Kostic M A, Dart R C
Rocky Mountain Poison and Drug Center, Denver Health Authority, Denver, Colorado 80230, USA.
J Toxicol Clin Toxicol. 2003;41(6):793-800. doi: 10.1081/clt-120025344.
Treatment thresholds for methanol poisoning are based on case reports and published opinion. Most guidelines recommend treatment for a methanol level > or = 20 mg/dL in a nonacidotic patient. No supportive data have been offered nor has the time of the exposure been addressed. For instance, no distinction has been drawn between a methanol level drawn 1 hr vs. 24 hr from ingestion. We analyzed all published cases of methanol poisoning to determine the applicability of the 20 mg/dL threshold in a nonacidotic patient, specifically those arriving early for care (within 6 hr) with a peak or near-peak blood methanol concentration.
Using predefined search criteria, a systematic review of the world literature was performed using MEDLINE and EMBASE. In addition, each article's references were hand searched for pre-1966 articles, as were fatality abstracts from all U.S. poison centers. Human cases were included if they reported a known time of a single methanol exposure, acid-base data, blood methanol, and blood ethanol (if not acidotic).
Dating to 1879, 372 articles in 18 languages were abstracted using a standard format; 329 articles (2433 patients) involved methanol poisoning, and 70 articles (173 patients) met inclusion criteria. Only 22 of these patients presented for care within 6hr of ingestion with an early methanol level. All but 1 patient was treated with an inhibitor of alcohol dehydrogenase (ADH). A clear acidosis developed only with a methanol level > or = 126 mg/dL. The patient that did not receive an ADH inhibitor was an infant with an elevated early methanol level (46 mg/dL) that was given folate alone and never became acidotic. Intra and inter-rater reliability were 0.95.
Nearly all reports of methanol poisoning involve acidotic patients far removed from ingestion. The small amount of data regarding patients arriving early show that 126 mg/dL is the lowest early blood methanol level ever clearly associated with acidosis. Contrary to conventional teaching, there are case reports of acidosis after only a few hours of ingestion. The data are insufficient to apply 20 mg/dL as a treatment threshold in a nonacidotic patient arriving early for care. Prospective studies are necessary to determine if such patients may be managed without antidotal therapy or dialysis.
甲醇中毒的治疗阈值基于病例报告和已发表的观点。大多数指南建议，对于非酸中毒患者，甲醇水平≥20mg/dL时进行治疗。目前尚无支持性数据，也未涉及接触时间。例如，未区分摄入后1小时与24小时测得的甲醇水平。我们分析了所有已发表的甲醇中毒病例，以确定20mg/dL阈值对非酸中毒患者的适用性，特别是那些在6小时内就诊且血液甲醇浓度达到峰值或接近峰值的患者。
使用预定义的搜索标准，通过MEDLINE和EMBASE对世界文献进行系统综述。此外，对每篇文章的参考文献进行人工检索，以查找1966年以前的文章，同时检索美国所有中毒控制中心的死亡摘要。如果人类病例报告了已知的单次甲醇接触时间、酸碱数据、血液甲醇和血液乙醇（如果未发生酸中毒），则纳入研究。
自1879年起，以标准格式提取了18种语言的372篇文章；其中329篇文章（2433例患者）涉及甲醇中毒，70篇文章（173例患者）符合纳入标准。这些患者中只有22例在摄入后6小时内就诊并测得早期甲醇水平。除了一名患者外，所有患者均接受了乙醇脱氢酶（ADH）抑制剂治疗。仅当甲醇水平≥126mg/dL时才出现明显的酸中毒。未接受ADH抑制剂治疗的患者是一名婴儿，其早期甲醇水平升高（46mg/dL），仅接受了叶酸治疗，且未发生酸中毒。评分者内和评分者间的可靠性为0.95。
几乎所有甲醇中毒报告都涉及远离摄入时间的酸中毒患者。关于早期就诊患者的少量数据表明，126mg/dL是迄今明确与酸中毒相关的最低早期血液甲醇水平。与传统观点相反，有病例报告显示摄入后仅数小时就发生了酸中毒。现有数据不足以将20mg/dL作为早期就诊的非酸中毒患者的治疗阈值。需要进行前瞻性研究，以确定此类患者是否可以在不进行解毒治疗或透析的情况下得到处理。
