Anti-HMGCR myopathy secondary to statins diagnosed in the emergency department

Statins (hydroxymethylglutaryl‐coenzyme A (HMG-CoA) reductase inhibitors) are a class of medication often used to control cholesterol levels. Anti-3-hydroxymethylglutaryl-coenzyme A reductase (anti-HMGCR) myopathy is a rare form of autoimmune myositis which presents as a result of statin therapy. In this report, we present the case of a 63-year-old male presenting to the emergency department (ED) with inability to ambulate, proximal muscle weakness, elevated creatine kinase (CK) and prior quadriceps muscle biopsy demonstrating highly active and chronic necrotizing myopathy. A presumptive diagnosis of anti-HMGCR myopathy was made in the ED, HMGCR antibody IgG was ordered, and was markedly elevated when it resulted a few days later. He was hospitalized and started on systemic corticosteroids and intravenous immunoglobulin (IVIG). He was ultimately discharged with home health, physical therapy, monthly IVIG infusions, prednisone taper starting at 80 mg daily, biweekly creatinine kinase measurements, and rheumatology and neurology follow-up. These measures successfully reduced his symptoms, and his mobility had increased at the time of follow-up to the point that he could again ambulate. Anti-HMGCR myopathy should remain on the emergency physician’s differential for a patient currently on or previously exposed to statins presenting with proximal muscle weakness. • Anti-HMGCR myopathy is a rare type of autoimmune myositis presenting after a patient begins statin therapy. • Anti-HMGCR myopathy diagnostic criteria: proximal muscle weakness, elevated serum CK and presence of anti-HMCGR antibodies. • Anti-HMGCR myopathy can persist after statins are discontinued. • Treatment may include systemic corticosteroids, intravenous immunoglobulin (IVIG) or steroid-sparing immunosuppressants.