Infectious Diseases
for the Medicine Boards
Christopher Hurt, MD
Division of Infectious Diseases
June 2010
What is sure to be on the boards
Topic
Number of Questions
Epidemiology
5-9
Critical care ID
1-4
CNS infections
1-3
Endocarditis and intravascular infections
0-3
Lower respiratory tract infections
1-5
Enteric infections
1-4
AIDS and HIV infection
2-4
Infectious/septic arthritis
1-2
Procedure- and device-related infections
1-2
Prevention of infectious diseases
2-4
ABIM Exam Blueprint, http://www.abim.org/pdf/blueprint/im_cert.pdf
2
What may be on the boards
Topic
Topic
GI complications of HIV
Heme/onc complications of HIV
Pulmonary complications of HIV
Skin and soft tissue infections
Upper respiratory tract infections
Lower respiratory tract infections
STDs and GU tract infections
UTIs
Osteomyelitis
Bacteremia/sepsis syndromes
Rheumatic fever
Nosocomial infections
Immunization
Specific causative organisms*
Miscellaneous ID disorders*
ID in the elderly
ID in women
*whatever the hell that means
ABIM Exam Blueprint, http://www.abim.org/pdf/blueprint/im_cert.pdf
3
What won’t be on the boards
• Dosages of antimicrobials
• Emerging pathogens
» 2009 H1N1 unlikely, but oseltamivir-resistant flu A could be
• Topics that are controversial or which have no consensus
guideline, such as…
» Treatment of multidrug-resistant TB or HIV
• Probably won’t ask you for second- or third-line
antimicrobial selections
» (that’s special torture reserved for ID boards)
• Bioterrorism ±
» (at least recognize wide mediastinum of inhalation anthrax)
4
Let’s go!
3/12/2016
5
Critical care ID - 1
• SIRS = 2 or more of: fever or hypotherm; tachycardia;
tachypnea/hypocarbia; leukocytosis or leukopenia
» NOT necessarily due to an infection
• Sepsis = SIRS plus micro-confirmed or observable infxn
• Severe sepsis = sepsis plus at least one sign of organ
hypoperfusion
» Mottled skin, delayed cap refill, decr UOP, lactatemia, AMS,
abnl EEG, thrombocyto, DIC, ALI/ARDS, cardiac dysfunction
• Septic shock = severe sepsis plus low MAP and/or
pressor requirement
6
Critical care ID - 2
• Drotrecogin alpha (Xigris)
» PROWESS = 96h infusion w/in 24h of presenting
• 28d mortality rate lower with drotrecogin
• Increased bleeding with drotrecogin
» Post-hoc analysis = of greatest benefit to most
severely ill, with APACHE II scores ≥25 or MSOF
» Lower incidence of MSOF among treated patients,
and they also had more rapid recovery of
cardiopulm function
3/12/2016
7
Critical care ID - 3
• Who should NOT get drotrecogin alpha (Xigris)
» Preggers or breast-feeding
» Severe thrombocytopenia (<30K)
» ANY invasive procedure within 12h of starting drug
• Spinal epidural anaesthesia is a favorite trivia bit
» Head trauma, intracranial surg, or CVA w/in 3mos
» Known hypercoagulable condition
» Patient not expected to live 28d post-infusion
» Acute pancreatitis with no identified source of infxn
3/12/2016
8
Critical care ID - 4
• Lines and bloodstream infections (BSIs)
» Yank all intravascular catheters as soon as feasible
• Dirtiness: femoral > IJ (drool!) > SCL
» If the line is okay, leave the damn thing alone – no
evidence that scheduled (q3-5d) line changes
help reduce nosocomial BSIs
» For site prep, use chlorhexidine gluconate (CHG)
over povidone/iodine (Betadine), if given a choice
3/12/2016
9
CNS Infections - 1
• Meningitis = pain, headache, lethargy, function OK
» Aseptic (viral or non-infectious) or bacterial
• Encephalitis = brain abnormalities
» Hemiparesis, AMS, flaccid paralysis, paraesthesias
• Distinctions usu based on CSF – viral dzs have lower
WBC counts, only modest protein elev, near-normal
glucose
» Don’t hang your hat on lymphs vs PMNs to help! You can
see lymphs in early or partially tx’d bacterial meningitis
