infectious disease Flashcards
clean surgical wound
no break techiniqueno inflammationclean areas: cardiac, vascular, neuro, ortho, ophtha
clean contaminated wound
POTENTIALLY colonized hollow viscus disrupted (head, neck, oral, abd, gym surg)minor break in procedure
contaminated wound
** penetrating trauma lt 4 hours old **inflammation already, MAJOR break in technique, major hollow organ spill
dirty wound
frank purulent drainage, abscess ** penetrating trauma gt 4 hours old **
clean areas of wounds
cardiac, vascular, neuro, ortho, ophtha
MRSA + central line relationship
87% bacteremic pts18-55% endocarditis ptshad central line
common MRSA sites
wounds, nares, trachea, perinum
MRSA - how resistance works
produce beta lactamasealtered penicillin-binding proteins (PBP) - rx efficacy needs high affinity between drug & PBP
- MRSA: at risk pops
aged / debilitatedmales/p surgery + lengthy hospymultiple invasive proceduresICU, trauma, burnindwelling cath, intravasc device, ET tube, ventprev hospyprior prolonged abx txpresence/size of wound
MRSA resistant to these meds
methicillinaminoglycosides: gentamicinerythromycintetracyclinescephalosporinsquinolones: cipro, floxin
what counts as epidemic
greater than 4 cases over baseline per month
MRSA + surgical pt care approach highlights
- tx remote infection prior to surgery (urine C&S + nasal swabs)- good control of glucose levels (150 ok, higher = increased infx risk)- special bathing protocol (air dry + chlorhexidine)- universal precautions always
MRSA + infected/colonized pt care highlights
CONTACT ISOLATION- gloves + hand wash most important- colonized + asymp + no surgical + no pna risk = NO NEED TO TREAT
MRSA: don’t need to treat who
pts who are… colonized + symp + no surgery + no pna risk
** MRSA TREATMENT ** x4
vanc (IV) 15 - 20 mg/kg/dose Q8-12 hrs- bacteremia - vanc or dapto 2 wk- infective endocarditis: vanc 6 wk- CAP (one of the following)– vanc IV 7-21 – linezolid (zyvox) PO/IV – clindamycin IV
vanc-resistant enterococcus
4th leading cause HAI in ICUintrinsic & acquired resistance possiblepoor prognosis w high mort rate
VRE key risk factors
- broad spectrum cephalosporins- parenteral vancomycin
** VRE TX OPTIONS **
newer abx: zyvoxcombo tx: pcn + vanc + gent
vanc resis r/t heavy use 3rd gen cephalosporins
klebsiella pneumoniae
** skin infection tx **
ORAL- clindamycin- bactrim (sulfa-tmp)- tetracycline- linezolid (zyvox)
** cellulitis organisms ** common / less (x3 each)
BOOYEAH: gram pos cocci- beta hemolytic strep (A, B, C, G, F)- staph aureus- MRSAEHHH?- gram neggies- h flu- non-spore forming anaerobes
cellulitis at risk pops
diabeteselderlypedal edemavenous or lymphatic compromiseobese: abdominal wall cellulitis
cellulitis s/s** + intensification + toxic
** erythema w irregular borders but “spreading” **tenderness, warmth, pain, edemalymphadenopathyno vesicles or bullaeINTENSIFY RAPIDLY (edema, eryth spread 6-36 hours)TOXIC: tachy(cardic/pneic), hypotensive, septicemia
spread of cellulitis s/s
INTENSIFY RAPIDLYeryth + ede 6 - 36 hours spread
important ddx for cellulitis
VTE nec fasc (appears toxic - HAS BULLAE and cellulitis don’t)
nec fasc s/s
skin necrosisbullaecrepitusanesthesia over skinrhabdomyolysisTOXIC!
** cellulitis w purulent drainage tx **
empirically for MRSA!!- clinda- bactrim- tetracycline (doxy)- linezolid (zyvox)
** non-purulent, no comorb cellulitis **
dicloxacillin 500 mg QIDcephalexin (keflex) 500 mg QIDclindamycin 300-450 mg q6 - 8 hrs ← pcn / cepha allergy
** acutely ill patient w cellulitis tx **
IV abxnafcillin (unipen or nafcil) 1-2 g IV q4hrscefazolin (ancef) 2 g IV q6hrsoxacillin 2gm IV q4hrsclindamycin 600-900 mg IV q8hr
cellulitis follow up
s/s resolved (typi within 24-48 hours)visible may take 72 hourslook for worsening
** recurrent cellulitis tx **
pcn 250-500 BID
tb transmission mode
airborne
primary TB
- infected but effective immune response not yet mounted- clinically & radiographically silent
progressive primary TB
5% infected, unable to contain organisms
** LATENT TB **
no active disease, cannot transmit10% progressive primary w/in 2 yearsactive tb will develop if immunocompromised or impaired (ex: prednisone)- pos ppd- neg CXR- no sx active tb
active TB
cough - at least 3 wks (dry to productive)fatigueweight lossanorexianight sweats***fever (low grade)blood streaked sputum (significant hemoptysis rare)bronchial breath soundsdullness to percussionRales, cracklesappears chronically ill, malnourished
gold standard tb diagnosis
CULTURE!!!!
