Histology USMLE Step 1 Practice Question
A 19-year-old female college student presents with a 2-day history of fever (39.2°C), petechial rash on her lower extremities and trunk, and progressive confusion. Vital signs: HR 112/min, BP 98/62 mmHg, RR 22/min, SpO2 98% on room air. Lumbar puncture reveals CSF with protein 180 mg/dL, glucose 18 mg/dL (serum glucose 95 mg/dL), and 450 WBC/μL (85% neutrophils). Blood cultures are pending. A skin biopsy from an involved petechial lesion is obtained. Histologic examination shows fibrinoid necrosis of small dermal vessels with dense neutrophilic infiltration, leukocytoclasis, and disruption of the vessel wall architecture. Which of the following best describes the pattern of vascular injury seen in this patient?
Answer choices
- AMedial hyaline sclerosis with smooth muscle cell degeneration
- BChronic granulomatous inflammation with giant cell formation
- CIntimal proliferation and fibrosis without acute inflammation
- DAcute necrotizing vasculitis with fibrinoid necrosis and leukocytoclasisCorrect answer
- EAtherosclerotic plaque with lipid core and fibrous cap
- FSmall vessel vasculitis with perivascular IgA immune complex deposition
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