Model Test keys-13-7-2015
1. B, Prospective study
Incidence rate can be calculated by cohort study, also known as prospective study.
Incidence rate:
Defined as "the number of NEW cases occurring in a defined population during a specified period of time"
Incidence =
No. of new cases of specific disease during a given time period X 1000
Population at risk during that period
Epidemiological study
Parameters calculated
Case control/retrospective study
Odds ratio
Cohort or prospective or longitudinal
study
Incidence rate
Relative risk
Attributable risk
Population attributable risk
Cross-sectional study
Prevalence
2. . Ans. is 'a' i.e. Staphylococcus
Staphylococcus is not a bacterial indicator of fecal pollution.
Bacterial indicators of fecal pollution are • Primary
- Coliform organism e.g. E. Coli (confirmatory in doubtful cases)
(Practically all coliforms are assumed to be of fecal origin unless proved otherwise)
• Supplementary
- Fecal streptococci &
- Clostridium perfringens
Fecal streptococci → Confirmatory evidence ofreccentfecal pollution of water in doubtful cases.
Clostridium perfringens → presence of spores indicate remote fecal pollution in absence of E. coli.
3. Answer is B (ICF):
The latest WHO initiative for classification of disability is the 'International Classification of Functioning,
Disability and Health' which is termed as 'ICF'
•The WHO first published an International Classification of Impairment. Disability and Handicap in 1980
and termed it as 'ICIDH'
•The WHO started the revision effort of 1CIDH in 1995 and after 5years of field trials, the pre final version
of the revised classification was drafted in 2000 and termed as the 'IC1DH II'
•The WHO finally endorsed the new version of ICIDH (ICIDH-II) in 2001, however the WHO referred this
new
classification as 'International Classification of Functioning, Disability and Health' and termed it as
'ICF' and not as ICIDH-2 'The second (latest) edition of International Classification of Impairment,
Disability and Handicaps (ICIDH) was endorsed with the title of 'International classification of,
Functioning Disability and Health' and referred to as '1CF" - WHO official publication on '[CF'
4. Ans is 'b'
Reliability or repeatability is a very important criterion of a screening test.
Reliability or repeatability: means that the test must give consistent result when repeated more than once
on the same
individual or material, under the same conditions. The repeatability of the test depends upon three major
factors: i)
observer variation ii) biological (or subject) variation & iii) errors related to technical methods.
Other important criteria of screening test are:
•Validity (accuracy): Validity refers to what extent the test accurately measures which it is supposed to
measure. If it is a cholesterol screening test, the question is: can it give accurate enough readings so that
the individual actually knows how high or low his or her cholesterol really is? In other words validity
expresses the ability of a test to separate or distinguish those who have the disease from those who do
not. For example glycosuria is a useful
screening test for diabetes, but a more valid or accurate test is the glucose tolerance test. Accuracy refers
to the closeness with which measured values agree with "true" values. Validity is determined by the
sensitivity and specificity of the test.
•Yield: is the amount of previously unrecognized disease that is diagnosed as a result of the screening
effort.
5. Ans is a i.e. Attitude
Attitudes:
•An attitude is a hypothetical construct that represents an individual's degree of like or dislike for an item.
•Attitudes are generally positive or negative views of a person, place, thing, or event.
•Attitudes are acquired characteristics of an individual. They are more or less permanent ways of
behaving. An attitude has been defined as a relatively enduring organization of beliefs around an object,
subject or concept which pre-disposes one to respond in some preferential manner.
•Attitudes are not learned from text-books, they are acquired by social interaction, e.g. attitude towards
persons, things, situations and issues (e.g. government policies. programmes and administrative
measures). "Attitudes are caught ami not taught .••
•Once formed, attitudes are difficult to change. The responsibility to develop healthy attitudes depends
upon parents, teachers, religious leaders, and elders. Ones success and failure in life depends upon ones
attitude.
Opinions and beliefs:
•Opinion are views held by people on a point of dispute. They are based on evidence available at the
time.
•Opinions by definition are temporary and provisional. They can be looked on as beliefs for the time
being.
•Beliefs, on the other hand are permanent, stable, almost unchanging. It is thus easier to give up one's
opinions when faced with facts; attitudes and beliefs do not succumb so easily.
Values:
•Values are considered subjective, vary across people and cultures and are in many ways aligned with
belief and bel ief systems.
•Types of values include ethical/moral values, doctrinal/ideological (religious, political)
values, social
values, and aesthetic values.
•Personal values developed very early in life may be resistant to change. They may be derived from those
of particular groups or systems, such as culture, religiorn, andpolitical party associations. However,
personal values are not universal; one's family, nation, generation and historical environment help
determine one's personal values.
•Values are related to the norms of a culture, but they are more general and abstract than norms. Norms
are rules for behavior in specific situations, while values identity what should be judged as good or evil.
Flying the national flag on a holiday is a norm, but it reflects the value of patriotism. Wearing dark
clothing and appearing solemn are normative behaviors at a funeral. They reflect the values of respect
and support of friends and family. Different cultures reflect different values.
6. Answer is A (MMR)
Pregnancy is a contraindication for administration of live vaccines MMR is a live vaccine, and
contraindicated in pregnancy. Hepatitis B and Rabies vaccines are inactivated or killed vaccines and may
be used in pregnancy
MMR vaccine and pregnancy(Immunization in Practice 2nd/I2l)
•MMR vaccines are contraindicated in pregnant women because of possible teratogenic effects of rubella
component
•MMR vaccines may be given to seronegative married women who are not pregnant, but they should be
advised to avoid pregnancy during next 3-4 monthsQ
•Although pregnancy is a contraindication to rubella vaccination (MMR), accidental rubella vaccination in
unsuspected pregnancy is not an absolute indication for termination ofpregnancyQ
Contraindications to vaccination with live vaccines
1.
PregnancyQ
2.
Immunodeficiency disease or states Q
(Includes persons whose immune response may be supressed because of leukemia, lymphoma,
malignancy or because of therapy with a drugs that cause immunosupression (carticosteroids, alkylating
agents, antimetabolites) and radiation
7 .Answer is A (Obstetric Haemorrhage)
The most common cause of Maternal mortality in India according to the Annual Report 2006-2007 (SRS
Data from 1998) of Ministry of Health and Family welfare (Govt, of India) is obstetric haemorrhage which
accounts for about one third (29%) of all deaths.
The most common causes of Maternal Mortality in India: Source: Annual Report 2006-2007 (Available
online)
Source: Ministry of Health & Family welfare: Govt. of India. Data is sourced from SRS 1998 (Sample
Registration System -1998)
Haemorrhage
Anemia
Sepsis
Obstructed labor
Abortion
Toxemia
Others
8 .Answer is D (Neonatal tetanus)
29%
19%
16%
10%
9%
8%
9%
The Integrated Management of childhood Illness initiative was taken to prevent morbidity and mortality
from five major childhood conditions namely, Diarrhea, Acute Respiratory tract infections (including otitis
media), Malaria, Malnutrition and Measles among children less than 5year of age.
Neonatal tetanus was not part of the initiative. Neonatal tetanus is the single best answer of exclusion
IMCI : Introduced for the following five major illness amongst under five
1.Diarrhea
2.Acute Respiratory tract infection (includes otitis mediaQ)
3.Ma1o.riaQ
4.Measles
5.MalnutritionQ
9. Ans. is 'd' i.e. Filaria
Transmission of arthropod-borne diseases occur by following methods:
I.Direct contact= In this method of spread, the arthropods are directly transferred man to man e.g.
scabies, pediculosis
2.Mechanical Transmission - Here the disease agent is transmitted mechanically by the arthropod. e.g.
housefly transmitted diseases
3.Biological Transmission - In biological transmission the disease agent multiplies or undergoes some
developmental change with or without multiplication in the arthropod host.1t is of three types:
a.Propagative - The agent merely multiplies in vector, but no change in form e.g. plague bacilli in rat flea.
b.Cyclopropagatlve - The agent changes in form & multiplies in the body of arthropod e.g. malarial
parasites in mosquito
c.Cyctodevelopmental= The disease agent undergoes cyclical changes but no multiplication e.g. filarial
parasite in culex mosquito and guinea worm embryo in cyclops.
Other methods
•Transovarian transmission - The infectious agent is transmitted vertically from the infected female to her
progeny in the vector e.g. Ticks transmitting Ricketssial diseases
•Trans-stadia/ transmission - Transmission of the disease agent from one stage of the life cycle to
another as for example nymph to adult e.g. Ticks.
10. Ans. is 'd' ie WHO recommends Danish 1331 strain for vaccine production
•WHO has recommended the 'Danish 1331' Strain Jor the production oj BCG vaccine and since 1967, the
BCG laboratory oj Guindy", Chennai is using 'Danish 1331' Strain for the production oj BCG vaccine.
•Normal Saline is recommended as diluent for BCG vaccine. The reconstituted vaccine should be used
within 3 hours and left over vaccine should be discarded.
•The Vaccine must not be contaminated with any antiseptic or detergent. I f alcohol is used to swab the
skin, it must be allowed to evaporate before the vaccine is given.
•Mantoux test normally because positive after 8 weeks of vaccination, but sometimes it takes about 14
weeks.
Other important points about BeG Vaccination
•There are two types of BCG vaccine - the liquid (fresh) vaccine and theJreeze - dried vaccine. Presently
freeze- dried vaccines being more stable are used.

Storage: BCG vaccines are stable for several weeks at ambient temp in a tropical climate,
and for up to 1 years if kept away from direct light and stored in a cool environment. The
vaccine must be protected from exposure to light during storage (wrapped up in double
layers of red or black cloth).
 Dosage: - Usual strength is 0.1 mg in 0.1 ml volume
- Dose to newborn aged below 4 weeks is 0.05 ml

Administration:
-Tntradermai" with tuberculin syringe.


Site of injection:
- Just above the insertion of the deltoid muscle.
Age of administration:
- Either at birth or at 6 weeks of age simultaneously with DPT
and polio.
 Duration of protection: - 15 to 20 years.
 Booster:
- Not advised under Expanded Programme of Immunization.
 Contraindications: - Unless specifically indicated, BCG should not be given to patients
suffering from*.
- Generalized eczema*
- Infective dermatosis"
- Hypogammaglobulinaemia*
- Patient with history of deficient immunity*.
 Phenomenon after vaccination *
- A papule develops at the site of inj 2 to 3 weeks after vaccination.
- It increases in size and reaches a diameter of 4 to S mm in about 5 weeks.
- The papule then ulcerates
- Healing occurs spontaneously to leave a tiny scar (4 to S mm in diameter) within 6 to J 2 weeks
11 .Ans. is'd' i.e. True negatives
Sensitivity is the ability of test to identify correctly all those who have the disease, i.e. 'true positives'.
Specificity is the ability of a test to identify correctly those who do not have the disease, i.e. 'true
negatives'
12. Ans. is 'b' i.e. Epidemic conjunctivitis
•Vision 2020: The Right to Sight, is a global initiative launched by WHO in Geneva in 1999 in coalition
with Task force of International NGOs'
•Globally, WHO hs identified 5 major blinding eye conditions, for immediate attention:
i) Cataract
h) Childhood blindness
hi) Trachoma
iv) Refractive errors and low vision
v) Onchocerciasis (River blindness)
•The Government of India has adopted 'Vision 2020: Right to Sight' under 'National Programme for
Control of Blindness' in 2001.
- Target diseases identified for intervention under 'Vision 2020' initiatives in India are:
i) Cataract
ii) Childhood blindness
iii] Trachoma
iv) Refractive errors and low vision
v) Corneal blindness
vi) Diabetic retinopathy
vii) Glaucoma
•Objective of Vision 2020 - is to eliminate avoidable blindness by the year 2020 and reduce the global
burden of blindness
13. Ans. is 'a' i.e. Ecological study
There are several ways in which we can study the relationship between a given exposure or risk factor
(for ego antiarrythmic drugs here in question) and its outcome (asthma in the given question).
Epidemiological Study
↓
↓
Observational studies
↓
Descriptive studies
↓
Analytical studies
↓
Experimental/Intervention studies
- Animal studies
- Case Reports
- Case Series
- C ross-sectiona I studies
- Ecological study
- Case control or
case reference study
- Cohort study
- Randomized controlled trials
- Field trials
- Community trials
•Observational studies allow nature to take its own course; the investigator measures but does not
intervene.
•Descriptive studies are those that investigate the distribution of disease in a population
•Analytical studies analyse the relationship between the disease and the causative factors.