• Meningoencephalitis = elements of both syndromes
3/12/2016
10
CNS Infections - 2
• Encephalitis
» Viral ~ = neuronal involvement by MRI
• Measles, VZV, CMV, influenza, arboviruses
• HSV-1 is responsible for most deaths in encephalitis
• West Nile is like polio or Guillain-Barré – flaccid
ascending paralysis
» Post-infectious aka acute dissem. encephalomyelitis
(ADEM) = neuronal sparing, perivascular inflamm w/
demyelination (often an incidentaloma on MRI)
3/12/2016
11
CNS Infections - 3
Meningitis – Viral and Noninfectious
• Viral – enteroviruses, HSV, HIV, WNV, VZV, mumps
» PCR is diagnostic tool, esp for entero and HSV/VZV
» Acute HIV can present with mono-like illness + meningitis
» HSV more likely culprit if pt presenting with 1° genital lesion
• Recurrent HSV-2 associated meningitis episodes = Mollaret’s
• Other bugs = RMSF (Rickettsia), Ehrlichia, Lyme (Borrelia)
• Non-infectious causes
» Malignancy (breast, lung, melanoma, GI, unk primaries)
» Drug-induced (NSAIDs, TMP/SMX, IVIG, OKT3 – immsupp)
3/12/2016
12
CNS Infections - 4
Meningitis – Bacterial
• Access CNS either through contiguous spread (e.g.,
parameningeal focus, sinus/middle ear) or
hematogenous
• Bugs in adult bacterial meningitis (up to age 60)
» Streptococcus pneumoniae – 60%
» Neisseria meningitidis – 20%
» Haemophilus influenzae – 10%
» Listeria monocytogenes – 6%
» Group B Streptococcus (agalactiae) – 4%
•3/12/2016
Over age 60, 70% S.pneumo and 20% Listeria
13
CNS Infections - 5
Meningitis – Bacterial
• Listeriosis has more seizures and focal neuro deficits,
presenting as rhomboencephalitis (ataxia, CN palsies,
nystagmus) – think this in an elderly meningitis vignette
• Gram stain buzzwords
» Gram-positive, lancet-shaped diplococci = S.pneumo
» Gram-negative diplococci = N.meningitidis (meningococcus)
» Gram-negative coccobacilli = H.flu
» Gram-positive rods or coccobacilli = Listeria
3/12/2016
14
CNS Infections - 6
Meningitis – Bacterial – TREATMENT
• DO NOT DELAY – if the Q frames pt languishing in ER for
hours before you see him, give abx before doing the LP
• Look for papilledema in lieu of getting a head CT
» If ß-lactam is an option, use it – cidal, penetrates the BBB
» Empirical therapy = hi-dose ceftriaxone + vancomycin
• Ceftriax 2gm q12 = meningococcus & PCN-sensitive
S.pneumo
• Vancomycin = PCN-resistant S.pneumo
• IF OVER AGE 50, add ampicillin (±gent) for Listeria
» Only scenario for adjunctive dexamethasone is highly
3/12/2016 suspected (or confirmed) pneumococcal meningitis
15
CNS Infections - 7
• Rhinocerebral zygomycosis not “mucormycosis”
» Hyperglycemic diabetic patient in HHS/HONK or DKA
» Acute sinusitis with fever, purulent nasal d/c, HA
» Periorbital or facial swelling ± proptosis
» Invasion of cavernous sinus leads to CN palsies (6&3, 4/5)
» Rhizopus spp. are most common culprits
• Not everyone’s favorite go-to fungus, Aspergillus
» These fungi are vaso-invasive, so on PEx you may see
black mucosal patches – it’s not the mould you’re seeing,
it’s infarcted tissue
» Treatment is with surgery FIRST and adjunctive amphoB
16
Endocarditis - 1
• 2007 Modified Duke criteria: 1 major + 1 minor, or 3 minors
Major
Minor
Two separate positive blood cxs
with typical organism of IE
Vascular phenomena
Viridans group streptococci
Streptococcus bovis (COLON CA)
Staphylococcus aureus
HACEK
Community-acquired Enterococcus
Arterial emboli
Septic pulmonary infarcts
Mycotic aneurysms
Intracranial hemorrhage
Conjunctival hemorrhages
Janeway lesions
Persistently positive BCxs
Fever (>38°C)
Single positive BCx for
Coxiella burnetii (Q fever)
or phase I IgG titer >1:800
Immunologic phenomena
Echocardiogram positive for IE
Other micro evidence
(i.e., unexpected bug)
TEE FIRST IF PROSTHETIC VALVES!
