Abstract：
BACKGROUND: Ethambutol is an antibiotic used as a first line drug in the treatment of tuberculosis and a vision threatening side effect of EMB is ethambutol-induced optic neuropathy (EON). The aim of the study is to create awareness about the potentiality of ethambutol to cause ethambutol-induced optic neuropathy, careful monitoring of dose and patient education.
METHODS: A retrospective observational study of 14 patients whose complete Anti- tubercular treatment records could be retrieved were included. Epidemiological data including age, sex, systemic illness were recorded. Duration between optic nerve toxicity , usage of ethambutol and the drug dosage were noted. Best corrected visual acuity, anterior segment examination including pupils, extraocular movements, colour vision, central fields and fundus examination were evaluated. The patients were followed up at one and three month intervals.
RESULTS: Associated systemic illness was found to be a confounding factor for the development of ethambutol-induced optic neuropathy. 57% of patients had diabetes mellitus followed by hypertension (14.2%), renal disease (7.1%). The average daily dose of Ethambutol ingested was 1078.5 mg (21 mg/kg) and this high dose could have been the primary cause for development of ethambutol-induced optic neuropathy. Vision ranged from total blindness to mild visual impairment and poor recovery of vision was noted even after discontinuing ethambutol.
CONCLUSIONS: Only a minority of patients showed improvement in visual function following discontinuation of ethambutol and the toxicity was found to be dose-dependent. Patients with comorbidities like renal impairment and diabetes mellitus appeared to be at greater risk. Ophthalmological examination before commencing treatment and periodic evaluation thereafter is mandatory.
METHODS: A retrospective observational study of 14 patients whose complete Anti- tubercular treatment records could be retrieved were included. Epidemiological data including age, sex, systemic illness were recorded. Duration between optic nerve toxicity , usage of ethambutol and the drug dosage were noted. Best corrected visual acuity, anterior segment examination including pupils, extraocular movements, colour vision, central fields and fundus examination were evaluated. The patients were followed up at one and three month intervals.
RESULTS: Associated systemic illness was found to be a confounding factor for the development of ethambutol-induced optic neuropathy. 57% of patients had diabetes mellitus followed by hypertension (14.2%), renal disease (7.1%). The average daily dose of Ethambutol ingested was 1078.5 mg (21 mg/kg) and this high dose could have been the primary cause for development of ethambutol-induced optic neuropathy. Vision ranged from total blindness to mild visual impairment and poor recovery of vision was noted even after discontinuing ethambutol.
CONCLUSIONS: Only a minority of patients showed improvement in visual function following discontinuation of ethambutol and the toxicity was found to be dose-dependent. Patients with comorbidities like renal impairment and diabetes mellitus appeared to be at greater risk. Ophthalmological examination before commencing treatment and periodic evaluation thereafter is mandatory.
摘要：
背景：乙胺丁醇是一种用作治疗结核病的一线药物的抗生素，EMB威胁视力的副作用是乙胺丁醇诱导的视神经病变（EON）。这项研究的目的是提高人们对乙胺丁醇引起乙胺丁醇引起视神经病变的潜力的认识。仔细监测剂量和患者教育。
方法：纳入了14例患者的回顾性观察性研究，这些患者的完整抗结核治疗记录可以检索到。流行病学数据，包括年龄，性别,记录系统性疾病。视神经毒性之间的持续时间，记录乙胺丁醇的用法和药物剂量。最佳矫正视力,包括瞳孔在内的眼前段检查，眼外运动,色觉,评估中央视野和眼底检查。每隔一个月和三个月对患者进行随访。
结果：发现相关的全身性疾病是乙胺丁醇诱导的视神经病变发展的混杂因素。57％的患者患有糖尿病，其次是高血压（14.2％），肾脏疾病（7.1%）。摄入乙胺丁醇的平均日剂量为1078.5mg（21mg/kg），这种高剂量可能是乙胺丁醇诱导的视神经病变发展的主要原因。视力范围从完全失明到轻度视力障碍，即使在停用乙胺丁醇后也注意到视力恢复不良。
结论：只有少数患者在停用乙胺丁醇后显示视觉功能改善，并且发现毒性是剂量依赖性的。患有肾脏损害和糖尿病等合并症的患者似乎面临更大的风险。必须在开始治疗之前进行眼科检查，然后进行定期评估。
方法：纳入了14例患者的回顾性观察性研究，这些患者的完整抗结核治疗记录可以检索到。流行病学数据，包括年龄，性别,记录系统性疾病。视神经毒性之间的持续时间，记录乙胺丁醇的用法和药物剂量。最佳矫正视力,包括瞳孔在内的眼前段检查，眼外运动,色觉,评估中央视野和眼底检查。每隔一个月和三个月对患者进行随访。
结果：发现相关的全身性疾病是乙胺丁醇诱导的视神经病变发展的混杂因素。57％的患者患有糖尿病，其次是高血压（14.2％），肾脏疾病（7.1%）。摄入乙胺丁醇的平均日剂量为1078.5mg（21mg/kg），这种高剂量可能是乙胺丁醇诱导的视神经病变发展的主要原因。视力范围从完全失明到轻度视力障碍，即使在停用乙胺丁醇后也注意到视力恢复不良。
结论：只有少数患者在停用乙胺丁醇后显示视觉功能改善，并且发现毒性是剂量依赖性的。患有肾脏损害和糖尿病等合并症的患者似乎面临更大的风险。必须在开始治疗之前进行眼科检查，然后进行定期评估。
