Portal Hypertension | Symptoms & Causes

What causes portal hypertension?

Portal hypertension results from a blockage in the portal vein. These blockages are defined by where they occur:

  • a prehepatic blockage affects the portal vein before it reaches the liver
  • a hepatic blockage affects the vein within the liver
  • a posthepatic blockage affects the vein after it leaves the liver

Prehepatic blockages are the most common cause of portal hypertension in children. They stem from blood clots or narrowing of the portal vein before it reaches the liver. In response, the body grows varices that bypass the blockage. This leads to what is called “cavernous transformation of the portal vein.” These bypass veins are usually full of twists and turns that are difficult for blood to pass through and thus increase pressure on the portal vein.

Cirrhosis is the most common cause of portal hypertension in adults, and the second most common cause in children. This progressive scarring of the liver is a result of long-term illness or damage to the liver. In a child with cirrhosis, the liver’s soft, healthy tissue is gradually replaced with hard, nodular tissue that blocks the flow of blood through the portal vein.

What are the symptoms of portal hypertension?

Portal hypertension itself usually has no symptoms, though a child may have symptoms of its complications:

  • gastrointestinal bleeding, black, tarry stools or vomiting of blood, caused by varices that rupture and bleed
  • swollen abdomen, caused by fluid buildup
  • vague discomfort in the upper left part of the abdomen, caused by an enlarged spleen

Because portal hypertension is itself often a complication of advanced liver disease, children with the condition may also experience symptoms of poor liver function:

  • poor weight gain or weight loss
  • jaundice
  • confusion or forgetfulness due to the presence of substances, such as toxins, in the bloodstream that are normally filtered by the liver