Common Infectious Diseases Flashcards
7 cards from real Internal Medicine Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Common Infectious Diseases flashcards as text
A healthcare worker sustains a needlestick from an HIV-positive patient. Post-exposure prophylaxis should ideally be started within what timeframe?
Answer: 72 hours
HIV post-exposure prophylaxis (PEP) should be initiated as soon as possible but within 72 hours of exposure to be effective.
Which clinical feature differentiates cellulitis from necrotizing fasciitis and should prompt urgent surgical evaluation?
Answer: Pain out of proportion to appearance with skin crepitus
Pain disproportionate to clinical appearance and crepitus (subcutaneous gas) are hallmark findings of necrotizing fasciitis requiring emergent surgical debridement.
A 45-year-old man presents with fever, right upper quadrant pain, and jaundice after a trip to Egypt. Ultrasound shows a cystic liver lesion. Serology is positive for Entamoeba histolytica. What is the treatment?
Answer: Metronidazole followed by paromomycin
Amebic liver abscess is treated with metronidazole to eradicate invasive disease, followed by a luminal agent like paromomycin to eliminate intestinal cysts.
Which laboratory finding is most consistent with Clostridium difficile colitis?
Answer: Positive stool toxin assay (GDH + toxin EIA)
Diagnosis of C. difficile infection requires detection of toxin; the two-step algorithm using GDH screening followed by toxin EIA or NAAT is standard.
A 22-year-old college student presents with fever, pharyngitis, and splenomegaly. Monospot test is positive. Which complication warrants restriction from contact sports?
Answer: Splenic rupture
Splenic rupture is the most feared complication of infectious mononucleosis, and patients should avoid contact sports for at least 3–4 weeks.
A patient presents with fever, cough, and bilateral hilar adenopathy on chest X-ray after exposure to bird droppings in the Ohio River Valley. What is the most likely diagnosis?
Answer: Histoplasmosis
Histoplasma capsulatum is endemic to the Ohio and Mississippi River Valleys and is associated with exposure to bat and bird droppings.
Which antibiotic class is contraindicated in a pregnant woman diagnosed with a chlamydial infection?
Answer: Tetracyclines
Tetracyclines (including doxycycline) are contraindicated in pregnancy due to effects on fetal bone and tooth development; azithromycin is the preferred alternative.