Supplementary Material for: Capecitabine-related fourth nerve palsy: a case report

Introduction: Capecitabine has rarely been associated with neurotoxicity. Cerebellar ataxia, multifocal leukoencephalopathy, and sensorimotor peripheral neuropathy have been reported in the literature. A case of 6th nerve palsy associated with capecitabine has also been described. This article reports the first case of capecitabine-related 4th nerve palsy.
Case presentation: A 72-year-old Caucasian woman was referred by the Oncology Department because she had been complaining of binocular diplopia for six months. The symptoms started one month after the introduction of capecitabine. A diagnosis of right 4th nerve palsy was made using the Parks three-step test and the Hess test. Neuroimaging analysis was negative. A slow but progressive deterioration of function was confirmed during a year of follow-up. On suspicion of a chemotherapy-related palsy, capecitabine was discontinued and switched to vinorelbine. Subsequent improvement of the clinical picture was confirmed within 2 months.
Conclusion: The recognition of chemotherapy-related neurotoxicity is of paramount importance in the management of oncology patients. Once secondary invasion of the brain or the orbit by the tumor itself is ruled out, it must be suspected to prevent further deterioration.

引言：卡培他滨（capecitabine）相关神经毒性较为罕见。现有文献已报道其可引发小脑共济失调、多灶性脑白质病及感觉运动性周围神经病，亦有卡培他滨相关性第6脑神经麻痹的病例记载。本文首次报告一例卡培他滨相关的第4脑神经麻痹病例。
病例介绍：1例72岁白人女性因持续6个月的双眼复视由肿瘤科转诊。该症状于开始使用卡培他滨治疗后1个月发作。通过Parks三步法（Parks three-step test）及Hess检查（Hess test）确诊为右侧第4脑神经麻痹。神经影像学检查结果为阴性。为期1年的随访证实患者功能呈缓慢进行性减退。鉴于怀疑该麻痹与化疗相关，遂停用卡培他滨，换用长春瑞滨（vinorelbine）治疗，2个月内患者临床症状得到明确改善。
结论：识别化疗相关性神经毒性对肿瘤患者的诊疗管理至关重要。在排除肿瘤本身继发侵犯颅脑或眼眶后，需高度怀疑此类不良反应，以防止病情进一步恶化。