Systemic Infectious Diseases Flashcards
Dx and Tx: Fish tank granuloma
Mycobacterium marinum, Rx: Clarithromycin + Ethambutol OR Rifampin
Dx: Rose thorn injury and rash
Sporothrix schenckii. Rx: Itraconazole (amphotericin B if systemic)
Dx and Tx: Dog and cat bite with
rapid infection
Pasteurella multocida. Rx: Amoxicillin-Clavulanate (augmentin —> “dogmentin”)
Dx: Reptile bites and infection
Salmonella
Dx: Sickle cell disease and joint
pain
Salmonella osteomyelitis
Dx: Cat scratch fever
Bartonella henselae. Tx: doxy; azithromycin in pregnancy
Dx and Tx: Human bite and
infection
Eikenella corrodens. Rx: amoxicillin-clavulanate
Dx: Gastroenteris on a cruise
ship
Norwalk virus
Dx: Gastroenteritis at a daycare
Rotavirus, (remember, there is a vaccine now).
Compare general Dx and Tx of
toxin-mediated vs. invasive
bacterial diarrheal illness
Toxin: abrupt onset, watery, non-bloody; Rx IVF, ± loperamide, ± Cipro (prolonged/severe ssx).
Invasive: gradual onset, bloody, systemic sx;
Rx: IVF, ± Cipro UNLESS kids or elderly patients with possible E. coli O157:H7 (can increase risk of HUS)
Dx: Watery diarrhea +
eggs/mayo
Staph. aureus (toxin)
Dx: Watery diarrhea + fried rice
Bacillus cereus (toxin)
Diarrhea + flatulence + recent
hiking and drinking from a fresh
water stream
Giardia lamblia. Parasitic infection. Test for it w/ a stool antigen (not ova and parasite). Rx: Metronidazole / tinidazole. People who are risk: hikers, children at daycare, and oral-anal sexual conduct.
Dx: Watery diarrhea + travel
Enterotoxgenic E. coli (toxin); if no blood in diarrhea, give 1 dose of Cipro 750mg. If pt traveled to southeast asia this is likely campylobacter and give 1,000mg of azithromycin,
Dx: Watery diarrhea +
meat/poultry
Clostridium perfringens (toxin)
Dx: Watery diarrhea + dark meat
fish + rash/itching
Scombroid (histamine fish toxicity). Dark fleshed, peppery tasting fish: tuna, mahi-mahi, mackerel. Excess histidine on fish broken down by bacteria to histamine. SSx: Histamine ingestion leads to anxiety, flushing, headache, palpitations, vomiting. Rx: antihistamines
Dx: Watery diarrhea +
carnivorous fish + neuro ssx
Ciguatera (toxin causes neuro ssx) - “hot cold reversal”
Dx: Bloody diarrhea +
undercooked eggs/chicken +
relative bradycardia
Salmonella typhi (invasive), cafeteria outbreaks, classically with high fever and relative bradycardia; can cause osteomyelitis in sickle cell patients.
Dx: Bloody diarrhea (severe) +
high fever + institutionalized
Shigella (invasive); can cause seizures in kids
Dx and Tx: Bloody diarrhea +
followed by weakness
Campylobacter (invasive). Associated: appendicitis mimic & Guillain- Barré; Rx: Azithro/Erythro (resistance to cipro)
Dx: Bloody diarrhea + farm
animals + appendicitis ssx
Yersinia (invasive); pseudoappendicitis (appy mimic) can cause terminal ileitis
Dx: Bloody diarrhea +
undercooked seafood +
alcoholic who gets very sick
Vibrio parahaemolyticus (invasive)
Dx: Bloody diarrhea + poorly
cooked ground beef/raw milk
E. coli O157:H7, associated with TTP (adults) and HUS (kids); NO
ANTIBIOTICS
Dx: Rice-water stools +
contaminated water
Vibrio cholerae (toxin). Oral rehydration tablets.
Dx and Tx: Profuse diarrhea
after recent antibiotics
Clostridium difficile (invasive). Rx: metronidazole or PO Vanco
Dx: Diarrhea + AKI ± low
platelets
E. coli O157:H7 causing TTP/HUS
Dx: Food-borne illness
associated with premature
delivery in pregnant patients
Listeria monocytogenes
What is the most common cause
of bacterial diarrhea in the US?
