Portal hypertension in schistosomiasis: pathophysiology and treatment.
In heavily infected young patients, there is a "non-congestive" phase of the disease with splenomegaly which can improve after chemotherapy. A strong correlation between hepatosplenic form and worm burden in young patients has been repeatedly shown. The pattern of vascular intrahepatic lesions, seems to depend on two mechanisms: (a) egg embolization, with a partial blocking of the portal vasculature; (b) the appearance of small portal collaterals along the intrahepatic portal system. The role played by hepatitis B virus (HBV) and C virus infections in the pathogenesis of liver lesions is variably considered. Selective arteriography shows a reduced diameter of hepatic artery with thin and arched branches outlining vascular gaps. A rich arterial network, as described in autopsy cases, is usually not seen in vivo, except after splenectomy or shunt surgery. An augmented hepatic arterial flow was demonstrated in infected animals. These facts suggest that the poor intrahepatic arterial vascularization demonstrated by selective arteriography in humans is due to a "functional deviation" of arterial blood to the splenic territory. The best results obtained in treatment of portal hypertension were: esophagogastric devascularization and splenectomy (EGDS), although risk of rebleeding persists; classical (proximal) splenorenal shunt (SRS) should be abandoned; distal splenorenal shunt may complicate with hepatic encephalopathy, although later and in a lower percentage than in SRS. Propranolol is currently under investigation. In our Department, schistosomatic patients with esophageal varices bleeding are treated by EGDS and, if rebleeding occurs, by sclerosis of the varices.
Departamento de Gastroenterologia, Faculdade de Medicina da Universidade de São Paulo, Brasil.
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Da Silva
D000818:Animals; D006224:Cricetinae; D004932:Esophageal and Gastric Varices / Q000188:drug therapy / Q000209:etiology / Q000601:surgery; D005500:Follow-Up Studies; D006471:Gastrointestinal Hemorrhage / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D006501:Hepatic Encephalopathy / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D006975:Hypertension, Portal / Q000188:drug therapy / Q000469:parasitology* / Q000503:physiopathology / Q000601:surgery; D015994:Incidence; D011433:Propranolol / Q000627:therapeutic use; D011446:Prospective Studies; D012189:Retrospective Studies; D012555:Schistosomiasis mansoni / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D012556:Schistosomicides / Q000627:therapeutic use; D015911:Sclerotherapy; D013156:Splenectomy; D013163:Splenomegaly / Q000209:etiology / Q000601:surgery; D013164:Splenorenal Shunt, Surgical / Q000009:adverse effects
D012556:Schistosomicides; D011433:Propranolol