Master the Boards: Infectious Disease Flashcards
If a patient has a rash to penicillin then what antibx do you recommend?
If a patient has an anaphylactic reaction to penicillin then what antibx do you recommend?
Rash: Cephalosporin
Anaphylaxis: Non-beta-lactam
2nd gen cephs have added coverage to ______ compared to 1st gen cephs.
Added anaerobe and more gram-negative bacilli
Why should ceftriaxone be avoided in neonates?
What 3rd gen cephalosporin has Pseudomonal coverage?
Ceftriaxone may cause impaired bilirubin metabolism
Cefotaxime
Name a 4th gen ceph
Cefepime
What is an important adverse effect of cefoxitin and cefotetan?
Depletion of prothrombin and increased risk of bleeding
What unique coverage does aztreonam have?
Does it cross-react with penicillin?
Only gram-negative bacilli, including Pseudomonas
No cross-reaction with penicilllin
Fluoroquinolones have coverage of what bacteria?
Which fluoroquinolone also has anaerobic coverage?
Gram negative bacilli, including Pseudomonas
Moxifloxcin has anaerobe coverages (thus can be used as a single agent in the treatment of diverticulitis i.e metronidazole doesn’t have to be added)
Do aminoglycosides have any anaerobic effect?
What are the major toxicities?
No.
Nephrotoxic, ototoxic
Cystitis in pregnant woman is best treated with _____.
NItrofurantoin
Fanconi Syndrome (Type II renal tubular acidosis proximal), photosensitivity, and esophagitis/ulcer are all adverse effects of _____.
Doxycycline
Patients allergic to penicillin but requiring treatment of syphillis may receive _________.
Doxycycline
What drug can cause both G6PD deficiency hemolysis and bone marrow suppresion?
Trimethoprim/Sulfamethoxazole
BM suppression because it’s a folate antagonist
What are your choices for tx of MRSA (5)?
What if it was a minor skin infection?
Vancomycin Linezolid Daptomycin Tigecycline Ceftaroline
Minor skin infection: TMP/SMX, Clindamycin, Doxycycline, Linezolid
You’re treating a MRSA patient and they develop elevated CPK levels, what are you treating with?
What if they showed signs of bone marrow toxicity?
Daptomycin: Elevated CPK
Linezolid: Reversible bone marrow toxicity
The presence of papilledema, seiures, focal neurologic deficits, or confusion should warrant what exam before conducting an LP in suspected meningitis?
CT head to r/o space-occupying lesion
What is empiric treatment of meningitis prior to knowledge of culture results?
What should be added to that therapy if the patient is neonate, old, immunocompromised, or pregnant?
Ceftriaxone, vancomycin, steroids
Add ampicillin for fear of Listeria infection
What is the most common neurological deficit in untreated bacterial meningitis?
CN 8 damage or deafness
Acyclovir has what adverse effect to keep in mind?
Renal toxicity since it precipitates in renal tubules
Is the radiologic test usually the answer in an ID question about the “most accurate test”?
No
Small vesicles or ulcers ID’d on exam of a patient with pharyngitis could move you towards what other two diagnoses?
HSV or Herpangina
Blood and WBC in stool in a patient with hemochromatosis or a recent blood transfusion may be cause by what pathogen?
Yersinia (has a high affinity for iron)
A patient eats some spoiled fish and develops wheezing, flushing, and a rash. What is the cause and what is the tx?
Scombroid
Anti-histamine
Elevation of which lab in hepatitis is associated with increased risk of mortality?
Prothrombin time (PT)
In addition to gram positive bacteria, what additional coverage to amoxicillin and ampicillin provide?
Other gram-negative bacilli
H. influenzae, E. coli, Listeria, Proteus, Salmonella
Does cystitis give urethral discharge?
No
A woman presents with symptoms of PID. What should you do before moving forward with treatment?
Rule out pregnancy
STD buzzwords
Painful ulcer
Chancroid (H. ducreyi)
STD buzzwords
Tender lymph nodes and suppurating
Lymphogranuloma venereum
Rank tests for determining syphilis based on accuracy or sensitivity
VDRL/RPR
Best initial test for determining HSV?
Most accurate?
Best initial: Tzanck smear
Most accurate: Viral culture
What diagnostic tests are used to confirm lymphogranuloma venereum?
