Long-term Complications of Schistosomiasis and Treatment
Schistosomiasis can cause significant long-term complications affecting multiple organ systems, with treatment focused on eradicating the parasite to prevent these complications. Praziquantel is the recommended treatment for all Schistosoma species infections, with dosing based on the specific species: 40 mg/kg as a single dose for S. mansoni, S. intercalatum, and S. guineensis, and 60 mg/kg in two divided doses for S. japonicum and S. mekongi infections. 1
Long-term Complications
Intestinal Complications
- Chronic or intermittent abdominal pain, weight loss, and diarrhea
- Very heavy infections can cause dysenteric illness or intestinal obstruction
- Chronic colonic ulceration leading to intestinal bleeding and iron deficiency anemia 1, 2
Hepatosplenic Complications
- Hepatosplenomegaly
- Hepatic "pipestem" fibrosis
- Portal hypertension with esophageal varices 1
- Liver cirrhosis in advanced cases 3
Urogenital Complications
- Hematuria, dysuria, and urinary tract infections
- Bladder tumors (squamous cell carcinoma) 1, 3
- Obstructive uropathy and bladder stones 1
- Kidney failure (affecting up to 33% of chronic cases) 3
- Terminal renal failure requiring hemodialysis (10%)
- Renal transplantation (5%)
Neurological Complications
- Acute myelopathy (most common with S. mansoni or S. haematobium)
- Presents with lower limb pain, lower motor dysfunction, bladder paralysis, and bowel dysfunction
- Cerebral disease (primarily with S. japonicum)
- Presents with seizures, motor or sensory impairment, or cerebellar syndrome
- Encephalopathy mimicking acute vasculitis (rare) 1
Other Complications
- Chronic S. japonicum infection has been tentatively linked to liver and colon cancers 1
- Impaired growth and development in children 2
Diagnostic Approach
Initial Evaluation
- Complete blood count with differential (eosinophilia is common)
- Serology (positive at 4-8 weeks but may be later) 1
- Concentrated stool microscopy (low sensitivity)
- Urine examination for S. haematobium
Advanced Testing
- Abdominal ultrasound to assess hepatosplenic involvement
- Upper gastrointestinal endoscopy if portal hypertension is suspected
- Colonoscopy and biopsy may provide histological diagnosis 1
- MRI for suspected neurological involvement 1
Treatment Protocol
Anti-parasitic Treatment
- For S. mansoni, S. intercalatum, and S. guineensis:
- Praziquantel 40 mg/kg as a single oral dose 1
- For S. japonicum and S. mekongi:
- Praziquantel 60 mg/kg in two divided doses 1
- When diagnosis is based on serology alone for Asia-Pacific schistosomiasis:
- Praziquantel 60 mg/kg in two divided doses 1
Management of Complications
For hepatosplenic disease:
- Monitor for development of portal hypertension
- Endoscopic management of esophageal varices if present 1
For urogenital disease:
- Evaluate patients with elevated serum creatinine and/or hematuria for bladder cancer and urinary obstruction 1
- Regular urological follow-up for patients with urinary tract involvement
For neurological involvement:
- Corticosteroid therapy may be required alongside antiparasitic treatment 1
Special Considerations
- Test for endemic coinfections (Salmonella, HBV, HCV, HIV) as targeted treatment may alter the aggressiveness of underlying glomerulonephritis or sequelae of schistosomiasis 1
- Kidney biopsy may be indicated in patients with suspected schistosomal glomerulonephritis, especially with viral coinfections 1
- Serology may remain positive for many years and cannot be used to assess treatment success 1
Clinical Pearls and Pitfalls
Pearls
- Eosinophilia is common but may decrease in older patients and those with urinary tract symptoms 3
- Direct parasitological diagnosis is more useful in patients with less than 5 years of residence in non-endemic countries 3
- Consider schistosomiasis in migrants from endemic areas with unexplained iron deficiency anemia 2
Pitfalls
- Relying solely on stool or urine microscopy can miss infections due to low sensitivity
- Failing to screen HIV-infected patients from endemic regions (17% seroprevalence reported) 4
- Overlooking schistosomiasis as a cause of unexplained eosinophilia in travelers and migrants
- Delaying treatment, which can lead to irreversible organ damage and complications 3
Early diagnosis and treatment are crucial to prevent the development of severe complications from chronic schistosomiasis, particularly in migrants from endemic regions who may have been infected for many years.