Walsh & Hoyt: Evaluation and Management of Abducens Nerve Palsy

There is a tendency to assume that all patients with an esotropia and unilateral or bilateral abduction weakness have an abducens nerve paresis. The physician should first consider the possibility that the condition is myopathic (e.g., thyroid eye disease)or neuromuscular (e.g., myasthenia gravis). A careful history and examination directed at these possibilities may be sufficient to eliminate them. Alternatively, the physician may need to perform further studies, including orbital MRI, thyroid function studies, serum assay for anti-acetylcholine and MuSK antibodies, and repetitive nerve stimulation and single-fiber electromyography.