4 Portal Hypertension

Pressure changes in cirrhosis

Portal hypertension is abnormally increased pressure in the portal venous system. In cirrhosis, scarring increases resistance to blood flow through the liver, producing increased pressure in the portal circulation.

In cirrhosis, clinically significant portal hypertension is defined by a hepatic venous pressure gradient (HVPG) of at least $10\ \mathrm{mm\,Hg}$. Increased pressure can enlarge the spleen, create collateral veins, and contribute to ascites and hepatic encephalopathy.

Varices and bleeding prevention

Varices are enlarged collateral veins, commonly found in the lower esophagus or stomach. A varix can rupture and cause sudden, severe gastrointestinal bleeding. Suspected variceal bleeding is a medical emergency requiring immediate care.

For a patient with cirrhosis and high-risk esophageal varices, nonselective beta-blocker therapy is a preventive option to reduce the risk of a first variceal bleed when there is no contraindication. If the patient cannot take or tolerate these medications, endoscopic variceal ligation may be used. The appropriate choice depends on the patient’s clinical circumstances.

Splenic enlargement and blood counts

Increased pressure in the splenic venous circulation can cause splenomegaly and hypersplenism. Blood congestion can enlarge the spleen, which may sequester blood cells. Hypersplenism may contribute to a low platelet count and sometimes low counts of other blood cells.

Stomach lining changes

Portal hypertensive gastropathy is a change in the stomach lining associated with portal hypertension and congestion. It can cause chronic or, less often, acute bleeding. This is distinct from bleeding caused by a ruptured esophageal varix.

Shunting and other complications

Collateral vessels can divert some blood from the intestine around the liver and into the systemic circulation. Substances from the intestine that would normally be processed by the liver can then reach the systemic circulation. This shunting can contribute to portosystemic encephalopathy.

Portal hypertension can also contribute to ascites. Together, its complications include varices, splenomegaly with hypersplenism, portal hypertensive gastropathy, ascites, and hepatic encephalopathy.