Portal hypertension

Overview

Portal hypertension means high blood pressure in the system of veins that carry blood from your digestive organs to your liver. This system, called the portal venous system, includes the large portal vein and smaller veins connected to it. Portal hypertension happens when blood gets blocked from or has trouble flowing through the liver.

A healthy liver filters blood, then returns it to the heart. But increased pressure in the portal venous system can force blood into other veins. This can lead to serious complications.

Portal hypertension can range from mild to severe. How severe it is depends on pressure levels in the portal venous system and the health of the liver. Mild portal hypertension may cause few or no symptoms and may be found during testing for another reason. Severe portal hypertension raises the risk of complications, such as bleeding in the digestive system, fluid buildup in the belly, and changes in thinking or alertness.

Some portal hypertension can be reversed, depending on the cause and how early it's found and treated. But most portal hypertension is caused by cirrhosis and cannot be cured or fully reversed. Ongoing treatment is needed to lower pressure and prevent and manage complications as well as treat the underlying cause.

Types

Healthcare professionals may describe portal hypertension based on where blood flow slows down or is blocked.

• Prehepatic portal hypertension. This is when blood flow slows or gets blocked before it reaches the liver. A common cause is a blood clot in the portal vein, called portal vein thrombosis.
• Intrahepatic portal hypertension. This is when blood has trouble moving through the liver itself.
• Posthepatic portal hypertension. In this type, blood flow slows down after leaving the liver.

A less common type is left-sided portal hypertension, also called sinistral portal hypertension. This rare type is high pressure that's mainly in the vein that drains the spleen, called the splenic vein. Left-sided portal hypertension is different from other portal hypertension in that the blockage usually happens because of pancreatic disease, such as pancreatitis, or surgery on the pancreas, not liver disease or cirrhosis. If left-sided portal hypertension is causing bleeding, the main treatment is to remove the spleen, called splenectomy, which usually cures the condition.

Causes

Portal hypertension is high blood pressure in the portal vein, which carries blood from your digestive organs to your liver. It happens when blood flow is blocked or slowed down.

The two most common causes of portal hypertension worldwide are scarring of the liver, called cirrhosis, and a parasitic infection of the liver called schistosomiasis. In Western countries, more than 90% of portal hypertension is caused by cirrhosis. Cirrhosis makes it hard for blood to flow through the liver.

The causes of portal hypertension can be grouped by where the blockage or slowing of blood flow happens. This could be in an area before blood reaches the liver, inside the liver or after blood leaves the liver.

Before blood reaches the liver, also called prehepatic

Some causes of a blockage in the portal vein, before blood reaches the liver include:

• A blood clot in the portal vein, called portal vein thrombosis.
• A blood clot in the vein that carries blood from the spleen to the liver.

In children, blood clots can happen from:

• Infections, such as sepsis or an infection in a newborn's umbilical cord stump.
• Dehydration.
• Changes in the anatomy of the portal vein that are found at birth, such as the vein being too narrow.

Inside the liver, also called intrahepatic

This is the most common area where blockages happen, most often caused by cirrhosis.

Some causes of intrahepatic portal hypertension include:

• Cirrhosis. In children, cirrhosis can be caused by autoimmune hepatitis, biliary atresia, chronic viral hepatitis and metabolic liver diseases. In adults, causes can include long-term alcohol use disorder, hepatitis B, hepatitis C and liver diseases, such as hemochromatosis, metabolic dysfunction-associated steatotic liver disease — formerly known as nonalcoholic fatty liver disease — primary biliary cholangitis and Wilson's disease.
• Conditions such as sarcoidosis and amyloidosis, which can cause cirrhosis.
• Infections such as schistosomiasis, which can cause cirrhosis.
• Other conditions that may not cause cirrhosis but can lead to portal hypertension.

You may hear intrahepatic portal hypertension described as:

• Presinusoidal portal hypertension. This means the blood flow is blocked before blood reaches certain small blood channels inside the liver called the sinusoids. This is typically not caused by cirrhosis but by other liver conditions or infections.
• Sinusoidal portal hypertension. This means the blood flow is blocked at the point of the sinusoids in the liver. Cirrhosis is a sinusoidal cause of portal hypertension.
• Postsinusoidal portal hypertension. This means the blood flow is blocked after blood has reached the sinusoids in the liver.

