Author(s)

Sean M. Gratton¹, Angela Herro², Jose Antonio Bermudez-Magner², John Guy²

¹Truman Medical Center, Department of Neurology and Cognitive Neuroscience, University of Missouri—Kansas City School of Medicine, Kansas City, USA.
²Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, USA.

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.

Myasthenia Gravis, Oculomotor Muscles, Muscular Atrophy

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.