Suspected Statin-Induced Respiratory Muscle Myopathy During Long-Term Inspiratory Muscle Training in a Patient With Diaphragmatic Paralysis

Abstract

Background and PurposeAbnormal lipids are associated with the development of coronary heart disease; for this reason, lipid-lowering agents have become a standard of care. The purposes of this case report are: (1) to highlight the association of impaired inspiratory muscle performance (IMP) with statin therapy and (2) to describe potentially useful methods of examining and treating people with known or suspected statin-induced skeletal myopathies (SISMs).Case DescriptionThe patient had breathlessness on exertion and a restrictive lung disorder from a right hemidiaphragmatic paralysis, for which he was prescribed high-intensity inspiratory muscle training (IMT). He had a secondary diagnosis of hyperlipidemia, which was treated with 40 mg of simvastatin after 5½ months of IMT.OutcomesThe improvements in IMP, symptoms, and functional status obtained from almost 6 months of high-intensity IMT were lost after the commencement of simvastatin. However, 3 weeks after termination of simvastatin combined with high-intensity IMT, the patient's IMP, symptoms, and functional status exceeded pre-statin levels.DiscussionThis case report suggests that high-intensity IMT can be used effectively in a patient with impaired diaphragmatic function and during recovery from a respiratory SISM. The marked reduction in IMP and inability to perform IMT resolved with the cessation of statin therapy. The case report also highlights the potential effects of SISMs in all skeletal muscle groups. The clinical implications of this case report include the potential role of physical therapy in monitoring and possibly facilitating the spontaneous recovery of an SISM, as well as the need to investigate the IMP of a person with dyspnea and fatigue who is taking a statin.