Polymyositis with abnormal liver function

A 65-year-old woman was found to have slowly progressive fatigue and weakness of all four proximal limbs of several months' duration. Initial laboratory studies revealed elevated serum transaminase but normal creatine phosphokinase (CPK) levels. An immune-mediated process was believed to be the mechanism of hepatic injury, after the exclusion of vital, metabolic, and other systemic factors. Later, progressive muscle weakness and dyspnea were noted with a positive antinuclear antibody test and a markedly elevated CPK level found. Muscle tissue and liver biopsies confirmed the diagnosis of polymyositis with liver involvement. Further studies revealed the polymyositis in this case was complicated with pneumonitis and serositis (pleuritis and pericarditis). Compared with the typical presentation of polymyositis showing elevated CPK, aspartate aminotransferase and lactate dehydrogenase levels, the initial clinical course in this case presented as abnormal liver function deserved only careful diagnosis and follow-up. The trends of clinical symptoms and the elevations of transaminase and CPK levels were parallel to the response to steroid dosage in this case. It reminds us to search for any associated liver disease when facing a patient with both polymyositis and abnormal liver function.