After the liver, also called posthepatic

Some causes of blockages after blood leaves the liver can include:

• Budd-Chiari syndrome.
• A condition that affects the sac around the heart, called constrictive pericarditis.
• Serious heart conditions, such as cardiomyopathy.
• A blockage, such as a blood clot, in the vein that carries blood to the heart.

If a cause cannot be found, you may hear that referred to as idiopathic.

Complications

Portal hypertension often is noticed only after complications start.

Complications can include:

• Fluid buildup in the belly, also called ascites. When the liver is damaged, such as with portal hypertension, the kidneys hold excess salt. The salt causes the body to hold onto water, and fluid builds up in the belly. This complication called ascites. With portal hypertension, fluid also may leak out of blood vessels into the belly. This happens because of the increased pressure in the portal vein system, Sometimes, ascites can become infected, called spontaneous bacterial peritonitis.

• Enlarged veins, also called varices, and bleeding. Increased blood pressure in the liver's portal vein system can force blood to seek other routes. This includes the veins of the esophagus, stomach and intestines. When pressure in those veins increases, it can cause the veins to enlarge, a condition called varices. Varices in the esophagus are called esophageal varices. Varices in the stomach are called gastric or stomach varices.

  Varices are fragile due to their thin walls. This increases the risk of bleeding. When varices bleed, blood can build up in the stomach. Larger varices are more likely to bleed. Spots on the skin over varices also suggest a higher risk of bleeding. Sometimes varices form in the rectum, where they can bleed. This is not the same as hemorrhoids.

• Changes in thinking or alertness. When the liver can't filter toxins from the blood, such as ammonia from the intestines, the toxins can build up and affect how the brain works. This is called hepatic encephalopathy. The condition can lead to confusion, changes in personality, trouble concentrating and, when severe, coma.
• Stomach and colon changes and bleeding. Pressure from portal hypertension can lead to more blood in blood vessels in the lining of the stomach and large intestine, also called the colon. This buildup of blood can cause those blood vessels to swell and bleed. The bleeding may be slow and ongoing. It's not usually a cause of a large amount of bleeding, but the bleeding can cause anemia. In the stomach, this is called portal hypertensive gastropathy. In the colon, it's called portal hypertensive colopathy.
• Enlarged spleen and low platelet count. The spleen acts as a filter for blood. When portal hypertension causes blood to back up and pool in the spleen, the spleen can swell in size, called splenomegaly. As the spleen enlarges, it can trap and destroy more blood cells, including platelets. This leads to a low platelet count, called thrombocytopenia. This condition can limit how well the blood clots and increase the risk of bleeding.
• Kidney failure. Portal hypertension is not the same as kidney failure. But high blood pressure in your liver from portal hypertension, along with fluid in the belly, called ascites, can contribute to kidney failure. This is called hepatorenal syndrome. Portal hypertension causes the blood vessels in your belly to widen. This can affect blood flow and mean your kidneys don't get enough blood. In addition, if portal hypertension leads to ascites, that fluid can become infected and trigger kidney failure.
• Low oxygen in the blood. High blood pressure in your liver from portal hypertension sometimes leads to the blood vessels in your lungs enlarging. These changes in the lungs make it hard for red blood cells to take in oxygen. Then the lungs can't send enough oxygen to the body. This condition is called hepatopulmonary syndrome.

Diagnosis

Healthcare professionals often diagnose portal hypertension by asking about your health history and doing a physical exam. A physical exam can show signs such as fluid buildup in the belly or an enlarged spleen. If you have known risk factors for portal hypertension, such as cirrhosis, as well as symptoms, that may be all that's needed to make the diagnosis.

Sometimes, your health professional may order blood tests and imaging tests. If the diagnosis isn't clear, portal vein pressure may be measured directly to find out how high it is. This is not often done because the test is invasive.

Blood and lab tests

Blood tests can show changes linked to portal hypertension.

• Complete blood count (CBC). This test measures the number of different cells in your blood, including platelets. Portal hypertension can enlarge the spleen, which may lower platelet counts. Low platelet levels, called thrombocytopenia, can suggest portal hypertension.
• Liver function tests. These blood tests check how well the liver is working. Results outside the standard range may suggest a liver disease that can cause portal hypertension.
• Other tests. You may have other lab tests, for example, to find out whether fluid in the belly, called ascites, is caused by portal hypertension or something else. A measurement called the serum-ascites albumin gradient (SAAG) can help tell this by comparing the level of a protein called albumin in the blood with the level of albumin in the fluid in the belly. A gradient measurement of 1.1 grams per deciliter (g/dL) or more means the fluid is likely caused by portal hypertension.

