BACKGROUND Lithium salts have been commonly used for prophylaxis and treatment of bipolar disorder and have numerous side effects. However, there has been no report of skew deviation and downbeat nystagmus associated with lithium. Herein, we report the first case of lithium-induced skew deviation and downbeat nystagmus. CASE PRESENTATION A 39 years-old woman presented with intermittent vertical diplopia and dizziness within 1-2 months. Ophthalmologic examination revealed downbeat nystagmus and 6 prism diopters of right hypertropia. Funduscopic examination showed mild incyclotorsion on right eye. However, ductions and versions were within normal range. Other neurological examinations were also normal. She had a history of bipolar disorder treated with daily 600-900 mg of lithium for past 6 years, and 2 months before the first visit, daily dose of lithium was increased to 1200 mg. We referred the patients to psychiatrist. Although the serum level of lithium was within the normal therapeutic range, her daily dose of lithium was reduced to 600 mg and then stopped. 6 days after cessation of lithium, down beat nystagmus and right hypertropia were completely resolved and symptoms did not recur over a year. CONCLUSION Even within a normal therapeutic range, downbeat nystagmus and skew deviation can occur as side effect of lithium. Dehydration may contribute to the neurotoxicity of lithium.

中文翻译：

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一例由锂引起的偏斜和震颤的眼球震颤。

背景技术锂盐已经普遍用于预防和治疗双相情感障碍并且具有许多副作用。但是，尚无与锂相关的偏斜和震颤的眼球震颤的报道。在这里，我们报道了锂引起的偏斜偏差和震颤的眼震的第一例。病例介绍一名39岁的女性在1-2个月内出现间歇性垂直复视和头晕。眼科检查发现眼球震颤和右斜视的6棱镜屈光度。眼底镜检查显示右眼轻度内旋。但是，归纳和版本在正常范围内。其他神经系统检查也正常。她有过去6年和第一次就诊前2个月每天接受600-900毫克锂治疗的躁郁症病史，锂的每日剂量增加到1200 mg。我们将患者转介给精神科医生。尽管锂的血清水平在正常治疗范围内，但她的锂日剂量降至600 mg，然后停止服用。锂停止使用6天后，下搏动性眼球震颤和右眼肥大症完全消失，症状一年没有复发。结论即使在正常的治疗范围内，由于锂的副作用，也会出现情绪低落的眼球震颤和偏斜。脱水可能会导致锂的神经毒性。下跳动性眼球震颤和右眼肥大症已完全解决，症状一年没有复发。结论即使在正常的治疗范围内，由于锂的副作用，也会出现情绪低落的眼球震颤和偏斜。脱水可能会导致锂的神经毒性。下跳动性眼球震颤和右眼肥大症已完全解决，症状一年没有复发。结论即使在正常的治疗范围内，由于锂的副作用，也会出现情绪低落的眼球震颤和偏斜。脱水可能会导致锂的神经毒性。