Glomerulonephritis
Osler nodes
Roth spots
Rheumatoid factor
17
Endocarditis – 2
• Indications for surgical intervention in IE
» Vegetations: persistent after systemic embolization, anterior
mitral leaflet veggies, ≥embolic events in first 2 weeks of
abx, increase in veggie size despite abx
» Valvular dysfunction: acute AI or MR with signs of ventricular
failure, CHF unresponsive to medical tx, valve rupture
» Perivalvular extension: valvular dehiscence/rupture/fistula,
new heart block, large abscess
3/12/2016
18
Endocarditis – 3
Native valves
• PCN-susceptible Viridans streptococci and S. bovis MIC≤0.12
1. Penicillin G or ceftriaxone, or vanc x 4 wks
2. PenG or ceftriaxone PLUS gentamicin x 2 wks (synergy)
• PCN-intermediate Viridans strep and S. bovis MIC>0.12, ≤0.5
1. PenG or ceftriaxone x 4 wks with gent for FIRST 2 wks
2. Vanc x 4 wks
• Staphylococcus aureus
»
NafcillinOSSA, oxacillinOSSA, or vancomycinORSA x 6 wks
• Enterococcus – gentamicin ENTIRE TIME
»
3/12/2016
Amp + gent x 4-6 wks, vanc + gent x 4-6 wks
19
Endocarditis – 4
Prosthetic valves
• PCN-susceptible Viridans streptococci and S. bovis MIC≤0.12
1. Penicillin G or ceftriaxone, x 6 wks, ± gent x FIRST 2
2. Vanc x 6 wks
• PCN-int or resistant Viridans strep and S. bovis MIC>0.12
1. PenG or ceftriaxone x 6 wks with gent for all 6 wks
2. Vanc x 6 wks
• Staphylococcus aureus
»
Naf/oxOSSA or vancORSA PLUS rifampin x ≥6 wks, w/gent FIRST
2
• Enterococcus – gentamicin ENTIRE TIME
»
3/12/2016
Amp + gent x 6 wks, vanc + gent x 6 wks
20
Endocarditis – 5
TAKE-HOME MESSAGES FOR ENDOCARDITIS
• Don’t memorize the Duke criteria – it’s intuitive
• Gentamicin shortens the course for “weak” bugs (LowPCN MIC Viridans group strep and S.bovis)
• If Enterococcus is present, must use gent entire course
• Prosthetic valve treatment is always 6 wks, sometimes
with adjunctive abx (e.g., rifampin, gent) depending on bug
• Staphylococcus treatment is always 6 wks
3/12/2016
21
Intravascular infections – 1
• Staphylococcus aureus and Salmonella are
associated with vascular (esp aortic) aneurysms
» Think about this dx if high-grade (persistent)
bacteremia in pt without endovascular material
• Syphilis (Treponema pallidum) was once a major
cause of aortitis – late presentation of dz
» Thoracic aortic dilatation with aortic regurgitation
3/12/2016
22
Intravascular infections – 2
• Rocky Mountain spotted fever
» Southeastern US (“tick belt” from Arkansas – NC – FL)
» Rickettsia ricketsii attach to vascular endothelium = leak
» Fever, severe HA, rash in 90% (beware pts of color!),
myalgias, focal neuro signs, thrombocyto, ARF, hypoNa
» Doxycycline ASAP – treat empirically; no good acute dx tool
3/12/2016
23
Lower respiratory tract infections - 1
Community-Acquired Pneumonia
• Bugs: Strep pneumo, Mycoplasma pneumoniae, H.flu,
Chlamhydophila pneumoniae, respiratory viruses, Legionella
• Outpatient tx
» Previously healthy, no abx w/in 3 mos? Macrolide or doxy
» Comorbidities? Respiratory FQ
• Inpatient, non-ICU – resp FQ
OR
OR
[ß-lactam + macrolide]
[ß-lactam + macrolide]
• Inpatient, ICU – ß-lactam PLUS [resp FQ or azithro]
» ß-lactam choices: cefotaxime, ceftriaxone, amp/sulbactam
» Pseudomonas? pip/tazo, cefepime, imi/mero
±
aminoglycoside
» MRSA/ORSA? ADD vancomycin or linezolid
3/12/2016
24
Lower respiratory tract infections - 2
Healthcare and Ventilator-Acquired Pneumonias
• Bugs: Pseudomonas, E.coli, Klebsiella, Acinetobacter, S.aureus
• Increased risk for multidrug resistant (MDR) bugs?
» Abx w/in 90d, current hospitalization ≥5d, high-freq of abx
resistance in unit, risk factor for HCAP (hospitalization x2d in prior
90d, nursing home resident, home infusion, dialysis, close contact)
• HAP/VAP if no known risk factors for MDR-bug (realistically, very rare)
» Ceftriaxone or levoflox/moxi or amp/sulbactam or ertapenem
• High risk for MDR-organisms or presenting with late-onset dz
» Antipseudomonal ß-lactam: cefepime, ceftaz, imi, mero, or pip/tazo
AND cipro, levo, amikacin, gent, or tobra
» If MRSA concern, ADD linezolid or vancomycin NOT daptomycin
25
Lower respiratory tract infections - 3
• BMT and SOT recipients
• Nocardia spp. – if in lung, think of brain, too!
