What is nonalcoholic steatohepatitis (NASH)?
Nonalcoholic 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 nonalcoholic 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 don't abuse alcohol.
What causes NASH?
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:
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.
- An ache in the upper right part of your belly.
It may take many years for NASH to become severe enough to cause symptoms.