Non-alcoholic fatty liver disease (NAFD) is one of the most common disorders of the liver. NAFD is one of the features of the metabolic syndrome which includes type 2 diabetes, hypertension, elevated serum cholesterol, obesity and polycystic ovary disease. Most patients with NAFD do not have all features of the metabolic syndrome; but having at least 2 other features is very common.
We use the term NAFD to differentiate this from alcohol induced fatty liver disease. Two types of NAFD exist. Simple fatty liver or steatosis. In this case fat accumulates within the liver but does not cause liver injury. The vast majority of these patients continue to have fat within the liver but the amount of fat does not change over decades and does not lead to liver damage. The other form of NAFD is non-alcoholic steatohepatitis or NASH. IN NASH the fat actually causes liver injury and this leads to scarring of the liver which increases over many years to cause cirrhosis. Patients with NASH tend to have elevated liver enzymes in the blood and type 2 diabetes. Patients with simple steatosis tend to have normal liver enzymes and do not have diabetes. There is currently no data to suggest that patients with simple steatosis can develop NASH. Patients have either one form of NAFLD or the other.
Many patients are found to have NAFD because they have undergone an imaging test of the liver such as an ultrasound or CT scan. However, such scans cannot differentiate whether this is simple steatosis or NASH. This can only be accomplished by performing a liver biopsy and examining a small piece of the liver under the microscope. Not all the patients with NAFD require a liver biopsy. Whether a liver biopsy will be helpful in the evaluation and management of a patient suspected of having NAFD can only be determined after a careful evaluation. This can be provided by Dr Shiffman or his staff at the Liver Institute of Virginia.
No treatment is required for patients with simple steatosis since this does not cause liver injury. The best treatment for NASH is weight loss and better control of diabetes. Weight loss reduces the amount of fat within the liver. This is true whether the patient has either simple steatosis or NASH. Weight loss in patients with NASH has been shown to reduce liver injury. In patients with morbid obesity and NASH, weight loss surgery has also been shown to reduce liver injury. More recently, Vitamin E has also been shown to reduce liver injury in patients with NASH.
Several new medications are currently being evaluated for patients with NASH. These new experimental treatments will soon be available at the Liver Institute of Virginia.