Treatment of Schistosomiasis
Praziquantel is the drug of choice for treating all forms of schistosomiasis, with dosing regimens based on the infecting Schistosoma species. 1, 2, 3
First-line Treatment
- For Schistosoma mansoni, S. intercalatum, and S. guineensis infections: Praziquantel 40 mg/kg orally as a single dose 1
- For Schistosoma japonicum and S. mekongi infections: Praziquantel 60 mg/kg orally in two divided doses 1
- For Schistosoma haematobium: Praziquantel 40 mg/kg orally as a single dose 4, 1
- Ensure sufficient dosage and duration to completely eradicate the organism from the body 4
Special Clinical Scenarios
Acute Schistosomiasis (Katayama Syndrome)
- Occurs 2-8 weeks after exposure to contaminated water, primarily in travelers 5
- Presents with eosinophilia (sometimes >5×10⁹/L), fever, dry cough, urticarial rash, and potentially pulmonary infiltrates 5
- Treatment approach:
- Praziquantel 40 mg/kg as a single dose, repeated at 6-8 weeks (eggs and immature schistosomules are relatively resistant to initial treatment) 5
- Corticosteroids (prednisolone 20 mg/day for 5 days) to reduce symptom duration 5, 1
- Consider administering steroids before anthelmintic therapy to prevent symptom exacerbation 1
Neuroschistosomiasis
- Praziquantel 40 mg/kg twice daily for 5 days for CNS involvement 1
- Combine with dexamethasone 4 mg four times daily, reducing after 7 days, for 2-6 weeks 1
Diagnostic Considerations
- Diagnosis of schistosomiasis requires:
- For acute schistosomiasis (Katayama syndrome), serology and stool/urine microscopy may be negative initially 5
- Test for endemic coinfections (Salmonella, HBV, HCV, HIV), as targeted treatment may alter disease progression 5, 4
Monitoring and Follow-up
- Serology may remain positive for years after successful treatment and cannot be used to assess treatment success 4, 1
- Monitor patients with hepatic fibrosis from schistosomiasis for the development of kidney disease 5, 4
- Evaluate patients with elevated serum creatinine and/or hematuria for bladder cancer and/or urinary obstruction, which are common complications of S. haematobium infection 5, 4
Common Pitfalls to Avoid
- Failing to adjust dosage based on Schistosoma species can lead to treatment failure 1
- Administering praziquantel during acute Katayama syndrome without steroids may worsen symptoms 1
- Consider potential co-infection with strongyloidiasis before starting corticosteroids, which could precipitate hyperinfection syndrome 1
- No immunosuppressive agents are indicated in schistosomal nephropathy beyond the corticosteroids used for acute management 5, 4
Additional Considerations
- Praziquantel is safe and efficacious against adult worms of all Schistosoma species infecting humans 2, 3
- Current concerns include the potential emergence of drug resistance and the fact that praziquantel does not prevent reinfection 2, 7
- For patients in endemic areas, prevention strategies including snail control, improved water/sanitation, and education are essential components of disease management 2, 3