Nonthyroid causes of extraocular muscle disease

Extraocular muscle involvement in orbital disease is most frequently seen a s a feature of thyroid orbitopathy (Graves' disease). However, a wide range of other conditions may alter the size, shape, and function of these muscl es, with characteristic clinical manifestations or abnormalities risible on orbital imaging. The differential diagnosis of muscle disease can be narro wed by careful analysis of clinical features and ancillary tests. Imaging f acilitates recognition in many cases, but in some instances, accurate diagn osis requires biopsy. This review highlights the differential diagnoses for diseases of extraocular muscles based on the clinical and investigative re cords of 103 patients at our institution combined with data from the world literature. We found that the most common nonthyroid causes of muscle disea se were inflammatory, vascular, and neoplastic processes (in decreasing ord er of frequency). Emphasis is placed on investigations that provide a logic al approach to, and appropriate management of, disease of the extraocular m uscles. (C) 1999 by Elsevier Science Inc. All rights reserved.