Portal Hypertension

Portal hypertension is defined as an increase in portal venous pressure above 5 millimeters of mercury.

When it exceeds 10 to 12 mmHg, the condition becomes clinically significant and starts to disrupt normal circulation.

The most common cause is cirrhosis, where fibrotic scarring within the liver obstructs blood flow.

Other causes can be classified as prehepatic, such as portal vein thrombosis, intrahepatic, like schistosomiasis, and posthepatic, like right heart failure.

As liver resistance increases, blood from the gastrointestinal tract is rerouted through collateral vessels that bypass the liver. These collateral pathways—such as those in the esophagus—help reduce portal pressure but also allow blood to bypass hepatic metabolism.

This reduced processing causes toxins, like ammonia, to accumulate in the blood and reach the brain, leading to hepatic encephalopathy.

Meanwhile, the rising pressure causes venous congestion in nearby organs. Varices can form in vulnerable areas such as the esophagus and stomach. These varices may rupture, leading to severe bleeding.