•Experimental or interventional studies involve an active attempt to change a disease determinant or the
progress of a disease (similar in design to experiments in other sciences)
Descriptive studies
•Descriptive studies are usually the first phase of an epidemiological investigation. These studies are
concerned with observing the distribution of disease or health-related characteristics in human population
and identify the characteristics with which the disease in question seems to be associated. These studies
provide clues to disease etiology and help in formulation of an etiological hypothesis.
•Case report - the simplest of the descriptive studies is the case report, which is often seen in medical
journals and describes an unusual feature or unusual association between the disease and some
exposure factor.
•Case series - a case series is a sequence of case reports with common elements such as similar clinical
features and suspected common exposures. They can be valuable early evidence for association
between exposures and diseases which can be studied in more detail subsequently; however as they
lack a control (comparison) group, the case series can result in false leads, wasted energy & resources.
•Cross-sectional or Prevalence study - in cross-sectional studies, we 'survey' several individuals at one
point in time and collect information on health status, health-related behaviours, and other exposure
factors. In this way we can estimate the burden of disease in a group of individuals and try to estimate
whether a particular exposure is linked to a disease or health outcome.
•Ecological or correlational study - an ecological or correlational study is one in which the unit of analysis
is an aggregate of individuals and information is collected on this group rather then on individual
members. The association between a summary measure of disease and a summary measure of
exposure is studied. E.g., There is a positive correlation between fat consumption and breast cancer
across many nations. Conclusion: Fat consumption is a risk factor for breast cancer. An error of
reasoning (Ecological Fallacy) occurs when conclusions are drawn about individuals from data that are
associated with groups, as relationships observed for groups may not necessarily hold for individuals, In
the above example, it is not possible to infer that the women with breast cancer actually had a
high fat consumption.
Analytical studies
•Analytical studies are the second major type of epidemiological studies. In contrast to descriptive studies
that look at the entire population, in analytical studies the subject of interest is the individual within the
population. The object is not to formulate, but to test hypotheses.
•Case Control - Sometimes it is necessary to study individuals in whom a disease has already occurred in
order to find out whether these individuals had been exposed to a particular risk factor. This is called a
case control study.
The cases are compared to a group of individuals who do not have the disease in question and the same
information on risk factors is collected from both groups. By doing this, we may be able to find out if a
particular risk factor is more common among the cases than controls and therefore suggest an
association between the risk factor and disease.
•Cohort study - In a cohort study, a group exposed to a particular factor and another group not exposed to
this factor are followed up over time to determine occurrence of disease. The incidence of disease in the
exposed group is compared to the incidence of disease in the unexposed group. This is called the
relative risk and it allows us to make a judgment on whether the exposure factor and the disease are
causally linked.
14. A
15. A
16.B
17.C
18.C
19.B
20.C
21.C
22.C
23.C
24.A
25.D
26.A
27.A
28.ANS.B
EXPLANTION:The Apgar score is a practical method of systematically assessing newborn infants immediately after
birth. A low score may be due to fetal distress but may also be due to a number of factors, including
prematurity and drugs given to the mother during labor. The Apgar score was not designed to predict
neurologic outcome. Indeed, the score is normal in most patients in whom cerebral palsy subsequently
develops, and the incidence of cerebral palsy is low in infants with Apgar scores of 0-3 at 5 min (but
higher than in infants with Apgar scores of 7-10). Low Apgar scores and umbilical artery blood pH predict
neonatal death. An Apgar score of 0-3 at 5 min is uncommon but is a better predictor of neonatal death
(in both term and preterm infants) than an umbilical artery pH ≤ 7.0; the presence of both variables
increases the relative risk of neonatal mortality in term and preterm infants. Infants who fail to initiate
respiration should receive prompt resuscitation and close observation. (See Chapter 88, page 536.)
Ref:- Nelson Textbook of Pediatrics 19th edn
29.ANS.C
EXPLANTION:See Table 88-2 for a key to assigning Apgar scores. This infant loses one point for color but otherwise
appears vigorous. (See Chapter 88, page 536.)
Apgar Evaluation of Newborn Infants*
Modified from Apgar V: A proposal for a new method of evaluation of the newborn infant, Res Anesth
Analg 32:260–267, 1953.
SIGN 0
1
2
Heart rate
Absent Below 100
Over 100
Respiratory effort
Absent Slow, irregular Good, crying
Muscle tone
Limp Some flexion of extremities
Active motion
Response to catheter in nostril (tested after oropharynx is clear) No response
Grimace
Cough
or sneeze
Color Blue, pale
Body pink, extremities blue
Completely pink
Factors Affecting the Apgar Score*
FALSE-POSITIVE (NO FETAL ACIDOSIS OR HYPOXIA; LOW APGAR SCORE)
Prematurity
Analgesics, narcotics, sedatives
Magnesium sulfate
Acute cerebral trauma
Precipitous delivery
Congenital myopathy
Congenital neuropathy
Spinal cord trauma
Central nervous system anomaly
Lung anomaly (diaphragmatic hernia)
Airway obstruction (choanal atresia)
Congenital pneumonia and sepsis
Previous episodes of fetal asphyxia (recovered)
Hemorrhage-hypovolemia
FALSE-NEGATIVE (ACIDOSIS; NORMAL APGAR SCORE)
Maternal acidosis
High fetal catecholamine levels
Some full-term infants
Ref:- Nelson Textbook of Pediatrics 19th edn
30.ANS.C
EXPLANTION:The eyes of all infants, including those born by cesarean section, must be protected against gonococcal
ophthalmia neonatorum by instillation of 1% silver nitrate drops or erythromycin (0.5%) or tetracycline
(1.0%) sterile ophthalmic ointments. An intramuscular injection of 1 mg of water-soluble vitamin K1
(phytonadione) is recommended for all infants immediately after birth to prevent hemorrhagic disease of
the newborn or transcutaneous bilirubin levels as indicated. Hepatitis B immunization before discharge
from the nursery is recommended for newborns with weight > 2 kg irrespective of maternal hepatitis
status. All states in the USA have neonatal screening programs, although the specific tests required vary.
Universal hearing screening of infants is recommended to ensure early detection of hearing loss and
appropriate, timely intervention. Routine measurement of the hematocrit or blood glucose value is not
necessary in the absence of risk factors. Screening for hyperbilirubinemia should include risk assessment
in all infants with measurement of serum. (See Chapter 88, page 538.)
Ref:- Nelson Textbook of Pediatrics 19th edn
31.ANS.D
EXPLANTION:See Table 88-5, Recommendations for Early Discharge from the Newborn Nursery. (See Chapter 88,
page 538.)
Recommendations for Early Discharge from the Normal Newborn Nursery*
Adapted from American Academy of Pediatrics, American College of Obstetricians and Gynecologists:
Guidelines for perinatal care, ed 5, Elk Grove Village, IL, 2002, American Academy of Pediatrics.
Uncomplicated antepartum, intrapartum, postpartum courses
Vaginal delivery
Singleton at 38-42 wk: appropriate for gestational age
Normal vital signs including respiratory rate <60 breaths/min; axillary temperature 36.1-37°C (97.098.6°F) in open crib
Physical examination reveals no abnormalities requiring continued hospitalization
Urination; stool × 1
At least two uneventful, successful feedings
No excessive bleeding after (2 hr) circumcision
No jaundice within 24 hr of birth; if jaundice, appropriate management and follow-up are in place
Evidence of parental knowledge, ability, and confidence to care for the baby at home:
Feeding
Cord, skin, genital care
Recognition of illness (jaundice, poor feeding, lethargy, fever, etc.)
Infant safety (car seat, supine sleep position, etc.)
Availability of family and physician support (physician follow-up)
Laboratory evaluation:
Syphilis
Hepatitis B surface antigen and vaccination or appointment for vaccination
Coombs’ test and blood type if clinically indicated
Expanded metabolic screening: phenylketonuria, thyroid, galactosemia, sickle cell
Hearing screening
No social risks:
Substance abuse
History of child abuse
Domestic violence
Mental illness
Teen mother
Homelessness
Barriers to follow-up
Source of continuing medal care is identified
Ref:- Nelson Textbook of Pediatrics 19th edn
32.ANS.B
EXPLANTION:See Table 88-7 for recommendations regarding drugs and breast-feeding. Cocaine and lithium are
contraindicated during pregnancy. See Table 88-8 for recommendations regarding infections and breastfeeding. Medical contraindications to breast-feeding in the USA include infection with HIV, human T-cell
leukemia virus types 1 and 2, cytomegalovirus (preterm infants), active tuberculosis (until appropriately
treated ≥ 2 wk and not considered contagious), and hepatitis B virus (until an infant receives hepatitis B
immune globulin and vaccine). (See Chapter 88, pages 539-540.)
Ref:- Nelson Textbook of Pediatrics 19th edn
33.ANS.D
EXPLANTION:See Table 89-1 for Factors Associated with High-Risk Pregnancy. The lowest neonatal mortality rate
occurs in infants of mothers who receive adequate prenatal care and who are 20-30 yr of age.
Pregnancies in both teenagers and women older than 40 yr, particularly primiparous women, are at
increased risk for intrauterine growth restriction, fetal distress, and intrauterine death. A short
interpregnancy interval is associated with increased risk. (See e89-1.)
Ref:- Nelson Textbook of Pediatrics 19th edn
34.ANS.B
EXPLANTION:The use of assisted reproductive technology (in vitro fertilization, intracytoplasmic sperm injection)
increases the risk of perinatal mortality, infant morbidity, prematurity, low and very low birthweight, and
cerebral palsy, largely because of the increase in multiple-fetus pregnancies with such technology; the
risks for birth defects are also increased, in part, because of epigenetic effects on gene expression. (See
e89-1.)
Ref:- Nelson Textbook of Pediatrics 19th edn
35.ANS.A
EXPLANTION:Oligohydramnios is associated with congenital anomalies; intrauterine growth restriction; severe renal,
bladder, or urethral anomalies; and drugs that interfere with fetal urination. Oligohydramnios becomes
most evident after 20 wk of gestation, when fetal urination is the major source of amniotic fluid. Rupture of
the membranes is the most common cause of oligohydramnios and must be ruled out if oligohydramnios
is suspected, especially if a normal-sized bladder is seen on fetal ultrasound evaluation. Oligohydramnios
causes fetal compression abnormalities such as fetal distress, clubfoot, spadelike hands, and a flattened
nasal bridge. The most serious complication of chronic oligohydramnios is pulmonary hypoplasia.
Polyhydramnios is associated with premature labor, abruptio placentae, multiple congenital anomalies,
and fetal neuromuscular dysfunction or obstruction of the gastrointestinal tract that interferes with
reabsorption of the amniotic fluid that is normally swallowed by the fetus. Increased fetal urination or
edema formation is also associated with excessive amniotic fluid volume. (See Table 89-4 and e89-2.)
Ref:- Nelson Textbook of Pediatrics 19th edn
36.ANS.E
EXPLANTION:Maternal immunologic diseases such as idiopathic thrombocytopenic purpura, systemic lupus
erythematosus, myasthenia gravis, and Graves disease, all of which are mediated by immunoglobulin (Ig)
G autoantibodies that can cross the placenta, frequently cause transient illness in the newborn. (See
Chapter 90, page 545, and Table 89-2, e89-2.)
Ref:- Nelson Textbook of Pediatrics 19th edn
37.ANS.A
EXPLANTION:Folic acid supplementation decreases the incidence and recurrence of NTDs. Because the neural tube
closes within the 1st 28 days of conception, periconceptional supplementation is needed for prevention. It
is recommended that women without a prior history of an NTD ingest 400 μg/day of folic acid throughout
their reproductive years. Women with a history of a prior pregnancy complicated by an NTD or a 1stdegree relative with an NTD should have preconceptional counseling and should ingest 4 mg/day of
supplemental folic acid beginning at least 1 mo before conception. Fortification of cereal grain flour with
folic acid is established policy in the USA and some other countries. The optimal concentration of folic
acid in enriched grains is somewhat controversial. The incidence of NTD in the USA and other countries
has decreased significantly since these public health initiatives were implemented. Use of some
antiepileptic drugs (valproate, carbamazepine) during pregnancy is associated with an increased risk of
an NTD. Women taking these medications should ingest 1 to 5 mg of folic acid/day in the preconception
period
Ref:- Nelson Textbook of Pediatrics 19th edn
38.ANS.C
EXPLANTION:Amniocentesis is required to determine the lecithin-sphingomyelin ratio. (See Chapter 90, page 548.)
