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Cryptosporidiosis — SCE Infectious Diseases MCQ

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ModerateHIV MedicineCryptosporidiosisSCE Infectious Diseases

A 40-year-old man with HIV (CD4 90, not on ART) presents with chronic diarrhoea and weight loss. Modified Ziehl-Neelsen stain of stool shows red-staining oocysts of 4–6 µm. What is the most likely organism and definitive management?

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Correct answer: A — Cryptosporidium; ART to restore immune function (no effective antimicrobial exists)

Modified acid-fast oocysts of 4–6 µm are diagnostic of Cryptosporidium species. In HIV with advanced immunosuppression, Cryptosporidium causes chronic, debilitating diarrhoea. No antimicrobial reliably eradicates Cryptosporidium in immunocompromised hosts — Nitazoxanide has limited efficacy when CD4 <100. The definitive management is immune reconstitution with ART; as CD4 recovers above 100, cryptosporidiosis typically resolves. Supportive care (hydration, nutrition) is essential.

Reference: BHIVA 2022 – OI guidelines; WHO 2021 – Cryptosporidiosis