Metabolic Syndrome: Nonalcoholic Fatty Liver Disease

Although nonalcoholic fatty liver disease (NAFLD) is not one of the defining criteria for metabolic syndrome, it is a common hepatic manifestation. NAFLD includes a spectrum of histologic findings ranging from simple steatosis, known as nonalcoholic fatty liver, to nonalcoholic steatohepatitis (NASH). To make the diagnosis of NAFLD, other etiologies of steatosis or hepatitis, such as hepatotoxic drugs, excessive alcohol intake, congenital errors of metabolism, or viral hepatitis, must be ruled out. After ruling out other conditions, the diagnosis of NAFLD often is made clinically, but a definitive diagnosis of NASH requires liver biopsy. As with other complications of metabolic syndrome, insulin resistance is thought to be an underlying etiology of NAFLD. Management strategies attempt to reverse or improve insulin resistance while minimizing liver damage. The strongest evidence supports lifestyle modifications with weight loss, but there is some evidence to support bariatric surgery, medical therapy with insulin-sensitizing agents, and/or pharmacotherapy to promote weight loss. Cardiovascular disease is the major cause of mortality in patients with NAFLD, so management must include modification of cardiovascular risk factors.