Ref:- Nelson Textbook of Pediatrics 19th edn
39.ANS.C
EXPLANTION:Cordocentesis, or percutaneous umbilical blood sampling, is used to diagnose fetal hematologic
abnormalities, genetic disorders, infections, and fetal acidosis. Under direct ultrasonographic
visualization, a long needle is passed into the umbilical vein at its entrance to the placenta or fetal
abdominal wall. Umbilical blood may be withdrawn to determine fetal hemoglobin, platelet concentration,
lymphocyte DNA, the presence of infection, or PaO2, pH, PCO2, and lactate levels. (See Chapter 90,
page 549.)
Ref:- Nelson Textbook of Pediatrics 19th edn
40.ANS.B
EXPLANTION:Examination of the fresh placenta, cord, and membranes may alert the physician to a newborn infant at
high risk and may help confirm a diagnosis in a sick infant. Amnion nodosum (granules on the amnion)
and oligohydramnios are associated with pulmonary hypoplasia and renal agenesis, whereas small
whitish nodules on the cord suggest a candidal infection. (See Chapter 90, page 552.)
Ref:- Nelson Textbook of Pediatrics 19th edn
41.ANS.A
EXPLANTION:The occurrence of monovular twins appears to be independent of genetic influence. Polyovular
pregnancies are more frequent beyond the 2nd pregnancy, in older women, and in families with a history
of polyovular twins. (See Chapter 91, page 553.)
Ref:- Nelson Textbook of Pediatrics 19th edn
42.ANS.E
EXPLANTION:In the fetal transfusion syndrome, an artery from one twin acutely or chronically delivers blood that is
drained into the vein of the other. The latter becomes plethoric and large, and the former is anemic and
small. Generally, with chronicity, 5 g/dL hemoglobin and 20% body weight differences can be noted in
this syndrome. (See Table 91-2, Chapter 91, page 554.)
Ref:- Nelson Textbook of Pediatrics 19th edn
43.ANS.B
EXPLANTION:-
VLBW infants weigh <1500 g and are predominantly premature. In the USA in 2008 the VLBW rates were
approximately 1.46% overall, 3.01% among blacks, and 1.18% among whites. The VLBW rate is an
accurate predictor of the infant mortality rate. VLBW infants account for over 50% of neonatal deaths and
50% of handicapped infants; their survival is directly related to birthweight, with approximately 20% of
those between 500 and 600 g and > 90% of those between 1250 and 1500 g surviving. The VLBW rate
has remained unchanged for black Americans but has increased among whites, perhaps because of a
rise in multiple births among whites. Perinatal care has improved the rate of survival of VLBW infants.
When compared with term infants, VLBW neonates have a higher incidence of rehospitalization during
the 1st yr of life for sequelae of prematurity, infections, neurologic complications, and psychosocial
disorders. (See Chapter 91, page 556.)
Ref:- Nelson Textbook of Pediatrics 19th edn
44.ANS.B
EXPLANTION:Neurologic maturity (nerve conduction velocity), in the absence of asphyxia, correlates with gestational
age despite reduced fetal weight. Physical signs may be useful in estimating gestational age at birth.
Commonly used, the Ballard scoring system is accurate to ±2 wk. An infant should be presumed to be at
high risk for mortality or morbidity if a discrepancy exists between the estimation of gestational age by
physical examination, the mother’s estimated date of her last menstrual period, and fetal ultrasonographic
evaluation. (See Figure 91-6, Chapter 91, page 557.)
Ref:- Nelson Textbook of Pediatrics 19th edn
45.ANS.E
EXPLANTION:Hypotension in term infants suggests shock from hypovolemia (hemorrhage, dehydration), the systemic
inflammatory response syndrome (bacterial sepsis, intrauterine infection, necrotizing enterocolitis),
cardiac dysfunction (left heart obstructive lesions—hypoplastic left heart syndrome, myocarditis,
asphyxia-induced myocardial stunning, anomalous coronary artery), pneumothorax, pneumopericardium,
pericardial effusion, or metabolic disorders (hypoglycemia, adrenal insufficiency–salt-losing adrenogenital
syndrome). (See e92-1.)
Ref:- Nelson Textbook of Pediatrics 19th edn
46.ANS.E
EXPLANTION:Convulsions should be distinguished from the jitteriness that may be present in normal newborns, in
infants of diabetic mothers, in those who experienced birth asphyxia or drug withdrawal, and in
polycythemic neonates. An examiner may stop the jitteriness resembling simple tremors by holding the
infant’s extremity; this jitteriness often depends on sensory stimuli and occurs when the infant is active,
and it is not associated with abnormal eye movements. (See e92-1.)
Ref:- Nelson Textbook of Pediatrics 19th edn
47.ANS.D
EXPLANTION:Infants with initial cord or initial blood pH < 6.7 have a 90% risk for death or severe neurodevelopmental
impairment at 18 mo of age. In addition, infants with Apgar scores of 0-3 at 5 min, high base deficit (>2025 mmol/L), decerebrate posture, and lack of spontaneous activity are also at increased risk for death or
impairment. These predictor variables can be combined to determine a score that helps with prognosis.
(See Table 93-5, Chapter 93, page 571.)
Ref:- Nelson Textbook of Pediatrics 19th edn
48.ANS.E
EXPLANTION:If the brain is not growing, the skull will not grow; therefore, a small head reflects a small brain, or
microcephaly. Conversely, a large head may be associated with a large brain, or macrocephaly, which is
most commonly familial but may be due to a disturbance of growth, neurocutaneous disorder (e.g.,
neurofibromatosis), chromosomal defect (e.g., Kleinfelter syndrome), or storage disorder. Alternatively,
the head size may be increased secondary to hydrocephalus or chronic subdural hemorrhages. In the
latter case, the skull tends to assume a square or boxlike shape, because the long-standing presence of
fluid in the subdural space causes enlargement of the middle fossa. (See e584-2.)
Ref:- nelson Textbook of Paed 19th Edition
49.ANS.D
EXPLANTION:Because infants and young children are not able to participate in formal strength testing, they are best
assessed with functional measures. Proximal and distal strength of the upper extremities can be tested
by having the child reach overhead for a toy and by watching him or her manipulate small objects. In
infants < 2 mo old, the physician can also take advantage of the palmar grasp reflex in assessing distal
power and the Moro reflex in assessing proximal power. Infants with decreased strength in the lower
extremities tend to have diminished spontaneous activity in their legs and are unable to support their
body weight when held upright. Older children may have difficulty climbing or descending steps, jumping,
or hopping. They might also use their hands to “climb up” their legs when asked to rise from a prone
position, a maneuver called Gowers sign (Fig. 584-5). (See e584-7.)
Ref:- nelson Textbook of Paed 19th Edition
50.ANS.C
EXPLANTION:The U.S. Public Health Service has recommended that all women of childbearing age and who are
capable of becoming pregnant take 0.4 mg of folic acid daily. If, however, a pregnancy is planned in highrisk women (previously affected child), supplementation should be started with 4 mg of folic acid daily,
beginning 1 mo before the time of the planned conception. The modern diet provides about half the daily
requirement of folic acid. To increase folic acid intake, fortification of flour, pasta, rice, and corn meal with
0.15 mg folic acid per 100 g was mandated in the United States and Canada in 1998. The added folic
acid will be insufficient to maximize the prevention of preventable neural tube defects. Therefore,
informative educational programs and folic acid vitamin supplementation remain essential for women
planning a pregnancy and possibly for all women of childbearing age. In addition, women should also
strive to consume food folate from a varied diet. (See Chapter 585, page 2001.)
Ref:- nelson Textbook of Paed 19th Edition
51.ANS.A
EXPLANTION:Hydrocephalus in association with a type II Chiari malformation develops in at least 80% of patients with
myelomeningocele. Generally, the lower the deformity is in the neuraxis (sacrum), the less likely is the
risk of hydrocephalus. The possibility of hydrocephalus developing should always be considered, no
matter what the spinal level. Ventricular enlargement may be indolent and slow growing or may be rapid
causing a bulging anterior fontanel, dilated scalp veins, setting-sun appearance of the eyes, irritability,
and vomiting associated with an increased head circumference. (See Chapter 585, page 2002.)
Ref:- nelson Textbook of Paed 19th Edition
52.ANS.D
EXPLANTION:Guidelines on the evaluation and treatment of a 1st unprovoked nonfebrile seizure include a careful
history and physical examination and brain imaging by head CT or MRI. Emergency head CT in the child
presenting with a 1st unprovoked nonfebrile seizure is often useful for acute management of the patient.
Laboratory studies are recommended in specific clinical situations: spinal tap is considered in patients
with suspected meningitis or encephalitis, in children without brain swelling or papilledema, and in
children in whom a history of intracranial bleeding is suspected without evidence of such on head CT. In
the 2nd of these, examination of the CSF for xanthochromia is essential. CSF tests can also confirm with
the appropriate clinical setup the diagnosis of glucose transporter deficiency, cerebral folate deficiency,
pyridoxine dependency, pyridoxal dependency, mitochondrial disorders, nonketotic hyperglycemia, and
neurotransmitter deficiencies. Electrocardiography (ECG) to rule out long QT or other cardiac
dysrhythmias and other tests directed at disorders that could mimic seizures may be needed. (See
Chapter 586, page 2019.)
Ref:- nelson Textbook of Paed 19th Edition
53.ANS.B
EXPLANTION:Although about 15% of children with epilepsy have had febrile seizures, only 2-7% of children who
experience febrile seizures proceed to develop epilepsy later in life. There are several predictors of
epilepsy after febrile seizures (Table 586-6). (See Chapter 586, page 2017.)
Ref:- nelson Textbook of Paed 19th Edition
54.ANS.A
EXPLANTION:Partial seizures account for approximately 40% of seizures in children and can be divided into simple
partial seizures, in which consciousness is not impaired and complex partial seizures, in which
consciousness is affected. Simple and complex partial seizures can each occur in isolation, one can
temporally lead to the other (usually simple to complex), or each can progress into secondary generalized
seizures (tonic, clonic, atonic, or most often tonic-clonic). These can take the form of sensory seizures
(auras) or brief motor seizures, the specific nature of which gives clues as to the location of the seizure
focus, as described earlier. Brief motor seizures are the most common and include (focal tonic, clonic or
atonic seizures. Often there is a motor (jacksonian) march from face to arm to leg, adversive head and
eye movements to the contralateral side, or postictal (Todd) paralysis that can last minutes or hours, and
sometimes longer. Unlike tics, motor seizures are not under partial voluntary control; seizures are more
often stereotyped and less likely than tics to manifest different types in a given patient. (See Chapter 586,
page 2021.)
Ref:- nelson Textbook of Paed 19th Edition
55.ANS.C
EXPLANTION:The syndrome of Rasmussen encephalitis is a form of chronic encephalitis that manifests with unilateral
intractable partial seizures, epilepsia partialis continua, and progressive hemiparesis of the affected side,
with progressive atrophy of the contralateral hemisphere. The etiology is usually unknown. Some cases
have been attributed to cytomegalovirus and others to anti-NMDA receptor autoantibodies. (See Chapter
586, page 2023.)
Ref:- nelson Textbook of Paed 19th Edition
56.ANS.B
EXPLANTION:Irreversible hepatic injury and death are particularly feared in young children (<2 yr old) who are on
valproate in combination with other antiepiletic drugs particularly those who might have inborn errors of
metabolism such as acidopathies and mitochondrial disease. Virtually all antiepileptic drugs can produce
sleepiness, ataxia, nystagmus, and slurred speech with toxic levels. (See Chapter 586, page 2032.)
Ref:- nelson Textbook of Paed 19th Edition
57.ANS.D
EXPLANTION:Only one drug should be used initially and the dose increased until complete control is achieved or until
side effects prohibit further increases. Then, and only then, may another drug be added and the initial one
subsequently tapered. Control with 1 drug (monotherapy) should be the goal, although some patients
eventually need to take multiple drugs. When appropriate, levels should also be checked upon addition
(or discontinuation) of a 2nd drug because of potential drug interactions. During follow-up, repeating the
EEG every few months may be helpful to evaluate changes in the predisposition to seizures. (See
Chapter 586, page 2030.)
