Nonalcoholic Fatty Liver Disease: Diagnosis and Treatment

Diagnosis

Laboratory studies include complete blood count (CBC), blood chemistry, liver function tests, and coagulation studies. It may also be useful to evaluate ammonia level for hepatic encephalopathy.

Alcoholic liver disease should be ruled out by history, physical examination, and laboratory testing, as necessary. NASH differs from alcoholic hepatitis in that the alanine aminotransferase (ALT) is generally greater than the aspartate aminotransferase (AST), and alkaline phosphatase and bilirubin are not generally elevated. However, liver function testing is not sufficient to make the diagnosis.

Ultrasound, CT scan, and MRI may be diagnostic. These tests can identify fatty liver and evaluate for other disorders, including biliary tract disease.

Liver biopsy may be useful if the cause of fatty liver is unclear. Biopsy will also reveal the grade and stage of disease to guide management and estimate prognosis.

Treatment

Weight loss is essential for overweight patients with NASH. Even modest weight loss (~5% of body weight) may have significant beneficial effects by alleviating diabetes and hypertension.

Exercise may be beneficial, with or without associated weight loss. Use of pharmacologic weight loss agents may be beneficial, although this treatment has not yet been adequately studied. Morbidly obese patients (BMI > 35 kg/m2) may consider surgical options, such as gastric bypass.

Diabetes mellitus in NASH patients should be treated as appropriate. Insulin–sensitizing drugs (eg, metformin, pioglitazone) may be especially useful and are also under investigation for use in nondiabetic patients with fatty liver, as they may reduce steatosis. Treatment of hyperlipidemia may decrease the progression of disease.

Rarely, patients with advanced disease may require liver transplantation.