Two Cases of Polymyositis Mimicking Acute Viral Hepatitis

A 25 year old male construction worker admitted to the hospital with fatigue, pruritus, dark urine, nausea, vomiting and jaundice. There was no abnormality in physical examination except subicterus. Biochemical evaluation revealed AST level of 1120 IU/L, ALT level of 2410 IU/L, AP level of 250 IU/L, GGT of 310 IU/L and total bilirubin level of 3.45 mg/dL. The patient had been diagnosed as criptogenic hepatitis after an extensive work- up for differential diagnoses. The patient presented, about one year later, with symptoms of weakness and generalized myopathic pain. On his physical examination, there was a loss of 4/5 in muscle strength. Muscle pain, muscle weakness and elevated liver enzymes led to the diagnosis of polymyositis which was confirmed by laboratory tests and EMG. The patient was started on prednisolon and the symptoms regressed rapidly. After one month, all the laboratory values were normal, but mild ALT elevation persistans. The second case was a 50 year old housewife presenting with weakness, lumbar pain and fever. In physical examination there was a weakness in muscles and ALT was 522 IU/L, AST: 844 IU/L, AP: 142 IU/L, GGT: 145 IU/L, total bilirubin: 1.1 mg/dL and CPK: 11.370 IU/L. These findings together with EMG, and muscle biopsy confirmed the diagnosis of polymyositis. The symptoms regressed with prednisolone. In conclusion, polymyositis should be considered in the differential diagnosis of acute viral hepatitis, because it can cause a tenfold increase in liver enzymes.