Updated: 1/3/2019


Review Topic
  • A 29-year-old woman presents to the emergency department with 2 weeks of fever and abdominal pain. She denies any sick contacts but did recently return from Kenya. Physical examination is notable for hepatomegaly, most prominent in the left hepatic lobe. She also has an urticarial rash in her left foot. Urine and stool microscopy are remarkable for schistosome eggs and a complete blood cell count demonstrates eosinophilia.
  • Definition
    • human infection caused by the Schistosoma trematode
  • Microbiology
    • the 3 major species that cause disease are
      • Schistosoma mansoni (Africa and South America)
        • causes intestinal tract and hepatosplenic disease
      • S. haematobium (Africa and Middle East)
        • causes genitourinary tract disease
      • S. japonicum (East Asia)
        • causes intestinal tract and hepatosplenic disease
  • Epidemiology
    • incidence
      • most cases occur in sub-Saharan Africa
  • Pathogenesis
    • female trematode lays eggs in the patient's capillaries → traverses the blood vessels and migrates to the intestines (S. mansoni and S. japonicum) or the bladder (S. haematobium) → causes an immune response leading to inflammation and fibrosis
  • Associated conditions
    • squamous cell bladder cancer (S. haematobium)
    • portal hypertension (S. mansoni and S. japonicum)
  • Prognosis
    • treatment may decrease organ pathology
  • Symptoms
    • pruritus after swimming ("swimmer's itch")
      • suggestive of larval penetration
    • fever
    • chills
    • myalgias and arthralgias
    • headache
    • abdominal pain
  • Physical exam
    • urticaria
    • angioedema
    • hepatomegaly
    • hematuria
  • Microscopy
    • schistosome eggs identified on microscopic exam of urine or stool
      • confirms the diagnosis
  • Serology
    • indication
      • if microscopy is unremarkable
    • tests
      • ELISA
      • radioimmunoassay
    • comments
      • typically negative in acute infection
  • Labs
    • eosinophilia
  • Malaria
    • differentiating factor
      • trophozoite ring within red blood cells in the peripheral blood smear
  • Medical
    • praziquantel
      • indication
        • treatment of choice for schistosomiasis
  • Squamous cell carcinoma of the bladder
  • Portal hypertension



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