Ref:- nelson Textbook of Paed 19th Edition
58.ANS.E
EXPLANTION:-
Migraine may have a variety of associated symptoms. In younger children, nausea and vomiting may be
the most obvious symptoms and often outweigh the headache itself. This often leads to the overlap with
several of the gastrointestinal periodic diseases, including recurrent abdominal pain, recurrent vomiting,
cyclic vomiting, and abdominal migraine. The commonality of all of these related conditions is an
increased propensity for the later development of migraine. Often, early childhood recurrent vomiting may
in fact be migraine, but the child is not asked about headache pain or is unable to describe headache
pain. Once this becomes clear, the earlier diagnosis of a gastrointestinal disorder is no longer
appropriate. When headache is present, vomiting raises the concern of a secondary headache,
particularly related to increased intracranial pressure. One of the red flags for this is the daily or near daily
early morning vomiting that increases in intensity as the intracranial pressure continues to build. When
the headache with vomiting episodes are episodic and not worsening, it is more likely that the diagnosis
is migraine. Vomiting and headache due to increased intracranial pressure are frequently present on first
awakening and remit with maintenance of upright posture. In contrast, if a migraine is present on first
awakening (a relatively infrequent occurrence in children), getting up and going about normal, upright
activities usually makes the headache and vomiting worse. (See Chapter 588, page 2041.)
Ref:- nelson Textbook of Paed 19th Edition
59.ANS.D
EXPLANTION:NF-1 is the most prevalent type, with an incidence of 1/3,000, and is diagnosed when any 2 of the
following 7 features are present: (1) Six or more café-au-lait macules over 5 mm in greatest diameter in
prepubertal individuals and over 15 mm in greatest diameter in postpubertal individuals. Café-au-lait
spots are the hallmark of neurofibromatosis and are present in almost 100% of patients. (2) Axillary or
inguinal freckling consisting of multiple hyperpigmented areas 2-3 mm in diameter. Skinfold freckling
usually appears between 3 and 5 yr of age. The frequency of axillary and inguinal freckling has been
reported to be greater than 80% by 6 yr of age. (3) Two or more iris Lisch nodules. Lisch nodules are
hamartomas located within the iris and are best identified by a slit-lamp examination (Fig. 589-2). They
are present in > 74% of patients with NF-1 but are not a component of NF-2. The prevalence of Lisch
nodules increases with age, from only 5% of children < 3 yr of age, to 42% among children 3-4 yr of age,
and virtually 100% of adults ≥ 21 yr of age. (4) Two or more neurofibromas or 1 plexiform neurofibroma.
(5) A distinctive osseous lesion such as sphenoid dysplasia (which may cause pulsating exophthalmos)
or cortical thinning of long bones (e.g., of the tibia) with or without pseudarthrosis. (6) Optic gliomas.
These are present in approximately 15% of patients with NF-1 and represent mostly low-grade
astrocytomas. They are the main CNS tumor with a marked increased frequency in NF-1. (7) A 1stdegree relative with NF-1 whose diagnosis was based on the aforementioned criteria. (See Chapter 589,
page 2047.)
Ref:- nelson Textbook of Paed 19th Edition
60.ANS.A
EXPLANTION:NF-2 is a rare condition, with an incidence of 1/25,000, and may be diagnosed when 1 of the following 4
features is present: (1) bilateral vestibular schwannomas; (2) a parent, sibling, or child with NF-2 and
either unilateral vestibular schwannoma or any 2 of the following: meningioma, schwannoma, glioma,
neurofibroma, or posterior subcapsular lenticular opacities; (3) unilateral vestibular schwannoma and any
2 of the following: meningioma, schwannoma, glioma, neurofibroma, or posterior subcapsular lenticular
opacities; (4) multiple meningiomas (2 or more) and unilateral vestibular schwannoma or any 2 of the
following: schwannoma, glioma, neurofibroma, or cataract. Symptoms of tinnitus, hearing loss, facial
weakness, headache, or unsteadiness may appear during childhood, although signs of a
cerebellopontine angle mass are more commonly present in the 2nd and 3rd decades of life. Although
café-au-lait spots and skin neurofibromas are classic findings in NF-1, they are much less common in NF2. Posterior subcapsular lens opacities are identified in about 50% of patients with NF-2. The NF2 gene
(also known as merlin or schwannomin) is located on chromosome 22q1.11. (See Chapter 589, page
2048.)
Ref:- nelson Textbook of Paed 19th Edition
61.ANS.C
EXPLANTION:Sydenham chorea (SC, St. Vitus dance) is the most common acquired chorea of childhood. It occurs in
10% to 20% of patients with acute rheumatic fever, typically weeks to months after a group A β-hemolytic
streptococcal infection (see Chapter 176.1). Peak incidence is at age 8 to 9 yr, with a female
predominance of 2:1. (See Chapter 590, page 2055.)
Ref:- nelson Textbook of Paed 19th Edition
62.ANS.C
EXPLANTION:More than a dozen loci for genes for torsion dystonia have been identified (DYT1-DYT20). One is the
autosomal dominant disorder dopa-responsive dystonia (DRD, DYT5a), also called Segawa syndrome.
The gene for DRD codes for GTP cyclohydrolase 1, the rate-limiting enzyme for tetrahydrobiopterin
synthesis, which is a cofactor for synthesis of the neurotransmitters dopamine and serotonin. Thus, the
genetic mutation results in dopamine deficiency. The hallmark of the disorder is diurnal variation;
symptoms worsen as the day progresses and may transiently improve with sleep. Early-onset patients,
who tend to present with delayed or abnormal gait due to dystonia of a lower extremity, can easily be
confused with patients with dyskinetic cerebral palsy. It should be noted that in the presence of a
progressive dystonia or diurnal fluctuation or if loss of previously achieved motor skills occurs, a prior
diagnosis of cerebral palsy should be re-examined. DRD responds dramatically to very small daily doses
of levodopa. The responsiveness to levodopa is a sustained benefit, even if the diagnosis is delayed
several years, as long as contractures have not developed. (See Chapter 590, page 2059.)
Ref:- nelson Textbook of Paed 19th Edition
63.ANS.A
EXPLANTION:CLINICAL MANIFESTATIONS — The clinical presentation of myocarditis is variable. Affected patients
can present with a broad clinical spectrum of disease that can be acute, fulminant, or chronic. Some
patients have a coexistent pericarditis.
Patients with viral myocarditis, the most common etiology in children, frequently have a prodrome of
fever, myalgia, and malaise several days prior to the onset of heart failure. Those with myocarditis due to
autoimmune disorders may have symptoms of systemic disease. Infants and children with acute
myocarditis often present with signs and symptoms of heart failure including dyspnea at rest, exercise
intolerance, syncope, tachypnea, tachycardia, and hepatomegaly.However, non-specific signs and
symptoms such as respiratory distress or gastrointestinal symptoms may be the most prominent features
at presentation, leading to an incorrect initial diagnosis in many children.Tachycardia and metabolic
acidosis may be important indicators of the extent of myocardial involvement. Supraventricular and
ventricular arrhythmias and complete heart block may be present.PHYSICAL EXAMINATION — In
symptomatic patients, the physical examination often reveals direct evidence of cardiac dysfunction.
Signs of respiratory distress resulting from left elevated atrial pressures and pulmonary venous
congestion include tachypnea and retractions.
S3 and occasionally S4 gallops may be present and are important signs of impaired ventricular function,
particularly when biventricular acute myocardial involvement results in systemic and pulmonary
congestion.
If the right or left ventricular dilation is severe, auscultation may reveal murmurs of functional mitral or
tricuspid insufficiency.
In acute fulminant myocarditis, signs of low cardiac output may be present, including hypotension, poor
pulses and perfusion, and altered mental status.
A pericardial friction rub and effusion may become evident in some patients with myopericarditis.
DIAGNOSTIC STUDIES — The initial evaluation of the child with suspected myocarditis includes chest
radiograph, electrocardiogram (ECG), and cardiac enzymes. An echocardiogram should be performed to
evaluate ventricular function and the degree of mitral regurgitation.Active myocarditis is defined as "an
inflammatory infiltrate of the myocardium with necrosis and/or degeneration of adjacent myocytes not
typical of the ischemic damage associated with coronary heart disease". The infiltrates usually are
mononuclear, but may be neutrophilic or, occasionally, eosinophilic
Borderline myocarditis is the term used if lymphocytic infiltration is present without myocyte destruction.
Ref:- www.uptodate.com 21.2
64.ANS.C
EXPLANTION:Prostaglandin E1 — In infants with or who have a clinical suspicion for a ductal-dependent congenital
heart defect, prostaglandin E1 ( alprostadil ) should be administered until a definitive diagnosis or
treatment is established.
The initial dose is dependent on the clinical setting as the risk of apnea, one of the major complications of
prostaglandin E1 infusion, is dose dependent.
•
If the ductus is known to be large in a patient with duct-dependent physiology, the initial dose is
0.01 µg/kg per minute. This scenario typically is seen in patients with echocardiographic confirmation of a
large patent ductus arteriosus who are cared for in a tertiary center that provides treatment for neonates
with cyanotic heart disease.
•
If the ductus is restrictive or the status of the ductus is unknown, the initial dose is 0.05 µg/kg per
minute. This is the standard dose used in patients who require transport to a center with expertise in the
care of neonates with cyanotic heart disease.
The dose of prostaglandin can be increased as needed to a maximum dose of 0.1 µg/kg per minute.
Complications of prostaglandin E1 infusion include hypotension, tachycardia, and apnea. As a result, a
separate reliable intravenous catheter must be in place to provide fluids for resuscitation. Intubation
equipment should be immediately available because apnea can occur at any time during infusion.
Deterioration of the clinical status after starting prostaglandin E1 usually indicates the presence of rare
congenital cardiac defects associated with pulmonary venous or left atrial obstruction. These include
obstructive (usually infradiaphragmatic) total anomalous pulmonary venous connection or various
conditions associated with a restrictive atrial septum (eg, hypoplastic left heart syndrome, cor triatriatum,
severe mitral stenosis or atresia, or D-transposition of the great arteries associated with restrictive atrial
shunting). These patients require urgent echocardiography followed by interventional cardiac
catheterization or surgery
Ref:- www.uptodate.com 21.2
65.ANS.D
EXPLANTION:Pulmonary atresia with intact ventricular septum (PA/IVS) is characterized by complete obstruction to
right ventricular outflow with varying degrees of right ventricular and tricuspid valve hypoplasia. Blood is
thus unable to flow from the right ventricle to the pulmonary artery and lungs, and an alternative source of
pulmonary blood flow is required for survival. If untreated, PA/IVS is a uniformly fatal form of structural
cardiac disease. Outcomes of surgical interventions are improving with a five-year survival rate of
approximately 80 percent.
PA/IVS consists of a wide variety of anatomical cardiac defects that are associated with the primary
lesion of pulmonary atresia. In 2000, the Congenital Heart Surgery Nomenclature and Database Project
established a unified reporting system for right ventricular outflow tract (RVOT) obstruction that defined
PA/IVS as a duct-dependent congenital malformation with a spectrum of lesions, which include
pulmonary atresia, variable degrees of hypoplasia of the right ventricle (RV) and tricuspid valve (TV), and
anomalies of the coronary circulation
Because of the diversity of anatomic findings, there is not a standard universal approach for PA/IVS
repair. Interventions (ie, biventricular, 1.5 ventricle, or univentricular repair) are based on the individual
morphologic features of the RV, TV, and coronary artery circulations.
Pulmonary valve atresia — In patients with PA/IVS, the underlying morphology of pulmonary atresia is
either valvar (membranous) or muscular.
Valvar (membranous) pulmonary atresia – In most cases, the pulmonary valve is atretic with a small valve
annulus, and identifiable but fused valve leaflets, which form a thin, intact membrane that causes RVOT
obstruction
In these patients, the RV and infundibulum (funnel-shaped muscular structure that forms the RVOT below
the pulmonary valve, also referred to as the conus arteriosus) are usually well developed.
