Internal Medicine Exam Common Infectious Diseases 3

Question 1

A healthcare worker sustains a needlestick from an HIV-positive patient. Post-exposure prophylaxis should ideally be started within what timeframe?

Accepted Answer

72 hours

Answer

HIV post-exposure prophylaxis (PEP) should be initiated as soon as possible but within 72 hours of exposure to be effective.

Question 2

Which clinical feature differentiates cellulitis from necrotizing fasciitis and should prompt urgent surgical evaluation?

Accepted Answer

Pain out of proportion to appearance with skin crepitus

Answer

Pain disproportionate to clinical appearance and crepitus (subcutaneous gas) are hallmark findings of necrotizing fasciitis requiring emergent surgical debridement.

Question 3

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?

Accepted Answer

Metronidazole followed by paromomycin

Answer

Amebic liver abscess is treated with metronidazole to eradicate invasive disease, followed by a luminal agent like paromomycin to eliminate intestinal cysts.

Question 4

Which laboratory finding is most consistent with Clostridium difficile colitis?

Accepted Answer

Positive stool toxin assay (GDH + toxin EIA)

Answer

Diagnosis of C. difficile infection requires detection of toxin; the two-step algorithm using GDH screening followed by toxin EIA or NAAT is standard.

Question 5

A 22-year-old college student presents with fever, pharyngitis, and splenomegaly. Monospot test is positive. Which complication warrants restriction from contact sports?

Accepted Answer

Splenic rupture

Answer

Splenic rupture is the most feared complication of infectious mononucleosis, and patients should avoid contact sports for at least 3–4 weeks.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Exam Common Infectious Diseases 3