liver and gallbladder disorders
Portal Hypertension
Introduction
Portal hypertension is abnormally high blood pressure in the portal vein (the large vein that brings blood from the intestine to the liver) and its branches. Cirrhosis of the Liver (scarring that distorts the structure of the liver and impairs its function) is the most common cause in Western countries. Portal hypertension can lead to a swollen abdomen ( Ascites ), abdominal discomfort, confusion, and bleeding in the digestive tract. Doctors base the diagnosis on symptoms and results of a physical examination, sometimes with ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), or Biopsy of the Liver . Drugs can reduce blood pressure in the portal vein, but if bleeding in the digestive tract occurs, emergency treatment is required. Treatment sometimes includes Liver Transplantation or creation of a tract through which blood can bypass the liver (portosystemic shunt). (See also Overview of Liver Disease .) The portal vein receives blood from the entire intestine and from the spleen, pancreas, and gallbladder and carries that blood to the liver. After entering the liver, the vein divides into right and left branches and then into tiny channels that run through the liver. When blood leaves the liver, it flows back into the general circulation through the hepatic vein. Two factors can increase blood pressure in the portal blood vessels: An increased volume of blood flowing through the vessels Increased resistance to the blood flow through the liver In Western countries, the most common cause of portal hypertension is increased resistance to blood flow caused by extensive scarring of the liver in Cirrhosis of the Liver . Cirrhosis is most often caused by Overview of Chronic Hepatitis (hepatitis that has lasted at least 6 months) Alcohol Use over a long period of time Fatty Liver None Portal hypertension leads to the development of new veins (called collateral vessels) that bypass the liver. These veins directly connect the portal blood vessels to veins that take blood away from the liver into the general circulation. Because of this bypass, substances (such as toxins) that are normally removed from the blood by the liver can pass into the general circulation. Collateral vessels develop at specific places. The most important are located at the lower end of the esophagus and at the upper part of the stomach. Here, the vessels enlarge and become full of twists and turns—that is, they become varicose veins in the esophagus (esophageal varices) or stomach (gastric varices). These enlarged vessels are Gastrointestinal Bleeding , sometimes seriously and occasionally with fatal results. Other collateral vessels may develop on the abdominal wall and at the rectum. Portal hypertension often causes the spleen to enlarge because the pressure interferes with blood flow from the spleen into the portal blood vessels. When the spleen enlarges, the number (count) of white blood cells can decrease (increasing the risk of infections), and the number (count) of platelets can decrease (increasing the risk of bleeding). Increased pressure in the portal blood vessels may cause protein-containing (ascitic) fluid to leak from the surface of the liver and intestine and to accumulate within the abdomen. This condition is called Ascites . 