[Venous thrombosis in gastroenterology].

Venous thrombosis involving the digestive tract affects the suprahepatic veins and the terminal part of the inferior vena cava, the portal vein and its roots. The etiology and diagnosis of this condition have made considerable progress. A thrombogenic disease can now be recognized in 90% of cases of involvement of the suprahepatic veins, and 75% of portal involvements. The most frequent causes are primary myeloproliferative syndromes, paroxysmal nocturnal hemoglobinuria, hereditary deficiency in coagulation proteins and circulating anticoagulants. The cause of involvement of the portal vein also include insults during biliary surgery and abdominal infections, particularly those caused by Bacteroides fragilis. Mechanical involvement due to compression finally plays a minor role in the etiology. Noninvasive techniques of diagnosis are now available, including ultrasound, computed tomography and magnetic resonance imaging. The expression of obstruction of the suprahepatic veins predominantly consists in ascites and hepatomegaly. Thrombosis of the portal vein preserving the mesenteric arches usually remains asymptomatic until the intrahepatic block is revealed by a digestive hemorrhage caused by portal hypertension. Isolate involvement of the splenic vein exceptionally causes the rupture of gastric or esophageal collateral veins. The treatment should combine the prevention of further thromboses by anticoagulants and the specific treatment of the venous obstruction. In case of suprahepatic obstruction, there are several methods of restoring a canal of drainage for hepatic blood. Their indications depend on the patency of the inferior vena cava and of the portal vein. In case of portal obstruction, portal-systemic bypass is feasible only if one of the major roots of the portal vein still is patent.(ABSTRACT TRUNCATED AT 250 WORDS)