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🧫 About
Cryptosporidiosis is an opportunistic protozoal infection caused by Cryptosporidium parvum or C. hominis.
It commonly affects the small intestine and causes watery diarrhoea.
In immunocompetent hosts it is self-limiting, but in advanced HIV infection it may be chronic and severe.
🦠 Aetiology
- Caused by ingestion of Cryptosporidium oocysts via contaminated food or water.
- Oocysts attach to and damage small-bowel epithelial cells, disrupting absorption.
- Seen especially in patients with HIV/AIDS, and may be associated with sclerosing cholangitis in chronic cases.
🧍♂️ Clinical Features
- Immunocompetent: Acute, self-limiting watery diarrhoea lasting 1–2 weeks.
- Immunocompromised (HIV): Chronic profuse watery diarrhoea, weight loss, anorexia, nausea, and vomiting.
- May lead to malnutrition, dehydration, and biliary involvement (cholangitis, cholecystitis).
🔍 Differentials
- Other causes of chronic diarrhoea in HIV:
- Isospora belli, Microsporidium, Giardia lamblia
- CMV colitis
- HIV enteropathy
- Non-infective causes: malabsorption, coeliac disease, pancreatic insufficiency.
🧪 Investigations
- FBC, U&E, LFTs - assess dehydration and hepatic involvement.
- Stool microscopy for ova, cysts, and parasites using a modified Kinyoun acid-fast stain (oocysts appear red).
- Antigen detection or PCR assays may improve sensitivity.
- Small-bowel biopsy shows oocysts attached to epithelial brush border (in severe cases).
💊 Management
- Supportive therapy: fluid and electrolyte replacement, antidiarrhoeals as appropriate.
- Optimise ART (HAART): immune restoration is key to resolution in HIV patients.
- Nitazoxanide may shorten duration in mild/moderate disease but is often ineffective in severe immunosuppression.
- Ensure food and water hygiene to prevent reinfection.
📚 References
🕓 Revision History
- Last updated: 02/10/2017 (content reviewed and enhanced 2025).
