A case of atorvastatin combined toxic myopathy and inflammatory myositis

Muscle toxicity is one adverse reaction reported with the use of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins). This toxicity may include asymptomatic elevations of muscle enzymes, weakness, myalgia, and myositis. High doses of statins, or the combination of statins with other anti-cholesterol medications, increase the risk of toxicity. In addition, case reports of systemic and autoimmune reactions such as lupus, nephritis, vasculitis, and myositis, suspected to be associated with statins, have been reported. Our 76-year-old patient demonstrates a case of serologically and biopsy-proven inflammatory polymyositis, combined with a statin toxic myopathy. His symptoms and enzyme abnormalities resolved with both the removal of the statin medication and the institution of immunosuppressive therapy. Investigation of muscle enzyme elevation and weakness that do not resolve with statin removal is warranted. Certain muscle biopsy findings, including mononuclear cell infiltrate, distinguish the etiology as inflammatory/possibly autoimmune and do not suggest statin myopathy.