Teaching Video NeuroImage: Upper Eyelid Nystagmus as a Manifestation of Wernicke Encephalopathy

A 53-year-old man with alcohol use disorder presented with Wernicke encephalopathy marked by confusion, gait unsteadiness, and binocular diplopia.Neuro-ophthalmic examination revealed upper eyelid nystagmus (ULN) (Video).Other causes were ruled out, like hypomagnesemia.Brain MRI showed mild bilateral medial thalamic hyperintensities (eFigure 1).High-dose thiamine supplementation resolved confusion and instability, but ULN persisted.ULN was present in primary gaze and all directions, with prominence in downgaze.ULN is a rare condition associated with various brainstem and cerebellar lesions.It may occur with vertical upbeat or gaze-evoked horizontal nystagmus or in isolation with convergence. 1 Proper eyelid coordination relies on reciprocal control between the levator palpebrae superioris and orbicularis oculi, mediated by the central caudal nucleus.The superior colliculus integrates visual-sensory input for orienting and saccades, while the pretectal region may inhibit phasic excitation of levator motor neurons. 2 Dysfunction in this pathway may underlie eyelid nystagmus in our patient.