Non-alcoholic fatty liver disease (NAFLD) is due to the accumulation of fat in liver cells in the absence of excessive alcohol intake. It is the most common cause of liver disease in Western countries. It is associated with many conditions, the most important being:

• Obesity
• Diabetes mellitus
• Malnutrition or rapid weight loss
• Certain medications and toxins

The severity NAFLD varies significantly:

• Isolated fatty liver – Minor abnormalities in liver tests with no impairment of liver function.
• Non-alcoholic steatohepatitis (NASH) – Significant abnormalities in liver tests, with inflammation in the liver caused by the excess fat. Damage to the liver from inflammation may cause fibrosis and cirrhosis.
• Liver cirrhosis – Untreated NASH may lead to liver cirrhosis and, ultimately, failure.

Diagnosis

If the condition is recognised and managed properly, progression of disease can be prevented. Diagnosis can be made with compatible blood results and radiological imaging. Non-invasive tests have been developed to determine the presence and degree of fatty infiltration and cirrhosis (e.g. Fibroscan). However, it may be necessary for a liver biopsy to be performed to assist with diagnosis.

Treatment
The mainstay of treatment for NAFLD is lifestyle modification i.e. dietary changes, weight loss and exercise. Responses to various drug therapies have been disappointing, but there is much ongoing research into other possible treatment options.