choice B) is not routine
practice except in persons with a PPD-positive skin test, which this patient
does not have.
Since the patient was tested for tuberculosis within the last year, and there is
no evidence that he is anergic, there is no indication to test him again at this
time (choice C).
The patient does not have active tuberculosis infection (choice D). Even if
his PPD test were positive, active infection requires documentation of the
organism in sputum by PCR or acid-fast staining.
Any patient with a CD4 count of less than 200 cells/mm3 should be
considered for prophylaxis therapy for at least PCP pneumonia and
toxoplasmosis (choice E).
A 27-year-old surgery resident comes to the emergency department after
lacerating his finger with a scalpel during a routine cholecystectomy. He says
that he was suturing the abdominal incision when the scrub nurse told him
that it appeared as if there was a cut in his left glove. He immediately ran to
the sink, removed his glove, and when he saw the cut he squeezed his finger
and held it in bleach for 3 minutes. Since he had only met the patient 20
minutes before the surgery, he does not know of her past medical history. He
appears calm, saying that he received the "full Hep B vaccinations series
before entering medical school and anyway, the woman does not appear to
be an intravenous drug user." You administer a tetanus vaccine and obtain
baseline laboratory studies for HIV, Hepatitis B, and Hepatitis C. An infectious
48
disease specialist happens to be in the emergency department, and you ask
her to talk to the resident about the possibility of post-exposure prophylaxis.
The surgery resident is pretty confident that the cholecystectomy patient is
"clean" and so he goes back to the surgery floor. He returns to the
emergency department a few hours later and tells you that the
"cholecystectomy woman" admitted to 20 unprotected sexual experiences
and a few "experiments" with intravenous drug use years ago. He reluctantly
agrees to be treated with zidovudine, lamivudine, indinavir, and interferon.
His laboratory studies finally return 1 week later and show:
He comes to your office to discuss the results. At this time the most accurate
statement about his condition is:
A. He has chronic Hepatitis B and can infect sexual partners at this
time
B. He has chronic Hepatitis B but cannot infect sexual partners at this
time
C. His laboratory studies are consistent with immunity from prior
Hepatitis B vaccination
D. His laboratory studies are consistent with immunity from prior
Hepatitis B vaccination and infection from the cholecystectomy patient
E. His laboratory studies are consistent with immunity from prior
Hepatitis B vaccination and remote infection with Hepatitis B
Explanation:
The correct answer is E. This surgery resident's laboratory studies are
consistent with immunity from prior Hepatitis B vaccination and remote
infection with Hepatitis B. An individual that receives the full series of the
Hepatitis B vaccine will be Hepatitis B surface antibody positive, which
indicates immunity. An individual with a remote Hepatitis B infection will be
Hepatitis B core antibody positive, mostly of the IgG class. The Hepatitis
core markers are indicative of either infection with or immunity to the
nucleocapsid that contains the viral DNA and RNA. This can only be
obtained from actual exposure to the virus, not by receiving the vaccine.
Patients who receive the Hepatitis B vaccine develop HBsAb without
developing HBcAb.
This patient does not have chronic Hepatitis B (choice A and choice B) and
therefore cannot transmit the disease. He has antibodies to the virus, both
HBcAb and HBsAb, indicating prior infection and prior vaccination. He would
have chronic Hepatitis B if he was HBsAg and HBcAb positive, and he would
have a high infectivity risk if was HBeAg positive, and low infectivity risk if he
was HBeAb positive.
49
It is incorrect to say that his laboratory studies are consistent with immunity
from prior Hepatitis B vaccination (choice C) because patients who receive
the Hepatitis B vaccine develop HBsAb without developing HBcAb.
His laboratory studies are not consistent with immunity from prior Hepatitis B
vaccination and infection from the cholecystectomy patient (choice D)
because of two reasons: the Hepatitis B virus has an incubation period of
one to six months (this has only been one week since exposure) and
patients who receive the Hepatitis B vaccine develop HBsAb without
developing HBcAb. Therefore, this patient's laboratory studies are consistent
with immunity from prior Hepatitis B vaccination and remote infection with
Hepatitis B, not with infection from the cholecystectomy patient. An acute
infection is characterized by the presence of Hepatitis B surface antigen and
Hepatitis B core antibody of the IgM class.
A 2-year-old boy is brought to the emergency department by his mother because of a 2day history of approximately 10 episodes per day of non-bloody watery bowel
movements. The child has also had a few episodes of non-bloody, non-bilious emesis.
