Obstruction of the extrahepatic portal vein (the blood vessel that carries blood with a large amount of nutrients from the small intestine into the liver) causes problems with blood flow into the liver, which increases the pressure within the portal vein. This, in turn, can be a symptom of portal hypertension.
Somewhere between 340 and 560 people per year are treated as either outpatients or inpatients.
It is slightly more common among males, with a male-to-female ratio of approximately 1:0.6. A definitive diagnosis is most commonly made among people under 20 years of age, followed by those in their forties and fifties.
The disease is broadly classified as either primary extrahepatic portal vein obstruction or secondary extrahepatic portal vein obstruction.
Although the causes of primary extrahepatic portal vein obstruction are unknown, angiodysplasia, coagulation disorder, and myeloproliferative disorder are thought to be involved.
The causes of secondary extrahepatic portal vein obstruction include neonatal omphalitis, tumor, extrahepatic portal vein obstruction associated with cirrhosis of the liver and idiopathic portal hypertension, gallbladder cholangitis, pancreatitis, and intra-abdominal surgery. However, there are also idiopathic cases.
It is not considered a genetic disease, but some patients are suspected of having some congenital element. This issue is currently being investigated.
Since the portal vein pressure markedly rises, some portal vein blood does not proceed to the liver and instead moves in a different direction. In such cases, the new routes taken by the blood are referred to as "collateral circulation." This collateral circulation causes extreme swelling of the veins in the abdominal wall, which in turn causes esophageal, gastric, and duodenal varices. Hepatic encephalopathy and ascites also occur, and in some cases, long-term treatment is required. If the spleen becomes enlarged, a condition known as hypersplenism occurs, which can lead to anemia. When the platelet count decreases and bleeding occurs, it becomes difficult for the bleeding to stop. When the pressure within the varices increases, the veins become unable to withstand the increased pressure. This leads to rupturing and bleeding, which causes symptoms such as hematemesis (vomiting of blood) and bloody bowel discharge. In some cases, bleeding can lead to shock and death.
In many cases, the disease causes developmental disorders in children. In children, it is often diagnosed because of nose bleeds.
Treatment is concentrated on the symptoms of portal vein hypertension (gastric and esophageal varices, edema, and hypersplenism). However, since portal vein hypertension continues throughout life, so-called intractable varices of the gastrointestinal tract occur. It is also known that the bleeding rate is higher than that of viral cirrhosis. In addition, due to the marked rise in portal vein pressure, heavy bleeding caused by temporary bleeding of varices occurs, which can lead to hemorrhagic shock.
1) Hemostasis treatment for varices
2) Treatments for hypersplenism
If the bleeding from gastrointestinal varices can be sufficiently controlled, the course is good.