Nonalcoholic fatty liver disease (non-alcoholic fatty liver disease, NAFLD) is the accumulation of abnormal amounts of fat within the liver.
Nonalcoholic fatty liver disease can be divided into isolated fatty liver in which there is only accumulation of fat, and nonalcoholic steatohepatitis (NASH) in which there is fat, inflammation, and damage to liver cells.
NASH progresses to scarring and ultimately to cirrhosis, with all the complications of cirrhosis, for example, gastrointestinal bleeding, liver failure, and liver cancer.
The development of nonalcoholic fatty liver disease is intimately associated with and is probably caused by obesity and diabetes.
Nonalcoholic fatty liver disease is considered a manifestation of the metabolic syndrome.
- The symptoms of nonalcoholic fatty liver disease are primarily those of the complications of cirrhosis in patients with NASH; isolated fatty liver infrequently causes symptoms and usually is discovered incidentally. The complications of cirrhosis include:
- Gastrointestinal (GI) bleeding
- Mental changes (encephalopathy)
- accumulation of fluid (ascites, edema)
- Liver cancer
- The differentiation of isolated fatty liver from NASH usually requires a liver biopsy.
- The most promising treatments for nonalcoholic fatty liver disease are
- diet,
- exercise,
- weight loss, and
- possibly bariatric surgery.
- Several drugs have been studied in the treatment of NASH. There is little evidence that any drug is effective in slowing the disease progression of NASH.
- Many diseases are associated with NASH and are part of the metabolic syndrome. These diseases should be screened for and treated, for example, high blood pressure, dyslipidemia and diabetes.
- Isolated fatty liver rarely progresses to NASH or cirrhosis.
- Nonalcoholic fatty liver disease, including NASH affects young children as well.
- NASH will become the number one reason for liver transplantation unless effective and safe treatments are found.