Infectious Disease Flashcards
`Treat MSSA with what IV antibiotics?
Oxacillin/nafcillin or cefazolin
Treat MSSA with what oral abx?
Dicloxacillin or cephalexin
Treat MRSA severe infection with one of these six abx:
Vancomycin Linezolid Daptomycin Ceftaroline Tigecycline Telavancin
Treat a minor MRSA infecdtion with one of three abx:
TMP/SMX
Clindamycin
or Doxycycline
Linezolid causes what adverse effect?
Thrombocytopenia
Interference with MAOI’s
Daptomycin causes what adverse effect?
Myopathy, rising CPK
Does Tedizolid affect platelets or MAOI’s?
NO
Patients with a penicillin allergy and rash can safely receive
cephalosporins
Which three medications are specific for streptococcus and will not treat staph?
Penicillin
Ampicillin
Amoxicillin
The only carbapenem that does not cover pseudomonas is
Ertapenem
Levofloxacin, gemifloxacin, and moxifloxacin are excellent ___ drugs
pneumococcal
The four beta-lactam antibiotics are
penicillin
cephalosporin
carbapenem
monobactam
Beta-lactamase inhibitors are
Clavulanate
Sulbactam
Tazobactam
Avibactam
The best abx for abdominal anaerobes is
Metronidazole
The only cephalosporins that cover anaerobes are
Cefoxitin and Cefotetan
Treat red man syndrome associated with vancomycin use by
Slowing the rate of the infusion. No need to switch the medication!
The best long-term therapy for CMV retinitis is
Valganciclovir
Treat candidemia with
fluconazole or caspofungin
The best agent for Aspergillus treatment is
Voriconazole (adverse effect is visual disturbance)
All -azoles can cause ___ toxicity at high dose
liver
Echinocandins do not cover
Cryptococcus
Do echinocandins have adverse effects?
NO, because they attack the 1,3 glucan synthesis step which is not in humans
Amphotericine is directly toxic to
renal tubules, resulting in renal tubular acidosis
When renal toxicity from amphotericine is described, the answer is
switch to liposomal amphotericin
Best initial test for suspected osteomyelitis
plain x-ray
Best second test for suspected osteo (if x-ray is negative but there’s clinical suspicion)
MRI
Most accurate test for osteo
bone biopsy and culture
The earliest finding of osteomyelitis on an x-ray is
periosteal elevation
How do you know how long to treat osteomyelitis?
Track the ESR!
If it’s still elevated after 4-6 weeks of therapy, surgical debridement might be needed
The most common cause of osteo is
staphylococcus
Can you use oral therapy for staphylococcal osteomyelitis?
NO! IV all the way
The only osteo that can be successfully treated with oral abx is caused by
salmonella and pseudomonas (gram negative)
To confirm osteo is caused by a gram negative organism is to do a
bone biopsy
Malignant otitis externa is really osteo of the
SKULL (freaky.)
Diagnose MOE with
MRI or bone biopsy/culture
Treat MOE with
surgical debridement and abx against pseudomonas
The “next step” in treatment of otitis media is
performing the most accurate test, tympanocentesis and aspirate of the TM for culture (RARELY necessary)
If diagnosis of influenza is unclear, the best next step is
viral rapid antigen detection testing of nasopharyngeal swab
Only use oseltamivir or zanamivir if the patient presents…
within 48 hours of onset of symptoms
For whom is the live attenuated flu vaccine (nasal inhalation) effective?
Those <50 without medical problems
Treat impetigo with
topical mupirocin or retapumulin; severe = oral dicloxacillin or cephalexin
Very bright red and hot skin =
Erysipelas (often on the face)
Order blood cultures in CCS
Best initial treatment for erysipelas =
oral dicloxacillin or cephalexin (just like severe impetigo!)
If cellulitis is on the table, don’t forget to rule out
clotting (DVT)
Fungi have ___ in their outer wall that is tougher than epithelial cells
chitin
Scalp or nail fungal infection should be treated with
oral antifungals (Terbinafine, itraconazole, griseofulvin)
Diagnostic testing for urethritis is either __ or __
urethral swab for gram stain etc
Nucleic acid amplification testing
Treat urethritis and cervicitis with __ and __
ceftriaxone IM and azithromycin or doxycycline (not in pregnant patients)
The single best test for chlamydia and gonorrhea is
NAAT
A measure of the severity of pelvic inflammatory disease is
leukocytosis
The most important thing to do in a woman with lower abd pain/tenderness is
exclude ectopic pregnancy
Haemophilus ducreyi causes a ___ ulcer
painful
Best initial test for a chancroid (painful genital ulcer) is
swab for gram stain and culture
Specialized medium is Nairobi or Mueller-Hinton agar
Treat chancroid with
IM shot of ceftriaxone OR a single dose of azithromycin
Lymphogranuloma Venereum (LGV) is caused by
chlamydia trachomatis
Treat LGV by
aspirating the bubo and giving doxycycline or azithromycin
What is a unique side effect of erythromycin?
