Liver Knowledge Base: Portal hypertension
The Hepatic Portal Circuit (see the diagram) is a circulation pattern part of the systemic circuit.
It is a double circuit where blood flows from the aorta to digestive organs (e.g. stomach and intestines), bringing nutrients from them into the blood. This blood is collected into veins which later merge into the hepatic portal vein.
The hepatic portal vein brings the blood to the liver where different chemical processes are undergone. Finally the blood returns to the right side of the heart through the inferior vena cava.
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 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.
What Causes Portal Hypertension?
The most common cause of portal hypertension is cirrhosis. 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.
What Are the Symptoms of Portal Hypertension?
The onset of portal hypertension may not always be associated with specific symptoms that identify what is happening in the liver. But if you have liver disease that leads to cirrhosis, the chance of developing portal hypertension is high.
The main symptoms and complications of portal hypertension include:
- Gastrointestinal bleeding : Black, tarry stools or blood in the stools; or vomiting of blood due to the spontaneous rupture and hemorrhage from varices
- Ascites (an accumulation of fluid in the abdomen)
- Encephalopathy or confusion and forgetfulness caused by poor liver function
- Reduced levels of platelets, structures that help form blood clots, or white blood cells, the cells that fight infection.
33 year old male patient with decompensated liver cirrhosis, ascites, and jaundice as a result of viral hepatitis.