He has not traveled out of the country recently and has not eaten any new foods. His
temperature is 38.4 C (101.1 F), blood pressure is 90/50 mm Hg, and pulse is 160/min.
The patient weighed 15 kg at his 2-year-old checkup a week ago and presently weighs
13.5 kg. His capillary refill is 2-3 seconds and his mucous membranes are slightly dry.
The most appropriate next step in the management of this infant is to
A. begin intravenous fluid therapy with an isotonic saline solution
B. begin intravenous fluid therapy with 1/4 NS and 20 mEq KCl/L
C. begin oral rehydration therapy and obtain a set of electrolytes
D. get a stool culture and start antibiotics
E. give the mother instructions regarding oral rehydration and send them home
Explanation:
The correct answer is A. Thanks to the 2-year-old check up we have a recent weight on
this child and that along with the physical exam and increased heart rate allows us to
recognize that this child is about 10% dehydrated. Therefore, he requires some IV fluid
therapy. The child should first receive a 20cc/kg bolus of isotonic saline solution and
then the rest of the course of the emergency department visit will depend on response
to the treatment. Most likely, the child will require another bolus of isotonic solution and
then may be placed on a standard IV solution. The parents must then be given strict
instructions as to the administration of oral rehydration and if the child improves with the
IV fluids and shows that he is capable of being rehydrated orally then they may be
discharged home. But the initial treatment is with isotonic saline.
Begin intravenous fluid therapy with 1/4 NS and 20 mEq KCl/L (choice B) is incorrect
because those are standard maintenance fluids and should be given only after the
boluses of isotonic solution are completed.
50
The oral rehydration fluid (choice C) being mentioned here is a fluid created by the
World Health Organization. It should not be given until after the initial management with
isotonic saline and possibly standard maintenance fluids, such as 1/4 NS and 20 mEq
KCl/L.
This case appears to be a case of viral gastroenteritis because of the fever and watery
stools along with the lack of history suggesting a bacterial cause (travel, eating at a
barbecue etc.). Therefore a stool culture (choice D) is not warranted and antibiotics
should not be started. Even if the stools were bloody and there was a history
suggesting a bacterial cause for the diarrhea (abrupt onset of diarrhea, bloody stool,
and no emesis) antibiotics should not be started until a result is obtained from a stool
culture. Following are some of the recommendations put out by the Red Book regarding
treatment of bacterial gastroenteritis: E. coli - Antibiotics are not necessary unless the
diarrhea becomes intractable (>3-4 days) and the isolate is seen to be susceptible to
oral antibiotic treatment. Generally the drug of choice is TMP-SMX. Staph aureus - No
antibiotic treatment is necessary. Salmonella - Antibiotics are only used for children
under 3 months of age, in children with immunodeficiencies, or if there is a positive
blood culture. Shigella - Use TMP-SMX if an isolate is recovered and is seen to be
susceptible. Campylobacter - If the results of the stool culture come back while the
patient is still symptomatic then giving azithromycin may help shorten the duration of
the diarrhea and prevent relapse.
Give the mother instructions regarding oral rehydration and send them home (choice E)
is incorrect because this child is symptomatic from his dehydration and therefore
requires IV therapy and cannot be sent home on oral rehydration therapy alone, though
this should be part of the process once the child has received the proper IV fluid
therapy.
A 22-year-old woman comes to the office because of a 2-day history of vaginal
discomfort and mild itching. She has been a long-time patient of yours and has admitted
to having 5 lifetime sexual partners. When questioned further, she admits to a frothy
vaginal discharge, which is yellowish-green in color. She describes the odor as "fishy".
She says that her symptoms worsen right before onset of menses. Physical examination
is unremarkable except for some mild abdominal discomfort. Pelvic examination shows a
"frothy" vaginal discharge and a friable cervix with numerous petechiae. The most likely
diagnosis is
A. Bacterial vaginosis
B. Candida albicans
C. normal vaginal discharge
D. Trichomonas vaginalis
Explanation:
The correct answer is D. The clinical picture in this patient is consistent with
Trichomonas vaginalis. Although the infection is often asymptomatic, men may develop
urethritis, and women may complain of a frothy vaginal discharge that is greenish-
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yellow in color that may have a fishy odor. Women may also have some lower
abdominal tenderness with more severe symptoms just before or just after
menstruation. On exam, the vaginal mucosa may be erythematous with an inflamed
and friable cervix. Women may also have a "strawberry cervix", a term used when there
are multiple petechiae on the cervix. Although a wet prep is positive in only 40-80% of
the cases, and therefore not necessary for diagnosis, seeing the trichomonads with
their flagella and jerky motility is diagnostic.