» Beaded, branching, filamentous bacteria, ± acid-fast
» Incidence has dropped due to TMP/SMX prophy use post-xp
» TMP/SMX or imipenem empirical tx, awaiting susceptibilities
» Get a CT of the head looking for ring-enhancing lesions
• Aspergillus spp.
» Marijuana smoking post-xp is a risk factor
» “Crescent sign” on chest CT is buzzword
» Vasoinvasive and tissue destructive
» AmphoB, echinocandin (caspo/mica/anidula), or vori/posa
26
Lower respiratory tract infections - 4
• Pneumocystis jiroveci (still called PCP)
» CD4 ≤ 200-250
• HIV and transplant pts +
fludarabine (CD4-penic)
» Nonproductive cough,
fever, insidious SOB
» Steroids if PaO2 <70
» Tx = IV TMP/SMX or
IV pentamidine*
3/12/2016
*Inhaled only for prophy
27
Lower respiratory tract infections - 5
• Mycobacterium tuberculosis
» TST/PPD is a crappy test, but don’t use “anergy” panel
» KNOW THE THRESHOLDS FOR POSITIVE TST/PPD!!!
5 mm
10 mm
HIV-infected
Recent immigrant from TB endemic country
Recent contact to case with active TB
IDUs
Abnormal CXR c/w prior pulmonary TB
Resident/employee of high-risk congregate
setting (jail, shelter, nursing home)
Organ transplant recipients
Mycobacteriology lab personnel
Other immune compromised
(steroids, TNF-a antagonists)
Children < 4 yo
Young people exposed to high-risk adults
15 mm is for everyone else (i.e., no known TB risk factors)
28
Lower respiratory tract infections - 6
• Mycobacterium tuberculosis
» Treatment always initiated with four drug “RIPE” regimen, at
weight-based dosing
• Isoniazid – hepatotoxicity, anion gap acidosis (I in MUDPILES)
• Rifampin – inducer of metabolism of other drugs, orange body
fluids, hepatotoxicity
• Ethambutol – optic neuritis (color blindness)
• Pyrazinamide – hepatotoxicity, nausea-inducing
» Pulmonary TB: total of 6 months treatment ALL ON DOT
• First 8 weeks on RIPE – if fully susceptible and smear negative
at 2 month recheck, then OK to narrow to just INH + Rifampin
29
Lower respiratory tract infections - 7
• Histoplasma, Coccidioides, Cryptococcus
» All gain entry through inhalation, then disseminate
» Histoplasma – Mississippi-Ohio River Valley, interstitial
pneumonia, mucocutaneous ulcers, splenomegaly, marrow
suppression, fibrosing mediastinitis, “coin” lesion in HIV–
» Coccidioides – Desert SW (Mexican immigrants and ecotourists), hilar adenopathy, arthralgias, erythema nodosum
(can be mistaken for sarcoidosis)
» Cryptococcus – pneumonitis is usually subclinical, may have
cryptococcomas of lung, can be normal hosts but if
compromised (HIV, steroids, transplant) need LP
3/12/2016
30
Enteric infections - 1
• Norovirus
» Rapid-onset explosive outbreak with quick resolution
• Child exposures, cruise ships, congregate living facilities
» Low infectious inoculum, highly transmissible
» Vomiting precedes abd cramping, fever (<50%), watery
diarrhea, constitutional sxs (HA, chills, myalgias) x 2-3d
» Can cause deaths among the elderly
» Treatment = oral rehydration, supportive care
• Antimotility and antisecretory drugs are okay to use
3/12/2016
31
Enteric infections - 2
• Dysentery = bloody stools; 4 main causes in US…
» Shiga toxin-producing E.coli (60% are O157:H7)
• Watery diarrhea becomes bloody in 1-5d; abd cramps, no fever
• Causes hemolytic-uremic syndrome if toxin reaches kidneys
» Shigella (outbreaks uncommon; more in developing world)
» Campylobacter – poultry, unpasteurized milk; Guillain-Barré
» Non-typhoid Salmonella – poultry, pet reptiles and turtles
• Treatments
» Shiga toxin-producing E.coli – Abx not recommended
» Shigellosis, salmonellosis – ciproflox, levoflox, azithro
» Campylobacter jejuni – azithro
32
Enteric infections - 3
• Clostridium difficile diarrhea
» Toxin assay for diagnosis, but don’t attempt test-of-cure
» Initial episode, mild-to-moderate
• Metronidazole 500mg PO (not IV) q8h x10-14d
» Initial episode, severe (WBC ≥15, Cr ≥1.5x premorbid level)
• Vancomycin 125mg PO (not IV) q6h x 10-14d
» Initial episode, severe and complicated by shock, megacolon
• Vancomycin 500mg PO or pNGT PLUS metronidazole 500 q8
• If complete ileus, consideration for intrarectal vancomycin
» First recurrence = same as initial episode
» Second recurrence = vancomycin taper
3/12/2016
33
HIV and AIDS - 1
• HIV-1 predominates
» HIV-2 limited to W. Africa
• ssRNA retrovirus
• AIDS is defined by:
» CD4 < 200 cells/µL
» CD4% < 14%
» Presence of AIDS-defining
illness at any CD4
3/12/2016
34
HIV and AIDS - 2
• ELISA = highly sensitive
» Better to have FP than miss a TP!