Salmonella; 2nd Campylobacter
What factors on hx prompt you
to get stools studies for patients
w/ diarrhea?
- Fever > 38.5C
- Symptoms for greater than 1 week
- Concerns for C.diff
- Immunocompromised or advanced age
- Underlaying IBD.
Dx and Tx: Botulism
Paralytic illness. Cause: Clostridium botulinum neurotoxins → blocks
ACh release at neuromuscular junction → flaccid paralysis. Forms: food borne (canned foods, honey), wound, infantile (most common).
SSx: floppy baby, constipation, weak cry (infants); CN/bulbar sx, dilated
pupils (differentiates from myasthenia), symmetric, descending flaccid
parlaysis / weakness (MC finding), parasympathetic blockade (dry
mouth/sore throat, urinary retention).
Tx: supportive care, resp.
monitoring (resp. failure = MCC death), antitoxin (Rx infants: BabyBIG,
Rx age>1: antoxin, abx (for wounds)
Leading cause of infertility?
Chlamydia trachomatis
Dx and Tx: Painless vesicular
lesions or ulcers to groin +
buboes (huge LNs)
Lymphogranuloma venereum (LGV). Chlamydia trachomatis. Rx: Doxy or Azithro (and treat partners), drain abscesses
Dx and Tx: Painful ulcer with
irregular borders to groin +
buboes (huge LNs)
Chancroid. Haemophilus ducreyi. SSx: looks like syphillis but the lesion is painful. Rx: CTX, Azithro or cipro (ANY one), drain abscesses
Dx: Neonate with copious
purulent discharge from eyes
Neisseria gonorrhoeae conjunctivitis. Tx: systemic cefotaxmine. Topical tx not enough.
Review the timing of the various
causes for neonatal conjunctivitis
Chemical: first 24 hours. Gonococcal: first 2-5 days. Chlamydial: 5 days to 2 weeks.
Tx for neonatal chlamydial
conjunctivas?
Systemic tx with azithromycin or erythromycin. Pt’s must be admitted to look for pneumonia as well.
Dx: “Gunmetal grey” pustules to
hands/skin, septic arthritis ±
tenosynovitis
Disseminated gonococcus. Arthritis-dermatitis syndrome. Gram-negative intracellular diplococci. Rx: IV ceftriaxone
Dx: Contact with armadillos
Leprosy. Mycobacterium leprae. Rx: dapsone + rifampin (+clofazimine for lepromatous disease)
Dx and Tx: Contact with prairie
dogs
Bubonic plague. Yersinia pestis. Rx: streptomycin, tetracycline,
doxycycline (alt. fluoroquinolones)
Most common cause of viral
pneumonia in adults?
Influenza
Dx and Tx: HIV + Lung Disease
+ Pancytopenia
Mycobacterium avium intracellulare (MAI). CD4 < 50. Rx: Rifampin + Ethambutol + Azithro/Erythro
Dx and Tx: Primary tuberculosis
Mycobacterium tuberculosis. Transmission via inhalation of droplets.
SSx: often asymptomatic. Can progress to latent or reactivation TB. Rx:
Isoniazid (INH) + Pridoxine (Vit B6) x9mo.
Most common CXR finding in
primary TB?
Most common overall: a single lobar infiltrate associated w/ hilar
adenopathy / children: pronounced hilar adenopathy / elderly: isolated
pleural effusion. Ghon complex: calcified lung lesion, ± calcified LNs
[a.k.a. Ranke complex] representing HEALED infection.
Immunocompromised pts often cannot form a Ghon complex.
Dx and Tx: Reactivation TB
SSx: often occurs if immunocompromised, other stressor; cough, fever,
night sweats, weight loss, hemoptysis. Dx: XR with upper lobe apical
lesions ± cavitation. Dx: MTB culture/PCR of sputum (takes weeks), AFB
smear (suggestive but not diagnostic, need culture to confirm). Tx: RIPE
(Rifampin, Isoniazid, Pyrazinamide, Ethambutol), respiratory isolation
(airborne precautions), test/treat contacts
Immunocompetent person
undergoes a high risk exposure
to TB, what should you do?
