Spontaneous upbeat nystagmus in acute Wernicke's encephalopathy
Upbeat Nystagmus, Jerk Nystagmus, Medullar OMS
Julia Carlson, MD, Department of Neurology, The Johns Hopkins School of Medicine; Daniel R. Gold, D.O. Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology -Head & Neck Surgery The Johns Hopkins School of Medicine
This is a 40-year-old woman presenting with imbalance, confusion and oscillopsia. Exam demonstrated upbeat nystagmus (UBN) in primary gaze that remained UB in all directions of gaze, with a slight torsional component (top poles beating toward right ear) in certain directions of gaze. Her nystagmus followed Alexander's law as UBN typically does -i.e., when looking in the direction of the fast phase (up), her UBN increased in intensity. She had developed thiamine deficiency due to poor oral intake resulting in a fifty-pound weight loss during a depressive episode. She was given IV thiamine upon presentation to the hospital, and symptoms and UBN improved partially. Wernicke's encephalopathy often includes characteristic ocular motor and vestibular findings1 often related to involvement of bilateral midline structures: UBN due to nucleus of Roller/nucleus intercalatus involvement and/or relative involvement of anterior semicircular canal (upward) pathways more than posterior canal (downward) pathways; vertical nystagmus may reverse direction with convergence; horizontal gaze-evoked nystagmus can be seen when nucleus prepositus hypoglossi (NPH)-medial vestibular nucleus (MVN) complex is involved; impaired horizontal vestibulo-ocular reflex (VOR) with relative sparing of vertical canal VOR due to NPH-MVN; ophthalmoparesis commonly related to involvement of the 6th nerve, although horizontal and vertical ophthalmoplegia is possible.1. Kattah JC. The Spectrum of Vestibular and Ocular Motor Abnormalities in Thiamine Deficiency. Curr Neurol Neurosci Rep 2017;17:40.
Spencer S. Eccles Health Sciences Library, University of Utah