• Western blot = highly specific
» Indeterminate Western blots are
rare… but can be caused by:
• Neoplasms, dialysis, thyroid dz,
bilirubinemia, SLE, pregnancy,
immunizations (tetanus, HIV)
nephrotic-range proteinuria
3/12/2016
35
HIV and AIDS - 3
• Acute retroviral syndrome is
a mononucleosis-like illness
» Fever
» Maculopapular rashThink syphilis, too!
» Mucocutaneous ulcers
» Pharyngitis ± tonsillar
enlargement
» Lymphadenopathy
» Meningitis (infrequent)
• DIAGNOSIS OF ACUTE HIV IS BY RNA, NOT Ab!!!
36
HIV and AIDS - 4
Initial mgm’t – Prophylaxis
• CD4 > 200, no prophylaxis necessary
• CD4 < 200
» Pneumocystis jiroveci and Toxoplasmosis
•
TMP/SMX > dapsone > atovaquone
•
Aerosolized pentamidine prevents ONLY Pneumocystis
» Do NOT need fluconazole for thrush “prophylaxis”
• CD4 < 50
» Mycobacterium avium complex (“MAI” doesn’t exist!)
•
Azithromycin 1200mg once weekly
37
HIV and AIDS - 5
Initial mgm’t – Antiretrovirals
• For CD4 < 200 or if AIDS-defining illness, everyone
should get on ARVs
» Recent (2009, so NOT on boards yet) evidence suggests
starting ARVs during some acute OIs reduces mortality
» For now, ABIM would say to start after stabilization, etc.
• Btw 200-350, recommended to start
• Over 350, decision btw pt and provider
38
HIV and AIDS - 6
Initial mgm’t – Antiretrovirals
• Current testable recommendations are probably slightly
out-of-date (circa 2008); field moving rapidly
Dual NRTI (any one row)
Companion (any one row)
EfavirenzNNRTI
Truvada® (tenofovir/emtricitabine)
Epzicom® (abacavir/lamivudine)
+
Atazanavir + ritonavirPI
Fosamprenavir + ritonavirPI
Lopinavir/ritonavirPI
Alternatives
Combivir® (zidovudine/lamivudine)
didanosine + lamivudine
+
NevirapineNNRTI
Atazanavir (“unboosted”) PI
Fosamprenavir (“unboosted”) PI
39
HIV and AIDS - 7
• Cryptococcal meningitis
» Malaise, headache, N/V, low-grade fevers, without much
meningismus or AMS
» Think of dx also in ALL, Hodgkin’s, or recent steroid use
» Get serum crypto Ag – India ink is rarely used
» Morbidity/mortality comes from increased ICP, so
get opening pressure on LP and perform serial LPs
• Can also place lumbar drain or ventricular drain, if needed
» Amphotericin B + flucytosine x14d for CNS disease
• THEN switch to oral fluconazole and stay on it until CD4 > 200
3/12/2016
40
HIV and AIDS - 8
Antiretroviral side effects
• ddI, d4T/stavudine, AZT/zidovudineNRTIs - lactic acidosis
• TenofovirNRTI - Fanconi-like syndrome w/“creatinine creep”
• AbacavirNRTI – hypersensitivity rxn (if HLA B*5701 present)
• EfavirenzNNRTI - teratogenic, causes vivid dreams
• NevirapineNNRTI - hepatotoxic if started with high CD4s,
SO AVOID USING NEVIRAPINE IN PEP REGIMENS
• IndinavirPI - nephrolithiasis
• RitonavirPI - “booster” agent, tons of drug-drug interactions
• AtazanavirPI - Gilbert-like syndrome of hyperbili ± jaundice
41
Antimicrobial adverse effects
• Sulfa drugs – rash, AIN/ARF, kernicterus in neonates
• TMP – hyperkalemia (decr renal tubular excretion)
• ß-lactams – marrow, seizures, AIN/ARF
• Daptomycin – rhabdomyolysis
• Metronidazole – disulfiram-like reaction with EtOH
• Oxacillin – hepatitis/transaminitis
• Pentamidine – pancreatitis, hypoglycemia
• Amphotericin – renal failure, rigors (meperidine)
• Vancomycin – “red man” (histamine release), nephro/ototox
(??)