- Test them now w/ PPD or interferon gamma and test them again in 3 months for conversion.
- if either of these tests are positive obtain a CXR and call an ID specialist.
What are the common side
effects of TB treatment with
RIPE?
Rifampin: orange body fluids, hepatotoxicity.
Isoniazid: neuropathy, hepatotixicity, seizures (in overdose, Rx: Vit B6).
Pyrazinamide:hepatotoxicity, teratogenic (pregnancy). Ethambutol: optic neuritis (redgreen color blindness)
Dx and Tx: Rapidly progressive
skin infection, unusually high HR,
and indifferent patient
Gas gangrene/myonecrosis. Clostridial myonecrosis (usually C.
perfringens). SSx: similar presentation to necrotizing fasciitis, tachy out
of proportion to fever, la belle indifference. Dx: subQ/intramuscular gas,
incision with foul-smelling “dishwater” fluid and dead muscle. Rx: abx
(amp + gent + clinda) + wide surgical debridement (dont delay abx)
Review the definitions of SIRS,
sepsis, severe sepsis, septic
shock
SIRS: Temp <36 (96.8) or >38 (100.4), Tachy >90, RR>20, WBC <4k or >12k or >10% bands.
Sepsis: SIRS + infection. Severe Sepsis: sepsis + end organ damage.
Septic Shock: sepsis + refractory hypotension.
Note: ITE/boards still test these concepts.
Review the key components of
Early Goal-Directed Therapy for
sepsis
Early IVF (30 cc/kg), early empiric antibiotics, MAP >65 (IVF or pressors),
SvO2>70%, CVP 8-12, transfuse pRBCs if Hct <30%. Note: strict
adherence to this regimen has been debunked by several recent trials,
but the necessity of adequate fluid resuscitation (30cc/kg) and early
antibiotics remains well-supported.
Empiric abx for sepsis
CAP: CTX + Azithro. HAP: Vanc+Zosyn. Urinary: Amp+Gent. Intraabdominal:
Amp+Gent+Metronidazole. Biliary: pip+tazo. Device related:
Vanc+Gent. Skin/Soft tissue: Vanco
Dx and Tx: Young woman with
high fever + rash + shock and
organ failure
Toxic Shock Syndrome. Cause: tampon, surgical or nasal packing or
other foreign body; bacterial superantigen. Staph (TSS): more common;
erythematous rash w/ desquamation, hypotension, fever, assoc. w/ fb;
Strep (STSS): fever, but less rash often with existing wound. Rx: remove
foreign bodies FIRST, supportive care, and antibiotics (clinda first to
reduce protein production, then empiric broad-spectrum for sepsis
coverage), IVIG for refractory cases
Dx and Tx: Primary syphilis
Treponema pallidum (spirochete). SSx: painless genital ulcer (chancre), regional LAD. Dx: VDRL/RPR are nonspecific and often negative at this stage. Tx: PCN G benzathine 2.4 million U IM x1
Dx and Tx: Secondary syphilis
Onset 5-8wks after primary. SSx: rash (papulosquamous) trunk →
palms/soles, condyloma lata. Dx: VDRL or RPR, confirm with FTA-ABS.
Tx: PCN G benzathine 2.4 million U IM x1 (if late disease three weekly
doses)
Dx and Tx: Tertiary syphilis
Onset: years after primary. SSx: gummatous lesions throughout body,
neurosyphilis (meningitis, dementia, Argyll-Robertson pupils
[accommodate but don’t react to bright light], tabes dorsalis [dorsal
column demyelination causing impaired proprioception and vibratory
sense [ataxia]). Dx: CSF-VDRL, confirm with FTA-ABS. Tx: admit for IV
PCN q4h x2wks
Dx: Worsened rash and toxicity
shortly after treatment of syphilis
Jarisch-Herxheimer reaction (2/2 endotoxin release from dying
spirochetes). Tx: Supportive.
Care plan if syphilis pt is allergic
to penicillin?
