357: MORE THAN MYALGIA: STATIN-INDUCED IMMUNE-MEDIATED NECROTIZING MYOPATHY

Abstract

Introduction: Statins rank amongst the top ten most prescribed medications in the United States for their cardiovascular benefits. Common toxic side effects include elevated liver enzymes and myalgia including rhabdomyolysis. We report a case of a previously healthy middle-aged female who recently started statin therapy and developed progressive muscle weakness requiring mechanical ventilation. Description: A 58-year-old female with recently diagnosed hyperlipidemia started on atorvastatin (40 mg) 2 months prior to presentation was admitted with 2 weeks of progressively worsening proximal muscle weakness and oropharyngeal dysphagia. Admission labs showed a significantly elevated creatine phosphokinase (CPK) (3,742 U/L) and aldolase level (41.1 U/L). She was empirically started on IVIG for presumed myasthenic crisis or possible inflammatory myositis. On day 2, she exhibited worsening proximal muscle weakness and an inability to lift her extremities against gravity. On physical exam, she had 1/5 strength of proximal muscle groups and 4/5 strength of distal muscle groups with an otherwise intact neuromuscular exam. On day 3, she had worsening dysphagia and aspiration pneumonitis requiring endotracheal intubation. An EMG showed myopathic features in the proximal musculature without any evidence of neuropathy. She was empirically started on steroids with some improvement. After 1 week, the anti-HmgCoA reductase antibody returned severely positive (>200). Given the high specificity of this test, her presentation was ultimately deemed consistent with statin induced immune-mediated necrotizing myopathy, and she was started on Cellcept (MMF) and high-dose steroids. Discussion: The case highlights the devastating consequences that can result from a very commonly prescribed medication class and the importance of actively evaluating for adverse medication effects. Statin therapies are guideline directed in patients with cardiovascular disease such as coronary artery disease and stroke. Myalgia without significant weakness are a common side effect and therapy includes discontinuing the offending agent. In the presence of severe weakness, statin induced immune-mediated necrotizing myopathy should be considered, as it could be detrimental and may require mechanical ventilation and treatment with immunosuppressants.