Clinical Feature and Treatment Outcomes of Necrotizing Autoimmune Myopathy in a Referral Neurological Center in Thailand.
TL;DR
Patients with anti-SRP-associated NAM were relatively more severe, and cancer screening should be considered in anti-HMGCR patients, and Rituximab was beneficial in individual patients.
Abstract
Background
Necrotizing autoimmune myopathy (NAM) is classified into 3 subtypes according to antibodies. Data from Southeast Asian populations remain limited.
Objective
To describe and compare clinical characteristics and treatment responses among the NAM subtypes.
Methods
Retrospective cohort included three subtypes of 29 patients with NAM. Demographics, clinical data, treatment approach, and responses were assessed and compared.
Results
There were 20 (68.97%) anti-signal recognition particle (SRP), 8 anti-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) (27.59%), and 1 (3.44%) seronegative patients. Anti-SRP, compared with anti-HMGCR patients, tended to be more severe with cardiac and respiratory involvement. They tended to have residual disabilities at 12 months, whereas most anti-HMGCR patients achieved near-complete functional recovery. Associated cancer was found in an anti-HMGCR-associated patient. Rituximab administration in patients who did not respond to first-line therapy resulted in clinical improvement.
Conclusions
Patients with anti-SRP-associated NAM were relatively more severe. Cancer screening should be considered in anti-HMGCR patients. Rituximab was beneficial in individual patients.