[Ultrasound diagnosis of bilharziasis]

Abstract

Aim: Schistosomiasis (Bilharzia, Bilharziasis) is one of the most prevalent tropical diseases, with an increasing number of cases being imported into Europe. Sonography is among the most valuable diagnostic tools for schistosomiasis-related organ lesions. This review outlines typical findings and their pathophysiological context.

Method and results: Bilharziasis of the urinary tract, usually due to Schistosoma (S.) haematobium, leads to diffuse or localized wall thickening of the bladder and the distal ureter with typical sonographic features. Upper urinary tract obstruction and--rarely--bladder carcinoma may complicate the course and can also be detected sonographically. The other species (S. mansoni, S. japonicum, S. mekongi, S. intercalatum) primarily cause (entero-) colitis; the value of sonography in this condition is yet undefined. In later stages, fibrotic liver involvement with portal hypertension may develop (hepatosplenic schistosomiasis), leading to typical ultrasound features which are nearly pathognomonic under endemic conditions: severe periportal echogenicity with S. mansoni, and a peculiar "network pattern" of echogenic septa with S. japonicum. Sonographic indicators of portal hypertension may be identified and graded.

Conclusion: In endemic areas in the tropics, sonography with simple portable machines offers a unique opportunity to investigate morbidity on the community level non-invasively in large field surveys; it has thus become an important tool of clinical and epidemiological research.