Department of Occupational Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
National Institute of Public Health, Prague, Czech Republic.
Basic Clin Pharmacol Toxicol. 2018 Feb;122(2):271-277. doi: 10.1111/bcpt.12899. Epub 2017 Sep 27.
The last eight survivors of 80 workers accidentally exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during production of herbicides based on trichlorophenoxyacetic acid in 1965-1967 in a chemical factory were followed. All were men, mean age 72.4 ± 1.3 years. Their current median TCDD blood level was 112 (46-390) pg/g lipids. Neurological examination revealed central nervous system impairment in all individuals and signs of polyneuropathy in 87.5%, which was confirmed by a nerve conduction study (NCS) in 75%. A Lanthony test demonstrated acquired dyschromatopsia in 87.5% of the patients, with deterioration of mean colour confusion index (CCI) from 1.52 ± 0.39 in 2010 to 1.73 ± 0.41 in 2016. Single-photon emission computer tomography (SPECT) of the brain showed focal reduction of perfusion in various brain locations in all patients and worsening in six patients. Visual-evoked potentials (VEP) was abnormal in 62.6% of individuals. Most patients complained of psychological problems. The neuropsychological test battery showed most positive impairments in the Trail Making Test evaluating processing speed (average level in the range of mild neurocognitive impairment), which correlated with mean CCI (p < 0.05).
Fifty years after exposure, blood levels of TCDD are still 10 times higher than the general population. NCS, VEP, Lanthony test and SPECT findings deteriorated from examination of these patients in 2004 and in 2010. The total of abnormal tests per patient in 2016 is very high. Minor differences among patients and their reduced count may explain why the number of impairments in 2016 does not correlate with TCDD blood level.
1965 年至 1967 年间，一家化工厂在生产基于三氯苯氧乙酸的除草剂时，80 名工人中有 80 人意外接触到 2,3,7,8-四氯二苯并对二恶英（TCDD），最后 8 名幸存者接受了随访。所有幸存者均为男性，平均年龄 72.4±1.3 岁。他们目前的 TCDD 血液水平中位数为 112（46-390）pg/g 脂质。神经系统检查显示所有个体的中枢神经系统受损，87.5%存在多发性神经病的迹象，75%的神经传导研究（NCS）证实了这一点。兰托尼测试（Lanthony test）显示，87.5%的患者存在获得性色觉障碍，平均色觉混淆指数（CCI）从 2010 年的 1.52±0.39恶化至 2016 年的 1.73±0.41。大脑单光子发射计算机断层扫描（SPECT）显示所有患者的大脑不同部位存在局部灌注减少，6 名患者病情恶化。视觉诱发电位（VEP）异常的个体占 62.6%。大多数患者有心理问题。神经心理学测试包显示，在评估处理速度的连线测试（平均水平处于轻度神经认知障碍范围内）中，大多数患者的认知能力受损最为明显，这与平均 CCI 相关（p<0.05）。
暴露 50 年后，TCDD 的血液水平仍比一般人群高 10 倍。NCS、VEP、兰托尼测试和 SPECT 的检查结果与 2004 年和 2010 年检查相比有所恶化。2016 年每位患者异常检查的总数非常高。患者之间的细微差异及其减少的数量可能解释了为什么 2016 年的损伤数量与 TCDD 的血液水平不相关。
