Ng Daniel Kwok-Keung, Chan Chung-Hong, Soo Man-Ting, Lee Robert Shing-Yan
Department of Paediatrics, Kwong Wah Hospital, Kowloon, Hong Kong.
Pediatr Int. 2007 Feb;49(1):80-7. doi: 10.1111/j.1442-200X.2007.02303.x.
Mercury is a well-known neurotoxin. There are three kinds of mercury exposure: elemental mercury poisoning, inorganic mercury poisoning and organomercury poisoning. Organomercury is the most toxic. Twenty-four hour urine for mercury and blood mercury are the gold standards for diagnosis of mercury poisoning, including low-level chronic mercury exposure. Other tests for mercury level are discussed. The purpose of the present paper was to review recent data on the nature, pathophysiology, pharmacokinetics, diagnostic methods, treatment and the linkage to neurodevelopmental disabilities of mercury exposure in children.
A literature search was undertaken of MEDLINE (1980-2003), and American Academy of Pediatrics, American Medical Association, American Dental Association, World Health Organization and Center for Disease Control websites. The search string 'mercury' was used in MEDLINE and articles were selected as appropriate by two independent reviewers. All relevant information was reviewed and data were extracted by two independent reviewers.
Based on the meta-analysis of the accuracy of hair mercury, hair mercury levels correlated with mercury level in blood (sample size weighted correlation coefficient, r w = 0.61), with 24 h urine ( r w = 0.46) and with cord blood ( r w = 0.64). However, the correlation for hair mercury level with 24 h urine level and blood level was not high enough to replace them in clinical decision-making of individual patient. Epidemiological evidence has shown that low-level mercury poisoning is not a cause of autism (relative risk = 0.49, 95%CI = 0.36-0.66). The risk of neurodevelopmental disabilities from low-level exposure to methylmercury from the regular consumption of fish is still controversial even after combining results from different epidemiological studies worldwide. There is a lack of data in the literature about the effect of chelation therapy in children with neurodevelopmental disabilities.
Mercury poisoning should be diagnosed only with validated methods. There is no evidence to support the association between mercury poisoning and autism.
汞是一种著名的神经毒素。汞暴露有三种类型：元素汞中毒、无机汞中毒和有机汞中毒。有机汞毒性最强。24小时尿汞和血汞是诊断汞中毒（包括低水平慢性汞暴露）的金标准。文中还讨论了其他汞水平检测方法。本文的目的是综述有关儿童汞暴露的性质、病理生理学、药代动力学、诊断方法、治疗以及与神经发育障碍的关联的最新数据。
对MEDLINE（1980 - 2003年）以及美国儿科学会、美国医学协会、美国牙科协会、世界卫生组织和疾病控制中心的网站进行了文献检索。在MEDLINE中使用检索词“汞”，由两名独立的评审人员酌情选择文章。所有相关信息均由两名独立的评审人员进行审查并提取数据。
基于对头发汞准确性的荟萃分析，头发汞水平与血汞水平（样本量加权相关系数，rw = 0.61）、24小时尿汞（rw = 0.46）以及脐血汞（rw = 0.64）相关。然而，头发汞水平与24小时尿汞水平和血汞水平的相关性不足以在个体患者的临床决策中取代它们。流行病学证据表明，低水平汞中毒不是自闭症的病因（相对风险 = 0.49，95%可信区间 = 0.36 - 0.66）。即使综合全球不同流行病学研究的结果，经常食用鱼类导致低水平甲基汞暴露引起神经发育障碍的风险仍存在争议。文献中缺乏关于螯合疗法对神经发育障碍儿童影响的数据。
汞中毒的诊断应仅采用经过验证的方法。没有证据支持汞中毒与自闭症之间的关联。