• Aminoglycosides –ototoxicity, c/i in myasthenia gravis
42
Infectious/septic arthritis - 1
• Diagnosis
» Arthrocentesis to eval for crystalline arthropathy
» Generally >50K cells/µL as threshold for septic joint
» Look for Gram-positives… #1 cause is S.aureus,
followed by streptococci
3/12/2016
43
Infectious/septic arthritis - 2
Monoarticular joint presentations
• Late Lyme arthritis (Borrelia burgdorferi)
» Knee > shoulder > ankle > elbow >
TMJ > wrist > hip
» Effusion is greater than the pain
» Fluid can meet WBC criteria for septic joint, but uncommon
» Diagnosis relies on serologies
• Gonorrhea
» Triad of migratory polyarthralgia, dermatologic lesions
(macules, papules/pustules), tenosynovitis
» Dx is by confirming genital or extragenital GC infection
44
STIs and GU tract infections - 1
• Gonorrhea (Neisseria gonorrhoeae)
» Gram-negative intracellular diplococcus
» Purulent urethritis or cervicitis
» Most cases resolve spontaneously – treat to prevent
disseminated gonococcal infection (DGI)
• Fevers, asymmetric mono/oligoarticular arthritis (knee, ankle) or
• Tenosynovitis - muscle pain; overlying papules w/hemorrhage
» Uncomplicated GU dz = IM ceftriaxone or PO cefixime, x1
» Extragenital dz or DGI = IM ceftriaxone, x1
» ALWAYS co-treat for Chlamydia with 1gm azithro, x1
» NEVER use a quinolone for an STI on the boards!
45
STIs and GU tract infections - 2
• Chlamydia trachomatis (and the catch-all, NGU)
» Includes Ureaplasma urealyticum, Mycoplasma genitalium
» Incubation period is longer for CT (1-4wks) than GC (2-6d)
» Clear (non-purulent) discharge; Gm stain = WBC, no bugs
» Treat with 1gm azithromycin PO, x1 or doxy 100 q12 x7d
• Pelvic inflammatory disease
» Can be from GC or CT, sometimes vaginal anaerobes
» Fitz-Hugh-Curtis = purulent perihepatitis with mild LFT chgs
» If pregnant, must admit the patient
» Tx w/ceftriaxone x1, doxy and metronidazole x14d
46
STIs and GU tract infections - 3
• Syphilis – RPRnon-treponemal, confirmtreponemal = MHA-TP, TP-PA
PCN x1 »
1° = painless chancre, ~21d after contact, lasting ~3-6 wks
PCN x1 »
2° = non-pruritic skin rash and mucous membrane lesions
• Rough, red or brownish spots on trunk, palms and soles
• Systemic symptoms with fever, LAD, sore throat, hair loss
• Syphilitic hepatitis (1° & 2°) = cholestatic, but alk phos >> bili
» Latent – seroreactivity without e/o disease
• Early latent – if acquired syphilis within the prior year
PCN x1
PCN x3 wks • Late latent – unknown acquisition date
» 3°/Late – evidence of end-organ damage – PCN x 3 wks
» Neurosyphilis – IV PCN x14d, desensitize in ICU if needed
3/12/2016
STIs and GU tract infections - 4
• Herpes
» Painful ulcerations of genital mucosa, usually from HSV-2
» Remember primary genital lesion assoc w/ HSV meningitis
» First episode: ACV, famciclovir, or vACV x 7-10d
» Suppressive therapy does reduce viral shedding and
prevent recurrent episodes
• ACV 400 q12, famciclovir 250 q12, or vACV 500 q24
3/12/2016
48
STIs and GU tract infections - 5
• Trichomoniasis
» If it’s moving fast on a wet prep, it’s Trichomonas vaginalis
» Frothy, thin, foul-smelling d/c for women; men often w/o sxs
» Kill it with metronidazole 2gm po, x1 unless pregnant, then
use metronidazole 500 q12h x7d. AVOID EtOH (disulfiram)
• Bacterial vaginosis – NOT an STI
» “Salt-and-pepper”
covered clue cell
Clue cells
Normal
» Fishy odor, pH > 5.0
» Metro 500 q12h x7d
3/12/2016
49
Hepatic infections - 1
• Hepatitis B
» dsDNA virus
» Blood and body fluids
are source
» Majority (95%) of
normal hosts
will clear virus
» Strong assoc w/HCC,
esp among Asians who
were vertically infected
3/12/2016
50
Diagnosis
1
sAg
2
eAg
3
cAb
4
eAb
5
sAb
Acute hepatitis
+
+
IgM
–
–
Window period*
–
+/ –
IgM
+/ –
–
Recovery
–
–
IgG
+/ –
+
Immunized
–
–
–
–
+
Chronic replicative
+
+
IgG
–
–
Chronic nonreplicative
+
–
IgG
+
–
*Order after acute infection: sAg+  sAg–,(anti)HBcIgM+  sAb+.
