Fatty liver (steatosis, non-alcoholic fatty liver disease) is a condition where the liver becomes infiltrated with fat. The fat is called steatosis, but when there is inflammation or scarring, it is called steatohepatitis or NASH. This condition can lead to fibrosis, or even cirrhosis of the liver. Up to 20% of the US population has fatty liver, and perhaps as many as 5% have NASH.
Most people with fatty liver are overweight or have diabetes or pre-diabetes (insulin resistance). Occasionally, medications can lead to fatty liver. Excessive alcohol use can also lead to steatosis.
Fatty liver is a silent condition. Although liver enzymes (AST and ALT) can be elevated, patients generally feel fine. Some complain of a dull pain under their right rib cage, and this is due to swelling of the liver. Usually blood tests lead to the diagnosis.
Blood tests indicating elevated liver enzymes usually lead to further evaluation. An ultrasound usually shows fat in the liver, but so will a CT scan or MRI scan. The only way to diagnosis steatohepatitis (NASH) is to biopsy the liver.
There is no FDA approved treatment for NASH, but general therapies include weight loss, control of diabetes, a healthy diet, and abstinence from alcohol. There are some new experimental therapies for fatty liver.
Fatty liver is the most common liver condition in the US. The aggressive variant is called NASH and should not be ignored. It can lead to cirrhosis!