Portal hypertension is a condition where there is an increase in the blood pressure of the portal vein. The portal vein carries blood from the bowel and spleen to the liver. The increase in portal vein pressure is caused by obstruction of blood flow due to scarring (liver cirrhosis) in patients with chronic liver disease.
Cirrhosis is the most common reason for developing portal hypertension. Cirrhosis develops when the liver is damaged from alcohol consumption, hepatitis B or C viruses as well as obesity. In cirrhosis, the scar tissue which forms inside the liver obstructs the flow of blood entering it through the portal vein and thereby increases the portal pressure.