Jorge C Kattah1, Ali Saber Tehrani2, Sascha du Lac2, David E Newman-Toker2, David S Zee2. 1. From the Department of Neurology (J.C.K., A.S.T.), University of Illinois College of Medicine; Illinois Neurologic Institute (J.C.K., A.S.T.), Peoria; Departments of Otolaryngology-Head and Neck Surgery (S.d.L., D.E.N.-T., D.S.Z.), Neuroscience (S.d.L., D.E.N.-T., D.S.Z.), and Neurology (S.d.L., D.E.N.-T., D.S.Z.), and Division of Neuro-Visual & Vestibular Disorders (D.E.N.-T.), Johns Hopkins University, Baltimore, MD. kattahj@uicomp.uic.edu. 2. From the Department of Neurology (J.C.K., A.S.T.), University of Illinois College of Medicine; Illinois Neurologic Institute (J.C.K., A.S.T.), Peoria; Departments of Otolaryngology-Head and Neck Surgery (S.d.L., D.E.N.-T., D.S.Z.), Neuroscience (S.d.L., D.E.N.-T., D.S.Z.), and Neurology (S.d.L., D.E.N.-T., D.S.Z.), and Division of Neuro-Visual & Vestibular Disorders (D.E.N.-T.), Johns Hopkins University, Baltimore, MD.
Abstract
OBJECTIVE: To explain (1) why an initial upbeat nystagmus (UBN) converts to a permanent downbeat nystagmus (DBN) in Wernicke encephalopathy (WE) and (2) why convergence and certain vestibular provocative maneuvers may transiently switch UBN to DBN. METHODS: Following a literature review and study of our 2 patients, we develop hypotheses for the unusual patterns of vertical nystagmus in WE. RESULTS: Our overarching hypothesis is that there is a selective vulnerability and a selective recovery from thiamine deficiency of neurons within brainstem gaze-holding networks. Furthermore, since the circuits affected in WE are commonly paraventricular, especially medially, just under the floor of the fourth ventricle where lie structures important for control of vertical gaze, we suggest the patterns of involvement in WE also reflect a breakdown in vulnerable areas of the blood-brain barrier. Many of the initial deficits of our patients improved over time, but their DBN did not. Irreversible changes in paramedian tract neurons, which project to the cerebellar flocculus, may be the cause. Here we suggest that conversion of UBN to permanent DBN points to thiamine deficiency and may argue for a chronic, nonprogressive DBN/truncal ataxia syndrome. Finally, we posit that the transient switch of UBN to DBN reflects abnormal processing of otolith information about linear acceleration, and often points to a diagnosis of WE. CONCLUSION: Recognizing the unusual patterns of transient switching and then permanent conversion of UBN to DBN in WE is vital since long-term disability from WE may be prevented by timely, parenteral high-dose thiamine.
OBJECTIVE: To explain (1) why an initial upbeat nystagmus (UBN) converts to a permanent downbeat nystagmus (DBN) in Wernicke encephalopathy (WE) and (2) why convergence and certain vestibular provocative maneuvers may transiently switch UBN to DBN. METHODS: Following a literature review and study of our 2 patients, we develop hypotheses for the unusual patterns of vertical nystagmus in WE. RESULTS: Our overarching hypothesis is that there is a selective vulnerability and a selective recovery from thiaminedeficiency of neurons within brainstem gaze-holding networks. Furthermore, since the circuits affected in WE are commonly paraventricular, especially medially, just under the floor of the fourth ventricle where lie structures important for control of vertical gaze, we suggest the patterns of involvement in WE also reflect a breakdown in vulnerable areas of the blood-brain barrier. Many of the initial deficits of our patients improved over time, but their DBN did not. Irreversible changes in paramedian tract neurons, which project to the cerebellar flocculus, may be the cause. Here we suggest that conversion of UBN to permanent DBN points to thiaminedeficiency and may argue for a chronic, nonprogressive DBN/truncal ataxia syndrome. Finally, we posit that the transient switch of UBN to DBN reflects abnormal processing of otolith information about linear acceleration, and often points to a diagnosis of WE. CONCLUSION: Recognizing the unusual patterns of transient switching and then permanent conversion of UBN to DBN in WE is vital since long-term disability from WE may be prevented by timely, parenteral high-dose thiamine.
Authors: H Mitoma; A Buffo; F Gelfo; X Guell; E Fucà; S Kakei; J Lee; M Manto; L Petrosini; A G Shaikh; J D Schmahmann Journal: Cerebellum Date: 2020-02 Impact factor: 3.847
Authors: Allison S Young; Sally M Rosengren; Mario D'Souza; Andrew P Bradshaw; Miriam S Welgampola Journal: J Vestib Res Date: 2020 Impact factor: 2.354