Admit for desensitization, they need PCN
Pathophysiology, Dx, and Tx:
Tetanus
Clostridium tetani spores which enter into wounds. Sources: dust, soil,
feces. Tetanospasmin = neurotoxin (blocks inhibitory [GABA] firing,
leads to unopposed excitatory firing). SSx: muscle spasticity (lockjaw,
painful tonic convulsions), but NORMAL mental status. Tx: supportive
(benzos, opioids, ± paralytics), wound care, abx (metronidazole > PCN),
Tdap vaccine (prevention) + tetanus IG (unimmunized + high risk
wounds
Review indications for tetanus
prophylaxis
≥3 vaccine doses + low risk wound: dT >10 yrs since last dose. ≥3
vaccine doses + high risk wound: dT >5 yrs since last dose. Uncertain or
< 3 vaccine doses + low risk wound: dT. Uncertain or <3 vaccine doses
+ high risk wound: dT & TIG. High risk wound: >6hrs old, contaminated
(dirt, saliva, feces), puncture/crush/avulsion wounds, fb, frostbite
Dx and Tx: Red rash to diaper
area with satellite lesions
Candida ; Rx: topical antifungals (also occurs in moist areas/skin folds esp. on diabetics)
Dx and Tx: Immunocompromised
+ odynophasia/dysphasia
Candida esophagitis; Rx: oral fluconazole, low threshold for IV for those who can’t tolerate PO.
Dx and Tx: Indwelling catheter +
yeast on blood cultures
Candida fungemia; Rx: Amphotericin B
Dx and Tx: AIDS + Diarrhea
Cryptosporidium, Isospora , CMV, M. avium; often unclear cause. Rx:
symptomatic care
Dx and Tx: Immunocompromised
+ Painless brown/black skin
lesions
Kaposi sarcoma (classically on face, chest, oral cavity), caused by HHV-8;
Rx: cryo or radiation. AIDS defining illness.
Dx and Tx: AIDS + white plaque
on oropharynx
Candida/Thrush: plaques scrape off (Rx: clotrimazole) vs. Oral Hairy
Leukoplakia: lateral tongue, can’t scrape off, caused by EBV, very
specific for HIV, NOT precancerous (DON’T confuse with oral leukoplakia
which is PRECANCEROUS, tobacco)
Dx and Tx: Meningitis and focal
neuro findings in AIDS pt
Cryptococcus neoformans (encapsulated yeast in soil with pigeon
poop), SSx: HA, neck pain, fever, AMS or CN abnormalities. Dx: CSF
cryptococcal antigen, LP with high opening pressure, + india ink stain
(send the CSF for cyptococcal antigen for confirmatory testing). Rx:
amphotericin B + flucytosine. MCC meningitis in AIDS.
Dx and Tx: Histoplasmosis
Dimorphic fungus. Found in spelunkers, caves, bird/bat droppings; can
cause epidemics if soil upturned. Endemic to Ohio and Mississippi River
valleys. SSx: flu-like sx, disseminated disease or chronic progressive
pulmonary disease (diffuse infiltrates and calcified nodes). Rx:
itraconazole, amphotericin B.
Dx and Tx: Immunocompromised
+ encephalitis + ring-enhancing
lesions on CT
Toxoplasmosis gondii (protozoan). Associated with cat poop, bad for fetus if infection occurs during pregnancy (TORCH). Tx: Pyrimethamine, sulfadiazine, folinic acid.
Dx: Travel + cyclical fever
Malaria. Plasmodium protozoan transmitted by female Anopheles
mosquito. Infects RBCs & hepatocytes. SSx: cyclical fevers (febrile
during periods of RBC rupture and merozoite spread), splenomegaly,
thrombocytopenia. Complicated dz: profound hypoglycemia, hemolytic
anemia, sz, coma. Dx: thick+thin blood smears (ring forms) ± Giemsa or
Wright stain.
Malaria Tx
Uncomplicated+chloroquine-sensitive (central america, Caribbean):
chloroquine. Uncomplicated+chloroquine resistant (South America,
South Asia, Africa): Quinine (hypoglycemia) + Doxy. Complicated or P.