Increases GI motility by increasing motilin release (causes nausea, vomiting, diarrhea)
Treat acyclovir-resistant herpes with
foscarnet (NOT ganciclovir!!)
The most accurate diagnostic test for syphilis is
Darkfield microscopic exam.
Symptoms of primary syphilis are
chancre and adenopathy
Sx of secondary syphilis are
Rash, mucous patch, alopecia areata, condylomata lata
Sx of tertiary syphilis are
Tabes dorsalis, Argyll-Robertson pupil, general paresis, and rarely a gumma or aortitis
Treat tertiary syphilis with
IV penicillin (desensitize if allergic)
Treat primary and secondary syph with
single IM shot of penicillin (doxycycline if allergic)
Jarisch-Herxheimer reaction is caused by
the release of pyrogens from the dying tremponemal. It’s self-limiting
Treat Jarisch-Herxeimer rxn with
aspirin. continue penicillin
“Donovan bodies” =
Klebsiella granulomatis (Granuloma Inguinale) Tx: Doxy, bactrim, or azithro
An immunostimulant that can be used to slough off benign warts is
Imiquimod
First line treatment of uncomplicated cystitis is
fosfomycin or nitrofurantoin orally for 3 days
If E. coli resistance is high in a case of cystitis, use
ciprofloxacin or levofloxacin
Complicated cystitis is treated with
7 days of bactrim or cipro. Complicated means anatomic abnormality is present
Only treat asymptomatic bacteriuria if the patient is
pregnant or getting urinary instrumentation
Nitrites=
gram negative bacteria in urine
A rare complication of pyelonephritis that doesn’t respond to treatment after 5-7 days is
perinephric abscess
Boggy prostate =
prostatitis
Tx: cipro or bactrim
Start therpay for HIV when CD4 is
500 without exception
-navir =
protease inhibitor
-gravir =
integrase inhibitors
Efavirenz is avoided in
Pregnancy and psychosis
Adverse effects of Tenofovir
RTA and Fanconi syndrome and decreased bone density
Abacavir fun fact
HLA-B *5701 mutation is a contraindication!
AE of Zidovdine
anemia
AE of didanosine and stavudine
pancreatitis and peripheral neuropathy
AE of Lamivudine
NONE
AE of indinavir
kidney stones
AE of all nucleoside reverse transcriptase inhibitors (-dine, abacavir, emtricitabine, tenofovir)
Lactic acidosis
AE of all protease inhibitors
hyperglycemia, hyperlipidemia
AE of NNRTI’s (-vire/viri/vira)
drowsiness (avoid with mental illness)
Standard of care for HAART is
two nucleoside and an integrase inhibitor
Pre-Exposure Prophylaxis is
tenofovir and emtricitabine BEFORE exposure
Post-exposure prophylaxis for needle-stick injury in HIV patient is
ART for a month, starting within 72 hours of exposure
What is notable on labs in pneuocystis pnemonia?
increased LDH
Most accurate test for PCP is
bronchoalveolar lavage
Treat PCP pneumonia with
IV bactrim
If there’s a rash, use IV pentamidine or the combo of clinda + primaquine
Prophylaxis for PCP is
bactrim, or dapsone if there’s a rash with bactrim
Do not use dapsone if there is a
G6PD deficiency!
HIV with CD4<50 and blurry vision =
CMV! Do a dilated optho exam , treat with ganciclovir or foscarnet
CSF of a patient with cryptococcus will show increased
lymphocytes.
Most accurate test for cryptococcus is
cryptococcal antigen gest
Treat crypto initially with ___ then __
amphotericin and 5-FC, then fluconazole
HIV and CD4<50 and focal neurological abnormalities
Progressive multifocal leukoencephalopathy, best test is CT or MRI
HIV and CD4<50 and wasting, weight loss, fever, fatigue =
Mycobacterium avium-intracellulare
-anemia due to bone marrow invasion; test bone marrow or liver biopsy
Treat MAI with
clarithromycin and ethambutol
Minor Dukes criteria for IE is
fever >38 C, Risk factors, Vascular findings, Immunological findings, and microbiologic findings
Major Dukes criteria for IE =
two positive blood cultures abnormal echocardiogram (intracardiac mass, valvular vegetation, abscess, or new partial dehiscence of prosthetic valve)
Fever + new murmur =
possible endocarditis; best next step is to do blood cultures!!
What are roth spots?
Retina spots a/w infective endocarditis
Culture negative endocarditis causes =
coxiella and bartonella
The only procedures that need prophylaxis for endocarditis are
dental procedures that cause bleeding (amoxicillin)
respiratory tract surgery
surgery of infected skin
Treat leptospirosis with
ceftriaxone or penicillin
Tularemia should be treated with
doxycycline, gentamicin, or streptomycin
Don’t eat pork in Mexico, South America, Eastern Europe or India cuz of this
Cysticercosis; Treat with albendazole
“morulae” on peripheral blood smear (inclusion bodies in white cells ) =
Erhlichia/Anaplasma
