A Rare Case of COVID-19 Related Necrotizing Myopathy

RESEARCH OBJECTIVES: To report a case of COVID-19 associated necrotizing myopathy. DESIGN: Case report. SETTING: Following the patient through acute hospitalization, acute rehab to outpatient therapy follow up. PARTICIPANTS: A 76-year-old man with known hypogammaglobulinemia on monthly IVIG infusions who presented to the hospital with 1 week of dyspnea and myalgias. He was a former athlete who participated in daily cardiovascular workouts before admission. He was found to have COVID-19 pneumonia. INTERVENTIONS: Patient was treated with remdesivir and oral dexamethasone. He was transferred to the ICU for 9 days where he received convalescent plasma, intravenous methylprednisolone, and high flow oxygen. He did not require intubation nor sedatives. MAIN OUTCOME MEASURES: Following transfer to the floor, he reported new-onset muscle weakness. Physical examination revealed symmetrical proximal upper and lower extremity weakness with elevated CK at 3665 IU/L. His atorvastatin was held, and steroids were tapered. However, his creatinine kinase continued to rise, peaking at 8335 IU/L. High dose methylprednisolone was resumed with improvement in creatinine kinase. Extensive myositis panel and Anti HMGCR antibody were normal. Thyroid studies revealed transient thyroiditis thought to be induced by COVID-19 infection that did not require treatment. RESULTS: Right thigh MRI revealed edema of the lateral thigh muscles. Biopsy of the quadriceps showed necrotizing myopathy. Electromyography and NCS revealed inflammatory/immune myositis. Findings were not typical for a steroid, endocrine, or disuse myopathy. He was discharged to an IRF at a dependent level with bilateral hip flexor strength 2/5, triceps 3+/5, and the remainder of his extremity muscles 5/5. By day 40, he was independent with a rolling walker with significant gains in strength. CONCLUSIONS: Timely recognition of COVID-19 related myopathy may prevent serious necrotizing muscle injury. AUTHOR(S) DISCLOSURES: None.