Complement fixation titers in blood
Nucleic acid amplification testing on swab
Tx Chancroid
Azithromycin (single dose)
Tx Lymphogranuloma venereum
Doxycycline
Patients with syphilis are at greater risk for what vascular complication?
Aortic aneurysm and aortic regurgitation
What is the treatment of syphilis in each stage (primary, secondary, and tertiary) and how does it change if penicillin allergic?
Primary and secondary: single dose IM benzathine penicillin (Doxycycline if allergic)
Tertiary: IV penicillin (penicillin desensitization if allergic)
What is a Jarisch-Herxheimer reaction and what is treatment?
Fever and worsening of symptoms after treating syphilis patient with penicillin
Give aspirin and antipyretics, it will pass on its own
What causes condyloma acuminate?
aka genital warts
HPV
A patient comes in with intense itching at his pubis and axilla (hair-bearing regions). You suspect pediculosis (crabs). What is tx?
Permehrin
Lindane can also be used but has more toxicity
What presents in the web spaces of the fingers and toes and burrows in the skin? What must be done to confirm a diagnosis?
What is tx?
Scrape and magnify the burrows to dx
Treat with permethrin
A patient presents with likely pyelonephritis but fails to improve on antibx therapy. What should be the next test done?
Imaging using ultrasound or CT to evaluate for a perinephric abscess and if present it must be drained
What is the best initial therapy in suspected endocarditis prior to results of cultures?
Vancomycin and gentamicin
What is the treatment of Viridans Strep endocarditis?
Ceftriaxone
What is the treatment of Enterococci endocarditis?
Ampicillin and gentamicin
What drug should be added to the treatment of Staph endocarditis if there is a prosthetic valve involved?
Rifampin
When should surgery be considered in endocarditis (6)?
CHF or ruptured valve/chordae tendinae Prosthetic valves Fungal endocarditis Abscess AV block Recurrent emboli while on tnibx
What is the most common agent responsible for culture-negative endocarditis?
What are the HACEK organisms?
MC: Coxiella (also Bartonella)
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Use ceftriazone for HACEK organisms
Haemophilus
Actinobacillus
Cardiobacterium
Eikenella
Kingella
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What is endocarditis prophylaxis?
In what situations would you offer the prophylaxis?
Amoxicillin
Significant cardiac defect: previous endocarditis, prosthetic valve, recent cardiac txp, unrepaired cyanotic heart disease
Risk of bacteremia: Dental procedure W/ blood, respiratory tract surgery that produces bacteremia
What is the most common neurologic and cardiac manifestation, respectively, of Lyme disease?
Neurlogic: Bell’s Plasy
Cardiac: AV block
What is generally the treatment of Lyme disease?
When it is advanced and involves cardiac or neurologic manifestations then what is tx?
Doxycycline
If advanced: IV ceftriaxone
Do patients with an asymptomatic tick bite receive ppx?
Generally no. They only receive a single dose of doxycyline if the tick was identified as Ixodes scapularis, the area is engorged, the tick was present on skin for 24-48 hours.
Is ELISA an effective test for evaluating HIV in neonates?
No. They need PCR or viral culture
What is the best initial test for detecting HIV infection? What is confirmatory?
Initial: ELISA
Confirmatory: Western Blot
Generally, what are each type of agent with the following names:
- navir
- udine/-bine
- navir: protease inhibitors
- udine/-bine: NRTIs
What are two entry inhibitors used in HIV?
What is an integrase inhibitor?
Entry inhibitors: Enfuvirtide, Maraviroc
Integrase inhibitor: Raltegravir
HIV adverse effect
Zidovudine
Anemia
HIV adverse effect
Stavudine and didanosine
Peripheral neuropathy and pancreatitis
HIV adverse effects
Abacavir
Hypersensitivity, Stevens-Johnson reaction
*Hypersensitivity is indicated by HLA B5701 status
HIV adverse effects
Protease inhibitors
Hyperlipidemia, Hyperglycemia
HIV adverse effects
Indinavir
Nephrolithiasis
HIV adverse effects
Tenofovir (NRTI)
Renal insufficiency
Can HIV medications generally be continued in pregnancy?
What is one drug avoided due to teratogenicity in animals?
Yes
Efavirenz is avoided (if already on prior to becoming pregnant then change to a protease inhibitor)
In what situations should a C-section be considered in an HIV positive pregnant woman?
If the CD4 count is 1000).
Zidovudine is given no matter what to reduce risk of vertical transmission
