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Fatty Liver



Danielle Tholey

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Jan 2023

Fatty liver is an abnormal accumulation of certain fats (triglycerides) inside liver cells.

  • People with fatty liver may feel tired or have mild abdominal discomfort but otherwise have no symptoms.

  • Sometimes fatty liver causes advanced liver disease such as fibrosis and cirrhosis.

  • A liver biopsy may be needed to confirm the diagnosis and to determine the cause and extent of the damage.

  • Doctors focus on controlling or eliminating the cause of fatty liver, such as metabolic syndrome or consumption of large amounts of alcohol.

Fatty liver (with or without fibrosis) due to any condition except consumption of large amounts of alcohol is called metabolic dysfunction associated steatotic liver disease (MASLD, formerly called nonalcoholic fatty liver disease [NAFLD]). MASLD develops most often in people with at least one of the components of metabolic syndrome:

  • Excess body weight

  • High fat levels in the blood (triglyceride and cholesterol)

  • Insulin resistance

Inflammation of the liver due to MASLD is called metabolic dysfunction-associated steatohepatitis (MASH, formerly called nonalcoholic steatohepatitis [NASH]). This inflammation may develop into scarring (fibrosis) and cirrhosis.

Causes of Fatty Liver

The most common causes of fatty liver in the United States and other Western countries are

The combination of excess body weight, insulin resistance, and high triglyceride and/or cholesterol levels is called metabolic syndrome Metabolic Syndrome Metabolic syndrome is characterized by a large waist circumference (due to excess abdominal fat), high blood pressure, resistance to the effects of insulin (insulin resistance) or diabetes,... read more . All of these conditions cause fat to accumulate in liver cells by causing the body to synthesize more fat or by processing (metabolizing) and excreting fat more slowly. As a result, fat accumulates and is then stored inside liver cells. Just consuming a high-fat diet does not result in fatty liver.

Did You Know...

  • Eating high-fat foods, by itself, does not cause fatty liver.

Symptoms of Fatty Liver

Fatty liver usually causes no symptoms. Some people feel tired or have vague abdominal discomfort. The liver tends to enlarge and can be detected by doctors during a physical examination.

Diagnosis of Fatty Liver

  • Blood tests

  • Imaging tests, such as ultrasonography

  • Sometimes a liver biopsy

If doctors suspect fatty liver, they ask about alcohol use. This information is crucial. Continued and excessive alcohol use can cause severe liver damage.

Blood tests to detect liver abnormalities Liver Blood Tests Liver tests are blood tests that represent a noninvasive way to screen for the presence of liver disease (for example, viral hepatitis in donated blood) and to measure the severity and progress... read more , such as inflammation, are important because inflammation may lead to cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more Cirrhosis of the Liver . Additional blood tests help exclude other causes of liver abnormalities, such as viral hepatitis. Ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI) of the abdomen can detect excess fat in the liver but cannot always determine whether inflammation or fibrosis is present (see Imaging Tests of the Liver and Gallbladder Imaging Tests of the Liver and Gallbladder Imaging tests of the liver, gallbladder, and biliary tract include ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangiopancreatography... read more ). Additionally, new imaging tests such as magnetic resonance elastography (MRE) or ultrasound elastrography can determine if scar tissue or cirrhosis is present. However, in people with obesity, the fibrosis score can sometimes be falsely elevated due to high fat content, and people may need a liver biopsy Biopsy of the Liver Doctors can obtain a sample of liver tissue during exploratory surgery, but more often they obtain a sample by inserting a hollow needle through the person's skin and into the liver. This type... read more .

Liver biopsy is the most accurate test and may be necessary to confirm the diagnosis. For the biopsy, a doctor gives a local anesthetic to lessen any pain, then inserts a long hollow needle through the skin and into the liver to obtain a small piece of liver tissue for examination under a microscope. The biopsy can help determine whether fatty liver is present, whether it resulted from alcohol or certain other specific causes, and how severe the liver damage is.

Treatment of Fatty Liver

  • Control or elimination of the cause

Treatment of fatty liver focuses on controlling or eliminating the cause of fatty liver. For example, people should

  • Stop taking any drug that could be causing fatty liver

  • Lose weight

  • Take measures to control diabetes or lower triglyceride levels

  • Stop drinking alcohol

A decrease in body weight of 5% can decrease fat content in the liver, a 7% decrease can reduce inflammation and nonalcoholic steatohepatitis, and a 10% decrease can help reverse scarring and fibrosis.

Doctors sometimes try giving vitamin E and thiazolidinediones (a class of drugs, including rosiglitazone and pioglitazone, that are used to treat diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Symptoms of diabetes may... read more ) to treat fatty liver that is not caused by alcohol. However, specialists are using these drugs less often because they often cause adverse effects and may not make a difference in the long-term. New drug treatments are being developed in clinical trials. Doctors can refer people to a liver specialist (hepatologist) to discuss whether they would be a good candidate for these new drugs.

Prognosis for Fatty Liver

Excess fat in the liver by itself is not necessarily a serious problem. For example, if alcohol is the cause, the fat can disappear, usually within 6 weeks, when people stop drinking. However, if the cause is not identified and corrected, fatty liver can have serious consequences. For example, if people continue to drink large amounts of alcohol or if a drug causing fatty liver is not stopped, repeated liver injury may eventually lead to cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more Cirrhosis of the Liver .

Drugs Mentioned In This Article

Generic Name Select Brand Names
Nolvadex, Soltamox
Alph-E-Mixed , AQUA-E, Aquasol E , Aquavite-E
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