Infectious Disease Flashcards
methicillin is not used because..
it causes allergic interstitial nephritis
penicillin used in tx for?
otitis media dental infection & endocarditis prophylaxis lyme disease (rash) UTI in pregnant women listeria enterocococcal infections
pipercillin, ticarcillin used in tx for?
cholecystitis ascending cholangitis pyelonephritis bacteremia HCAP VCAP neutropenia & fever
-covers enterobacteria, pseudomonas, strep, anaerobes
penicillin rash vs anaphylaxis. what do you switch tx to?
cephalosporin
non-beta-lactam antibiotic
cefotetan & cefoxitin (2nd generation) tx & SE
- tx PID (with doxycycline)
- SE: inc bleeding risk, disulfiram-like reaction
ceftriaxone use in tx for?
- pneumococcus
- meningitis
- CAP
- gonorrhea
- lyme (involving heart & brain)
-avoid in neonates (imp oared biliary metabolism)
carbapenems covers which types of bacteria?
(imi, mero & doripenem
- gram(-)bacilli
- anaerobes
- strep
- staph
- neutropenia & fever
aztreonam covers which types of bacteria?
- gram(-) bacilli only
- includes Pseudomonas
-no cross reactivity with penicillins
ciprofloxicin used in tx for?
cystitis
pyelonephritis
diverticulitis (+ metronidazole)
GI infections
-moxifloxicin = single agent for diverticulitis without metronidazole
floroquinolone SE?
cipro, gemi, levo and moxifloxacin
- bone growth abnormalities in kids and pregnant women
- tendonitis (achilles tendon rupture)
-contraindicated in children
amino glycosides used in tx for? SE?
gentamicin, tobramycin, amikacin
- bowel, urine, bacteremia from gram (-)
- synergisitic with beta-lactams against enterococci & staph
-SE: nephro & ototoxic
doxycycline uses? SE?
- chlamydia
- lyme (rash, joint, Cr VII palsy)
- MRSA skin
- rickettsia
- syphilis (ONLY if allergic to penicillin)
-SE: tooth discoloration, Fanconi (type II RTA), photosensitivity
TMP-SMX uses? SE?
trimethoprim-sulfamethoxazole
- cystitis
- PCP tx & prophylaxis
- MRSA cellulitis
-SE: rash, hemolysis (G6PD deficiency), marrow suppression (via folate antagonism)
nitrofurantoin use?
cystitis in pregnant women
staph & strep tx?
- oxacillin/ nafcillin/ dicloxacillin
- 1st gen cephalosporins: cefazolin, cephalexin
- floroquinolones
- macrolides (3rd line)
MRSA tx?
- vancomycin
- linezolid
- daptomycin
- tigecycline
- ceftaroline
-minor MRSA infections: TMP-SMX, clindamycin, doxycycline
oral anaerobe tx?
- penicillin (G, V, amp/ amoxicillin)
- clindamycin
- metronidazole (GI)
- pipercillin, carbapenems, 2nd gen cephalosporins
meningitis vs encephalitis vs abscess = fever + headache +
meningitis: stiff neck, photophobia
encephalitis: confusion
abscess: focal neurologic deficit
bacterial meningitis causes?
-strep pneumo = most common
- group B strep (neonates)
- H flu (dec since vaccinations)
- Neisseria meningitis
- listeria (immunocompromised pts; requires ampicillin)
- staph -after neurosurgery
meningitis in AIDS pts cause?
cryptococcus
meningits dx
lumbar puncture = most accurate
CSF dx? bacterial vs viral
bacterial: 1000s neutrophils, elevated protein (marked in TB), decreased glucose, positive gram stain (not in TB)
viral: lymphocytes, no change in protein or glucose
head CT before LP if?
- papilledema
- seizures
- focal neurologic deficits
- confusion
-start broad spectrum therapy before CT
bacterial antigen test used when?
