liver is the accumulation of fat in liver cells. Simple fatty liver
is not a disease, since it does not damage the liver, but is a condition
that can be identified by taking a sample of liver tissue (liver biopsy)
and examining it under a microscope. Another term often used to describe
this condition is fatty infiltration of the liver.
accumulates in the liver usually in connection with heavy use of alcohol,
extreme weight gain or diabetes mellitus. Fatty liver can also occur
with poor diet and certain illnesses, such as tuberculosis, intestinal
bypass surgery for obesity, and certain drugs such as corticosteroids.
Fatty liver is usually suspected in a patient with the diseases or conditions described above. The patient may have an enlarged liver or minor elevation of liver enzyme tests. Several studies show that fatty liver is one of the most common causes of isolated minor elevation of liver enzymes found in routine blood screening.
find out for certain whether a patient has fatty liver requires that
a sample of liver tissue be obtained (biopsy). Images of the liver obtained
by an ultrasound test or by a computed tomography (CT) scan can suggest
the presence of a fatty liver. In the ultrasound test, a fatty liver
will produce a bright image in a ripple pattern. A CT scan will show
a liver that is less dense than normal.
is not certain how fatty liver occurs. A patient has fatty liver when
the fat increases the weight of the liver by 5 percent. Possible explanations
for fatty liver include the transfer of fat from other parts of the
body, or an increase in the extraction of fat presented to the liver
from the intestine. Other explanations are that the liver reduces the
rate it breaks down and removes fat. Eating fatty food by itself does
not produce a fatty liver.
Simple fatty liver is not associated with any other liver abnormalities such as scarring or inflammation. It is a common finding in patients who are very overweight or have diabetes mellitus.
Patients who drink too much alcohol for many years may develop alcoholic liver damage that includes fatty liver. Alcoholism could also result in inflammation of the liver (alcoholic hepatitis) and/or scarring (alcoholic cirrhosis). Evidence suggests that while fatty liver is usually present in patients with excessive intake of alcohol, fatty liver does not by itself lead up to the development of alcoholic hepatitis or alcoholic cirrhosis.
inflammation of the liver associated with an increase of fat deposits
may occur in middle-aged, overweight, and often diabetic patients who
do not drink alcohol. This disease, which resembles alcoholic hepatitis,
is called nonalcoholic steatohepatitis (NASH). This fatty tissue in
the liver may break up (steatonecrosis) and the patient may develop
cirrhosis (scarring of the liver). Some studies have shown that 20 percent
to 40 percent of people who are grossly overweight will develop NASH.
However, just because a patient is grossly overweight does not mean
he will develop NASH. Some researchers have connected the development
of NASH with poor control of diabetes mellitus, rapid weight loss, or
in women, the taking of hormones (estrogen).
treatment of fatty liver is related to the cause. It is important to
remember that simple fatty liver does not require treatment, since it
does not result in damage to liver cells or clinical disease. Obese
patients with fatty liver will have reduction or loss of excess fat
in liver cells, as well as in other cells in the body, if substantial
weight loss can be achieved. Patients who drink alcohol to excess will
also have a loss of fat in the liver when alcohol is discontinued. Good
control of diabetes mellitus with diet, drugs, or insulin also decreases
the fat content in the liver.
The American Liver Foundation is the only national, nonprofit voluntary health organization dedicated to preventing, treating, and curing liver disease through research and education.