tb dx
exposure hx, predisposing factors, s/sppd CXR: infiltrates, nodular densities in apical region of upper lobes3 early morning sputum specimens- acid-fast bacilli on smear- positive sputum culture bronchoscopy (bronchoalveolar lavage)gastric morning aspirate (after an overnight fast) - culture only, can’t smear
may have diminished reaction to PPD testing x4
malnourishedimmunosuppressedunderlying bacterial/viral infection
HIV patients + tb
anergistic
considered PPD conversion
wheal increases 10 mm+ within 2 years - needs follow up
** tb test interp: high
greater than 5HIV/AIDSclose contact tb positiveCXR = “old” healed tb
** tb test interp: moderate
greater than 10persons from high incidence country (asia, africa, latin america)IVDUunderserved, low incomeinsititutionalizedgastrectomy, jejunoileal bypass10% under IBWCKD, DMcorticosteroids or immunosuppressantleukemia, lymphoma, other cancers
** tb test interp: low
greater than 15everyone else
** CDC TB TX RECS **
4 rx = prevent resistance development- INH- rifampin- PZA- ethambutolmonitor liver & renal fxn- weekly culture + sputum smear x6 weeks then mo- mo f/u s/s AE
tb rx AE
INH, rifampin, PZA - hepatotoxicPZA - ↑ uric acid levelsethambutol - optic neuritis
ethambutol monitoring
visual acuity & red/green color perception (causes optic nerve damage)
protease inhibitor and rifampin
CONTRAINDICATEDalt: rifabutin
FUO criteria
illness - 3 wks durationgt 100.4 F / 38.3 C several occasions undx after 3 office visits / 3 days in hospital3x s/s severe enough to require evaluation
hospital associated FUO
over 38.3 C (several occasions)admission cultures negativeundx after 3 days
neutropenic FUO
THINK CHEMOover 38.3 Cneutrophils less than 500neg culturesundx after 3 daysdifferentials: fungal, occult bacterial infx
HIV-associatied FUO
over 38.3 C- 4 wk outpt- 3 days inptwill see CMV, fungal infection, pneumocystis pneumonia
common causes of FUO
tuberculosisendocarditis (recent dental work? murmur?)gallbladder diseaseHIV (primary or opportunistic infection)systemic infection: tb, endocarditis, CMV, Epstein Barrinfection: 25-40% cancer: 25-40% (lymphoma, leukemia)undx: 10-15%
common abscess sites/sources
liver, spleen, kidney, brain, bonegall bladder (cholecystitis)UTIdental abscess paranasal sinuses
big tx no no with FUO
NO STEROIDSmasks fever, exacerbates infectious process
anion gap + FUO
Na - (CO2 + Cl)normal: 10 - 1216+ – losing bicarb or retaining H
fever 101+ tx
NSAID: naproxen 250 mg BIDget blood cultures first - remember, can take 3 to 5 days to grow
when to admit FO
- appears “toxic”2. declining rapidly with / without weight loss3. neutropenic (chemo)4. s/p transplant within 6 mo
PIs, NNRTIs - interactions
metabolized by Cyp450 system, can be inhibitor, inducer, and substrate
Ritonavir, Cobicistat - interactions
avidly bind Cyp34A enzyme & can yield very high levels of competing compounds
HIV drugs: key drugs resulting in interactions
Versed Statins Cafergot Rhythmol Viagra Rifampin Fluticasone
viral load & CD4 count: goals & use
viral load
- monitor this value!
- goal: undetectable @ under 20 - 75 copies/mL
CD4 count
- AIDS defining: under 200/uL (level at which ↑ risk opportunistic infection)
- reference range: 500 - 2000 cells/uL
HIV: ELISA
enzyme-linked immunosorbent assay - rapid test
most commonly used screening method
HIV: western blot
most widely accepted confirmatory assay for detection of ab to HIV retrovirus
kernig’s sign
straighten bent leg = pain
sign of meningitis
brudzinski sign
flex neck = flex knee
sign of meningitis