Bacterial vaginosis (BV) (choice A) is a syndrome seen in sexually active females which
is usually asymptomatic but often presents with a thin, white, foul smelling discharge
which people often describe as "fishy". BV is usually not associated with pruritus,
dysuria, or abdominal pain. BV is the most prevalent vaginal infection in sexually active
females. Although not completely clear, causes are thought to include Gardnerella
vaginalis, Mycoplasma hominis, and anaerobic bacteria. In order to diagnose BV, a
woman must have at least 3 of the following: a whitish gray non-inflammatory vaginal
discharge that adheres to the vaginal wall, a vaginal fluid pH greater than 4.5, a "fishy"
odor to the vaginal fluid either before or after mixing with 10% potassium hydroxide, and
a wet mount that shows "clue" cells, which are epithelial cells with smudged borders
due to bacteria adherent to the cell membrane
Yeast infections are caused by overgrowth of Candida albicans(choice B) often due to
factors such as pregnancy, antibiotic use, diabetes, and oral contraceptive use. Some
women report predisposition to yeast infections immediately preceding menstruation.
These women usually present with complaints of intense pruritus and burning
accompanied by a thick white "cottage cheese"-like vaginal discharge. In a woman with
a yeast infection, you would expect to see yeast and pseudohyphae on a wet mount.
Normal vaginal discharge (choice C) is usually a scant to moderate amount of clearwhite colored discharge. There is usually no strong odor present. There are many
lactobacilli and normal epithelial cells.
A 6-year-old girl is brought to the clinic because of a 24-hour history of an " itchy, red
rash." Over the past 7 days she has not been feeling well. She had a fever reaching 39.3
C (102.8 F), a headache, and muscle aches. Her mother treated her with
acetaminophen and these symptoms resolved. Now she has this rash that appeared
over night, as the other symptoms resolved. Her temperature is 37 C (98.6 F). Physical
examination shows an erythematous facial rash on the cheeks and a symmetric,
maculopapular, lace-like rash on the arms, buttocks, and thighs. The remainder of the
examination is unremarkable. Laboratory studies show:
At this time the most correct statement about her condition is:
A. Droplet precautions should be used to prevent the spread of infection
B. Intravenous immunoglobulin therapy should be given
C. Pregnant women should not have contact with this patient
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D. She should return to school after this office visit
E. She should be given a blood transfusion to prevent an aplastic crisis
Explanation:
The correct answer is D. This patient has the classic symptoms of an erythema
infectiosum (fifth disease), which is an infection caused by Parvovirus B19. Patients
with this disease are only infectious before the onset of the rash, during the period with
the nonspecific febrile illness. The virus typically only causes a significant, severe
illness in individuals with sickle cell disease and other hemoglobinopathies. In rare
cases, has parvovirus, during pregnancy, been associated with fetal hydrops and death.
But as stated earlier, this patient can go back to school because she is no longer
contagious.
Droplet precautions used to prevent the spread of infection (choice A), is unnecessary
at this stage in the disease because this patient is no longer infectious. Droplet
precautions are used in hospitals for those caring for patients with diseases that are
transmitted through droplets containing microorganisms. They are used to prevent the
host from catching the infection if the infected patient coughs or sneezes on them or
during procedures such as suctioning or bronchoscopy. Droplet precautions require a
mask if within 3 feet of the patient and or in a private room. In addition to standard
precautions, parvovirus B19 requires droplet precautions for those caring for these
hospitalized patients.
Intravenous immunoglobulin therapy (choice B) is given to immunocompromised
patients with chronic parvovirus infection. Supportive care is all that is indicated for this
patient.
Since this patient is no longer infectious, it is incorrect to say that pregnant women
should not have contact with this patient (choice C).
Parvovirus B19 is associated with thrombocytopenia, neutropenia, and red blood cell
aplasia usually in patients with sickle cell disease and other hemoglobinopathies.
Transfusions are used in these patients with aplastic crises. Transfusions are not
routinely given in previously healthy children who have parvovirus B19 infection to
prevent aplastic crises. Since this patient's complete blood count is normal, she should
NOT be given a blood transfusion to prevent an aplastic crisis (choice E).