-pts given antibiotics prior to LP
culture may be falsely negative
cryptococcal dx?
- india ink
- cryptococcal antigen
meningitis tx?
ceftriaxone + vancomycin + steroids
-while waiting for culture and gram stain
dexamethasone use?
- lowers mortality in strep pneumo
- 1000s of neutrophils
-combined with ceftriaxone + vancomycin
ampicillin use in meningitis?
listeria infection
- immunocompromised pts
- can’t use cephalosporins
Neisseria meningitis close contacts tx?
rifampin or ciprofloxacin
- those who kiss, share cigs/eating utensils, have major fluid contact
- not HC workers
encephalitis cause & dx & tx
- HSV = most common
- dx: PCR of CSF
- tx: acyclovir; foscarnet
acyclovir vs foscarnet
- foscarnet has more nephrotoxicity than acyclovir
- foscarnet used in acyclovir-resistant HSC
- different MOAs
most sensitive PE finding of otitis media?
immobility of tympanic membrane
-other findings: redness, bulging, dec light reflex, fever
otitis media tx
- amoxicillin
- usually self-resolving
pharyngitis px & dx
pain + nodes + exudate + fever + NO cough/ hoarseness
- often Group A beta-hemolytic strep
- dx: rapid strep test
other causes of pharyngitis?
HSV herpangina (coxsackie A) diptheria vincent angina EBV
pharyngitis tx
- penicillin or amoxicillin
- clindamycin or macrolide
influenza px
- arthralgias/myalgias
- cough
- fever
- headache
- n/v (children)
influenza dx & tx
-dx: nasopharyngeal swab
- tx: oseltamivir or zanamivir (within 48 hours; shorten duration)
- symptomatic tx if >48 hours
Associations for bacterial diarrhea: salmonella campylobacter E coli 0157:H7 Shigella (shiga toxin) vibro yersinia clostridium difficile
poultry Guillain-Barre Syndrome HUS = fragment cells, low platelets, high BUN/ creatinine HUS shellfish & cruise ships hemochromatosis, blood transfusions antibiotcs
infectious diarrhea dx?
blood and/or fecal leukocytes = best initial
- lactoferrin has a higher specificity
- stool culture = most accurate
no blood or WBCs in infectious diarrhea
viral Giardia (camp/hiking) cryptosporidosis (AIDS <100; AFS) bacilllus cereus (preformed toxin) staph (preformed toxin) scombroid (found in fish; tx with antihistamine; rapid onset)
infectious diarrhea tx
- fluids
- fluids + ciprofloxacin (severe)
Giardia diarrhea tx
metronidazole or tinidazole
-cipro does not cover it
cryptosporidiosis diarrhea tx
nitazoxanide & tx underlying AIDS
viral, b. cerus, staph diarrhea tx
fluid support
hepatitis E
- worst in pregnancy (fulminant hepatitis)
- East Asia
- feco-oral
elevated PT time indicates?
60% of liver destruction
PCR levels = amount of active viral replication
indicates…
indicates response to hepatitis therapy
hepatitis B serologic patterns
HBsAg = acute/chronic infection; 1st to inc
HBeAg = acute, infectivity measure HBcAb = IgM(acute) or IgG(resolved) HBsAb = resolved
HBV vaccination serology
HBsAb ONLY
-negative HBsAg, HBeAg, HBcAb
HBV “window period” serology
HBcAg (IgM then IgG)
-negative HBsAg, HBeAg, HBsAb
No HBsAg indicates
you can’t transmit infection
e-antigen indicates
- tx is needed since there is active disease replication
- indicates transmissibility from pregnant woman to child
-whereas HBeAb does NOT require tx
HAV & HEV tx?
none
HBV tx?
acute: none
chronic: entecavir or adefovcir, tenofovir, lamivudine or telbivudine or interferon (IM) —monotherapy
HCV tx?
