Brokalaki Chrysoula, Kararizou Evangelia, Dimitrakopoulos Antonis, Evdokimidis Ioannis, Anagnostou Evangelos
Department of Neurology, Eginition Hospital, University of Athens, Athens, Greece.
J Neuroophthalmol. 2015 Dec;35(4):390-5. doi: 10.1097/WNO.0000000000000275.
Cerebellar ataxia is an uncommon manifestation of hypothyroidism with unknown pathomechanism. The few descriptions of the clinical phenotype range from limb, gait, and trunk ataxia to various ocular motor abnormalities. We evaluated a 62-year-old woman with previously undetected severe hypothyroidism who presented with prominent saccadic intrusions and gait ataxia. She had high titers of antithyroid autoantibodies and anti-glutamic acid decarboxylase (anti-GAD) antibodies. Horizontal eye movement recordings revealed a series of nearly continuous pseudoharmonic square wave jerks (SWJs) constituting a square wave oscillation. Amplitudes reached maximum values of about 4, and wave frequency approached 100 cycles per minute. Thyroxine substitution and corticosteroid administration had little effect on SWJ parameters. The square wave oscillation nearly completely resolved after a single treatment session with intravenous immunoglobulin suggesting a causal link between an autoimmune process and the cerebellar dysfunction. Current concepts of the genesis of saccadic intrusions favor a role for anti-GAD antibodies in the etiology of SWJs.
小脑共济失调是甲状腺功能减退症的一种罕见表现，其发病机制尚不清楚。关于临床表型的少数描述范围从肢体、步态和躯干共济失调到各种眼球运动异常。我们评估了一名62岁的女性，她之前未被检测出患有严重甲状腺功能减退症，表现为明显的眼球跳动性侵入和步态共济失调。她有高滴度的抗甲状腺自身抗体和抗谷氨酸脱羧酶（抗GAD）抗体。水平眼动记录显示一系列几乎连续的伪谐波方波急跳（SWJs），构成方波振荡。振幅达到约4的最大值，波频率接近每分钟100次循环。甲状腺素替代和皮质类固醇给药对SWJ参数影响不大。静脉注射免疫球蛋白单次治疗后，方波振荡几乎完全消失，提示自身免疫过程与小脑功能障碍之间存在因果关系。目前关于眼球跳动性侵入发生机制的概念支持抗GAD抗体在SWJs病因中起作用。
