Ultrasonography of periportal fibrosis in schistosomiasis mansoni in Brazil

In patients with hepatosplenic schistosomiasis, characteristic thickening of the walls of the portal vein in the hilus and its central and peripheral branches is observed. In an area of high prevalence of the disease in Brazil, 424 individuals older than 5 years have been examined by abdominal ultrasonography and 146 presented fibrosis, classified as central in 31 (21%), peripheral in 56 (38%), and both central and peripheral in 59 (40%). The mean ages of the subjects in the 3 groups were 45.7, 24.1 and 31.9 years, respectively (P<0.05). The presence of central fibrosis was associated with the presence of peripheral fibrosis (odds ratio 10.7, P<0.000001). Splenomegaly was found in 16% and 15% of individuals with peripheral and both central and peripheral fibrosis, respectively. No subject with central but no peripheral fibrosis and splenomegaly was identified. We conclude that central fibrosis occurs among older subjects but should not be considered a criterion for advanced disease.