Pearls & Oy-sters: Paroxysmal ocular tilt reaction

Abstract

In skew deviation, one eye is higher than the other, causing vertical diplopia. Skew deviation is a prenuclear disorder resulting from imbalance in otolith input to the oculomotor system, produced by unilateral lesions anywhere from the otoliths to the interstitial nucleus of Cajal in the rostral midbrain,1 and as such is one component of the ocular tilt reaction.2,3 We report a woman with a history of fluctuating diplopia after resection of a left thalamic angioma. She was shown to have intermittent paroxysmal ocular tilt reaction episodes superimposed on a tonic ocular tilt reaction. A 64-year-old woman initially presented at age 55 with malaise, headache, and imbalance, leading to the discovery on neuroimaging of a vascular malformation in the left thalamus. Following resection, she had persistent vertical diplopia on downgaze, and episodes several times a day of vertical diplopia in other gaze positions, associated with a sense of twisting of her eyes. For 9 years she had been on both gabapentin and carbamazepine, with uncertain effect: she reported some modest reduction in episodes with increasing the dose of gabapentin from 600 mg/day to 1,200 mg/day. Visual acuity, tests of color vision with pseudo-isochromatic plates, visual fields by confrontation, pupils, …