Purchase this article with an account.
SA Newman, F Gonzalez-Fernandez; Thyroid Orbitopathy-Oblique Muscle Involvement . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1462.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:Enlarged extraocular muscles with chronic, inflammatory changes, deposition of ground substance, and eventual fibrosis are the hallmarks of thyroid orbitopathy. Rectus muscles are not involved in equal proportion with the inferior and medial rectus most commonly affected. Little data exists on oblique muscle involvement in thyroid orbitopathy. Methods:In a series of twelve patients with thyroid orbitopathy undergoing inferior oblique (IOM) surgery at the University of Virginia, specimens of the excised IOM were studied for histopathologic abnormalities. These were compared with fifteen control cases of patients with IOM specimens obtained while undergoing inferior oblique surgery for IV nerve palsy. All cases were done between January 2000 and June 2001. Results:Twelve cases of thyroid orbitopathy ranged in age from 45 to 78 with a mean of 67. The patients with non-thyroid muscle surgery ranged in age from 5 to 79 with a mean of 41. There were four men and eight women in the thyroid group and eleven men and four women in the non-thyroid group. Five of the twelve patients demonstrated no histopathologic abnormality, the seven that did demonstrated perivascular lymphocytic cuffing, mild focal chronic lymphocytic inflammation, areas of endomysial inflammation, and in one case mild myopathic changes with increased variation suggestive of hyperinnervation. Of the 15 cases in the control group, one patient demonstrated mild regional degenerative changes, one showed nonspecific mild myopathic changes with centrally placed nuclei, and one patient had evidence of focal collections of lymphocytes in regions of the adipose tissue as well as in the muscle. This last case in retrospect had clinical findings suggestive of other ocular motility problems possibly related to previous orbital inflammatory disease. Conclusion:The IOM in patients with thyroid orbitopathy not uncommonly shows evidence of focal inflammatory changes similar to those seen in the rectus muscles. This is not an invariable finding, and no obvious correlation can be made with restrictive phenomena. The relative risks to the individual extra ocular muscles in thyroid orbitopathy remains unexplained.
This PDF is available to Subscribers Only