Muscular pulmonary atresia – In about 20 to 25 percent of patients, there is obliteration of the muscular
infundibulum resulting, in muscular pulmonary atresia
Muscular pulmonary atresia is usually associated with severe right ventricular hypoplasia, increased risk
and severity of coronary artery abnormalities, and poor outcome
Right ventricle — There is great variation in the morphology of the RV, ranging from a severely
hypoplastic small cavity with marked muscular hypertrophy to a large, dilated, thin-walled chamber. This
variation is due to the degree of intracavity muscular overgrowth. Normally, the RV is composed of three
parts (tripartite): an inlet, a body (trabecular), and an outlet. The majority of patients with PA/IVS will have
a well-formed tripartite RV (59 to 83 percent); others will have a bipartite RV due to apical trabecular
overgrowth resulting in a small ventricle composed of an inlet and body, but no discernible outlet (15 to
34 percent); and a small number of patients will have a unipartite RV due to both infundibular and apical
trabecular overgrowth, resulting in a severely hypoplastic RV with only a detectable inlet (2 to 8
percent)Tricuspid valve — The size of the TV is highly variable, and the valve is often small and
dysplastic with stenosis and/or regurgitation. The size of the tricuspid annulus correlates with the size and
morphology of the RV and the presence of coronary abnormalities, and is a factor in deciding on the
choice of intervention (biventricular versus univentricular repair) Coronary arteries — In the normal heart,
the myocardium is predominantly perfused via diastolic flow from the aorta to the coronary arteries. In
patients with PA/IVS, abnormal connections between the RV and the coronary arteries are common due
to the high pressure in the dysplastic right ventricular cavity
Postnatal presentation — Neonates with PA/IVS present with cyanosis due to an obligate right-to-left
shunt at the atrial level
Although infants may have mild tachypnea or hyperpnea, severe respiratory distress is uncommon and
differentiates these patients from those with cyanosis due to a pulmonary cause (eg, neonatal respiratory
distress syndrome). In addition, these infants generally have a benign fetal and birth history.
If untreated, PA/IVS is an almost uniformly fatal disease; approximately 50 percent of children will die
within two weeks of birth and 85 percent by six months
Because PA/IVS is a ductal-dependent lesion, closure of the patent ductus arteriosus (PDA) generally
results in rapid clinical deterioration and life-threatening consequences, including severe metabolic
acidosis and hypoxemia, seizures, cardiogenic shock, cardiac arrest, and death. Rarely, prolonged
survival can occur with pulmonary blood flow maintained by a persistent PDA or systemic artery to
pulmonary artery blood flow via one or more collateral blood vessels
Ref:- www.uptodate.com 21.2
66.ANS.C
EXPLANTION:Tetralogy of Fallot (TOF) includes the following major features -Right ventricular outflow tract obstruction
Ventricular septal defect (VSD)
Deviation of the origin of the aorta to the right so that it overrides the VSD
Concentric right ventricular (RV) hypertrophy
TOF accounts for approximately 10 percent of all cases of congenital heart disease and is one of the
most common cyanotic congenital heart defects
Reparative surgery, which is usually performed electively in the first year of life permits over 85 percent of
children with TOF to survive to adulthood
TOF is also the most common cyanotic malformation to reach adulthood without surgical repair.
The clinical presentation of patients with TOF depends chiefly upon the degree of RV outflow obstruction:
Children with severe obstruction have inadequate pulmonary flow, and typically present in the immediate
newborn period with profound cyanosis
Children with moderate obstruction and balanced pulmonary and systemic flow usually come to clinical
attention during elective evaluation for a murmur
Children with minimal obstruction may present with increased pulmonary blood flow and heart failure
Most children with TOF are symptomatic and cyanotic. In general, the earlier the onset of systemic
hypoxemia, the more likely that severe pulmonary stenosis or atresia is present. Later, dyspnea on
exertion, clubbing, and erythrocytosis are common.Tet spells — Hypercyanotic (or "tet") spells can be
associated with almost total occlusion of the RV outflow tract (RVOT) and profound cyanosis. They
typically occur when an infant becomes agitated, sometimes upon awakening crying from a deep sleep.
Hypercyanotic “tet” spells may require rapid and aggressive step-wise treatment that starts with
placement of the patient in a knee-chest position to increase systemic vascular resistance, which
promotes movement of blood from the right ventricle into the pulmonary circulation rather than the aorta.
This may be followed by more aggressive therapy of intravenous morphine and a fluid bolus. The
mechanism of action of morphine is unclear, while fluids improve RV filling and pulmonary flow. The role
of bicarbonate therapy to treat an associated lactic acidosis is uncertain.Surgical procedures
Blalock-Taussig shunt — Blalock and Taussig first reported successful surgical palliation of TOF in 1945
The procedure, which has since come to bear their names, used a subclavian artery to create an aortato-pulmonary artery connection. The success of this procedure changed the previously dismal outlook for
this disease. The technique has been modified and is now usually performed using a Gortex tube to
create the connection.
Intracardiac repair — Intracardiac repair of TOF was reported by Lillehi in 1954
It consists of patch closure of the ventricular septal defect and enlargement of the RVOT. The latter is
accomplished by relieving pulmonary stenosis, resecting infundibular and subinfundibular muscle bundles
and if necessary by a transannular patch, creating unobstructed flow from the RV into the pulmonary
arteries
Ref:- www.uptodate.com 21.2
67.ANS.D
EXPLANTION:One hormone important in osmoregulation is anti-diuretic hormone, or ADH. It is produced in a part of the
brain called the hypothalamus and then stored and released from an organ called the pituitary gland,
which is positioned just below the hypothalamus. Osmoreceptor cells located in the hypothalamus
monitor the osmolarity of blood, triggering the release of ADH when an increase in the blood osmolarity is
detected.
The hormone is discharged into the bloodstream and reaches the kidney. The main targets of ADH are
the distal convoluted tubules and the collecting ducts of the kidney, where the hormone increases the
permeability of the epithelium to water. This amplifies water reabsorption, which reduces the osmolarity of
the blood.
By negative feedback, the subsiding osmolarity of the blood reduces the activity of osmoreceptor cells in
the hypothalamus, and less ADH is secreted. When very little ADH is released, as would occur after
consumption of a large volume of water has lowered the blood osmolarity, then the kidneys would absorb
little water, resulting in copious excretion of dilute urine. (Voluminous urination is called diuresis, and it is
because ADH opposes this state that it is called antidiuretic hormone.) Alcohol can perturb water balance
by inhibiting the release of ADH, causing excessive loss of water in the urine and dehydrating the bodyperhaps some of the symptoms of a hangover are due to this dehydration. Normally, however, blood
osmolarity, ADH release, and water reabsorption in the kidney are all linked in a feedback loop that
contributes to homeostasis.
Urine osmolarity has no single “normal” value. It can be as low as 50 mOsm/L, as high as 1,200 mOsm/L,
or any value in between. Normal urine osmolarity depends on the person’s plasma osmolarity and water
status. For example, in a person who is dehydrated, the kidneys should concentrate the urine; in this
case, “normal” urine osmolarity is higher than plasma osmolarity (i.e., 300 mOsm/L [hyperosmotic]). In a
person who is drinking water, the kidneys should dilute the urine; in this case, “normal” urine osmolarity is
lower than plasma osmolarity (i.e., 300 mOsm/L [hyposmotic]).
The question about regulation of urine osmolarity is really asking how plasma osmolarity is maintained
constant at a value of 290 mOsm/L. Constant plasma osmolarity is possible because the amount of water
reabsorbed by the collecting ducts varies according to the body’s need, as follows.
In a person who is dehydrated, plasma osmolarity increases. As a result, osmoreceptors in the anterior
hypothalamus are stimulated, triggering the release of antidiuretic hormone (ADH) from the posterior
pituitary. ADH circulates to the kidneys and increases the water permeability of the principal cells of the
late distal tubule and collecting ducts. As a result, water is reabsorbed into the bloodstream, and the urine
is rendered hyperosmotic. The water that is reabsorbed helps to restore plasma osmolarity back to
normal
The proximal tubule reabsorbs solute and water isosmotically. Two later segments of the nephron are
impermeable to water: the thick ascending limb and the early distal tubule (diluting segments). These
segments reabsorb solute, but do not reabsorb water; the water that is “left behind” in the tubular fluid
(free water, or solute-free water) dilutes the tubular fluid with respect to the plasma. In the presence of
ADH, this free water is reabsorbed by the late distal tubule and collecting ducts until the tubular fluid
equilibrates osmotically with the surrounding interstitial fluid. In the collecting ducts, which pass through
the medulla and papilla of the kidney, the tubular fluid equilibrates with the corticopapillary osmotic
gradient. The osmolarity of the final urine becomes equal to the osmolarity at the tip of the papilla (1,200
mOsm/L).
In a person who is drinking water, plasma osmolarity decreases, inhibiting osmoreceptors in the anterior
hypothalamus and inhibiting the release of ADH from the posterior pituitary. When circulating levels of
ADH are low, the principal cells of the late distal tubule and collecting ducts are impermeable to water.
Instead of water being reabsorbed by these segments of the nephron, it is excreted and the urine
becomes hyposmotic. The water that was ingested is excreted in the urine and, as a result, plasma
osmolarity returns to normal
The thick ascending limb and early distal tubule dilute the tubular fluid by reabsorbing solute and leaving
free water behind in the tubular fluid, as discussed earlier. When ADH is suppressed or is absent, this
free water cannot be reabsorbed by the late distal tubule and collecting ducts; as a result, the urine
remains dilute, or hyposmotic, with an osmolarity as low as 50 mOsm/L.
Untreated diabetes mellitus is associated with polyuria and polydipsia. The polyuria occurs as a result of
osmotic diuresis that is caused by unreabsorbed glucose
dDAVP, a vasopressin (ADH) analogue, which acts just like the endogenous ADH that is lacking. Thus,
exogenous dDAVP increased the water permeability of the principal cells of the late distal tubule and
collecting ducts. As a result, water was reabsorbed from these segments, urine became hyperosmotic,
and urine flow rate decreased. As this water was reabsorbed into the bloodstream, plasma osmolarity
was reduced to normal.
Ref:- Physiology: Cases and Problems
by Linda S. Costanzo
4th Edition published by Wolters Kluwer
68.ANS.E
EXPLANTION:Loss of effective circulating blood volume resulting in inadequate organ perfusion
Blood loss exceeds ability to compensate and tissue and organ perfusion decrease. At the tissue level,
hypoperfusion leads to inadequate oxygenation, anaerobic metabolism, cell death.
Compensated shock:
Patient’s physiologic reserve prevents significant alteration in vital signs.
Decompensated shock:
Loss of circulating volume overcomes patient’s physiologic reserve, resulting in signification alteration in
vital signs.
Blood loss estimate:
Total blood volume ~7% of ideal body weight (4,900 mL in 70 kg adult) or 70 mL/kg
Multiply 70 mL/kg times body weight (kg) times percentage loss as determined by class of hemorrhage.
RISK FACTORS
Trauma
Chronic or acute illness
Physical anomalies
Medications (anticoagulants)
Genetics:
Arteriovenous malformations
Bleeding disorders
Other genetic anomalies
ETIOLOGY
Trauma—penetrating and blunt:
Abdominal:
Splenic injury (40% of abdominal hemorrhage)
Liver injury (20% of abdominal hemorrhage)
Chest:
Hemothorax
Aorta or great vessel injury
Pelvis:
Pelvic fracture with vascular injury
Vascular malformations:
May lead to thoracic, intraperitoneal, or retroperitoneal bleeding
Aneurysms:
Abdominal aortic aneurysm most common
Mycotic aneurysm secondary to endocarditis
Aortogastric fistula
Arteriovenous malformations
Abortion: Complete, partial, or inevitable
Ectopic pregnancy
Epistaxis
Fractures (especially pelvis and long bones)
GI bleeding
Hemoptysis
Malignancies
Mallory-Weiss tear
Placenta previa
Postpartum hemorrhage
Retroperitoneal bleeds
Splenic rupture
Vascular injuries
DIAGNOSIS
SIGNS AND SYMPTOMS
Class I hemorrhage: Loss of up to 15% of blood volume (up to 750 mL in 70-kg adult):
HR <100
BP normal
Respiratory rate (RR) 14–20
Increased or normal pulse pressure
Slight anxiety
Class II hemorrhage: Loss of 15–30% of blood volume (750–1,500 mL):
Tachycardia: HR >100
BP normal, or slightly low systolic BP
Tachypnea: RR 20–30
Narrowed pulse pressure
Mild anxiety
Small decrease in urine output
Class III hemorrhage: Loss of 30–40% of blood volume (1,500–2,000 mL):
Marked Tachycardia: HR >120
Hypotension: BP decreased
Marked Tachypnea: RR 30–40
Marked narrowing of pulse pressure
Significant change in mental status: Confusion
Delayed capillary refill
Marked decrease in urine output
Class IV hemorrhage: Loss of >40% of blood volume (>2,000 mL):
HR >140
Marked hypotension: BP decreased
RR >35
Very narrow pulse pressure
Depressed mental status: Confusion, lethargy, loss of consciousness
Negligible urine output
Cold and pale skin
Pediatric Considerations
Children often have greater physiologic reserve than adults and can preserve normal vital signs longer.
