Makindo Medical Notes

🐛 Schistosomiasis (Bilharzia) is caused not by the worms themselves but by the immune response to their eggs. 💊 Praziquantel is the treatment of choice — it can reverse up to 90% of organ damage if given promptly. ⚠️ Katayama fever may progress to neurological complications → treat early.

🌍 About

• Caused by parasitic worms living in fresh water snails.
• Also known as Bilharzia.

💧 Sources of Infection

• Ponds, lakes, rivers, reservoirs, canals.
• Showers with unfiltered lake/river water.
• Not acquired from sea water or chlorinated swimming pools.

📌 Geographical Distribution

• Endemic in Africa, South America, the Caribbean, the Middle East, and Asia.

🦠 Microbiology

• Schistosoma mansoni → intestinal & liver disease.
• Schistosoma haematobium → bladder disease, ↑ risk of bladder cancer.
• Schistosoma japonicum → intestinal & liver disease.

🔄 Lifecycle

• Parasite lives in freshwater snails.
• Snails release invasive form = cercariae.
• Infection via direct skin contact → worms burrow through skin.
• Parasites migrate to liver, bowel, bladder → release eggs in urine/faeces.

⚡ Acute Infection

• Often asymptomatic.
• Initial “swimmer’s itch” = itchy papular rash at entry site.
• Weeks later: fever, urticaria/rash, cough, diarrhoea, myalgia, malaise.

🌡️ Katayama Fever (Acute Schistosomiasis)

• Seen 4–8 weeks post exposure (esp. *S. mansoni*).
• Due to hypersensitivity reaction as parasites migrate through portal & pulmonary circulation.
• Features: fever, eosinophilia, serum-sickness type illness.
• Stool microscopy often negative (low egg burden); serology useful in non-endemic settings.

⏳ Chronic Infection

• Anaemia, abdominal pain, hepatosplenomegaly, portal hypertension.
• GI: diarrhoea, blood in stool, colonic polyps/strictures.
• GU: cystitis, dysuria, haematuria; risk of bladder cancer (S. haematobium).
• Neuro: seizures, weakness, leg numbness.

🧪 Investigations

• Bloods: Anaemia, eosinophilia; U&E (immune complex nephritis); LFTs (hepatitis).
• CXR: Pulmonary infiltrates, granulomas.
• Stool/urine microscopy: Detect ova (may need concentration methods).
• Serology: Helpful early & in travellers from non-endemic areas.

💊 Management

• Praziquantel = treatment of choice (single-day course, often repeated).
• Best given once worms have matured (weeks after exposure); may require repeat dosing.
• Corticosteroids can be used in acute Katayama fever or neurological disease to dampen inflammation.
• Early treatment reverses much organ damage within months.