interferon + ribavirin + telaprevir/boceprevir
interferon SE
- arthralgia/myalgia
- leukopenia & thrombocytopenia
- depression & flu-like symptoms
ribavirin SE
anemia
UTI dx?
urinanalysis –> shows inc WBCs
-microbe: E. coli
UTI causes
- stones
- strictures
- tumor
- BPH
- DB (dec effectiveness of WBCs)
- foley catheter
- neurogenic bladder
UTIs in men due to?
anatomic abnormality
- must image
- best initial test: urinanalysis >10WBCs
- most accurate: urine culture
UTI tx
- quinolones (cipro)
- TMP-SMX
- nitrofurantoin
- cephalexin
- 3 day tx
- 7 day tx for anatomic abnormality –also need imaging
- culture if recurring infection
pyelonephritis tx
- ampicillin + gentamicin (renal-excretion, thus good penetration of infection)
- ciprofloxacin
- must cover gram(-) bacilli
-imaging to look for anatomic abnormalities causing infection/ to prevent future infections
unresolving pyelonephritis, next step?
- sonogram or CT scan to look for perinephric abscess
- drain
- culture to guide therapy
urethritis dx & microbes
- men: urethral swab = best initial
- women: self-administered vaginal swab
-nucleic acid amplification test (NAAT) = most accurate
- for gonorrhea & chlamydia
- also mycoplasma, ureaplasma
urethritis tx
- gonorrhea –cefixime (oral) or ceftriaxone (IM)
- chlamydia –azithromycin (oral) or doxycycline
cervicits px & dx & tx
- px: inflamed “strawberry” cervix
- dx: self-administered swab for NAAT
- tx: cefixime/ceftriaxone & azithromycin/doxycycline
PID px
- lower abdominal tenderness & pain
- fever
- cervical motion tenderness (via bimanual exam)
-EXCLUDE PREGNANCY FIRST with this px
PID dx
- cervical swab for culture & NAAT = most specific
- laparoscopy = most accurate (rarely used)
-culture needed for gonorrhea (to determine resistance)
PID tx inpatient
inpatient: cefoxitin or cefotetan (2nd gen cephalosporins) + doxycycline
- 2nd gen cephalosporins cover anaerobes
- clindamycin & gentamicin (for penicillin anaphylaxis)
PID tx outpatient
ceftriaxone & doxycycline +/- metronidazole
-levofloxacin & metronidazole (for penicillin anaphylaxis)
genital ulcer types:
- painless
- painful
- LN tender & suppurating
- vesicles prior to ulcer
- syphilis
- chancroid (H ducreyi)
- lymphogranuloma venereum (Chlamydia)
- HSV
genital ulcer dx:
- syphilis
- chancroid
- lymphogranuloma venerium
- HSV
- dark-field microscopy; VDRL, RPR; FTA
- stain & culture (gram-)
- complement fixation titers in blood
- Tzanck prep, viral culture
syphilis dx
-dark-field = most accurate bc actually see the organisms
- VDRL or RPR = 75% sensitive (1/4 false negative)
- FTA = confirmatory
genital ulcer tx:
- syphillis
- chancroid
- lymphogranuloma venereum
- HSV
- IM benzathine penicillin (doxy if allergic)
- azithromycin (single dose)
- doxycycline
- acyclovir, valacyclovir, famciclovir; foscarnet
secondary syphilis px
- rash (palms & soles)
- alopecia areata
- mucous patches (mouth & genitals)
- condylomata lata
tertiary syphilis px
- neurosyphilis
- stroke from vasculitis
- tabes dorsalis = loss of position & vibration sense, incontinence, cranial nerve
- general paresis
- Argyll Robertson pupil (reaction to accommodation, but not light)
- aortitis
- gummas
false positive VDRL/RPR in?
