Portal hypertension is the increase in blood pressure in the portal circulation. It’s a clinically significant condition that affects a large population around the world. It also may have dangerous symptoms and complications.
To understand this condition better, we should know about the portal circulation and its importance.
- Portal venous system (portal circulation): The main vessel in this system is the portal vein, which connects the liver and the digestive system; it receives the blood from the lower part of the esophagus, stomach, intestine, pancreas, gall bladder, and spleen. The veins that carry the blood from these areas unite to form the portal vein, which enters the liver. The blood in these veins may carry toxins and harmful substances from the digestive system. In the liver, the portal vein gives small branches through the liver, which enable the liver to filtrate this blood. After filtration, this blood leaves the liver through the hepatic vein to enter the systemic circulation and the heart as clean blood free from toxins. This portal circulation represents 75% of the blood flow into the liver: the liver receives its oxygenated blood through the hepatic artery, representing 25% of the blood flow into the liver.
Any condition obstructing the blood flow through the liver will increase the portal vein’s blood pressure, and the small veins that drain into it (Portal hypertension). Portal hypertension may lead to dangerous complications as gastrointestinal bleeding.
- Thus, we will discuss portal hypertension and cover it from different aspects. We will answer the following questions about it:
- What are the causes of portal hypertension?
- What are its symptoms and signs?
- How the doctors diagnose it?
- What are the treatment options for it?
Causes of portal hypertension
Portal hypertension results from obstructed blood flow through the liver, which may be due to intrahepatic, pre hepatic, or post hepatic causes.
Liver cirrhosis is the leading cause of portal hypertension. It means the scarring of the liver after liver diseases. It damages the portal vein’s smooth inner wall, which makes resistance against the blood flow through it and increases blood pressure within it. Many causes may lead to liver cirrhosis, such as:
- Alcohol abuse
- Hepatitis A and Hepatitis C
- Parasitic infections like bilharziasis
- Iron overload in the body (Hemochromatosis)
- Wilson’s disease (defect in the copper metabolism leads to its accumulation within the liver)
- Fatty liver: accumulation of large amounts of fat within the liver
- Bile ducts diseases like biliary atresia
- Cystic fibrosis
These conditions may end in liver cirrhosis, which is the main and the most common cause of portal hypertension.
Pre hepatic causes
- Portal vein thrombosis: Blood clots in the portal vein or its branches may block the blood flow through the liver and cause portal hypertension.
- Splenomegaly may cause portal hypertension by increasing blood flow through the portal vein.
- Congenital abnormalities in the portal vein, such as its narrowing (congenital portal vein atresia) or its absence
Post hepatic causes
- Hepatic vein thrombosis: Blood clots in the hepatic vein prevent blood flow from the liver to the systemic circulation, which results in portal hypertension.
- Right-sided heart failure (such as in restrictive pericarditis) reduces the venous return to the heart, which increases blood pressure in the portal circulation.