Perianal Fistula in HIV — SCE Infectious Diseases MCQ

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ModerateHIV MedicinePerianal Fistula in HIVSCE Infectious Diseases

A 35-year-old man with HIV (CD4 300, VL <50 on ART) develops a painful perianal fistula. Examination under anaesthesia reveals a complex trans-sphincteric fistula. MRI confirms the anatomy. Swab from the fistula grows mixed enteric flora. What is the most important consideration for this patient?

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Correct answer: A — Exclude Crohn disease and anal cancer — complex perianal fistulae in HIV require thorough investigation including biopsy to rule out malignancy

Complex perianal fistulae in HIV-positive patients require thorough investigation. While some are simple cryptoglandular fistulae, important differential diagnoses include: Crohn disease (particularly in patients with colonic symptoms), anal carcinoma (HPV-related), LGV proctitis (Chlamydia L-serovars), and less commonly TB. Biopsy of the fistula tract is essential to exclude malignancy and granulomatous disease. Surgical management follows standard colorectal principles (seton insertion for complex fistulae) and is not contraindicated by HIV status.

Reference: BHIVA 2022 – Surgical considerations in HIV; ACPGBI 2024 – Perianal fistula