What Is Portal Hypertension?

Portal hypertension is an increase in the blood pressure within a system of veins called the portal venous system. Normally, the veins come from the stomach, intestine, spleen, and pancreas, merge into the portal vein, which then branches into smaller vessels and travels through the liver. If the vessels in the liver are blocked, it is hard for the blood to flow causing high pressure in the portal system.

When the pressure becomes too high, the blood backs up and finds other ways to flow back to the heart, where it is pumped to the lungs, where it gets rid of waste products and picks up oxygen. The blood can travel to the veins in the esophagus (esophageal varices), in the skin of the abdomen, and the veins of the rectum and anus (hemorrhoids) to get around the blockages in the liver.

The most common cause of portal hypertension is cirrhosis of the liver. Cirrhosis results from scarring of a liver injury caused by hepatitis, alcohol abuse, or other causes of liver damage. In cirrhosis, scar tissue blocks the flow of blood through the liver.

Other causes of portal hypertension include blood clots in the portal vein, blockages of the veins that carry the blood from the liver to the heart, and a parasitic infection called schistosomiasis. Sometimes the cause is unknown.

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Source: MedicineNet.com
http://www.medicinenet.com/portal_hypertension/article.htm