A 33-year-old HIV-positive man with a CD 4 count of 125 comes to the clinic with
multiple bumps on his face, requesting that they be removed by liquid nitrogen. He
states he has had multiple molluscum lesions which recur every so often and his
previous doctors have removed them with the "freezing" technique. He recently
discontinued all of his antiretroviral medications due to lack of motivation and was
referred for psychiatric evaluation. He reports that in the past 2 months he has
experienced frequent low-grade fevers, headaches, and myalgias. His temperature is
38.1 C (100.6 F), blood pressure is 110/70 mm Hg, pulse is 70/min, and respirations are
16/min. He appears cachetic with temporal wasting. There are over 20 papules with
central umbilication measuring 0.2-1.5 cm in diameter on his face. In most of the lesions,
the central dimples are covered with a hemorrhagic crust. Superficial ulcerations are
appreciated on oral mucosa. Multiple 0.5-1.0 cm mobile lymphadenopathy are present in
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cervical and supraclavicular regions. The most appropriate next step in management is
to
A. biopsy one of the lesions to rule out cutaneus cryptococcosis
B. give him acyclovir and ask him to come back in 2 months
C. tell him there is no medical indications to treat these lesions, which are of
cosmetic concern
D. diagnose this as tinea faciei and start treatment with topical terbinafine
E. treat the lesions with liquid nitrogen and have patient return to clinic as needed
Explanation:
The correct answer is A. Cutaneous cryptococcosis is primarily an opportunistic
infection with Cryptococcus neoformans which affects the central nervous system. The
disease is subacute and mild headaches, fever, and malaise are the predominant
features. Cutaneous cryptococcosis in HIV infection usually presents as small papules
with central umbilication covered with hemorrhagic crust. Tumors and ulcerative lesions
of skin or mucous membranes are also seen. Often, the lesions resemble Molluscum
contagiosum, herpes infection, and Kaposi sarcoma. Whenever presented with an
immunosuppressed patient with lesions resembling molluscum, always bear in mind
other deep fungal infections. If there is enough doubt, biopsy the lesions for culture and
warn the laboratory that cryptococcus is suspected, since the culture form is highly
contagious.
Acyclovir (choice B) is incorrect because herpes may be in the differential of cutaneous
cryptococcus. One should rule out more dangerous infection first before treating blindly.
No treatment (choice C) is incorrect because, as mentioned above, immunosuppressed
patients are at a much higher risk for deep fungal infection and this patient's CD4 count
is well under 200.
Tinea faciei (choice D) is incorrect because this is a superficial fungal infection that
usually does not result in papules and is not associated with systemic symptoms such
as fever and malaise as in this patient.
Treating the lesions with liquid nitrogen (choice E) as if these are typical Molluscum
contagiosum lesions is incorrect as described above.
A 3-week-old infant is brought into the office by her mother for a newborn examination.
Her birth was without incident; however she received ampicillin and gentamicin for 2
days after birth for rule-out sepsis. The blood and cerebrospinal fluid cultures were
negative and she was therefore discharged home with the mother on day of life 3. She
has been breast fed exclusively and is feeding every 3 hours without difficulty. She is
voiding and stooling regularly. The mother notes, however, that for the past 1 weeks she
has had reddened skin over the diaper area and cries frequently until her diaper is
changed. She has tried using zinc oxide cream at every diaper change, but the rash has
persisted. On physical examination, you note a bright red eruption over the perineal
area, which involves the intertriginous areas. There are sharp borders with pinpoint
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satellite papules and scattered pustules. The remainder of the exam is unremarkable.
KOH preparation of the pustular material reveals pseudohyphae and spores. The most
appropriate therapy at this time is
A. continue zinc oxide
B. frequent exposure to air
C. intravenous cephalexin
D. oral fluconazole
E. topical acyclovir
F. topical nystatin
Explanation:
The correct answer is F. This infant has candidal diaper dermatitis, which is a common
occurrence in infants after receiving antibiotic therapy. It has a characteristic bright red
appearance with satellite lesions and a sharply demarcated border. KOH preparation
reveals the classical pseudohyphae and budding yeasts that are characteristic of
candida. Topical antifungals, such as nystatin, are the treatment of choice.
