Recognition and Management of Children with Nonalcoholic Fatty Liver Disease

Drug-Induced

Drug-induced liver injury (DILI) can present with elevated serum aminotransferases (hepatocellular pattern), an elevated bilirubin (cholestatic pattern), or a mixed picture. Idiosyncratic DILI in children is commonly caused by antimicrobial or central nervous system agents and usually presents with a hepatocellular injury pattern. Substance abuse, including alcohol, is common and should also be investigated as the source of underlying liver disease.

Muscle Disease

Aspartate aminotransferase (AST) and ALT are present in hepatocytes, myocytes, and red blood cells, among other tissues. Thus, children with congenital myopathies or myositis can have elevated aminotransferases, typically with the AST higher than the ALT. In these patients, checking a creatine phosphokinase (CPK) level may lead to the correct diagnosis and limit unnecessary testing.

Other Metabolic Disorders

Myriad metabolic disorders present with liver disease and/or elevated serum aminotransferase levels. Individually, these conditions are rare but, collectively, are relatively common. Two of the more occult conditions—lysosomal acid lipase deficiency (LAL-D) and alpha-1 antitrypsin (A1A) deficiency—are discussed in further detail below.

LAL-D is an autosomal recessive disease resulting in the accumulation of cholesterol esters and triglycerides in lysosomes. Patients typically present with hepatomegaly and mildly elevated aminotransferases, an elevated LDL, low HDL cholesterol, and increased hepatic echogenicity on ultrasound. If a biopsy is obtained, microvesicular steatosis is predominant as opposed to macrovesicular steatosis found in NAFLD. The diagnosis of LAL-D can be made on a commercially available dry blood spot enzymatic assay or genetic testing and treatment has recently been FDA approved.

A1A deficiency is an autosomal recessive disease diagnosable by an alpha-1-antitrypsin phenotype. The clinical presentation is characterized by neonatal cholestasis in the infantile form and by hepatitis, cirrhosis and portal hypertension in older children. Classic symptoms of emphysema and chronic lung disease present in adulthood.

• What further testing should be performed in children with suspected NAFLD?

For obese children with an elevated ALT or evidence of increased hepatic echogenicity, ESPGHAN recommends targeting the workup according to the child’s age [36]. According to their consensus statement, they recommend an upfront, thorough laboratory evaluation in children less than 10 years of age and consideration of a liver biopsy upon completion. For children over 10 years of age at low risk for NASH or fibrosis, additional laboratory evaluation is suggested 3 to 6 months after failed lifestyle interventions. In general, the recommended workup includes testing for conditions discussed in the section above such as viral hepatitis, AIH, Wilson’s disease, and others. If negative, ESPGHAN states that a liver biopsy should be “considered.”

The question of whether or not to obtain a liver biopsy is controversial, though there are several clear advantages to doing so. First, biopsy is the gold standard test for diagnosing NAFLD and there are no highly accurate, noninvasive tests currently approved for use in children. Second, biopsy is a more definitive means of ruling out competing diagnoses such as AIH. Third, biopsy may provide prognostic data. In a retrospective adult study of 136 patients, for example, those who presented with simple steatosis had a roughly 3% chance of progressing to cirrhosis within 10 years. If a patient within this cohort presented with NASH, however, the progression risk was approximately 30% within 5 years [42,43]. Fourth, due to potential side effects of medications, position papers recommend obtaining a liver biopsy prior to the initiation of pharmacotherapy [37]. Lastly, the risk for serious morbidity from a liver biopsy is low [44,45]. Alternatively, one must acknowledge the risks of liver biopsy: morbidity, sampling bias, invasiveness, cost, and sedation risks in children.