Necrotizing myopathy: clinicoserologic associations

Necrotizing myopathy (NM) is distinguished from idiopathic inflammatory myositis (IIM) by dominance of myofiber necrosis, lack of mononuclear inflammatory infiltrates, and presence of antibodies to signal recognition particle (SRP).

The clinical features of 64 cases of NM were determined. Measurement of autoantibodies was undertaken on stored sera from 23 patients with NM. The incidence of malignancy was determined from the South Australian Cancer Registry.

NM patients showed male predominance (61%), more frequent myalgias, and higher creatine kinase (CK) levels compared with IIM patients. Patients with NM had a high incidence of systemic lupus erythematosus (SLE) (21%), hypertension (11 of 17, 65%), and diabetes mellitus (3 of 13, 23%). No patient had antibodies to SRP. NM patients showed no altered risk for malignancy compared with the South Australian population (P = 0.86).

NM is associated with SLE, hypertension, and diabetes mellitus. Comprehensive assessment of cardiovascular risk is indicated in NM, which raises the possibility of targeted interventions.