Because sAg drops before sAb detectable,
3/12/2016
only way to confirm HBV at that point is cIgM
51
Prevention of infectious diseases - 1
• Endocarditis prophylaxis
» 2007 ACC / IDSA guidelines changed this radically
» Cardiac abnormalities for which prophylaxis is reasonable
• Prosthetic valve or prosthetic material used for valve repair
• Prior history of infective endocarditis
• Congenital heart disease – repaired or unrepaired
• Cardiac transplant recipients with valvulopathy
» Dental – any manipulation of gingival tissue or periapical
region of teeth, or perforation of oral mucosa
• Amoxicillin 2gm 30-60 minutes before procedure
» GI and GU tract procedures don’t get prophylaxed for IE
3/12/2016
52
Prevention of infectious diseases - 2
• Malaria prophylaxis
» Big question is, can chloroquine (CQ) be used or not?
• Sensitive = Mexico  Costa Rica; Argentina; Turkey  Iraq
• Resistant = All of Africa; all of Asia; Panama  Argentina
» If CQ sensitive: Chloroquine or hydroxychloroquine
• Start 1-2 wks before travel, take once weekly and x4 wks after
» If CQ resistant (in general order of preference):
• Atovaquone/proguanil: 1-2d before travel, daily, x7d after home
• Doxycycline: 1-2d before travel, daily, x4 wks after home
• Mefloquine: 2 wks before travel, weekly, x4 wks after home
» Psychotic episodes, szs, mental status changes with mefloquine
3/12/2016
53
Prevention of infectious diseases - 3
• Immunizations
» NEVER give live virus vaccine to pregnant women
or HIV-infected patients with CD4 < 200
• Live attenuated influenza, varicella, zoster, MMR,
yellow fever (can be given in pregnancy if @ risk)
» Tetanus toxoid (as Td) and inactivated influenza
are okay in pregnancy, preferably after 1st trimester
» HAV & HBV, pneumococcal & meningococcal
conjugate vaccines are prob safe in pregnancy;
no data
3/12/2016
54
Prevention of infectious diseases - 4
• Hospital precautions
» Airborne – varicella (incl zoster/shingles), TB, measles
» Droplet – H.flu, meningococcus, diphtheria, pertussis,
Strep pharyngitis, adenovirus, influenza, RSV
» Contact – C.diff, norovirus, RSV, pediculosis (crabs),
scabies, ORSA/MRSA, VZV
» Shingles can come off airborne & contact once dry, crusted
• Handwashing is required for C.difficile infections –
alcohol-based sanitizers don’t kill the spores
3/12/2016
55
Prevention of infectious diseases - 5
• Influenza
remember drift = year-to-year; shift = pandemics
» Moving target; unlikely pandemic H1N1 will appear on
ABIM
» Prophylaxing close contacts is appropriate; use OST or ZNV
based on what
the question stem
tells you about
strain
Influenza strain
Oseltamivir (OST)
Zanamivir (ZNV)
Adamantanes
A / H3N2
(Seasonal)
S
S
R
A / H1N1
(Seasonal)
R
S
S
A / 2009 H1N1
(Pandemic)
S*
S
R
B
S
S
R
* Sporadic resistance to oseltamivir was reported during the 2009 H1N1 pandemic;
all isolates remained sensitive to zanamivir
Prevention of infectious diseases - 6
• Meningococcus
» Vaccine covers serogroups A, C, Y, W-135 – but misses B,
the major cause in the US (not included in any vaccine)
» Everyone in the pt’s room will want treatment/prophylaxis
(and we often prophylax many more than need it)
» For the boards, it’s close contacts to respiratory droplets
• Anyone with prolonged exposure (8h or more) w/in 3 feet
» Dorm roommate, but not classmates or other casual contacts
• Anyone directly exposed to oral secretions w/in 1 wk of dx
» Boyfriend/girlfriend, anyone doing CPR or intubating pt
» Rifampin 600 q12 x2d, ciproflox 500 x1, ceftriax 250 x1
3/12/2016
57
Prevention of infectious diseases - 7
• Prevention of VAP
» Use orotracheal intubation, vs nasotracheal/assisted
» Avoid NGTs – use OGTs
» Continuous aspiration of subglottic secretions, if available
» Maintain adequate ETT cuff pressure, to occlude trachea
and prevent leakage into the lower respiratory tract
» Extubate as early as possible (minimize vent time)
» Keep patient in semirecumbent position (30-45°),
esp when receiving an enteral feeding
» Oral decontamination with chlorhexidine gluconate (± data)
» Avoid sedation regimens that depress cough reflexes
58
Prevention of infectious diseases - 8
• HIV PEP
» Two different guidelines exist: occupational and non
» Start ARVs within 72h, ideally within first 20 mins
» Risk increases with the gauge of the needle
• Hollow-bore needle > scalpel > suture needle
» Data support using dual NRTI therapy by itself, but
recommendation is to give the patient HAART
• Combivir (zidovudine/lamivudine) or Truvada
(tenofovir/emtricitabine) PLUS Kaletra (lopinavir/ritonavir) or
efavirenz
3/12/2016
• AVOID NEVIRAPINE DUE TO RISK OF HEPATOTOXICITY
AT HIGH CD4 COUNTS
59
Lightning round!
