Walsh & Hoyt: Acute Necrotyzing Myopathy

Acute necrotizing myopathy is a rare and, often times, rapidly fatal noninflammatory disorder that occurs in association with various carcinomas. Affected patients experience rapidly progressive proximal weakness associated with painful and tender muscles and, in many cases, difficulty swallowing and breathing. Elevated serum creatine kinase and urine myoglobin concentrations are present. Muscle necrosis without an inflammatory component characterizes the major pathologic findings. The features that differentiate acute necrotizing myopathy from polymyositis include the rapid course, presence of myoglobinuria, lack of response to corticosteroid treatment, and absence of inflammation on muscle biopsy in the former condition. The pathogenesis of acute necrotizing myopathy is unknown. There is no treatment for the progressive necrotic process. Death occurs in most patients within several weeks to months following the onset from complications related to inability to swallow or respiratory failure.