Zinc oxide (choice A) and frequent exposure to air (choice B) are appropriate therapies
for irritant diaper dermatitis, which is caused by harsh soaps, detergents, and the
ammonia-laden environment within the diaper. This dermatitis is also erythematous, but
classically spares the intertriginous creases.
Intravenous cephalexin (choice C) is inappropriate because there is no indication of
bacterial infection requiring IV antibiotics.
Oral fluconazole (choice D) is not indicated since this infection responds very well to
topical antifungals.
Topical acyclovir (choice E) is incorrect as the etiology of this infection is not viral.
A previously healthy 20-year-old man comes to his college medical clinic for headaches
and low-grade fevers. He is discharged home with the diagnosis of a "viral syndrome"
and instructed to get ample rest. Approximately three hours later his roommate calls 911
reporting that his friend is unconscious and not arousable. On arrival the paramedics find
a lethargic, febrile man lying on the floor and unresponsive. The patient is stabilized and
he is rushed emergently to the local hospital where an abdominal CT scan shows
bilateral adrenal hemorrhages. His blood pressure is 80/40 mm Hg and his pulse is
110/min. He appears very ill and continues to be non-responsive. The most appropriate
study at this time is a/an
A. Cort-Stim test
B. cortisol level
C. high-dose ACTH stimulation test
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D. insulin response test
E. low-dose ACTH stimulation test
Explanation:
The correct answer is B. This patient has bilateral adrenal hemorrhages in the setting of
fulminant disseminated Neisseria sepsis. This is called the Waterhouse-Friderichsen
Syndrome. The patient therefore almost certainly has acute adrenal insufficiency. In a
critically ill patient, a random cortisol level that is low confirms this diagnosis.
A Cort-Stim test (choice A) is a test whereby synthetic ACTH is administered and the
cortisol response is measured one hour later. It is more sensitive at detecting adrenal
insufficiency but is both too time-consuming and unnecessary in this patient. The
threshold for supplying exogenous steroids is very low so all that is needed is a
suspicion for insufficiency that a random cortisol level can easily provide.
A high-dose ACTH stimulation test (choice C) or low-dose ACTH stimulation test
(choice E) are both very sensitive tests that require 24 hours to perform. They both are
useful at quantifying adrenal function so that differentiation between various causes of
adrenal insufficiency can be made. However, they are not the most appropriate studies
in this acute situation.
The insulin response test (choice D) is another method used to indirectly assess
adrenal function but will not be useful in this patient since the goal is rapid direct
assessment of her adrenal function.
A 71-year-old man with osteoarthritis comes to the office complaining of a painful "bandlike" rash across his left chest. He denies ever having a similar rash before. He plays
golf 3 times per week and takes only nonsteroidal antiinflammatory agents for pain from
his arthritis. His temperature is 37.0 C (98.6 F). On his left chest, in the T5 dermatomal
distribution, is a macular-papular, erythematous rash that is painful to the touch. There is
mild weeping of some of the papules. The most appropriate therapy is at this time is
A. antibiotics
B. antifungal agents
C. corticosteroids
D. ganciclovir
E. gabapentin
Explanation:
The correct answer is D. The patient has herpes zoster, also known as shingles. The
disease is a result of reactivation of latent varicella zoster virus in the dorsal root
ganglia. The disease follows a dermatomal distribution and is very painful. The goals of
therapy are to hasten the resolution of the symptoms and to prevent the development of
postherpetic neuralgia, an often crippling neuropathic pain disorder resulting from the
shingles infection. The drugs best able to accomplish both of these goals are the oral
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antiretroviral drugs, ganciclovir, acyclovir, and famciclovir.
Neither oral antibiotics (choice A) nor oral antifungal agents (choice B) have any role in
the treatment of this disease, since it is a reactivation of a viral infection. Unless there is
evidence of a superinfection with a bacterial or fungal etiology, these classes of drugs
should be avoided.
The use of corticosteroids (choice C) for this disease will exacerbate the symptoms.
Although dermatologists liberally utilize steroid therapy, its use in this case acts as an
immunosuppressive agent and will exacerbate the primary manifestations of rash and
pain.
Gabapentin (choice E) is used for the treatment of postherpetic neuralgia and other
neuropathic pain syndromes. Gabapentin is structurally related to the neurotransmitter
GABA (gamma-aminobutyric acid) but it does not interact with GABA receptors, as it is
not converted metabolically into GABA or a GABA agonist, and it is not an inhibitor of
GABA uptake or degradation. It has no utility in treatment of acute shingles.
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