Immune-mediated necrotising myopathy: a rare cause of hyperCKaemia

Immune-mediated necrotising myopathy (IMNM) is a type of inflammatory myopathy characterised by acute or subacute severe proximal muscle weakness, significantly elevated creatine kinase levels, and prominent myofibre necrosis and regeneration with little or no inflammation. A subtype of IMNM identified by anti-HMG-CoA reductase (HMGCR)antibodies has been shown to be associated with statin exposure. Treatment of IMNM consists of immunosuppression with steroids, steroid-sparing agents, intravenous immune globulin and/or biologics. We present here a case of anti-HMCGR-associated IMNM and review the pathophysiology, diagnosis and treatment to increase physician awareness of this rare and debilitating condition.