Statin-Induced Myositis with Concomitant Myocarditis

Statins are commonly prescribed medications that provide many significant cardiovascular benefits for both primary and secondary prevention in patients with and without coronary artery disease. Known adverse effects of these medications include varying degrees of muscle toxicity, including myalgia, myopathy, and rare cases of necrotizing myositis, hepatic dysfunction, and central nervous system changes. Despite known adverse effects, statins are rarely associated with myocarditis. Statins can cause skeletal muscle myopathy and myositis by upregulating HMG-CoA reductase (HMGCR) in muscle tissue, resulting in antibody-mediated inflammation. A similar proposed mechanism is likely possible within cardiac myocytes. We present a rare case of statin-induced necrotizing myositis with concomitant cardiac involvement. Severe skeletal muscle myositis was confirmed by lower extremity MRI and biopsy findings. In association, elevated and plateaued high-sensitivity troponin without evidence of cardiac ischemia warranted cardiac MRI, which further confirmed myocarditis due to inflammation within a non-vascular distribution. Given its rare presentation, the treatment for statin-induced cardiac toxicity is unclear; however, the patient in this case report was treated with pulse-dose intravenous steroids and indefinite discontinuation of statin medications.