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Flashcards in 4 Infectious Disease Deck (48)
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Cipro, Levo, Moxi: how to think about them:

All are good against G negs, and get better with G positives. Starting fro Cipro (good UTI) to Levo, to Moxi (good PNA).


Abx for CAP PNA?

Why Moxi not good?

outpt: azithro
inpt: Cef + azithro

Moxi: works, but try not to use b/c breed resistance to quinolones in UTIs



Vanc + Zosyn


Meningitis abx
add ampicilin for what criteria? (6)

Cef + Vanc.
+ ampicillin in young/old, + acyclovir if suspect herpes
+steroids possibly.

1. elderly
2. neonate
3. mab
4. chemo
5. HIV
6. transplant


UTI abx for:
1. ambulatory UTI
2. ambulatory pyelo
3. inpt pyelo
4. sick as shit

1. cipro, amox, or nitrofurantoin
2. Cipro
3. ceftriaxone
4. vanc+ zosyn


which UTI abx to use in pregnancy

nitrofurantoin (macrobid) is only one


Cellulitis abx (3 main choices)

1. cephazolin (keflex). -- Outpt, for possible strep

These if you think MRSA:
2. Bactrim
3. Clinda


Pt with suspected meningitis. Who needs CT scan first?

Focal neuro deficit
Lesion over puncture site


Pt with HIV and suspected meningitis. You get LP, which shows 97% lymphs, 250 WBCs, high protein, low gluc, high opening pressure. No bact seen on Gram stain.

What tests to order?

1. RPR for syphilis
2. cryptococcal Ag
3. AFB smear and culture


HIV ppx at what CD4 count, what med, and what backup meds?
(3 infections)

1. PCP. <200. Bactrim, Dapsone, Atovaquone

2. Toxo. <100. Bactrim, Primaquine

3. MAC. <50. Azithro


IRIS--immune reconstitution inflamm syndrome

what is this

Starting HAART during severe infection can lead to poor outcome. Eg, in HIV pt with meningitis, HAART can cause immune response to increase ICP and cause herniation and death.


Your post-op pt develops PNA at post-op day 3. Allergic to penicillin with anaphylaxis. What can you give him?

HAP. So normally Vanc and Zosyn, but pen allergic.

MRSA: Vanc or Linezolid
Pseudomonas: Penem. Cipro covers pseudomonas but not enough strep. Ceftriaxone or Cefepime possible if allergy was just rash.


Person comes to ED with possible HIV exposure (needle stick, rape, condom failures). Do what

PEP. 2+1 retroviral for 4 weeks. Get viral load PCR


Pt with possible acute HIV. What test to get?

Get PCR for viral load.
NOT ELISA b/c it takes 6 weeks after infxn to create Ab.


HIV pt with PCP PNA. What tx, and when to add steroids?

Bactrim. Add prednisone if PaO2<70


TB: primary vs reactivation lesions: where in lungs?

primary: usu in middle and lower lobes

reactivation: apices, where O2 is highest


PPD screen:

who's in which category

(> or equal)

>5mm: very sick.
HIV, TB close contacts, immunocompromised

>10mm: normal ppl with risk factors.
prison, military, healthcare, homeless

>15mm: no risk factors
soccer mom in Wyoming


Asx TB screening. What to do if?

1. PPD +, CXR -
2. PPD+, CXR +

1. No active infection. Latent. PPx INH for 9mo, + VitB6

2. Don't know if latent or active. Do AFB.
1) AFB+: active TB, do RIPE. actively infectious!!
2) AFB-: latent TB. PPx INH for 9mo, + VitB6


Sick pt in ED, you suspect active TB. How to approach, and what tests?

1. CXR looking for apical lesions.

2. Sputum AFB smears and cultures. CXR + or -, can't r/o active TB, so get these even negative CXR. 3 AM AFB smears, or 3 smears q8h.

3. If +culture, then active TB. RIPE.

If -culture, then Latent TB but sxs NOT caused by TB. Do PPx INH x9mo, and look for something else, maybe malignancy.


When is TB sputum culture positive a false positive?

False positive with MAC. Can occur with pt with suspected acute TB with CXR- but Cx+.


TB drug side effects

Rifampin--red urine/eye/tears
Isoniazid--neuropathy (give B6)
Ethambutol--color vision

ALL have Hepatotox.


SIRS, sepsis, and severe sepsis criteria:

Temp <36, >38
HR >90
RR >20 or pCO2<32
WBC <4, >12, or >10% bands

severe sepsis: SIRS+source, + organ dxsfunction:
-Vessels: SBP<90 or 40 less than nl
-Tissue: lactate >4
-Renal: elevated BUN, Cr
-Liver: LFTs, coags
-Heart: Trops
-Brain: AMS



Confusion, new onset
Urea >7 (or BUN>19)
RR 30+
BP: SBP <90 or DBP =60
Age 65+

1: outpt
2. outpt with close f/u, or admit
3-5: admit, with possible ICU


pt with suspected meningitis: You give empiric abx before CT and LP. How much time you have to get LP?

2-hr window to collect CSF


Fungal skin infections: how to approach?
1. 3 presentations to know
2. how to dx
3. tx

1. patchy alopecia, patchy skin discoloration, itchy burning feet

2. dx with KOH prep and cx, but usu not necessary.

3. Hair or nail involvement? if so, systemic antifungals--over several months.

Otherwise, topical. Terbinafine for several weeks.


erysipeloid vs typical cellulitis

erysipeloid: with ascending lymphangitis, caused by strep

Typical: staph: expanding erythema


Ostemyelitis risk factors and bugs

-penetrating sneakers
-sickle cell
-erysipeloid (hands)

-strep pyo


Osteomyelitis tx

Vanc+Zosyn immediately only if toxic, then abx based on sens:
-1 time bone bx for cx and sens. Do this quickly so broad spec abx doesn't spoil the bx.
-tx for 4-6 weeks.
-CRP, ESR, and MRI qweek.


Pt in ED with suspected gas gangrene on skin. What things to do next?

Suspicion based on creptius. Get XR to look for air (spec, not sens)

-Call surgery for emergency debridement. Start PCN and Clinda. Consider hyperbaric O2


CAP, HCAP, HAP, VAP definitions

HCAP: recently hospitalized within 90 days, reside in nursing home or long-term care facility, or received parenteral antimicrobial tx, chemo, or wound care within 30 days.
HAP: 48h+ after admission.
VAP: 48h+ after intubation