OJOph  Vol.4 No.4 , November 2014
Atrophy and Fibrosis of Extra-Ocular Muscles in Anti-Acetylcholine Receptor Antibody Myasthenia Gravis
Abstract: Myasthenia gravis (MG) is an autoimmune disorder involving the neuromuscular junction that frequently affects the extra-ocular muscles (EOMs). It has been described as a very rare cause of bilateral EOM atrophy, but histological analysis of such cases is lacking. A 66-year-old man presented with two months of right eyelid drooping and vertical diplopia. Examination showed bilateral ophthalmoparesis and complete right ptosis. The remainder of his exam was normal, and an MRI showed small EOMs. Acetylcholine receptor antibodies were elevated, establishing the diagnosis of MG. Oral corticosteroids and pyridostigmine followed by azathioprine improved his ptosis, but not his ophthalmoparesis. One year later he had surgical correction of his diplopia, and the resected superior rectus muscle showed complete replacement of EOM by connective tissue. MG can rarely cause bilateral EOM atrophy, which is characterized histologically by fibrosis in the muscle itself. Atrophy in the EOMs of a myasthenic patient may indicate a poor response to medical management alone.
Cite this paper: Gratton, S. , Herro, A. , Bermudez-Magner, J. and Guy, J. (2014) Atrophy and Fibrosis of Extra-Ocular Muscles in Anti-Acetylcholine Receptor Antibody Myasthenia Gravis. Open Journal of Ophthalmology, 4, 117-119. doi: 10.4236/ojoph.2014.44019.

[1]   Russell, D. (1953) Histological Changes in the Striped Muscles in Myasthenia Gravis. The Journal of Pathology and Bacteriology, 65, 279-289.

[2]   Fenichel, G. (1966) Muscle Lesions in Myasthenia Gravis. Annals of the New York Academy of Sciences, 135, 60-67.

[3]   Fenichel, G. and Shy, G. (1963) Muscle Biopsy Experience in Myasthenia Gravis. Archives of Neurology, 9, 237-243.

[4]   Oosterhuis, H. and Bethlem, J. (1973) Neurogenic Muscle Involvement in Myasthenia Gravis. A Clinical and Histopathological Study. Journal of Neurology, Neurosurgery Psychiatry, 36, 244-254.

[5]   Chan, J. and Orrison, W. (2007) Ocular Myasthenia: A Rare Presentation with MuSK Antibody and Bilateral Extraocular Muscle Atrophy. British Journal of Ophthalmology, 91, 842-843.

[6]   Okamoto, K., Ito, J., Tokiguchi, S. and Furusawa, T. (1996) Atrophy of Bilateral Extraocular Muscles: CT and Clinical Features of Seven Patients. Journal of Neuro-Ophthalmology, 16, 286-288.