Adverse effects caused by statins, are usually well tolerated. However, their use has been related to several myopathic syndromes, such as: creatin kinase (CK) elevation, myalgia, weakness, myositis, and even fatal rhabdomyolysis. We describe a case of immunomediated necrotizing myopathy, who presented uncommon manifestations like proximal weakness, dysarthria, dysphagia and cervical muscle weakness. It is important suspect this pathology even though it does not present in a common way, mainly in patients with risk factors, such as statin users. A 53-year-old man, simvastatin user, presented with myalgias, progressive muscular weakness, and elevated transaminases and CK. The magnetic resonance imaging (MRI) showed fatty infiltration in the muscles and edema. The electromyography showed a polyneuromyopathic pattern. Typical and specific myositis-related antibiodies were negative. The muscular biopsy did not show signs of an inflammatory infiltration. The diagnosis of immune-mediated necrotizing myopathy related to statins was confirmed by the clinical data and the presence of anti-hydroximethylglutaryl coenzymeA reductase (anti-HMG-CoA) antibodies. The drug was discontinued, and steroids were started, with subsequent improvement; however, the patient presented a reappearance of symptoms and an elevation of enzymes, for which intravenous immunoglobulin was started with a favorable outcome. Conclusions: Immune mediated necrotizing myopathy in statin users must be considered and differentiated from other autoimmune entities such as inclusion body myopathy, dermatomyositis and polymyositis, as this will determine the therapeutic plan and patient prognosis.

Maria de los Angeles completed her internal medicine specialty at the age of 29 years from Universidad Nacional Autonoma de México, México. She has collaborated in different national research projects in Mexico and has collaborated in a book chapter for the Internal Medicine Council in Mexico