Schistosomiasis

Background

• Caused by parasitic trematodes of the species Schistosoma
• Reservoir is freshwater snails
• Endemic in areas of Africa and Southern Asia
• The Cercariae (the stage of trematode released by the snail) can infect by direct penetration through the skin
• Infects >200million people worldwide with 10% suffering severe consequences

DDx

• UTI
• STD
• Intestional parasites
• Travelers diarrhea

Diagnosis

• Mostly a chronic condition
  • Second most common cause of esophageal varicies worldwide
  • Greatly elevated bladder cancer rates in endemic areas
  • Can cause renal failure, liver failure, pulmonary hyptertension, GI bleeds and rarely CNS symptoms
    • Mostly through fibrosis of affected organs
  • Genitourinary schistosomiasis
    • Caused by sores in the genital tract
    • May persist even after treatment
    • Greatly increases risk of HIV infection

• Acute presentations
  • Cutaneous rash/itching from cercariae penetration (immediate)
  • Katayama fever-Fever, Abdominal pain, Fatigue, Cough, Diarrhea, Eosinophilia (lasts 4-8 weeks)

• Diagnosis
  • ELISA
  • PCR from stool or urine
  • Stool and Urine for ova/parasites
    • biopsy may be needed for those who do not show ova/parasites in stool/urine
  • CBC, Alk Phos, GGT, ALT/AST, Cr, Blood Cx
  • Consider US for hepatosplenic (periportal fibrosis) or urinary disease (hydro)
  • Echo and CXR for pulmonary HTN and/or cor pulmonale
  • Consider CT or MRI for CNS disease or further w/u of periportal fibrosis

Treatment

• Praziquantel 20mg/kg PO for two doses in 1 day
  • S.japnonicum requires 3 doses in 1 day

Sources

• Wikipedia
• CDC.gov/parasites/schistosomiasis
• Uptodate
• Tintinalli