li-10-3Disorders of portal vein system By Dr. E Orfei
All obstructive conditions of the portal vein system will cause pre-hepatic portal hypertension
1-Congenital anomalies of portal vein.
Aplasia, strictures and complete occlusion after birth similar to the occlusion of the umbilical vein and of the ductus venosus of Arantius.
2-Cavernomatous transformation of portal vein.
It may occur as a congenital anomaly or as an acquired condition following an infection of the umbilical vein or a reanalyzed thrombosis.
3- Pegot-Cruveilhier anomaly.It is the congenital caput medusae due to persistence of the umbilical vein, which cause the visible dilatation of the veins around the umbilicus.
It is the acquired caput medusae caused by portal hypertension. Under increased portal pressure it is thought that the veins around the obliterated umbilical vein, the paraumbilical veins, become distended and carry the blood the paraumbilical veins through the lfalciform ligament. From here the blood flows to the system of the inferior vena cava and to the heart. The portal blood bypasses the liver. The distended paraumbilical veins are well visible under the skin (caput medusae). Any condition causing portal hypertension may lead to this complication.
5- Portal vein thrombosis.
It is more frequent in children following an omphalitis or an umbilical catheterization. Intra-abdominal infections blood dyscrasias and hepatic tumors are the most common causes in adults. It is diagnosed by imaging techniques. It must be recognized from Budd-Chiari syndrome. If the thrombosis is slow and does not extend to the mesenteric vein, which is a common complication, and its cause subsides, it may resolve by recanalization. It should not be treated before a "bleeding episode" Most of the times it is a rapid fatal disease. The treatment would be a spleno-renal shunt.
6-Portal vein aneurysm.
It may occur at the spleno-portal junction and causes portal hypertension. It is rare. Usually it does not rupture unless it is punctured especially during a liver biopsy not preceded by a control for vascular anomalies with an ultrasound.
7-Slenic vein thrombosis.
It can be an isolated event. The pressure in the splenic region is increased while it remains normal in the portal vein and mesenteric vein. It will cause gastric hemorrhages. Therefore it should be treated as soon as it is discovered. The most common causes are: chronic pancreatitis, pancreatic carcinoma, renal tumors, retroperitoneal fibrosis.
8-Extrinsic compression of the portal vein.
It is produced by masses and fibrosisng inflammations of pancreas and retroperitoneal tissues.
It could be either intrahepatic or extrahepatic occurs with Rendu-Osler- Weber syndrome, trauma, liver biopsy or ruptured aneurysm.