Fungal and Parasitic Infections USMLE Step 1 Practice Question
A 58-year-old man with type 2 diabetes mellitus (HbA1c 10.2%) presents to the emergency department with a 5-day history of rapidly progressive foot pain and tissue necrosis. He reports stepping on a thorn while gardening 1 week prior. On examination, his right foot shows a black eschar on the plantar surface with surrounding violaceous erythema, warmth, and significant edema extending to the mid-calf. Vital signs: temperature 38.8°C, heart rate 105 bpm, blood pressure 148/92 mmHg, respiratory rate 21/min, oxygen saturation 97% on room air. Laboratory studies show WBC 13,200/μL, creatinine 1.3 mg/dL, and glucose 385 mg/dL. A skin biopsy with KOH preparation reveals broad, non-septate hyphae invading blood vessel walls. Blood cultures remain sterile after 48 hours. Which of the following is the most appropriate initial management?
Answer choices
- AImmediate aggressive surgical debridement followed by high-dose IV amphotericin BCorrect answer
- BIV liposomal amphotericin B with delayed surgical consultation after culture results
- CIV caspofungin monotherapy with topical antifungal dressing and observation
- DIV posaconazole with conservative bedside debridement and broad-spectrum antibiotics
- EOral itraconazole with local wound care, elevation, and vascular surgery consult
- FIV fluconazole with empiric vancomycin pending repeat cultures
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