3/12/2016
60
Streptococcus pneumoniae, an encapsulated (“halos”) Gram+ diplococcus
Strep = pairs and chains
Staph = clusters
3/12/2016
61
Shingles from varicella-zoster virus
in a young male patient receiving
chemotherapy
Ramsay-Hunt syndrome = facial nerve paralysis, ear pain, and
loss of taste sensation in anterior 2/3 of tongue,
from VZV reactivation in geniculate ganglion
3/12/2016
62
Proper technique for measuring TST/PPD (left)
Scar from Bacille-Calmette Guerin (BCG) vaccine (right)
3/12/2016
63
Purpuric skin lesions of disseminated meningococcemia
Waterhouse-Friderichsen syndrome is adrenal hemorrhage from N.meningitidis
3/12/2016
64
Disseminated primary varicella in adults shows multiple stages of healing,
sometimes pustular (left image) – smallpox has all lesions at same stage
65
3/12/2016
Multiply parasitized RBCs with characteristic “headphone”
form (arrow) of Plasmodium falciparum malaria
66
Nodular, hyperpigmented, sometimes violaceous lesions of Kaposi sarcoma,
caused by human herpesvirus 8 (aka KS-HV)
3/12/2016
67
Painless genital ulcer (chancre) of primary syphilis
3/12/2016
68
3/12/2016
Slightly umbilicated papules of molluscum contagiosum
(a poxvirus) in an HIV-infected patient.
69
Cellulitis from Streptococcus pyogenes. Using adjunctive clindamycin
for the first 72h is reasonable, to shut of toxin production – if concern for TSS.
3/12/2016
70
Plaques of thrush from Candida albicans in an HIV-infected patient.
3/12/2016
71
Thin, frothy cervical discharge from Trichomonas vaginalis.
3/12/2016
72
Lymphangitic spread of Sporothrix schenckii, a thermal dimorphic mould.
Rose gardening is the buzzword.
If fresh or brackish water exposure, think Mycobacterium marinum.
3/12/2016
73
Tinea versicolor from Malassezia furfur. Can also cause sepsis in
critically ill patients receiving TPN.
3/12/2016
74
Widened mediastinum from Bacillus anthracis inhalation. Ciprofloxacin.
3/12/2016
75
Ring-enhancing lesions of cerebral toxoplasmosis in an AIDS patient.
No reliable way to radiographically distinguish toxo from CNS lymphoma.
3/12/2016
76
Pruritic skin lesions in webspaces, from the scabes mite (Sarcoptes scabei).
3/12/2016
77
Vaginal candidiasis. Single dose of fluconazole 150 or 200.
3/12/2016
78
Cryptococcus neoformans on India ink prep.
Halos are the organism’s polysaccharide capsule.
3/12/2016
79
Measles exanthem – but could also be a morbilliform (measles-like) drug eruption.
3/12/2016
80
Epidemiology - 1
Test result
+
–
Disease status
+
–
TP
FP
FN
D+
TN
D–
T+
T–
N
Sensitivity: probability of positive test in those with disease
TP / (TP+FN) = TP / D+
Specificity: probability of negative test in those without disease
TN / (TN+FP) = TN / D–
3/12/2016
81
Epidemiology - 2
Test result
+
–
Disease status
+
–
TP
FP
FN
D+
TN
D–
T+
T–
N
PPV: probability of having disease in those who test positive
TP / (TP+FP) = TP / T+
NPV: probability of not having disease in those who test negative
TN / (TN+FN) = TN / T–
3/12/2016
82
Prevalence: what proportion has the disease right now?
_____________# cases____________
all those with dz PLUS at risk for dz
3/12/2016
83
Incidence: what proportion develop the disease over time?
__________# new cases__________ over time t
all those with dz PLUS at risk for dz
3/12/2016
84
Epidemiology - 5
PPV and NPV depend on
prevalence
•Tests perform better
when used in a higher
prevalence group
•This is why we don’t test
for influenza (usually) in
the “off-season”
0% -------------------->
3/12/2016
2%
Figure from Bill Miller
85