Spontaneous Upbeat Nystagmus in Acute Wernicke's Encephalopathy

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: 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. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: Always consider the possibility of Wernicke's encephalopathy when a patient presents acutely with spontaneous UBN, in addition to a brainstem stroke, demyelinating lesion, or encephalitis. (Video and legend created with the assistance of Dr. Julia Carlson) https://collections.lib.utah.edu/ark:/87278/s6h74j6d