Systemic responses to blood loss in the pediatric patient include:
Volume loss <25%: Weak, thready pulse and tachycardia; lethargy, irritability, and confusion; cool,
clammy skin; decreased urine output/increased urine specific gravity
Volume loss 25–40%: Tachycardia; marked change in consciousness; dulled response to pain; cyanotic,
cold extremities with decreased capillary refill; minimal urine output
Volume loss >40%: Hypotension, tachycardia, or bradycardia; comatose; pale, cold skin; no urine output
Pregnancy Considerations
Physiologic maternal hypervolemia requires greater blood loss to manifest maternal perfusion
abnormalities which may result in decreased fetal perfusion.
Geriatric Considerations
Underlying disease and medications may alter responses to hemorrhage and blood loss.
History
Thorough health and past medical history:
Underlying disease, risk factors, age
Medications
Trauma
Physical Exam
Complete physical exam to determine shock class category and assess for hemorrhage source
Vital signs including HR, RR, BP
Temperature
Mental status (anxiety, confusion, lethargy, obtundation, coma)
Capillary refill and skin perfusion
Pulse pressure
Abdominal examination
Pelvic/rectal exam for bleeding as indicated
ESSENTIAL WORKUP
Thorough history and physical examination
IV access for resuscitation
Hemoglobin and hematocrit levels
Blood type and cross-match
DIAGNOSTIC TESTS & INTERPRETATION
Lab
CBC
Blood type and cross-match
Coagulation studies:
PT, PTT
International normalized ratio
Other measures of tissue hypoperfusion:
Arterial blood gas
Base deficit
Serum lactate level
Serum electrolytes
Pregnancy test/b-HCG
Imaging
CXR:
Hemothorax:
Blunt chest injuries
Thoracic arteriovenous malformation
Pelvic radiograph for possible occult fracture
Focused Abdominal Sonography for Trauma (FAST exam):
Abdominal trauma
Possible abdominal aortic aneurysm
Nontraumatic intraperitoneal hemorrhage
Fluid in Morrison’s pouch implies significant hemorrhage or ascites.
Negative findings do not rule out intraperitoneal hemorrhage.
Endovaginal US:
Positive pregnancy test
Fluid in the cul-de-sac
Ectopic pregnancy
Abdominal CT scan (once patient stable):
Detects both intraperitoneal and retroperitoneal hemorrhage
Abdominal aortic aneurysm
Diagnostic Procedures/Surgery
Insert Foley catheter:
Monitor urine output.
Nasogastric tube:
For undifferentiated hypovolemic shock to rule out GI hemorrhage
Diagnostic peritoneal lavage:
For unstable trauma patients when US fails to show intraperitoneal hemorrhage
Endoscopy:
In the setting of upper or lower GI bleeding
Angiography:
Pelvic fracture
Retroperitoneal hemorrhage
Lower GI bleeding
Embolization therapy for bleeding from arterial sources can be performed.
DIFFERENTIAL DIAGNOSIS
Cardiac tamponade
Tension pneumothorax
Cardiogenic shock
Sepsis
Adrenal insufficiency
Neurogenic shock
TREATMENT
The goal is to restore organ perfusion with fluids and to control source of hemorrhage. Controversy exists
as to whether aggressive fluid resuscitation can increase bleeding risk.
Approach is to balance goal of organ perfusion and risks of rebleeding and may vary with type of patient:
In blunt trauma patients, maintenance of BP may take precedence to reduce risk of traumatic brain injury
In penetrating trauma patients with hemorrhage, delayed aggressive fluid resuscitation until definitive
control may reduce bleeding risk
PRE-HOSPITAL
Rapid assessment and transport to appropriate care center
IV access and fluid resuscitation are standard, though delaying aggressive fluid resuscitation may be
warranted in cases of penetrating trauma with hemorrhage.
INITIAL STABILIZATION/THERAPY
Airway and breathing:
Intubation as indicated by patient’s respiratory and mental status
100% oxygen via face mask should be administered.
Circulation:
2 large-bore peripheral IV lines (16-gauge or larger)
Central venous line or venous cutdown (saphenous) may be necessary.
Intraosseous route may be considered
Aggressive crystalloid resuscitation
1-to-1 rule: For 1 unit volume of blood loss, give 3 volumes of crystalloid.
Early transfusion class III or IV hemorrhage:
Type-specific and cross-matched blood is preferred when time permits, often 1 hr.
Type-specific blood is usually available within 10–15 min.
Type O blood can be used in immediate, life-threatening situations (type O Rh-negative blood only for
women of child-bearing age).
ED TREATMENT/PROCEDURES
Place patient on continuous monitor.
NPO status, strict bed rest
Control hemorrhage (direct pressure, pelvic fixation/stabilization, etc.).
Central venous access may be indicated for CVP monitoring, but placement of such lines should not
interfere with resuscitation measures.
Continually reassess patient for clinical response/deterioration:
Vital signs, mental status, and urine output.
Follow serial blood gas, lactate level, and hemoglobin/hematocrit measurements.
Maintain urine output at 50 mL/hr.
Response to initial fluid resuscitation is the key to determining subsequent therapy:
Rapid response to fluid indicates minimal (<20%) blood loss.
Transient response to volume resuscitation indicates ongoing hemorrhage or inadequate resuscitation;
continue fluid and blood administration and rapidly obtain necessary studies and consultations.
Minimal or no response to volume resuscitation indicates ongoing severe blood loss; immediate
angiography or surgical intervention is warranted.
Use fluids warmed (~39°C [102.2°F]) by microwave ovens, fluid warmers.
Transfuse platelets and coagulation factors as indicated.
Consider autotransfusion devices with tube thoracostomy treatment and decompression of large
hemothoraces.
Specialty consultation and additional procedures (surgery) as indicated by cause and source of
hemorrhagic shock
Pediatric Considerations
Access may be obtained by intraosseous route after 1 or 2 unsuccessful attempts at peripheral access.
Maintain urine output at 1 mL/kg/hr for children and 2 mL/kg/hr for infants.
Pregnancy Considerations
Optimizing perfusion and treatment of the mother is treatment of choice for fetus.
MEDICATION
First Line
IV Fluids:
Crystalloids: NS or lactated Ringer
Adults: 1- to 2-L bolus
Pediatric: 20 mL/kg bolus:
Reassess for clinical response/deterioration.
Blood products: Cross-matched, type-specific, O-positive, or O-negative:
O-negative should be reserved for women of child-bearing age
Adult: Initiate with 4–6 units of packed RBCs.
Pediatric: 10 mL/kg of packed RBCs
Second Line
Other blood products:
Platelets
Coagulation factors, such as fresh frozen plasma and cryoprecipitate
Individual coagulation factors (factor VII), Antifibrinolytic agents, Hemoglobin-based oxygen carriers,
Perfluorocarbons:
Under study, but of no proven benefit
Ref:- Rosen & Barkin’s 5-Minute Emergency Medicine Consult
by Jeffrey J. Schaider, Roger M. Barkin, Stephen R. Hayden, Richard E. Wolfe, Adam Z. Barkin, Philip
Shayne, and Peter Rosen
4th edition published by Wolters Kluwer
69.ANS.B
EXPLANTION:Erythropoietin (EPO) is an approximately 34-kDa glycoprotein made mainly in the kidney by fibroblast-like
type I interstitial cells in the cortex and outer medulla
EPO is a growth factor related to other cytokines, and it acts through a tyrosine kinase-associated
receptor
to stimulate the production of proerythroblasts in the bone marrow, as well as the development of red
cells from their progenitor cells. In fetal life, the liver, rather than the kidney, produces EPO. Even in the
adult, Kupffer cells in the liver produce some EPO.
Four lines of evidence indicate that the stimulus for EPO synthesis is a decrease in local PO2. First, EPO
synthesis increases with anemia. Second, EPO production increases with lowered renal blood flow. Third,
EPO synthesis increases with central hypoxia (i.e., low arterial Po 2), such as may occur with pulmonary
disease or with living at high altitude
In all three of these cases, local PO2 falls as tissues respond to a fall in O2 delivery by extracting more
O2 from each volume of blood that passes through the kidney. Finally, EPO production increases when
Hb has a high O2 affinity. Here, the renal cells must lower PO2 substantially before O2 dissociates from
Hb. Thus, mutant hemoglobins with high O2 affinities, stored blood (which has low 2,3-DPG levels), and
alkaline blood all lead to increased EPO production.
Besides local hypoxia, several hormones and other agents stimulate EPO production. For example,
prostaglandin E2 and adenosine appear to stimulate EPO synthesis by increasing intracellular levels of
cyclic adenosine monophosphate. Norepinephrine and thyroid hormone also stimulate EPO release.
Finally, androgens stimulate, whereas estrogens inhibit, EPO synthesis, explaining at least in part why
women in their childbearing years have lower hematocrit levels than do men.
Because the kidneys are the major source of EPO, renal failure leads to reduced EPO levels and anemia.
The development of recombinant EPO has had a major impact in ameliorating the anemia of chronic
renal failure.
Ref:- Medical Physiology
by Walter F. Boron and Emile L. Boulpaep
2nd edition published by Elsevier
70.ANS.C
EXPLANTION:Carotid sinus, not body, contains baroreceptors
The carotid sinus reflex arc is composed of an afferent limb arising from mechanoreceptors in the internal
carotid artery and terminating in midbrain centers in the vagal nucleus and the vasomotor center. The
efferent limb innervates the sinus and atrioventricular nodes via the vagus nerve and the parasympathetic
ganglia and also inhibits sympathetic nervous tone to the heart and blood vessels. The site of the
abnormality that causes the hypersensitive response has not been established.
DIAGNOSIS — The initial evaluation of syncope should include history, physical examination, and an
electrocardiogram (ECG).
A history of syncope following accidental manipulation of the carotid sinuses should be sought although it
is rarely present. Absence of such a history does not exclude carotid sinus syndrome.
Ref:- www.uptodate.com
71.ANS.A
EXPLANTION:Vagal efferent fibers originate in the dorsal motor nucleus of the vagus and the nucleus ambiguous.
These innervate the heart, vocal cords, and other laryngeal and pharyngeal muscles, and also provide
parasympathetic input to the gastrointestinal viscera
Because the right vagus nerve provides more innervation to the cardiac atria than the left vagus nerve,
electrical stimulation of the left vagus nerve is generally used in clinical practice to avoid adverse cardiac
effects.However, right-sided VNS has been reported safe in at least one case series, and in animal
studies it appears equally effective against seizures as left-sided stimulation .The vagus nerve stimulator
(VNS) is a battery-powered device similar to a cardiac pacemaker. Stimulating leads are surgically placed
around the left vagus nerve in the carotid sheath and are connected to an infraclavicular subcutaneous
programmable pacemaker
A noninvasive, transcutaneous vagal nerve stimulator that targets the auricular branch of the vagus nerve
of the left tragus has been developed and appears promising in a pilot study
Ref:- www.uptodate.com
72.ANS.B
EXPLANTION:The hydrostatic pressure in the capillaries tends to force fluid and its dissolved substances through the
capillary pores into the interstitial spaces. Conversely, osmotic pressure caused by the plasma proteins
(called colloid osmotic pressure) tends to cause fluid movement by osmosis from the interstitial spaces
into the blood. This osmotic pressure exerted by the plasma proteins normally prevents significant loss of
fluid volume from the blood into the interstitial spaces.
Also important is the lymphatic system, which returns to the circulation the small amounts of excess
protein and fluid that leak from the blood into the interstitial spaces. In the remainder of this chapter, we
discuss the mechanisms that control capillary filtration and lymph flow function together to regulate the
respective volumes of the plasma and the interstitial fluid.
four primary forces that determine whether fluid will move out of the blood into the interstitial fluid or in
the opposite direction. These forces, called “Starling forces” in honor of the physiologist who first
demonstrated their importance, are:
The capillary pressure (Pc), which tends to force fluid outward through the capillary membrane.
The interstitial fluid pressure (Pif), which tends to force fluid inward through the capillary membrane when
Pif is positive but outward when Pif is negative.
The capillary plasma colloid osmotic pressure (Πp), which tends to cause osmosis of fluid inward through
the capillary membrane.
The interstitial fluid colloid osmotic pressure (Πif), which tends to cause osmosis of fluid outward through
the capillary membrane.
If the sum of these forces—the net filtration pressure—is positive, there will be a net fluid filtration across
the capillaries. If the sum of the Starling forces is negative, there will be a net fluid absorption from the
interstitial spaces into the capillaries.
net filtration pressure (NFP)
NFP is slightly positive under normal conditions, resulting in a net filtration of fluid across the capillaries
into the interstitial space in most organs. The rate of fluid filtration in a tissue is also determined by the
number and size of the pores in each capillary, as well as the number of capillaries in which blood is
flowing. These factors are usually expressed together as the capillary filtration coefficient (Kf). The Kf is
therefore a measure of the capacity of the capillary membranes to filter water for a given NFP and is
usually expressed as ml/min per mm Hg net filtration pressure.
