What Happens
Non-alcoholic steatohepatitis (NASH) is a part of a
group of liver diseases known as non-alcoholic fatty liver disease (NAFLD). The
buildup of fat in the cells of the liver is called fatty liver, or steatosis,
and in itself is not harmful. Many people have fatty liver. In NASH, the fat
buildup causes inflammation of the liver, which can lead to symptoms such as
fatigue, weight loss, and weakness.
NASH typically appears in people during middle age, in their 40s
and 50s, but it can happen earlier or later in life. It occurs equally in men
and women.
Early on, the buildup of fat does not affect the function of the
liver, and you will have no symptoms. As fat continues to build up and
inflammation occurs, liver function begins to decline and symptoms develop.
This inflammation may lead to scarring and severe damage of the liver. There is
no clear reason why some people with fatty liver develop NASH and others do
not.
After the liver has been damaged, there is a much greater chance
that the damage will continue and get worse. In some cases, the disease
progression can stop and even reverse on its own without treatment. But in
other cases NASH can slowly get worse and cause scarring (fibrosis) of the
liver, which leads to
cirrhosis. Cirrhosis means that the liver has become
scarred and hardened and is not able to work normally.
NASH progresses to cirrhosis in about 15% to 20% of cases.2