Blood and lab test findings help guide the need for more testing, but they do not confirm portal hypertension on their own.

Imaging tests

Imaging helps show the effects of increased pressure in the portal vein system.

• Ultrasound. An ultrasound of the belly, called an abdominal ultrasound, can show an enlarged spleen, fluid in the belly and changes in the size of the portal vein. These findings may suggest portal hypertension. A special type of ultrasound called Doppler ultrasound shows the direction and speed of blood flow in the portal vein and nearby vessels. Slowed or altered blood flow patterns may suggest portal hypertension. However, ultrasound does not directly measure portal pressure.
• Upper endoscopy. This test allows a healthcare professional to look directly at the esophagus and stomach using a flexible tube with a camera. This test can find enlarged veins called varices.
• CT scan. This test shows detailed cross-sectional images, also called slices, of the liver and surrounding blood vessels. An enlarged spleen or new, enlarged or twisting veins, called collateral veins or varices, are possible signs of portal hypertension. CT also may show the underlying cause, such as scarring of the liver called cirrhosis.
• Magnetic resonance imaging (MRI). This test shows detailed images of soft tissues, including the liver and blood vessels. It also can show enlarged veins, changes in blood flow and other features linked to portal hypertension. A test called magnetic resonance elastography also might be done. This test can measure liver tissue stiffness to help show whether portal hypertension is high enough to cause complications. Portal hypertension that can cause complications also is called clinically significant.

Imaging tests show different signs that suggest portal hypertension. But they do not directly measure how high the pressure is.

Measuring portal pressure

If a diagnosis of portal hypertension isn't clear, portal pressure may be measured in one of two ways.

• Indirect method. This is done using a tube called a catheter that's placed into the veins that move blood from the liver to the heart rather than in the portal vein itself. During the test, the pressure is measured both when blood is blocked by a small balloon at the end of the catheter and when blood is not blocked by the balloon. The difference between those two numbers is called the hepatic venous pressure gradient (HVPG). It is an indirect estimate of pressure in the portal vein.

  Portal hypertension is defined as an HVPG greater than 5 millimeters of mercury (mm Hg). When the HVPG reaches 10 mm Hg or more, the risk of complications increases. An HVPG greater than 12 mm Hg is linked to a higher risk of bleeding from enlarged veins.

• Direct method. Though much less common, direct measurement of portal pressure may be done by placing a catheter into the portal vein.

How serious is portal hypertension?

Portal hypertension ranges from mild to severe. How severe it is depends on how high the pressure is and whether complications have happened. Lower pressure levels may not cause symptoms. Higher pressures, especially above 10 to 12 mm Hg, are linked to a greater risk of conditions such as bleeding or fluid buildup.

Diagnosis

Can portal hypertension be cured?

If the underlying cause of portal hypertension is reversible, the liver may heal and reverse or cure the portal hypertension. For example, if viral hepatitis is the cause, treating it may resolve both conditions. If a liver transplant is done for advanced liver disease, the donated liver also could cure the underlying cause. Medicines and other procedures do not cure portal hypertension. But they can help protect the body from further damage and complications and improve some symptoms.

Lifestyle and home remedies

If you have portal hypertension, lifestyle changes may help protect the liver and reduce the risk of portal hypertension complications:

• Don't drink alcohol. Even a single glass of alcohol can damage your liver further. This is true for all types of alcoholic drinks.
• Eat a low-sodium diet. Extra salt can cause your body to hold on to fluids. This can worsen swelling in your belly and legs. Use herbs rather than salt to season your food. Choose prepared foods that are low in sodium.
• Protect yourself from infections. If you have cirrhosis, your body can have trouble fighting off infections. Protect yourself by avoiding people who are sick and washing your hands often. Get vaccinated, for example, for hepatitis A and B, influenza, and pneumonia.
• Use nonprescription medicines carefully. Liver damage makes it harder for your liver to process medicines. For this reason, ask a healthcare professional before taking any medicines, including those you can get without a prescription. Do not take ibuprofen (Advil, Motrin IB, others), aspirin or aspirin-containing products unless your care team tells you. A health professional may recommend that you take acetaminophen (Tylenol, others) in low doses for pain relief.
• Follow your healthcare team's instructions. Follow any diet recommendations, take medicines as prescribed, and get your blood tests and medical exams at the recommended times. Also watch for signs of complications and take action as advised by your care team.