Falciparum: Quinidine IV (QT prolongation)
What is the most
dangerous/severe strain that
causes malaria?
P. falciparum: cerebral malaria, “Blackwater” fever, death; Rx: IV
quinidine
Dx and Tx: traveler + myalgias
and fever
Dengue fever. Dengue virus + transmitted Aedes aegypti mosquito.
Common in Caribbean (Puerto Rico). SSx: high fever, dramatic myalgias
(“break-bone fever”), morbilliform rash. Dx: serology or ELISA,
leukopenia + thrombocytopenia. Rx: supportive
What is the cause, vector, and
treatment of Lyme disease?
Ixodes tick (deer tick) carrying Borrelia burgdorferi, primarily in northeast
US & Wisconsin; tick bite history is often absent. Rx: doxycycline,
CNS/cardiac involvement: IV CTX. Pregnant, children <8 Rx: Amoxicillin
What are the typical stages of
Lyme disease?
Stage 1: erythema migrans (“bull’s eye”) rash (1 wk). Stage 2: neuro
changes (meningoencephalitis = MC neuro finding with CN palsies -
bilateral Bell’s palsy), cardiac changes (variable AV block = MC cards
finding); (days to weeks). Stage 3: arthritis, neuro sx (months to years).
Tx: Doxy for everything other than severe carditis or neurological
manifestations, use IV ceftriaxone
Describe prophylactic tx of Lyme
disease
Criteria: tick attached for ≥ 36hrs, ppx started within 72 hours of tick removal. Other factors: tx if tick engorged. Rx: single dose Doxy
Dx, vector, and Tx: Recent hiking
or camping, rash spreading
inwards (“centripetal”,
palms/soles)
Rocky Mountain Spotted Fever. Rickettsia rickettsii. Transmission: wood
tick (Dermacentor andersoni), eastern US (Carolinas, Oklahoma). SSx:
fever (MC sx), centripetal (towards trunk) rash (palms+soles), calf
tenderness. Labs: low platelets, hypoNa. Rx: ALWAYS doxycycline
(even children)
Dx and Tx of Ehrlichiosis
Ehrlichia spp. with tick vector. South central & south Atlantic US. SSx:
abrupt onset fevers/chills/myalgias/rigors (differentiates from other tick
borne illnesses) ± rash. Labs: leukopenia, thrombocytopenia, and
elevated LFTs. Rx: Doxy, alt. Rifampin
Dx and Tx: Fever, exudative
pharyngitis, posterior
lymphadenopathy
Infectious mononucleosis. Epstein-Barr virus (EBV); Exam: ±
splenomegaly (risk rupture, limit contact/activity). Rx: supportive.
Dx: Mono + amoxicillin for
presumed strep
90% develop maculopapuluar rash (NOT an allergy)
What are associated lab
abnormalities found in patients
with mono?
Atypical lymphocytes, +heterophile antibodies (monospot test),
hemolytic anemia, thrombocytopenia, elevated LFTs, false positive RPR
or VDRL
What is the difference between
genetic drift and genetic shift?
Antigenic drift: minor mutation. Antigenic shift: major mutation; often used in context of influenza (orthomyxovirus) and HA/NA surface antigens
What defines a pandemic flu?
When antigenic shift takes place and a new strain of the influenza virus emerges.
Who is at high risk for death with
influenza and what is the usual
cause of death?
Extremes of age and pregnant women are highest risk; most common cause of death is secondary pneumonia.
What is the appropropriate tx
regimen and complications of tx
for influenza?
Oseltamivir/Tamiflu (GI sx) or Zanamivir/Relenta (bronchospasm,
wheezing) = Neuraminidase inhibitors if within 48hr of sx onset or hospitalized; No Amantadine/Rimantadine (both CNS sx) 2/2 resistance.
Dx and Tx: Rat poop and ARDS
Hantavirus. Transmitted via aerosolized rodent excretions. SSx:
Hantavirus pulmonary syndrome - ARDS, thrombocytopenia. Starts with
a flulike syndrome and is then rapidly progressive (and therefore many
patients are discharged and return critically ill). Rx: supportive
What is the location of dormant
herpes simplex?
