What is non-alcoholic steatohepatitis (NASH)?
Non-alcoholic steatohepatitis (NASH) is liver inflammation and damage caused by a buildup of fat in the liver. It is part of a group of conditions called non-alcoholic fatty liver disease. You may be told you have a "fatty liver." Many people have a buildup of fat in the liver, and for most people it causes no symptoms and no problems. But in some people, the fat causes inflammation and damages cells in the liver. Because of the damage, the liver doesn't work as well as it should.
NASH can get worse and cause scarring of the liver, which leads to cirrhosis. But the disease doesn't always get worse.
NASH is similar to the kind of liver disease that is caused by long-term, heavy drinking. But NASH occurs in people who use little or no alcohol.
What causes it?
Experts don't know why some people with a buildup of fat in the liver get NASH and some don't. It could be that something in the environment triggers the inflammation in those people. Or maybe it runs in their families.
Things that put people at risk for NASH and for liver damage include:
- Insulin resistance and type 2 diabetes.
- High cholesterol and high triglycerides.
- Metabolic syndrome.
Most people who have NASH are 40 to 50 years old and have one or more of the problems listed above. But NASH can happen in people who have none of these risk factors.
What are the symptoms?
You may have no symptoms in the early stages of NASH. Most people who have NASH feel fine and don't know that they have it.
As NASH progresses and liver damage gets worse, you may start to have symptoms such as:
- Fatigue (feeling tired all the time).
- Weight loss for no clear reason.
- General weakness.
- An ache in the upper right part of your belly.
It may take many years for NASH to become severe enough to cause symptoms.
How is it diagnosed?
No single test can diagnose NASH. Your doctor will ask you about other health problems you've had.
To see if fat is building up in your liver and to rule out other diseases, your doctor may do tests such as:
Your doctor may do a liver biopsy to be sure that you have NASH. In a liver biopsy, your doctor takes a sample of tissue from your liver and checks it for signs of NASH.
How is NASH treated?
Treatment for NASH includes managing conditions that increase your risk for NASH or make it worse. You can:
- Reduce your total cholesterol level.
- Reach a healthy weight. Losing 3% to 10% of your total body weight can make a difference. Bariatric surgery may help with long-term weight loss. footnote 1
- Control diabetes.
- Get immunized. Having NASH increases your risk for infections, so it's important to get all recommended vaccines.
- Stop or cut back on drinking alcohol.
- Exercise regularly.
Also, ask your doctor or pharmacist about all the medicines you are taking. Some may harm your liver.
In some cases, your doctor may suggest medicine to control or reverse liver damage caused by NASH.
- Chalasani N, et al. (2018). The diagnosis and management of nonalcoholic fatty liver disease: Practice guidance from the American Association for the Study of Liver Diseases. Hepatology, 67(1): 328–357. DOI: 10.1002/hep.29367. Accessed April 7, 2021.
Current as of:
February 10, 2021
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
W. Thomas London MD - Hepatology
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