Torsional Nystagmus Due to Medullary Pilocytic Astrocytoma

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Identifier Torsional_nystagmus_medullary_tumor
Title Torsional Nystagmus Due to Medullary Pilocytic Astrocytoma
Alternative Title Video 5.18 Torsional nystagmus due to medullary tumor from Neuro-Ophthalmology and Neuro-Otology Textbook
Creator Daniel R. Gold, DO
Affiliation (DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
Subject Jerk Nystagmus; Rotary Nystagmus; OMS Medulla
Description 𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This is a 30-year-old woman who experienced headaches which led to an MRI and the diagnosis of a right medullary pilocytic astrocytoma, confirmed pathologically. Examination was performed a year after the initial diagnosis, and several months prior to this exam oscillopsia was experienced for the first time. MRI demonstrated that the cystic portion had increased in size and it was thought that her newly appreciated nystagmus and resultant oscillopsia were related to this interval change. On exam, she had spontaneous torsional nystagmus, which was unidirectional in right and left gaze, with the top poles beating towards the right ear in each position. Saccades, smooth pursuit and the vestibulo-ocular reflex were unremarkable. Pure torsional nystagmus is almost always central in origin. An acute destructive lesion (e.g., vestibular neuritis) causing unilateral vestibular loss will cause contralesional horizontal-torsional nystagmus related to unopposed semicircular canal (SCC) afferents contralaterally. For pure torsional nystagmus to result from a peripheral lesion, certain SCCs must be spared (e.g., both horizontal SCCs, which will cancel out so that a horizontal jerk component is not seen; both vertical SCCs on one side) while others must be strategically damaged (e.g., both vertical SCCs on the opposite side). In contrast, damaging the central fibers originating from both vertical SCCs on one side due to a medullary lesion is a much more common cause of torsional nystagmus. Pure torsional nystagmus may also result from unilateral interstitial nucleus of Cajal (ipsiversive nystagmus) or rostral interstitial medial longitudinal fasciculus (contraversive) injury, while vertical-torsional nystagmus may result from medullary (direction can be less predictable depending on how caudal or rostral the injury occurs), medial longitudinal fasciculus (ipsiversive), or superior cerebellar peduncle localizations, among others. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This patient experienced headaches which led to an MRI and the diagnosis of a right medullary pilocytic astrocytoma, confirmed pathologically. Examination was performed a year after the initial diagnosis, and several months prior to this exam oscillopsia was experienced for the first time. MRI demonstrated that the cystic portion had increased in size and it was thought that her newly appreciated nystagmus and resultant oscillopsia were related to this interval change. On exam, she had spontaneous torsional nystagmus, which was unidirectional in right and left gaze, with the top poles beating towards the right ear in each position. Saccades, smooth pursuit and the vestibulo-ocular reflex were unremarkable. Pure torsional nystagmus is almost always central in origin. An acute destructive lesion (e.g., vestibular neuritis) causing unilateral vestibular loss will cause contralesional horizontal-torsional nystagmus related to unopposed semicircular canal (SCC) afferents contralaterally. For pure torsional nystagmus to result from a peripheral lesion, certain SCCs must be spared (e.g., both horizontal SCCs, which will cancel out so that a horizontal jerk component is not seen; both vertical SCCs on one side) while others must be strategically damaged (e.g., both vertical SCCs on the opposite side). In contrast, damaging the central fibers originating from both vertical SCCs on one side due to a medullary lesion is a much more common cause of torsional nystagmus. Pure torsional nystagmus may also result from unilateral interstitial nucleus of Cajal (ipsiversive nystagmus) or rostral interstitial medial longitudinal fasciculus (contraversive) injury, while vertical-torsional nystagmus may result from medullary (direction can be less predictable depending on how caudal or rostral the injury occurs), medial longitudinal fasciculus (ipsiversive), or superior cerebellar peduncle localizations, among others. https://collections.lib.utah.edu/ark:/87278/s6n62k3m
Date 2018-02
Language eng
Format video/mp4
Type Image/MovingImage
Collection Neuro-Ophthalmology Virtual Education Library: Dan Gold Collection: https://novel.utah.edu/Gold/
Publisher North American Neuro-Ophthalmology Society
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah
Rights Management Copyright 2016. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright
ARK ark:/87278/s6n62k3m
Setname ehsl_novel_gold
ID 1295178
Reference URL https://collections.lib.utah.edu/ark:/87278/s6n62k3m
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