Dorsal root ganglion, reactivated with stress/immunocompromise
What are the classic
locations/presentations for HSV
1 and 2 and how are they
diagnosed?
HSV-1: mouth, stomatitis, keratitis (possible corneal ulcer), vesicles on
digits (Whitlow); HSV-2: anus, genital, & neonatal (C-section if pregnant
and in labor). Dx: Tzanck smear (multi-nucleated giant cells), viral
culture. Rx: acyclovir
Compare the presentation and
treatment of chickenpox vs.
shingles (Varicella Zoster Virus)
Primary varicella (chickenpox): highly contagious, incubation ~2wks.
SSx: crops of vesicles in various stages of healing. Rash: “dew drop
rash on a rose petal”, starts on hairline → chest, palms/soles (+mucous
membranes). Rx: healthy/age <12: supportive, monitor for bacterial
superinfection; immuncompromised, age >12 = acyclovir. Shingles:
reactivation of dormant VZV. SSx: prodrome (itching, burning), rashpainful
vesicular eruption (usually unilaterally in a single dermatome), Rx:
acyclovir, steroids (controversial), pain control. Complication: postherpetic
neuralgia
Dx: Bell’s palsy and vesicle on
ear
Ramsay-Hunt syndrome/Zoster Oticus (VZV of CN VIII)
Dx: Vesicle on tip of nose
Hutchinson’s sign, V1 zoster, predicts corneal involvement/ulceration
(Zoster Ophthalmicus)
Treatment of herpes zoster
ophthalmicus?
Systemic oral anti-virals and topical steroids. This happens when the nasociliary branch of CN V is infected with VZV. Emergent
ophthalmology follow up is needed.
Tx of pregnant or
immunocompromised pt after
exposure to VZV?
Send titers to check for immunity, and if negative give varicella zoster
IG.
Pregnant woman presents with
SOB and wide spread itchy
vesicular rash in various stages
of development.
Varicella pneumonia. Tx: Admit and tx with IV acyclovir. VZIG IS NOT ENOUGH treatment.
what is the definition of
disseminated zoster?
Involvement of 3 or more dermatomes.
What animals are high risk for
rabies transmission?
Domestic animals: cats > dogs (dogs in developing coutries are HIGH
risk). Wild animals (account for ~90% cases in US): bats (MCC in US) >
raccoons > skunks > foxes > coyotes, mongooses. NOT rabbits or
rodents.
What are symptoms of rabies
infection?
Incubation 3-7wks, pain/paresthesia at bite site, hydrophobia (drinking water causes painful spasm), seizure, encephalitis, death
What is the treatment for rabies?
There is no treatment for active disease. PEP: HRIG (at wound site), HDCV (rabies vaccine): 5 injections over a month. PEP (vaccine + RIG) for close proximity with a bat and exposure cannot be ruled out (e.g. awakening to find bat in room, unattended children)
What defines AIDS?
HIV with CD4 < 200 OR AIDS defining illness (esophageal candidiasis,
cryptococcus, CMV, Kaposi, PCP, toxoplasmosis, TB (in an nonendemic
area)
What is the usual presentation of
acute HIV infection?
Acute HIV (Seroconvesion) Syndrome. Often missed, 2-4wk postexposure.
SSx: non-specific viral syndrome (fever, rash, LAD, myalgias).
Most infectious stage of HIV (high viral load + shedding), but antibody
testing will be negative as seroconversion takes 3-12 wk post-exposure.
How is HIV diagnosed
ELISA: to screen (sensitive), oral swab, delayed (+) weeks to months.
HIV-1/2 immunoassay & Western blot: to confirm; (sensitive + specific),
blood test.
What opportunistic infections are
more likely below the following
CD4 counts: <500, <200, <100,
<50
<500: TB, HSV, VZV, Kaposi’s sarcoma. <200: PCP, HIV
encephalopathy, candidiasis, PML. <100: toxoplasmosis,
histoplasmosis, cryptococcus. <50: CMV (GI, pulm, retina), MAC avium,
CNS lymphoma. NOTE: HIV pts get all usual infections as well, but
have increased risk of opportunistic as CD4 drops.
What common lab test can be
used as a surrogate to
determine CD4 count?
