Diagnostic challenges of nonalcoholic fatty liver disease (NAFLD) in children of normal weight

Summary Background Nonalcoholic fatty liver disease (NAFLD) is generally regarded as affecting the overweight or obese. Though previously reported, the notion that NAFLD occurs in the presence of normal body weight (adult BMI < 25) is unfamiliar in adults and problematic in children. Normal-body-weight NAFLD accounts for approximately 15% of all NAFLD and may be more prevalent with certain ethnicities. Case We describe a case of a child who appeared to have normal-body-weight NAFLD, on the basis of typical age of presentation, ultrasonographically evident hepatic steatosis and compatible liver histology, including a NAFLD activity score of 7, but was shown conclusively to have cystic fibrosis. Further we present a clinical strategy for diagnosis of childhood NAFLD, which would discriminate between this patient and actual normal-body-weight NAFLD children in our clinical practice. Conclusion NAFLD requires affirmative diagnostic criteria and should not be merely a diagnosis of exclusion.