The arterial and venous lines meet each other at a value of 17 mm Hg. Therefore, the capillary pressure
must have remained at this same level of 17 mm Hg throughout these maneuvers; otherwise, either
filtration or absorption of fluid through the capillary walls would have occurred. Thus, in a roundabout
way, the “functional” capillary pressure in this tissue is measured to be about 17 mm Hg.
It is clear that the isogravimetric method, which determines the capillary pressure that exactly balances all
the forces tending to move fluid into or out of the capillaries, gives a lower value compared with the
capillary pressure measured directly with a micropipette. A major reason for this is that capillary fluid
filtration is not exactly balanced with fluid reabsorption in most tissues. The fluid that is filtered in excess
of what is reabsorbed is carried away by lymph vessels in most tissues. In the glomerular capillaries of
the kidneys, a very large amount of fluid, approximately 125 ml/min, is continuously filtered.
Ref:- Guyton and Hall Textbook of Medical Physiology
by John E. Hall
12th edition published by Elsevie
73.ANS.E
EXPLANTION:Mammalian Diving Reflex
A certain degree of protection against submersion hypoxia has been proposed to occur in the form of a
response similar to the diving reflex observed in seals and other air-breathing diving mammals. The ability
of these animals to remain submerged for periods up to 20 minutes is due to a remarkable redistribution
of blood flow that occurs after diving underwater. While heart, brain, and lungs remain adequately
perfused, blood flow to tissues resistant to hypoxia (i.e., gastrointestinal tract, skin, and muscle) is
markedly reduced. Significant bradycardia occurs with a reduction in cardiac output. Such a response,
albeit quantitatively less, is also observed in humans after total body immersion. The mammalian diving
reflex acts as an oxygen-conserving adaptation in response to submersion. It has been proposed that this
reflex is most active in infancy and is potentiated by fear and low water temperature. A combination of
marked bradycardia and impalpable pulses resulting from vasoconstriction may make the victim appear
dead at a time when mouth-to-mouth resuscitation could be life-saving. Clinical studies involving children
and adults have failed to demonstrate an efficient diving reflex in response to cold-water submersion.
Young children had a significantly decreased breath-hold duration and consequently a weaker dive
response compared with older children and adults. The role of the mammalian diving reflex in enabling
children to withstand prolonged cold-water submersion thus remains controversial.
Ref:- Pediatric Critical Care
by Bradley P. Fuhrman, Jerry J. Zimmerman, Joseph A. Carcillo, Robert S.B. Clark, Monica Relvas,
Alexandre T. Rotta, Ann E. Thompson, and Joseph D. Tobias
4th edition published by Elsevier
74.ANS.A
EXPLANTION:Local control of blood flow ensures that only working muscles with increased metabolic demands receive
increased blood and oxygen delivery. If the legs alone are active, leg muscle blood flow should increase,
whereas arm muscle blood flow remains unchanged or is reduced. At rest, skeletal muscle receives only
a small fraction of the cardiac output. In dynamic exercise, both total cardiac output and relative and
absolute output directed to working skeletal muscle increase dramatically
Cardiovascular control during exercise involves systemic regulation (cardiovascular centers in the brain,
with their autonomic nervous output to the heart and systemic resistance vessels) in tandem with local
control. For millennia, our ancestors successfully used exercise both to escape being eaten and to catch
food; therefore, it is no surprise that cardiovascular control in exercise is complex and unique. It is as if a
brain software program titled “Exercise” were inserted into the brain as work begins. Initially, the motor
cortex is activated; the total neural activity is roughly proportional to the muscle mass and its work
intensity. This neural activity communicates with the cardiovascular control centers, reducing vagal tone
on the heart (which raises heart rate) and resetting the arterial baroreceptors to a higher level. As work
rate is increased further, lactic acid is formed in actively contracting muscles, which stimulates muscle
afferent nerves to send information to the cardiovascular center that increases sympathetic outflow to the
heart and systemic resistance vessels. However, despite this muscle chemoreflex activity, within these
same working muscles, low PO2, increased nitric oxide, vasodilator prostanoids, and associated local
vasoactive factors dilate arterioles despite rising sympathetic vasoconstrictor tone. Increased sympathetic
drive does elevate heart rate and cardiac contractility, resulting in increased cardiac output; local factors
in the coronary vessels mediate coronary vasodilation. Increased sympathetic vasoconstrictor tone in the
renal and splanchnic vascular beds and in inactive muscle reduces blood flow to these tissues. Blood
flow to these inactive regions can fall 75% if exercise is strenuous. Increased vascular resistance and
decreased blood volume in these tissues help maintain blood pressure during dynamic exercise. In
contrast to blood flow reductions in the viscera and in inactive muscle, the brain autoregulates blood flow
at constant levels independent of exercise. The skin remains vasoconstricted only if thermoregulatory
demands are absent.
Dynamic exercise, at its most intense level, forces the body to choose between maximum muscle
vascular dilation and defense of blood pressure. Blood pressure is, in fact, maintained. During strenuous
exercise, sympathetic drive can begin to limit vasodilation in active muscle. When exercise is prolonged in
the heat, increased skin blood flow and sweating-induced reduction in plasma volume both contribute to
the risk of hyperthermia and hypotension (heat exhaustion). Although chronic exercise provides some
heat acclimatization, even highly trained athletes are at risk of hyperthermia and hypotension if work is
prolonged and water is withheld in demanding environmental conditions.
Oddly, for dynamic exercise, the elevation of blood pressure is most pronounced when a medium muscle
mass is working. This response results from the combination of a small, dilated active muscle mass with
powerful central sympathetic vasoconstrictor drive. Typically, the arms exemplify a medium muscle mass;
shoveling snow is a good example of primarily arm and heavily isometric exercise. Shoveling snow can
be risky for people in danger of stroke or heart attack because it substantially raises systemic arterial
pressure. The elevated pressure places already-compromised cerebral arteries at risk and presents an
ischemic or failing heart with a greatly increased afterload
In acute dynamic exercise, vagal withdrawal and increases in sympathetic outflow elevate heart rate and
contractility in proportion to exercise intensity
Factors enhancing venous return also aid cardiac output in dynamic exercise. These include the “muscle
pump,” which compresses veins as muscles rhythmically contract, and the “respiratory pump,” which
increases breath-by-breath oscillations in intrathoracic pressure
Maximal dynamic exercise yields a maximal heart rate: Further vagal blockade (e.g., via pharmacologic
means) cannot elevate heart rate further. Stroke volume, in contrast, reaches a plateau in moderate work
and is unchanged as exercise reaches its maximum intensity
This plateau occurs in the face of ever-shortening ventricular filling time, testimony to the increasing
effectiveness of the mechanisms that enhance venous return and those that promote cardiac contractility.
Sympathetic stimulation decreases left ventricular volume and pressure at the onset of cardiac relaxation
(as a result of increased ejection fraction), leading to more rapid ventricular filling early in diastole. This
helps maintain stroke volume as diastole shortens. Even in untrained people, the ejection fraction (stroke
volume as a percentage of end-diastolic volume) reaches 80% in strenuous exercise.
The larger left ventricular volume in people chronically active in dynamic exercise leads directly to larger
resting and exercise stroke volume. A simultaneous increase in vagal tone and decrease in β-adrenergic
sensitivity enhance the resting and exercise bradycardia seen after training, so that in effect the trained
heart operates further up the ascending limb of its length–tension relationship. Nevertheless, resting
bradycardia is a poor indicator of endurance fitness because genetic factors explain a much larger
proportion of the individual variation in resting heart rate than does training.
Chronic, dynamic exercise is associated with increased circulating levels of high-density lipoproteins
(HDLs) and reduced low-density lipoproteins (LDLs), such that the ratio of HDL to total cholesterol is
increased. These changes in cholesterol fractions occur at any age if exercise is regular. Weight loss and
increased insulin sensitivity, which typically accompany increased chronic physical activity in sedentary
people, undoubtedly contribute to these changes in plasma lipoproteins. Nonetheless, in people with
lipoprotein levels that place them at high risk for coronary heart disease, exercise appears to be an
essential adjunct to dietary restriction and weight loss for lowering LDL cholesterol levels. Because
exercise acutely and chronically enhances fat metabolism and cellular metabolic capacities for βoxidation of free fatty acids, it is not surprising that regular activity increases both muscle and adipose
tissue lipoprotein lipase activity. Changes in lipoprotein lipase activity, in concert with increased lecithin–
cholesterol acyltransferase activity and apo A-I synthesis, enhance the levels of circulating HDLs.
Evidence from interventional studies repeatedly demonstrates the effectiveness of proper diet and
exercise in the prevention of metabolic syndrome and type 2 diabetes in a broad range of subjects.
Ref:- Medical Physiology: Principles of Clinical Medicine
by Rodney Rhoades and David R. Bell
4th edition published by Wolters Kluwer
75.ANS.B
EXPLANTION:Response to the Valsalva Maneuver
The Valsalva maneuver consists of a forced expiration against a closed glottis or mouthpiece with a
calibrated air-leak. Characteristic changes in heart rate and blood pressure occur during and after
performance of the maneuver and relate to changes in cardiac vagal efferent and sympathetic vasomotor
activity as a result of stimulation of carotid sinus and aortic arch baroreceptors and other intrathoracic
stretch receptors. For clinical purposes, it may be adequate simply to record the heart rate responses with
a heart rate monitor or an ECG. For more detailed information of the changes in heart rate and blood
pressure, however, it is necessary to use a servo-plethysmomanometer device (Finapres) or record from
an intra-arterial needle
The test is performed with the subject in a semirecumbent position with a rubber clip over the nose. The
subject is then required to blow into a mouthpiece (with a calibrated air-leak) connected to a mercury
manometer and to maintain an expiratory pressure of 40 mmHg for 15 seconds while the heart rate is
recorded. The normal response has four stages. Stages 1 and 3 are artifactual and are characterized by
an increase (stage 1) or a decline (stage 3) in blood pressure because of the increase or decrease,
respectively, in intrathoracic pressure at the beginning and end of the maneuver. In stage 2, the reduction
in venous return leads to a progressive decline in systolic, diastolic, and pulse pressure, accompanied by
a tachycardia resulting from increased cardiac sympathetic activity. The decline in blood pressure is
arrested after about 5 to 8 seconds by a reflex vasoconstriction. With release of the blow at the end of the
maneuver, the artifactual decline in mean blood pressure as a result of the release of intrathoracic
pressure (stage 3) is followed by a rebound in blood pressure to above resting levels because of the
persisting peripheral vasoconstriction and the increased cardiac output that follows the increased venous
return to the heart. This overshoot in the blood pressure, which varies in extent depending upon age, is
accompanied by a compensatory, vagally induced bradycardia.
Abnormalities of the Valsalva response in dysautonomic patients may take the form of a loss of the
tachycardia in stage 2 or of the bradycardia in stage 4; or a lower heart rate in stage 2 than in stage 4.
Other abnormalities include a decline in mean blood pressure in stage 2 to less than 50 percent of the
resting mean pressure or loss of the overshoot in systolic pressure in stage 4. With isolated impairment of
efferent sympathetic vasoconstriction, the blood pressure fails to show an overshoot in stage 4, and
consequently there is no compensatory bradycardia despite otherwise intact baroreflex pathways.
When the response to the Valsalva maneuver is studied simply by recording the ECG, the Valsalva ratio
is calculated by dividing the longest interbeat interval occurring after the maneuver by the shortest
interbeat interval during it. The highest ratio from three successive attempts, each separated by 2
minutes, is recorded. The ratio reflects both parasympathetic (vagal) and sympathetic function. The
normal range of values depends on age, the duration of the forced expiration, and the extent to which
intrathoracic pressure is increased. A value of 1.1 or less is regarded commonly as abnormal and a value
greater than 1.2 as normal, but in normal subjects younger than 40 years the ratio usually exceeds 1.4.
Low values sometimes are recorded in patients with heart and lung disease. The Valsalva ratio is
sometimes normal when the blood pressure response is abnormal.
