In some cases, these inflammatory processes involve the ureteric orifices or urethra, causing stricture formation and obstruction. These abnormalities may lead to hydronephrosis and, in a small percentage of cases, renal failure. In addition, they increase the risk of recurrent bacterial urinary tract infections.

PRESENTATION

Acute. Shortly after contact with cercariae, a small number of individuals develop local urticaria followed by macular rash. In previously unexposed persons, the rash is usually self-limited and brief. In sensitized individuals, it may develop into a pruritic maculopapular rash that persists for several days.

About 1 to 3 months after schistosomal infection, a small number of previously unexposed individuals may develop a fulminant febrile illness called Katayama fever. The syndrome coincides with the onset of egg production, and it typically causes diarrhea, hepatosplenomegaly, eosinophilia, pulmonary infiltrates, and (in rare cases) central nervous system involvement. Signs and symptoms usually spontaneously resolve after 10 to 12 weeks.