- antiphospholipid syndrome
- endocarditis
- malaria, AIDS, IV drug, infection, older age
-false positive often have lower titers
Jarisch-Herxheimer reaction
=fever + headache + myalgias after syphilis tx
- uncomfortable, but no danger to pt
- give ASA & antipyretics
-desensitization for neurosyphilis & pregnant women
condylomata acuminata microbe, px, tx
- papillomavirus (HPV)
- px: visual appearance of warts
-tx: cryotherapy with liquid nitrogen; surgery for large, podophyllin, imiquimod (gentle)
crabs = pediculosis px, tx
- hair-bearing areas (axilla, pubis)
- itchy
-tx: permethrin (less SE than lindane)
scabies px, tx
- very small
- b/t fingers, toes, elbows
-tx: permethrin, oral ivermectin
endocarditis px & dx
-px: fever + new murmur
- dx: blood cultures
- echo only if (+)blood cultures (TTE) –> TEE if (-)TTE
endocarditis complications:
- splinter hemorrhages**
- Janeway lesions (flat & painless)
- Osler nodes (raised & painful)
- Roth spots (back of eye)
- mycotic aneurysm (embolic infection into brain)
- GN & hematuria –>death
- conjunctival petechiae
- septic emboli to lungs
empiric therapy for endocarditis
vancomycin + gentamicin
viridans strep endocarditis tx
ceftriaxone or penicillin for 4 weeks
stap aureus endocarditis tx
oxacillin, nafcillin, cefazolin
fungal endocarditis tx
amphotericin & valve replacement
MRAS/staph epidermidis endocarditis tx
vancomycin
enterococci endocarditis tx
ampicillin & gentamicin
surgery for endocarditis in cases of?
acute valve rupture
CHF
most common culture negative endocarditis =
coxiella & bartonella
-not HACEK organisms
endocarditis prophylaxis for:
cardiac defect + risk of bacteria
- prosthetic valve, previous endocarditis, cardiac transplant, unrepaired cyanotic HD
- dental work with blood, respiratory tract surgery
- amoxicillin prior to procedure
- clindamycin, azithromycin, clarithromycin
tick must be attached for how long to get lyme disease?
24 hours
most common joint affected by lyme disease?
knee
neurologic manifestations of lyme disease?
bell’s palsy (face) or Cr VII
cardiac manifestation of lyme disease (untreated)?
transient AV block = most common
-myocarditis, ventricular arrhythmia
lyme disease tx
rash/joint/Cr VII –> doxycyline or amoxicillin
cardiac/neurologic –> IV ceftriaxone
HIV dx
- ELISA = best initial; very sensitive
- western blot = confirmation
-viral culture in infants
viral load testing via
PCR-RNA levels
- measures response to therapy
- dx in babies
as viral load decreases, CD4 cells ______
increase
–> dec opportunistic infections
HIV initial drug regimen
emtricitabine + tenofovir + efavirenz
- 1 combo tablet
- 3 drugs from 2 different classes (RTI, NRTI, PI)
RTI (= nucleoside reverse transcriptase inhibitors) MOA
- stop transcription of viral DNA in infected T cells
- “-vudines”
NRTI MOA
- stops viral transcription
- efavirenz > etravirine, nevirapine
protease inhibitors
- “-avirs”
- AIDS virus drugs
- cause hyperlipidemia & hyperglycemia
entry inhibitors
- enfuvirtide
- maraviroc
- blocks HIV from entering cell
- works well in combo with other drugs
integrase inhibitor
- raltegravir
- virus already transcribed, but cannot enter T cell DNA material
SE: zidovudine stravudine & didanosine abacavir protease inhibitor indinavir tenofovir
- macrocytic anemia
- peripheral neuropathy & pancreatitis
- hypersensitivity, Stevens-Johnson Reaction
- hyperlipidemia & hyperglycemia
- nephrolithiasis
- renal insufficiency
HIV drug avoided in pregnancy?
efavirenz (NRTI)
baby of HIV mother.. tx?
- zidovudine during delivery
- for 6 weeks after delivery
-C section if viral load>1000
