Hepatopulmonary syndrome

This lung condition causes low oxygen levels and shortness of breath in some people with advanced liver disease.

Update Date: 18.09.2026

Overview
Symptoms
Causes
Risk factors
Diagnosis
Treatment
Preparing for an appointment

Overview

Hepatopulmonary syndrome is a condition in which low oxygen levels in the blood are caused by enlarged blood vessels in the lungs. Hepatopulmonary (hep-uh-toe-POOL-moe-nar-e) syndrome affects the lungs of some people who have advanced liver disease.

When the tiny blood vessels in the lungs become enlarged, also called dilated, it's more difficult for red blood cells to take in oxygen. This results in the body not having enough oxygen. The exact link between advanced liver disease and this lung condition isn't yet known.

Oxygen therapy may improve blood oxygen levels to some degree. A liver transplant is the only way to correct hepatopulmonary syndrome.

Symptoms

Early in the disease, there are often no symptoms of hepatopulmonary syndrome. Symptoms usually develop and worsen gradually. They may include the following:

  • Shortness of breath. This is usually the first symptom. Often, it's worse when sitting or standing, and it gets better when lying flat on the back.
  • Clubbing of the fingers. This is where the fingertips become rounder than usual.
  • Spider angioma. This is the term for tiny blood vessels that appear below the surface of the skin that look somewhat like spiders.
  • Cyanosis. This is a change in skin color caused by low blood oxygen. The color of the skin and lips may be pale blue or gray.

Causes

Hepatopulmonary syndrome is a complication of advanced liver disease.

Hepatopulmonary syndrome also may be caused by portal hypertension. This is high blood pressure in the vein that brings blood to the liver to be filtered. Portal hypertension is often caused by long-term liver disease, but it also can happen when there is no underlying liver disease.

Researchers continue to explore the link between liver disease and hepatopulmonary syndrome.

Disease-related changes in the liver start activity that causes the tiny blood vessels in the lungs to dilate and undergo other changes. The result is that blood can't efficiently exchange gases. Red blood cells release carbon dioxide and pick up oxygen as they should.

Risk factors

Not all cases of advanced liver disease lead to hepatopulmonary syndrome. It's not clear why some people with advanced liver disease develop the condition.

Genes with certain changes may increase the risk of getting hepatopulmonary syndrome.

Diagnosis

A diagnosis of hepatopulmonary syndrome is based on evidence of these three factors:

  • Liver disease or portal hypertension.
  • Dilated blood vessels in the lung.
  • Low blood oxygen levels.

Screening for hepatopulmonary syndrome is generally a part of the care for people with long-term liver disease. Diagnostic tests that may be used include the following:

  • Blood gas levels. Blood samples are taken from an artery. These samples are tested for oxygen and carbon dioxide levels. Oxygen levels also may be measured with a device clipped to a finger called a pulse oximeter.
  • Echocardiogram. This ultrasound of the heart — when used with a substance to enhance the image — can show signs of blood flow typical of hepatopulmonary syndrome or other lung conditions.
  • Lung function test. This test measures how well your lungs are exchanging carbon dioxide and oxygen when you breathe into a device. This may show changes in function due to hepatopulmonary syndrome or help your healthcare professional find another cause of symptoms.
  • Nuclear medicine lung perfusion scan. This imaging technique uses a safe radioactive protein injected into the blood that's tracked by a special camera. This scan shows if and how much the blood vessels in the lungs are dilated. It also can show to what degree low blood oxygen levels are due to hepatopulmonary syndrome.
  • CT scan. A CT scan is important for ruling out other possible causes of symptoms.

Treatment

A liver transplant is the only treatment to correct the changes in the blood vessels in the lungs. For most people with hepatopulmonary syndrome who get a liver transplant, blood oxygen levels gradually increase over several months to a year.

Until a liver transplant is done, you'll likely have oxygen therapy. This is done with a device that delivers oxygen through a tube attached to your nose or through a face mask.

Preparing for an appointment

Generally, screening for hepatopulmonary syndrome is a regular part of care for long-term liver disease.

What you can do

You can take a role in managing liver disease by:

  • Keeping all appointments with your primary healthcare professional and any specialist managing your liver disease.
  • Following your treatment plan and taking all medicines as prescribed.
  • Scheduling appointments when there are changes in symptoms or new symptoms.

If possible, bring a family member or friend to your appointment to take notes to help you remember the information you're given. Before your appointment, make a list of:

  • Symptoms, including those that may not be related to your main concern.
  • Medicines, vitamins or supplements you take, as well as the doses and reason for taking each one.

What to expect from your doctor

Your healthcare professional may ask the following questions:

  • Do you have shortness of breath?
  • Do you have shortness of breath when you are exercising?
  • Have you noticed the appearance of spiderlike veins on your skin?
  • Are you following your treatment plan for liver disease?
  • Are you getting treatment for other conditions?
  • Have you started taking new medicines or stopped taking any medicines?

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