Non-alcoholic fatty liver disease: a brief review

The term 'non-alcoholic fatty liver disease' (NAFLD) includes cases with steatosis alone and those with non-alcoholic steatohepatitis (NASH). Usually there are no signs or symptoms, sometimes fatigue or pain, and apart from hepatomegaly the condition is revealed by abnormal liver biochemistry or by abdominal ultrasound. Most cases are associated with overweight or diabetes. Liver enzymes are usually elevated, especially GGT, ASAT and ALAT. Other conditions, including alcohol abuse and autoimmune hepatitis, have to be excluded. The diagnosis of steatosis can be made with ultrasound or CT scan. A liver biopsy is often needed to exclude other disease and to assess inflammation and fibrosis. Cirrhosis can develop. NAFLD is usually caused by two 'hits': the 'first hit' is peripheral insulin resistance, causing steatosis. The 'second hit' is caused by reactive oxygen species, inducing vicious cycles leading to inflammation. Weight loss, metformin or thiazolidinediones can improve NAFLD by increasing insulin sensitivity. Radical scavengers such as vitamin E, betaine and perhaps also urodeoxycholic acid may improve the hepatitis component. Further studies on treatment are needed.