Immune-Mediated Necrotizing Myopathy

**Semantic type:** Disease or Syndrome

**Definition:** A subgrouping of the inflammatory myopathies characterized by severe proximal weakness, elevated creatine kinase levels, and myofiber necrosis. They can be further distinguished by the presence or absence of associated autoantibodies, including anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), anti-signal recognition particle (SRP), and antibody negative immune-mediated necrotizing myopathy (IMNM).

**Synonyms:** - IMNM - NAM - Necrotizing Autoimmune Myopathy