Acute Myositis in Three Adult Men with Rapid Resolution (P4.9-040)

Objective: To describe a case-series of three adult men with rapid resolution of myositis. Background: Acute viral myositis is characterized by muscle pain, weakness and elevated serum creatinine kinase after a suspected viral illness. It is a known, but rare, entity that occurs more commonly in children than adults. Design/Methods: Not applicable. Results: Three men ranging in age from 37 to 41 years presented within a span of 18 days in late summer of 2018 with a similar clinical course. Each had a fever (ranging from 101 to 103 °F) and then developed significant muscle weakness (e.g. inability to pick up or open items, ambulate without falling or climb stairs) over the course of 1–4 days. On examination, one man had bilateral wrist/hand weakness and the other two had bilateral full arm and proximal leg weakness (weakness ranged from 3–4/5). Creatinine kinase (peak ranged from 957 to 2121 U/L), C - reactive protein (ranged from 13.7 to 25.3 mg/L), serum myoglobin (ranged from 158 to 250 mcg/L), serum aldolase (ranged from 9.7 to 11.3 U/L) was elevated in all three men. Two of the three men had elevated thyroid peroxidase antibodies (general population has elevation in 8 to 27%). One man had positive Coxsackie antibodies; the other two had negative respiratory viral panels. Electromyogram/nerve conduction study in all three revealed no definite abnormalities. Each patient was discharged from the hospital in 2–3 days with resolution or near-resolution of his weakness. Conclusions: A syndrome of acute myositis with rapid resolution in three middle-aged men is described. Although a viral etiology was suspected, the role of thyroid peroxidase antibodies in two is unexplained. Disclosure: Dr. Danielson has nothing to disclose. Dr. Ranasinghe has nothing to disclose. Dr. Sultan has nothing to disclose. Dr. Riggs has nothing to disclose.