Refractory Severe Anti-SRP Myopathy that Improved with Long-term Rehabilitation Therapy: A Case Report.

Background: Immune-mediated necrotizing myopathy (IMNM) is a type of autoimmune myositis. Anti-signal recognition particle (SRP) antibodies are highly specific to this disease.

Case: A 76-year-old woman presented with a 4-month history of acute progressive limb muscle weakness and dysphagia. Blood examination revealed significantly elevated creatine kinase (CK) (3472 U/L) and SRP antibody positivity. The patient was near-bedridden and required alternative nutrition. She was treated with oral prednisolone and intravenous immunoglobulin. Rehabilitation therapy was initiated after confirming the decline in CK levels. She started with exercises on the bed and exercise load was gradually increased. Videofluoroscopic swallowing study showed severely weakened pharyngeal contractions and aspiration. Her symptoms improved slowly. She started transferring to a wheelchair after 2 months, gait training using parallel bars after 4 months, and was administered a paste diet once a day after 5 months. Rituximab was administered as additional treatment. Thereafter, the patient started gait training with a walker. The oral paste diet was increased to three times per day after 7 months, and a regular diet was adopted after 9 months. After 11 months, she was discharged home after achieving modified near independence in all activities of daily living.

Discussion: : Low-intensity rehabilitation therapies were initiated under the supervision of therapists with regular follow-up and progression of exercise intensity based on multidisciplinary team discussions. If CK levels indicate that the disease has stabilized, early intervention in rehabilitation is important to prevent declining physical function.