This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Investigations

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Seek expert advice.

Laboratory investigations:

  • microscopic examination for schistosome eggs - should be carried out at least two months after the last known fresh water contact
    • in stools
      • by observing even a single egg in thick smears of stool specimens (2-10 mg) with or without suspension in saline
      • as many as three specimens may be needed to make a diagnosis in some patients
      • rapid, simple, and inexpensive Kato-Katz thick smear stool examination
        • recommended by WHO for intestinal schistosomiasis when the intensity of infection is high
        • requires 40-50 mg of faeces
        • has specificity of 100% but its sensitivity varies with prevalence and intensity of infection, as well as with the number of stool specimens collected and slides prepared for microscopy.
    • in urine
      • S haematobium eggs can be detected on microscopy in a urine sample concentrated by sedimentation, centrifugation, or filtration and forced over a paper or nitrocellulose filter
      • urine should ideally be collected when there is maximum excretion of eggs - between 10am-2pm
  • PCR based assays for detection of schistosome DNA in faeces or sera and plasma
  • biopsy of bladder or rectal mucosa - may be useful for diagnosis in patients with a typical clinical presentation of schistosomiasis in the absence of eggs in urine or faeces
  • serological assays
    • detects antibodies against schistosomal antigens
    • most techniques detect IgG, IgM, or IgE against soluble worm antigen or soluble egg antigen by enzyme-linked immunosorbent assay (ELISA), indirect haemagglutination, or immunofluorescence.
    • useful for symptomatic travellers, but for people in endemic regions serology cannot differentiate between active infection and past exposure
    • positive test may be diagnostic in patients who are not excreting eggs e,g - Katayama syndrome
  • additional supportive laboratory evidence of schistosomiasis include:
    • eosinophilia (>80% of the patients) with acute infections
    • anaemia and thrombocytopenia - in chronic and advanced disease
    • increased prothrombin time is indicated by an increased INR - may be seen in chronic and advanced disease
    • hypoalbuminaemia
    • raised concentrations of urea and creatinine
    • hypergammaglobulinaemia and hypoalbuminaemia - in chronic and advanced disease (1,2)

Radiology

  • chest radiography
    • pulmonary infiltrates can be seen in acute cases (Katayama syndrome)
  • abdominal ultrasound
    • can establish extent of liver and spleen pathology in intestinal schistosomiasis
  • pelvic ultrasound
    • useful in urinary schistosomiasis to identify the extent of bladder, ureteral and renal pathology (1,2)

Additional investigations:

  • cystoscopy - reveals characteristic "sandy patches" (1)
  • abdominal X-ray - bladder calcification
  • intravenous urogram - may demonstrate hydro-ureter, hydronephrosis or filling defects in the bladder

Reference:


Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.