Steatotic liver disease (previously known as "fatty liver") is an abnormal accumulation of certain fats (triglycerides) inside liver cells. Steatotic liver disease can be related to excess weight and metabolic risk factors such as diabetes, cholesterol and high blood pressure as well as toxins like alcohol or occasionally medications or genetic disorders.
People with fatty liver usually don't have symptoms, but may feel tired.
Sometimes steatotic liver disease progresses to more advanced liver disease such as fibrosis (scarring) and cirrhosis (severe scarring that causes permanent damage).
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 steatotic liver disease, such as metabolic syndrome or consumption of large amounts of alcohol.
(See also Overview of Liver Disease.)
The fatty liver may or may not be inflamed. Inflammation of the liver due to fatty liver is called steatohepatitis. This inflammation may develop into scarring (fibrosis). Fibrosis often progresses to cirrhosis (scarring that distorts the structure of the liver and impairs its function).
Fatty liver 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 mostly in people with fatty liver plus at least one of the components of metabolic syndrome:
Excess body weight
High fat levels in the blood (triglyceride and cholesterol)
High blood pressure
Insulin resistance or diabetes
Inflammation of the liver due to MASLD is called metabolic dysfunction-associated steatohepatitis (MASH, formerly called nonalcoholic steatohepatitis [NASH]). This inflammation may develop into fibrosis and cirrhosis.
Causes of Steatotic Liver Disease
The most common causes of steatotic liver disease in the United States and other Western countries are:
Consumption of large amounts of alcohol
Obesity
Metabolic risk factors, such as excess body weight, insulin resistance (as can occur in diabetes), high levels of fats (triglycerides and cholesterol) in the blood, and high blood pressure
Toxins
Certain medications, including corticosteroids, tamoxifen, and certain chemotherapy agentsCertain medications, including corticosteroids, tamoxifen, and certain chemotherapy agents
Hereditary metabolic disorders (for example, Gaucher disease, Wilson disease, alpha-1 antitrypsin deficiency)
Pregnancy
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. Simply consuming a high-fat diet does not result in fatty liver but may contribute to risk factors that can lead to steatotic liver disease.
Rarely, fat accumulates in the liver during late pregnancy. This disorder, called fatty liver of pregnancy or microvesicular steatosis, is usually considered a different disorder from fatty liver.
Did You Know...
|
Symptoms of Steatotic Liver Disease
Fatty liver usually causes no symptoms. Some people feel tired. The liver can be enlarged and can sometimes be detected by doctors during a physical examination.
Diagnosis of Steatotic Liver Disease
Blood tests
Imaging tests, such as ultrasound, FibroScan, or MR elastography
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 such as inflammation are important because inflammation may lead to cirrhosis (scarring that distorts the structure of the liver and impairs its function). Additional blood tests help rule out other causes of liver abnormalities such as viral hepatitis. Ultrasound, 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 (scarring) is present (see Imaging Tests of the Liver and Gallbladder). Additionally, 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.
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 Steatotic Liver Disease
Control or elimination of the cause
Medication (in patients with advanced scar tissue or damage)
Treatment of fatty liver focuses on controlling or eliminating the cause of fatty liver. For example, people should:
Stop taking any drug or medication that could be causing fatty liver
Lose weight
Take measures to control diabetes, cholesterol, and blood pressure
Stop drinking alcohol
Follow a Mediterranean diet
Depending on how much weight is lost, a decrease in body weight can decrease fat content in the liver, reduce inflammation and nonalcoholic steatohepatitis, and help reverse fibrosis (scarring).
Doctors sometimes try giving vitamin E and thiazolidinediones (a class of medications, including rosiglitazone and pioglitazone, that are used to treat Doctors sometimes try giving vitamin E and thiazolidinediones (a class of medications, including rosiglitazone and pioglitazone, that are used to treatdiabetes) to treat fatty liver that is not caused by alcohol. However, specialists are using these medications less often because they often cause side effects and may not make a difference in the long term. Vitamin E, in particular, can be toxic at doses that are too high. Patients with advanced scar tissue or damage may be eligible for a medication called resmetirom which can reverse fatty liver in 30% of patients and improve scar tissue in 25% of patients. Additional new treatments are being developed in clinical trials. A liver specialist (hepatologist) can help people decide whether they would be a good candidate for these new medications.) to treat fatty liver that is not caused by alcohol. However, specialists are using these medications less often because they often cause side effects and may not make a difference in the long term. Vitamin E, in particular, can be toxic at doses that are too high. Patients with advanced scar tissue or damage may be eligible for a medication called resmetirom which can reverse fatty liver in 30% of patients and improve scar tissue in 25% of patients. Additional new treatments are being developed in clinical trials. A liver specialist (hepatologist) can help people decide whether they would be a good candidate for these new medications.
Prognosis for Steatotic Liver Disease
Excess fat in the liver by itself is not necessarily a serious problem, although the cause of fatty liver could be a serious problem, and the progression of disease from fatty liver to inflammation or scarring can be a serious problem. If alcohol is the cause, the fat can disappear 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 or medication causing fatty liver is not stopped, repeated liver injury may eventually lead to cirrhosis (scarring that distorts the structure of the liver and impairs its function).
