Detection of early liver fibrosis in patients with intestinal schistosomiasis: sonographic and histologic findings in Schistosoma mansoni infection.

BACKGROUND: Ultrasound (US) is a quite economical and noninvasive technique for morbidity assessment in intestinal schistosomiasis and it is widely used in order to detect organ-specific schistosomiasis-associated changes even if it may be invalidated by low reproducibility of measurements and high interobserver variance. Reports on histological assessment in patients with intestinal schistosomiasis mansoni are unusual because liver biopsy is not commonly feasible in endemic areas and it is not warranted for ethical reasons. This short report is a retrospective analysis of sonographic and histologic findings in patients with early liver pathology, in view of the pathogenesis and morbidity assessment of intestinal schistosomiasis, in a European hospital setting. PATIENTS AND METHODS: Seven immigrants from Madagascar with chronic diarrhea or Schistosoma mansoni egg detection in feces were admitted to our department. All of them were subjected to clinical, biochemical and ultrasound examination following current World Health Organization (WHO) guidelines. Each patient underwent percutaneous liver biopsy.
RESULTS: Abdominal ultrasonography showed schistosomiasis image patterns or US signs of liver involvement only in one out of seven patients while histological findings showed dense discrete fibrous tissue formation in five out of seven patients. In three out of seven patients liver biopsy also showed inflammatory infiltration of eosinophils and macrophages with periportal granulomas with S. mansoni eggs. Considering the mean egg intensity of three stool specimens as the gold standard, US showed a sensitivity of 16% with a negative predictive value (NPV) of 16% and a specificity of 100% with a positive predictive value (PPV) of 100%. Liver biopsy showed a sensitivity of 83% with a NPV of 50% and a specificity of 100% with a PPV of 100%.
CONCLUSION: In our small study, US seemed to underestimate hidden liver fibrosis in intestinal schistosomiasis. In some European clinical settings, histological evaluation by liver biopsy may be a useful tool to detect early liver pathology in schistosomiasis mansoni. These findings could provide additional information for studies from endemic areas where US is commonly used for morbidity assessment.