Extrahepatic portal vein obstruction and portal vein thrombosis in special situations: Need for a new classification (original) (raw)

2015, Saudi Journal of Gastroenterology

Noncirrhotic portal hypertension (NCPH), as it generally is termed, is a heterogeneous group of diseases that is due to intrahepatic or extrahepatic etiologies. In general, the lesions in NCPH are vascular in nature and can be classified based on the site of resistance to blood flow as "prehepatic," "hepatic," and "posthepatic." The "hepatic" causes of NCPH can be subdivided into "presinusoidal," "sinusoidal," and "postsinusoidal [Table 1]." Portal vein thrombosis was first seen by Stewart and Balfour in the late 1860s in a patient with splenomegaly, ascites, and variceal dilatation. Kobrich coined the term cavernoma to describe spongy appearance of portal vein (PV). [1] Generally a hypercoagulable state, intra-abdominal infection/peritonitis, and PV anomaly (PV stenosis and atresia) are considered important predisposing factors of EHPVO; however, vast majority of cases are due to primary thrombosis of the PV and often with more than one cause. Accurate epidemiological data on PVT is difficult to obtain. Prevalence of autopsy research in the United States and Japan ranges from 0.05% to 0.5% population prevalence of portal vein thrombosis (PVT) studied by Ogran et al. seen on autopsy series is 1%. [2] Thus PVT is responsible for 5%-10% of all cases of portal hypertension in western countries. Of all cases of portal hypertension (PHT) in developing countries, 40% are attributed to PVT. In children, EHPVO accounts for 80% cases of PHT. [3] Incidence of PVT among liver cirrhotics ranges from 0.6% to 64.1%. [4] After cirrhosis, EHPVO is the most common cause of portal hypertension globally. In the Indian subcontinent, 20%-30% of all variceal bleeds are due to EHPVO. In Japan, 10%-20% of variceal bleeds and in the west, 2%-5% of variceal bleeds are due to EHPVO. Clinical presentation of PVT is different in acute and chronic thrombosis. This depends on development and extent of collateral circulation. Intestinal congestion and ischemia with abdominal pain, fever, diarrhea, rectal bleeding, distension, sepsis, and lactic acidosis with or without splenomegaly are common features of acute PVT.