Acute and subacute orbital myositis.

Of 12 consecutive patients (nine women and three men ranging in age from 18 to 70 years) with orbital myositis, four had histories of ocular or systemic autoimmune disease. Five patients treated within two weeks of developing acute orbital pain and extraocular muscle dysfunction were classified as having acute myositis. They responded to corticosteroids within 72 hours although three had single recurrences during six- to 16-month follow-up periods. No patients were heterotropic or proptotic at the final examination. Seven patients with less severe or atypical symptoms who had delays of two or more months between onset and treatment were classified as having subacute myositis. All had recurrences with five having two or more. Three required supplemental radiation therapy during seven- to 20-month follow-up periods. At the final examinations, six patients had motility defects and one had proptosis, indicating that delays in treatment may lead to recurrences, extraocular muscle dysfunction, and proptosis.