Isolated neck extensor myopathy: is it responsive to immunotherapy?

[focal myositis]

To determine if isolated neck extensor myopathy (INEM ) is responsive to immunosuppressive treatment .We retrospectively reviewed charts of patients with INEM from 2002 to 2008 to identify patients and determine the response to immunomodulatory therapy . Clinical , electrodiagnostic , histologic , and radiographic data were reviewed .Four patients were identified during the study period . Three were women . The age of onset of neck extensor weakness ranged from 58 to 78 years . Serum creatine kinase levels were within normal limits in all patients . None had clinical , laboratory , or electrophysiological findings to suggest a generalized neuromuscular disorder . On electrodiagnostic studies , all patients had myopathic changes with or without irritative features in cervical paraspinal muscles . No inflammation was present on muscle biopsy from three of the patients . All patients received one or more immunosuppressive agents . Neck strength improved by 1 point or greater on the Medical Research Council scale in all subjects with a peak response observed between 3 and 6 months after treatment initiation .A trial of immunosuppressive agents should be offered to patients with INEM because a subset will improve . Rigorously defined , INEM is a noninflammatory myopathy . However , a focal myositis could be missed on muscle biopsy and may explain the favorable response to treatment .