Your liver is the largest solid organ in your body and performs many vital functions. It filters toxins, supports metabolism and immunity, helps digest fats, stores nutrients, and regulates cholesterol, proteins, and hormones. You can’t survive without it. One common sign of a liver problem is an enlarged liver, known as hepatomegaly.

Many conditions can cause hepatomegaly, including the autoimmune disease primary biliary cholangitis (PBC). In autoimmune diseases, the body’s immune system mistakenly attacks its own healthy cells and tissues. In this article, we’ll explain what causes hepatomegaly, how it’s diagnosed, and how it relates to PBC.

What Is Hepatomegaly?

When your liver is swollen beyond its normal size, it’s considered enlarged. This condition might be temporary, or it could be a sign of a long-term underlying condition.

Hepatomegaly often doesn’t cause any symptoms. However, some people do experience some of the following, especially when liver disease is causing hepatomegaly:

• Right upper quadrant abdominal pain or fullness
• Fatigue
• Nausea and vomiting
• Jaundice (yellowing of the skin and eyes)

Your doctor might be able to feel the enlarged liver during a physical exam by pressing around your abdomen and ribs. Follow-up imaging and testing can confirm a diagnosis and reveal what’s causing hepatomegaly.

What Causes Hepatomegaly?

Many conditions can cause an enlarged liver. In general, it results from one of four main causes. Below, we outline each of these causes and their common triggers.

Fat and Toxin Accumulation

Too much fat or other substances stored in the liver can cause it to swell. Conditions that can cause this include:

• Metabolic dysfunction-associated steatotic liver disease — Causes fat to build up in the liver in people who drink little or no alcohol
• Alcoholic liver disease
• Gaucher’s disease — A genetic disorder that causes fat to build up in the liver and other organs
• Amyloidosis — Abnormal proteins build up in the liver
• Hemochromatosis — A genetic disorder that causes too much iron to build up in the liver
• Wilson’s disease — A genetic disorder where copper builds up in the liver
• Alpha-1-antitrypsin deficiency — A genetic disorder that causes inflammation and damage to the liver

Inflammation and Infections

Certain types of infection or inflammation in the body can cause the liver to enlarge. Inflammation can be caused not only by germs and infections but also by exposure to harmful substances like alcohol.

Some specific conditions include:

• Viral infections — Including hepatitis A, B, or C, and infectious mononucleosis
• Bacterial or parasitic infections — Such as liver abscess, a pocket of pus in the liver, or echinococcosis, a parasitic disease caused by tapeworms
• Cirrhosis — Scarring of the liver from alcoholism or hepatitis
• Toxic hepatitis — Can happen after a medication overdose (such as acetaminophen or amiodarone)

Abnormal Growths

Some types of cancerous and noncancerous growths can cause the liver to enlarge. These include:

• Liver cancer
• Benign (noncancerous) liver tumors
• Leukemia and lymphoma (both blood cancers)
• Metastatic cancer (cancer from other parts of the body that spreads to the liver)

Blood or Fluid Accumulation

Certain conditions can interfere with how blood and other fluids flow through the liver. If blood flow is blocked or the blood vessels in the liver become enlarged, the liver can swell. This can also happen if any of the other organs or vessels that feed fluids into the liver become damaged.

Some conditions that can cause blood or fluid accumulation in the liver include:

• Budd-Chiari syndrome — The veins that allow blood to leave the liver become blocked.
• Right-sided heart failure
• PBC — The bile ducts that run through the liver become damaged and cause bile buildup.
• Primary sclerosing cholangitis — Similar to PBC, in which inflammation affects the bile ducts both inside and outside the liver

Risk Factors

There are also many risk factors for hepatomegaly, and most are connected to what causes it. You could be at increased risk for hepatomegaly from the following:

• Drinking excessive amounts of alcohol
• Taking high doses of medications, supplements, or vitamins
• Having infections, such as those caused by hepatitis viruses
• Having a higher body weight or obesity or eating an unhealthy diet high in sugar and fat

How Common Is Hepatomegaly?

Because hepatomegaly by itself often doesn’t cause any symptoms, it’s hard to say how many people have this condition. A survey of more than 2,000 healthy volunteers found that about 12 percent of people had an enlarged liver.

How Is Hepatomegaly Diagnosed?

Imaging tests are used to look at the size of the liver. These scans might include:

• Ultrasounds — Show a picture of your internal organs using sound waves
• CT scans — Create a 3D image of your body using X-rays
• MRI scans — Use magnetic fields to create an image of your organs

A healthcare professional will interpret these scans to determine if you have hepatomegaly.

Typically, they will measure the length of the liver along the midclavicular line — a vertical line that runs from the middle of your collarbone down toward your belly button. The average length along this line is about 4 to 5 inches. A liver is considered enlarged if it measures more than about 6 to 6.25 inches, or 15.5 to 16 centimeters (the unit of measure generally used by radiologists).

Blood and Urine Tests

Your doctor may order blood and urine tests to check how well your liver is working and look for possible causes of liver disease. If disease is causing your liver to enlarge, these tests may also show signs that it’s damaged or not working properly.

Other Tests

You might need to get other tests that are specific to the underlying cause of an enlarged liver. For example, if your healthcare provider thinks you may have liver cancer, they may take a small sample of the liver (called a liver biopsy) to test for cancer cells.

Can PBC Lead to Hepatomegaly?

PBC can lead to an enlarged liver. In PBC, the body’s immune system attacks and damages the liver, specifically the cells that make up the liver’s bile ducts. A bile duct is a tube that carries bile, a fluid that’s important for digestion.

PBC’s attack on the liver causes long-term inflammation. In the early stages, due to liver inflammation and bile accumulation, the liver can enlarge. As the disease progresses, this inflammation kills cells in the liver and creates liver scarring. Eventually, enough scar tissue can build up that blood vessels in the liver become blocked or backed up. When this happens, the blood pressure in the liver increases (called portal hypertension). Portal hypertension can create an enlarged liver. With more scarring of the liver, advanced scarring or cirrhosis develops, which causes the liver to harden and shrink.

Hepatomegaly is more common in the early stages of the disease, affecting about 75 percent of those with PBC.

How Is Hepatomegaly Treated in People With PBC?

Although liver damage from PBC can’t be reversed, several treatment options can slow the progression of the disease. Treatments that reduce inflammation can also reduce PBC complications, such as liver enlargement.

General treatment options for PBC include the following:

• Doctors may prescribe medications that help clear bile out of the liver.
• A liver transplant may be needed if medication no longer keeps liver function stable. Outcomes after liver transplant for those with PBC are usually very good.

In addition, if you have portal hypertension with PBC, there are specific medical treatments to control it and prevent complications. Reducing high blood pressure in your liver, one of the causes of hepatomegaly in PBC, can also help reduce liver swelling.

The Bottom Line

An enlarged liver can have many causes, and in people with PBC, it’s often one of the early changes doctors look for. While hepatomegaly may not always cause symptoms, it can be a sign that the liver isn’t working as it should. Getting the right diagnosis and starting treatment early can help protect your liver and lower the risk of complications over time.

Talk With Others Who Understand

On myPBCteam, the social network for people with primary biliary cholangitis and their loved ones, members come together to ask questions, give advice, and share their tips with others who understand life with primary biliary cholangitis.

Have you been told your liver is enlarged because of PBC? Have you talked to your healthcare team about what it means for your outlook and treatment? Share your experiences in the comments below, or start a conversation by posting on your Activities page.