ELEVATED AMINOTRANSFERASE ACTIVITY AS AN INDICATION OF MUSCULAR-DYSTROPHY - CASE-REPORTS AND REVIEW OF THE LITERATURE

Five male children are reported in whom incidental recognition of elev ated serum alanine aminotransferase (ALT) activity initiated investiga tion to identify the cause of suspected hepatocellular injury, All fiv e were later diagnosed with X chromosome-linked muscular dystrophy. Th e serum level of ALT, generally considered to be specific for hepatoce llular injury, was increased two to 25 times above normal in all the r eported cases. Paradoxically, the increase in ALT activity was greater than that of serum aspartate aminotransferase (three to 16 times norm al), an enzyme whose elevation is generally recognized as being less s pecific and indicative of muscle, cardiac, kidney, pancreatic, red blo od cell or hepatic injury. At presentation to the gastrointestinal ser vice, one case, age 2.5 months, had no symptoms or signs of neuromuscu lar dysfunction, while the other four had previously unrecognized hype rtrophy of the calves, proximal limb weakness, positive Gower's sign o r delayed gross motor skills. All five patients had marked elevation o f serum creatine kinase activity and histopathologically confirmed mus cular dystrophy. The practical clinical implication of this report is that children with elevated serum ALT, in the absence of other signs a nd symptoms of hepatic injury, amy have occult muscular disease - most frequently muscular dystrophy. Although the clinical signs of muscula r dystrophy may be subtle or absent, early determination of creatine k inase will suggest the correct diagnosis and minimize extensive and in vasive investigation focusing on hepatic injury.