Necrotizing Myopathy in the Setting of Antisynthetase Syndrome

Antisynthetase syndrome is a systemic autoimmune process characterized by a constellation of clinical manifestations (myositis, interstitial lung disease, polyarthritis, fevers, Raynaud’s phenomenon and cutaneous rashes). We report the muscle biopsy findings in a 64-year-old male with a past medical history of multiple sclerosis, hypertension, diabetes and depression who presented with an upper respiratory and muscle weakness and pain. He had an elevated white blood cell count, serum creatinine kinase, Westergren sedimentation rate and C reactive protein. Electromyography studies demonstrated evidence of a necrotizing myopathy. He was treated initially with antibiotics for pneumonia and subsequently received methylprednisolone and IVIG. A left deltoid muscle biopsy showed inflammatory myopathic changes. Extensive antibody testing was performed and revealed an OJantibody. The paucity of inflammation on his biopsy may be related to his prior treatment with immunosuppressive agents or may be related to tissue sampling.