Absolute lymphocyte count (ALC). ALC < 1000→ suggests CD4 < 200
What is the time range for
starting post-exposure
prophylaxis after HIV exposure?
Should start within 72hr
Dx and Tx:
Immunocompromised +
pneumonia with severe
dyspnea/hypoxia + high LDH
PJP pneumonia. Pneumocystis jirovecii (formerly PCP). Most common
opportunistic infection in AIDS. SSx: fever, cough, desat on exertion.
Dx: CXR shows interstitial perihilar infilatrates (“bat wing” pattern). Rx:
TMP-SMX, steroids (indications: children, PO2< 70 mm Hg [~SaO2
~93%], A-a gradient > 35)
What are possible side effects
with pentamidine (Tx for PCP
pna)
Hypoglycemia, hypotension, pneumothorax
What are the appropriate
outpatient tx for PCP
pneumonia?
TMP-SMX; For sulfa allergic people: Primaquine + clindamycin, or TIMdapsone.
Pentamidine can be given but it’s only available in IV and
inhalation forms making outpatient therapy complicated. It also has many side effects. v
What are typical CT (noncontrast
and contrast) findings
with Toxoplasmosma
encephalitis?
Non-contrast CT: multiple subcortical lesions in basal ganglia. Contrast
CT: ring-enhancing lesions with surrounding edema. Rx: Pyrimethamine,
sulfadiazine and leucovorin
Dx: Ring-enhancing intracranial
lesions with 1) focal neuro deficit
or 2) generalized AMS
Focal deficits: Toxoplasma. Generalized AMS: CNS lymphoma
(hyperdense focal lesions, CD4 < 50)
Dx: HIV + CD4 <200, focal
neurologic deficits with
nonenhancing white matter
lesions
PML (JC virus)
Dx and Tx: Progressive
blindness in AIDS patient
CMV retinitis. Exam shows “fluffy white perivascular lesions (cotton wool
spots) with areas of hemorrhage.” Rx: IV Gancyclovir
What factors increase the risk of
transmission after occupational
exposure to HIV?
Deep injury, visible blood, hollow bore needle from vein or artery, late
stage HIV/AIDS or high viral load; transmission risk is 0.3% with
needlestick, 0.1% with mucous membrane exposure
What are the guidelines for postexposure
prophylaxis for HIV?
HIV+ and <72hr: HAART for 28d; if low risk and >72hr no treatment is
necessary. All others per clinical judgement.
What are potential oral antibiotic
options for community acquired
MRSA?
Clindamycin, TMP-SMX, doxycycline (requires IV vanco if hospital acquired)
Dx: Skin lesion, Gram positive
rod
Anthrax
Dx and Tx: Cutaneous vs.
pulmonary anthrax
B. anthrasis (Gram positive rod). Cutaneous: pruritic, black eschar + painful LAD over 1-2wks. Pulmonary: due to inhaled spores (not
contagious), flu-like sx. CXR shows wide mediastinum; rapid
progression to sepsis + death. Rx: cipro
Dx and Tx: Pneumonic and
bubonic plague
Yersinia pestis. Pulmonic: inhaled aerosolized rat droppings, very
contagious, severe pna, bio-terrorism agent. Bubonic: transmitted via flea bite, causes buboes + acral necrosis (black/dead distal extremities), may travel to lungs (contagious at this stage). Rx: streptomycin, gentamicin, doxycycline.
What risk factor is most strongly
associated with cellulitis?
Lymphedema
What is the appropriate
management of a patient with a
tick bite, target rash, and Bell’s
palsy?
CT and LP followed by ceftriaxone with concern for disseminated
Lyme/CNS Lyme
What is the most infectious bloodborne
pathogen?
Hep B, followed by Hep C and HIV
Dx and Tx: military recruit or
college student with fever, HA,
petechial rash
Meningococcemia. Neisseria meningitidis (aerobic, gram-negative
diplococcus). Rx: CTX + Vanco. Most common complication: Myocarditis
with CHF or conduction abnormalities. Comments: Waterhouse-
Friderichsen syndrome: bilateral adrenal hemorrhage +
meningococcemia
