Necrotizing Autoimmune Myopathy
An inflammatory myopathy characterized by muscle fiber necrosis with minimal inflammatory infiltrate, associated with specific autoantibodies.
Full Definition
Necrotizing autoimmune myopathy (NAM) is a subtype of inflammatory myopathy characterized by prominent muscle fiber necrosis and regeneration with relatively little inflammatory cell infiltration compared to polymyositis or dermatomyositis. The condition is strongly associated with specific autoantibodies, particularly anti-SRP (signal recognition particle) and anti-HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) antibodies. Patients typically present with severe proximal weakness and markedly elevated creatine kinase levels. Unlike other inflammatory myopathies, NAM often requires more aggressive immunosuppression and may be triggered by statin exposure in cases associated with anti-HMGCR antibodies.
Usage
Usage note: Hyphenate compound modifiers. May be abbreviated as NAM in context.
In Context
- "Necrotizing autoimmune myopathy was diagnosed based on biopsy findings and positive anti-SRP antibodies." — Inflammatory myopathy workup
- "The muscle biopsy showed features consistent with necrotizing autoimmune myopathy." — Pathology report