Teaching Video NeuroImages: Bilateral abducens ocular neuromyotonia
Kavin Vanikieti and Joseph F. Rizzo
Neurology September 05, 2017; 89 (10)
RESIDENT AND FELLOW SECTION http://n.neurology.org/content/89/10/e128
A 44-year-old woman with a history of resolved nasopharyngeal carcinoma presented with an 8-month history of transient binocular horizontal diplopia. She received complete concurrent chemoradiotherapy 7 years ago. Following prolonged eccentric gaze to the right, she developed involuntary contraction of right lateral rectus, which resulted in 60 seconds of right exotropia. These events also occurred following prolonged eccentric gaze to the left, which resulted in left exotropia (video 1). Treatment with carbamazepine improved her symptoms (video 2). Ocular neuromyotonia should be included as a differential diagnosis of transient diplopia, especially in those who have undergone prior radiotherapy to the parasellar region.1
Video 1 – Pretreatment
Following prolonged eccentric gaze to the right, the patient developed involuntary contraction of right lateral rectus, which resulted in right exotropia. Each episode lasted approximately 60 seconds and then the eyes returned to normal alignment. These events also occurred following prolonged eccentric gaze to the left, which resulted in left exotropia.
Video 2 – Post Treatment
Complete resolution with carbamazepine
Teaching Slides – PowerPoint Presentation
Reference: 1. Leigh RJ, Zee DS. The Neurology of Eye Movements, 5th ed. Oxford: Oxford University Press; 2015:615.