Hepatopulmonary syndrome is a complication of liver disease that occurs when blood vessels in your lungs expand. This expansion of the blood vessels can interfere with your lungs’ ability to transfer oxygen to your red blood cells. The most prominent symptom is shortness of breath.

Hepatopulmonary syndrome is usually considered a rare condition because it only affects people with liver disease, but it’s relatively common among people with chronic liver disease.

Studies suggest that 5% to 32% of people with cirrhosis in liver transplantation centers have hepatopulmonary syndrome.

Stay with us as we take a deeper look at hepatopulmonary syndrome, including its symptoms, treatment, and outlook.

One of the many functions of your liver is to remove toxins from your blood. Liver disease can interfere with your liver’s ability to remove these toxins, which can damage the blood vessels in your lungs. This damage can cause two lung conditions:

  • hepatopulmonary syndrome when the blood vessels expand
  • portopulmonary hypertension when the blood vessels constrict

Enlargement of blood vessels in people with hepatopulmonary syndrome can interfere with the body’s ability to transfer oxygen to red blood cells. Red blood cells carry oxygenated blood to tissues throughout your body.

Hepatopulmonary syndrome usually develops after years of liver disease. It can develop in people with mildly impaired or severely impaired liver function.

The hallmark symptom of hepatopulmonary syndrome is severe shortness of breath, which is reported in about 95% of people. About 82% of people have symptoms of liver disease before developing lung symptoms.

Some people experience platypnea, which is shortness of breath that’s worse when standing or sitting upright and improves when lying down. It affects as many as 88% of people with hepatopulmonary syndrome.

Other symptoms can include:

  • spider angioma, a red or purple “spider” pattern on your skin from widened blood vessels
  • finger or toe clubbing, enlargement of your fingers or toes that causes that nail to curve over the tips
  • cyanosis, a bluish tint to your lips and skin

Hepatopulmonary syndrome is caused by the widening of the blood vessels in your lungs, which makes it harder for your lungs to transfer oxygen to your red blood cells. The most common underlying cause is cirrhosis.

Cirrhosis is scarring of your liver that’s caused by chronic liver diseases or conditions such as hepatitis or alcohol overuse. No specific underlying cause of cirrhosis has been linked to an increased chance of developing hepatopulmonary syndrome.

In rare cases, hepatopulmonary syndrome can develop because of short-term liver diseases such as acute hepatitis.

In a 2020 study, researchers found evidence that children with biliary atresia develop hepatopulmonary syndrome more often and at a younger age than children with other types of chronic liver disease.

Hepatopulmonary syndrome can develop in people of any age, sex, and ethnicity. White individuals may develop it more often. It’s also more common in smokers than in nonsmokers.

Doctors may suspect that you have hepatopulmonary syndrome if you have unexplained oxygen saturation under 96%. Oxygen saturation is a measure of how much oxygen your red blood cells are carrying. It’s commonly measured by using a painless device that clips to your finger called a pulse oximeter.

An oxygen saturation under 96% is particularly suggestive of hepatopulmonary syndrome if you also have one of the following:

Chest X-rays and CT scans often don’t show signs of hepatopulmonary syndrome, but a lack of findings from these tests isn’t enough to rule it out.

Doctors use a variety of noninvasive tests to diagnose hepatopulmonary syndrome. They include:

  • pulmonary function tests to measure your lung function
  • a 6-minute walk test to see how your blood oxygen levels decrease with exercise
  • an abdominal ultrasound or CT scan to look for liver abnormalities
  • blood tests such as:
  • an echocardiogram (cardiac ultrasound) to take images of your heart and see if blood vessels in your lungs are dilated
  • a macroaggregated albumin lung perfusion scan, in which a small amount of radioactive substance is injected into your body so that lung dilation can be detected by a special camera

Hepatopulmonary syndrome is often a late or missed diagnosis. It takes people an average of 4.8 years from the time respiratory symptoms start to receive a definitive diagnosis.

Oxygen therapy may be recommended if you have severe hypoxemia. Hypoxemia is an abnormally low concentration of oxygen in your blood. Oxygen therapy may be recommended until you can undergo a liver transplant.

Liver transplantation is the only known effective therapy for hepatopulmonary syndrome and usually leads to significant improvements in oxygenation within 1 year of transplant. About 80% to 85% of people see improvements.

Small studies have also investigated other treatments, such as:

  • somatostatin
  • amiltrine
  • indomethacin
  • plasma exchange
  • aspirin

None of these have proven to be effective or have been approved by the Food and Drug Administration (FDA).

Hepatopulmonary syndrome worsens the outlook for people with the underlying liver disease. People with hepatopulmonary syndrome and cirrhosis have about twice the mortality rate as people with only cirrhosis. Hepatopulmonary syndrome is associated with poorer quality of life and poorer daily function.

The average survival time after hepatopulmonary syndrome diagnosis is 10.5 months compared with 40.8 months for people with chronic liver disease without hepatopulmonary syndrome. Half of people who aren’t candidates for liver transplantation die within 2 years, most often due to complications of liver disease.

Can a liver transplant cure hepatopulmonary syndrome?

Liver transplant is the only known effective treatment for hepatopulmonary syndrome. Some people with severe hepatopulmonary syndrome still have reduced survival even after a liver transplant.

How common is hepatopulmonary syndrome?

Hepatopulmonary syndrome is rare overall because it only affects people with liver disease, but it’s considered a relatively common complication in people with liver disease. It’s thought to affect 5% to 32% of people with cirrhosis in liver transplantation centers.

What’s the difference between hepatopulmonary syndrome and portopulmonary hypertension?

Portopulmonary hypertension is another complication of liver disease that affects your lungs. It’s characterized by constriction of the blood vessels in your lungs that can cause symptoms like shortness of breath and fatigue.

Can I have hepatopulmonary syndrome without liver disease?

Hepatopulmonary syndrome only develops in people with liver disease. About 18% of people develop symptoms of hepatopulmonary syndrome before symptoms of liver disease.

When was hepatopulmonary syndrome discovered?

The concept of hepatopulmonary syndrome was proposed in 1977 based on the results of autopsy and clinical studies.

Hepatopulmonary syndrome is a complication of liver disease in which blood vessels in your lungs expand. This widening of blood vessels makes it harder for your lungs to properly oxygenate your blood. The most common symptom is severe shortness of breath.

The only known effective treatment for hepatopulmonary syndrome is a liver transplant. The majority of people see an improvement in their symptoms within a year after the surgery.