Perianal Disease HIV Investigation — SCE Infectious Diseases MCQ

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ModerateSTIsPerianal Disease HIV InvestigationSCE Infectious Diseases

A 40-year-old man with HIV (CD4 350, VL <50) develops a large perianal abscess with complex fistula. He is MSM. The surgical team plans examination under anaesthesia with drainage and seton insertion. What additional testing should be sent from the abscess/fistula tissue?

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Correct answer: E — Histology (to exclude Crohn disease, malignancy — particularly anal SCC — and granulomatous disease) plus microbiological culture (aerobic, anaerobic, TB) plus Chlamydia NAAT (to exclude LGV as a cause of perianal inflammation)

Complex perianal disease in HIV-positive MSM requires thorough investigation: (1) histology to exclude Crohn disease and malignancy (anal SCC — HPV-related, increased in HIV), (2) microbiological culture (standard aerobes/anaerobes plus TB culture — perianal TB occurs), (3) Chlamydia NAAT — LGV (serovars L1–L3) can cause severe proctitis and perianal disease mimicking Crohn disease. This comprehensive approach prevents missed diagnoses in a high-risk population.

Reference: BHIVA 2022; BASHH 2019 – LGV; ACPGBI 2024