Blood Pressure Variation
Change in Posture
The effect of postural change on blood pressure is important. The blood pressure is recorded with the
subject supine and at rest for at least 10 minutes. The patient then stands with the arm held horizontally
to avoid the hydrostatic effect of the column of blood in the dependent arm leading to a falsely elevated
blood pressure. The blood pressure is taken immediately on standing and then at 1-minute intervals for 5
minutes. In normal subjects a slight decline in systolic pressure may occur, and diastolic pressure
typically increases slightly. A decline that is greater than 20 mmHg in systolic pressure or 10 mmHg in
diastolic pressure within 3 minutes of gaining an upright posture generally is regarded as abnormal.13
A tilt-table can also be used to evaluate postural changes in blood pressure, but the response may differ
from that obtained by standing because there is less enhancement of the venous return to the heart by
contraction of leg and abdominal muscles, and thus greater peripheral pooling of blood. After the patient
has been supine for 10 minutes, the table is tilted to an angle of at least 60 degrees, and the patient
remains in this upright position for 10 minutes. Blood pressure can be measured with a
sphygmomanometer or by continuous recordings from digital arteries using the Finapres device
mentioned earlier, which accurately records pressure changes. Prolonged testing (for up to 60 minutes)
on a tilt-table at an angle of at least 60 degrees is being used increasingly to evaluate patients with
suspected syncope.
The measurement of blood pressure in the sitting and standing positions actually has low diagnostic
accuracy, and the more time-consuming method of head-up tilt-testing is preferred.14 Many studies have
shown that blood pressure changes with posture are unrelated to age, but there is no agreement on this
point and asymptomatic postural hypotension is common in elderly patients. Postural hypotension occurs
in a variety of medical contexts including cardiac disease, endocrine disorders, and hypovolemia, and in
patients taking medications such as antihypertensive drugs, dopaminergic medication, and CNS
depressants. Thus, detailed investigation may be necessary to clarify the cause of the postural
hypotension, including other tests of autonomic function such as the response to the Valsalva maneuver.
The measurement of blood pressure in the sitting and standing positions actually has low diagnostic
accuracy, and the more time-consuming method of head-up tilt-testing is preferred.14 Many studies have
shown that blood pressure changes with posture are unrelated to age, but there is no agreement on this
point and asymptomatic postural hypotension is common in elderly patients. Postural hypotension occurs
in a variety of medical contexts including cardiac disease, endocrine disorders, and hypovolemia, and in
patients taking medications such as antihypertensive drugs, dopaminergic medication, and CNS
depressants. Thus, detailed investigation may be necessary to clarify the cause of the postural
hypotension, including other tests of autonomic function such as the response to the Valsalva maneuver.
Ref:- www.uptodate.com
76.ANS.A
EXPLANTION:Tet spells — Hypercyanotic (or "tet") spells can be associated with almost total occlusion of the RV
outflow tract (RVOT) and profound cyanosis. They typically occur when an infant becomes agitated,
sometimes upon awakening crying from a deep sleep.
Hypercyanotic “tet” spells may require rapid and aggressive step-wise treatment that starts with
placement of the patient in a knee-chest position to increase systemic vascular resistance, which
promotes movement of blood from the right ventricle into the pulmonary circulation rather than the aorta.
This may be followed by more aggressive therapy of intravenous morphine and a fluid bolus. The
mechanism of action of morphine is unclear, while fluids improve RV filling and pulmonary flow. The role
of bicarbonate therapy to treat an associated lactic acidosis is uncertain.
If the above measures fail, intravenous beta blockers (eg, propranolol or esmolol ) can be administered.
The presumed mechanism of benefit is relaxation of the right ventricular outflow tract (RVOT) with
improved pulmonary blood flow. If this is insufficient, systemic afterload can be increased with
intravenous phenylephrine , which, as with assumption of the knee-chest position, promotes right
ventricular flow into the pulmonary circulation rather than the aorta.
Emergent complete surgical repair or an emergency aorticopulmonary shunt (ie, Blalock-Taussig shunt) is
necessary if all of these measures fail.
Ref:- www.uptodate.com
77.ANS.E
EXPLANTION:In tricuspid atresia, there is a developmental failure of the tricuspid valve, isolating the RA from the RV.
There are three types of tricuspid atresia, based on the relationship of the great vessels to the ventricles,
otherwise known as ventriculoarterial concordance. Type I, the most common (60–80%), consists of
normal ventriculoarterial concordance. Type II (15–25%) consists of d-transposition, and Type III (3%)
consists of l-transposition. In most cases of tricuspid atresia, the RV is hypoplastic, an ASD is present,
and pulmonary blood flow is restricted 2° pulmonary stenosis or atresia. Together, these malformations
lead to R → L shunting and varying degrees of cyanosis. Those patients with unobstructed pulmonary
blood flow develop pulmonary overcirculation and CHF. Consequently, the initial palliative surgical
management of this defect depends on the magnitude of pulmonary blood flow; the initial procedure may
be either a modified Blalock-Taussig systemic-to-PA shunt or a PA band. The subsequent definitive
surgical management consists of a bidirectional Glenn shunt and a modified Fontan procedure. Patients
undergo these operations sequentially or, in rare cases, directly to the definitive Fontan operation.
The systemic-to-PA shunt, developed by Blalock and Taussig in 1944, was the first palliative treatment
for this condition. Later, other shunts were introduced by Potts (descending aorta-to-left PA) and
Waterston (ascending aorta-to-right PA). In 1958, Glenn described a shunt from the SVC to the right PA
applied specifically to patients with tricuspid atresia. A modification of this shunt to a bidirectional
cavopulmonary anastomosis was performed clinically by Azzollina in 1974 and has since gained
widespread acceptance. In 1971, Fontan proposed a surgical repair for tricuspid atresia based on
separation of the right and left circulations. Subsequent modifications to Fontan’s original operation were
designed to bypass the RV and direct systemic venous return to the pulmonary circulation. The most
recent modifications divert vena caval blood directly to the PA—now referred to as a total cavopulmonary
connection (modified Fontan). In 1988, Laks suggested leaving a small ASD between the right and left
circulations, creating a R → L shunt for the purposes of augmenting systemic CO while still maintaining
adequate oxygenation.
Modified Blalock-Taussig (B-T) shunt:
In neonates with tricuspid atresia or other single ventricle variants with low pulmonary blood flow, a
modified B-T shunt is the procedure of choice. The preferred approach is through a midsternotomy. The
right PA and the right innominate and subclavian arteries are mobilized. The patient is heparinized and
clamps are applied on the right PA and the innominate/subclavian arteries. Arteriotomies are performed
and a Gore-Tex tube graft is interposed and anastomosed to the right PA and the subclavian/innominate
arteries. The size of shunt (3–4 mm) is dictated by patient size and arterial anatomy. Alternatively, the
procedure can be performed via right thoracotomy or through a left thoracotomy if the morphology
dictates a left-sided shunt. A midline approach can be used for any variation of the shunt and also gives
the option of using CPB in case of patient instability.
Pulmonary artery banding:
In patients with tricuspid atresia or other variants of single ventricle and increased pulmonary blood flow,
PA banding is performed to protect the pulmonary vascular bed, prevent pulmonary HTN, and prevent
CHF. A midline sternotomy is the preferred approach. The main PA is exposed and a 2–3 mm wide strip
of Silastic band is placed around the main PA and tightened to adjust the pulmonary blood flow. The goal
is a SaO2 of ∼80–85%.
Bidirectional Glenn shunt:
A standard median sternotomy approach is used. If concomitant intracardiac repairs are not anticipated,
the bidirectional Glenn shunt may be performed without CPB by placing a temporary shunt between the
high SVC and the RA. If the patient has a preexisting Blalock-Taussig shunt on the right, it is divided after
instituting CPB. A shunt on the left side may be left open, while the bidirectional Glenn shunt is created
on the right. The SVC is divided and the cardiac end is oversewn. The remaining caval end is
anastomosed end-to-side to the superior aspect of the right PA
Fontan procedure:
The heart is accessed via a standard median sternotomy. Previously placed systemic-to-PA shunts are
dissected and occluded prior to bypass. Bicaval cannulation and CPB with hypothermia are used. The
IVC is transected at its PA junction and a Gore-Tex tube graft is interposed end-to-end between the IVC
and the inferior surface of the right PA. This operation, in conjunction with the previously performed
bidirectional Glenn shunt, establishes a total cavopulmonary connection (Fig. 12.4-1B). After completing
the anastomosis, the aortic cross-clamp is removed, the heart is rewarmed and the patient is weaned
from CPB. Fenestration of the Fontan circuit may be desirable in high-risk patients, but is generally not
required in patients with tricuspid atresia and good ventricular function. Our current standard is to perform
the Fontan procedure without using cardiopulmonary bypass.
Variant procedure or approaches:
A RA→RV connection can be performed in patients with tricuspid atresia without pulmonary obstruction
and an adequately functioning RV. This is accomplished with a direct anastomosis or a valved/nonvalved
conduit (e.g., aortic homograft, Dacron graft).
Ref:- Anesthesiologist’s Manual of Surgical Procedures
by Richard A. Jaffe, Stanley I. Samuels, Clifford A. Schmiesing, and Brenda Golianu
4th edition published by Wolters Kluwe
78.D
79.A.The hepatoduodenal ligament (free margin of the lesser omentum) contains three major structures.
The portal vein, the proper hepatic artery, and the common bile duct (along with lymphatics and
autonomics). Of the three major structures, the portal vein is posterior to the other two. The common bile
duct occupies the right edge and the artery the left edge.
80.E.In the female pelvis the rectouterine pouch (Pouch of Douglas) represents the lowest pocket in the
pelvic cavity when the patient is in the standing postion, causing excess fluid in the pelvis to collect in this
area. Fluid in this pouch can be aspirated by passing a needle through the posterior vaginal fornix.
(Culdocentesis).
81.B.The most likely response is #2: beginning in the umbilical region and moving to the right iliac fossa.
The appendix is part of the midgut and is innervated by visceral afferents from the T10 spinal cord level.
Initially, the appendix swells and "pain" is referred to the area of the umbilicus. Usually the pain is
described as a dull, aching feeling. As the appendix continues to enlarge, it eventually contacts the
parietal peritoneum covering the internal surface of the anterior abdominal wall, which is innervated by
somatic afferents. When this occurs, pain is felt in the right iliac fossa.
82.B.The surgeon's finger has been placed in the omental foramen, the entrance to the omental bursa. In
the free edge of the lesser omentum and anterior to the surgeon's finger are the hepatic artery proper, the
common bile duct, and the portal vein. Posterior to the omental foramen and the surgeon's finger is the
inferior vena cava.
83.A.The superficial inguinal ring is an opening in the aponeurosis of the external oblique through which
the contents of the inguinal canal pass. In a direct inguinal hernia, the hernial sac, a peritoneal sac
sometimes containing intestinal contents, can enlarge this opening, requiring reconstruction during an
open surgical repair.
84.C.The anterior scrotal area is supplied by the ilioinguinal nerve. This nerve is located on the external
surface of the spermatic cord as it exits the superficial inguinal ring. It can be damaged because of this
relationship during the surgical repair of a direct inguinal hernia.
85.C.The pudendal nerve is the primary nerve carrying sensory fibers from and motor fibers to the
perineum. Therefore, branches of the pudendal nerve innervate the external genitalia, including the
posterior portion of the scrotum. The ilioinguinal nerve supplies the anterior scrotal area. The other
choices listed are related to the visceral division of the nervous system.
86.B.Contraction of the cremaster muscle (causing a slight elevation of the testicle) as a result of stroking
the skin of the upper medial thigh constitutes the cremasteric reflex. It involves the afferent and efferent
branches of the genitofemoral nerve. (L1, L2).
87.A.The pudendal nerve is the primary nerve carrying sensory fibers from the perineum, including the
anus. Branches of this nerve will need to be anesthetized before the surgical repair.
88.C.Damage to the urethra in th buld of the penis would result in the extravasation of urine into the
superficial perineal space. From there it could ganin access to the scrotal sacs, and the potential space
between the superficial and deep fascias of the penis. Subsequent to filling these spaces urine could rise
under the superficial fascia (Scarpa’s layer) of the skin of the lower abdomen.
89.B.
90.B.The ureter passes inferior to the uterine artery, just lateral to the cervix, as it crosses the pelvic floor.
All of the other structures listed are outside the area of this procedure.
91.D.Pain of ureteric colic is referred to the proximal anterior aspect of thigh (groin) via supply of the
genitofemoral nerve (L1)
92.A
93.B.
94.A
95.B.The spermatic cord contains the pampiniform plexus of veins, which condenses to form the
testicular vein after the termination of the spermatic cord.
96.C.
97.D
98.C
99.C
100.A