[Periportal fibrosis in Schistosoma mansoni schistosomiasis. An ultrasonographic study in the area of Nkolbisson (Cameroon)].

PURPOSE

The appearance of Symmers' periportal fibrosis (SPF) is considered a major event in the natural history of Schistosoma mansoni infection, because of the risk of portal hypertension and subsequent intestinal hemorrhage. Ultrasonography has been found useful in the assessment of this lesion. We undertook the present study to determine the prevalence of SPF in Nkolbisson (near Yaoundé), where previous studies had shown Schistosoma mansoni infection to be endemic.

METHODS AND MATERIALS

147 patients more than 15 years old (mean age: 32 years) were prospectively studied during a 3 month period. 107 subjects (51 male, and 56 female) were excreting Schistosoma mansoni eggs in the stools (mean egg output = 336 egg/g), and 40 controls had a negative stool exam. A medical history, a physical examination, and an abdominal ultrasound examination were performed on each subject. The degree of SPF was graded according to Homeida's scale.

RESULTS

39 Subjects (24 male, 15 female) with positive stool examination had SPF giving a prevalence rate of 37%, while it was found to be 5% for controls. 28 patients had mild fibrosis (grade I), 7 patients had moderate fibrosis (grade II), and 4 patients had severe fibrosis (grade III). Higher prevalence rates of SPF were associated with longer duration of infection and very high egg outputs (> 1,000 egg/g). The positive predictive value of hepatomegaly or splenomegaly for the presence of SPF was 0.52, and the negative predictive value 0.69.

CONCLUSION

We conclude that SPF affects a significant proportion of infected patients and ultrasonography is a valuable tool in the study of this lesion in our patients.