Derkits David R, Meggs William J, Parker Cote Jennifer L
Department of Emergency Medicine Brody School of Medicine at East Carolina University Greenville North Carolina USA.
J Am Coll Emerg Physicians Open. 2022 Mar 10;3(2):e12689. doi: 10.1002/emp2.12689. eCollection 2022 Apr.
Nitromethane is a primary nitroalkane used as a solvent and a fuel that may be toxic by ingestion, inhalation, or contact. Its presence can be detected in serum of exposed persons, but levels are not readily available to guide patient care. Nitromethane has been shown to falsely elevate serum creatinine when clinical laboratories use Jaffe assays to measure creatinine; enzymatic assays are not affected. Ex vivo experiments have demonstrated a linear relationship between serum nitromethane and the elevation in Jaffe assay creatinine. This case report demonstrates an elevation of creatinine measured by Jaffe assay with normal creatinine measurement by enzymatic assay after exposure to nitromethane.
A 21-month-old girl ingested an unmeasured quantity of a hobby fuel, a fuel containing methanol, nitromethane (20%), and lubricants used in miniature internal combustion engines, such as remote-controlled cars. She was initially evaluated at a community hospital, treated empirically for methanol toxicity with fomepizole and folic acid, and transferred to a university hospital for further management. By 19 hours after ingestion, methanol was below detection, but a serum creatinine of 2.63 mg/dl raised concern for kidney injury. Toxicology consultation recognized that the creatinine had been measured using a Jaffe assay and recommended a repeat creatinine using an enzymatic assay, which was within normal limits. The patient remained an inpatient for further evaluation, which permitted trending of her Jaffe assay creatinine over a 3-day period. The Jaffe assay creatinine demonstrated a gradual decline; repeat enzymatic assay creatinine remained within normal limits.
The decline in this pediatric patient's Jaffe assay creatinine is consistent with first-order clearance of nitromethane, which has been previously described in adult exposures. This case demonstrates how Jaffe assay-derived serum creatinine may be useful in the pediatric population to establish, quantify, and trend nitromethane exposure with essential concurrent use of an enzymatic assay to determine actual creatinine.
硝基甲烷是一种伯硝基烷烃，用作溶剂和燃料，可通过摄入、吸入或接触产生毒性。在接触者的血清中可检测到其存在，但尚无现成的水平数值来指导患者护理。当临床实验室使用碱性苦味酸法测定肌酐时，已证明硝基甲烷会错误地升高血清肌酐水平；酶法测定不受影响。体外实验已证明血清硝基甲烷与碱性苦味酸法测定的肌酐升高之间存在线性关系。本病例报告展示了在接触硝基甲烷后，碱性苦味酸法测定的肌酐升高，而酶法测定的肌酐正常。
一名21个月大的女孩摄入了未计量的一种业余爱好用燃料，该燃料含有甲醇、硝基甲烷（20%）以及用于微型内燃机（如遥控汽车）的润滑剂。她最初在一家社区医院接受评估，接受了甲吡唑和叶酸对甲醇中毒的经验性治疗，随后被转至一家大学医院进行进一步治疗。摄入后19小时，甲醇低于检测水平，但血清肌酐为2.63mg/dl，这引发了对肾损伤的担忧。毒理学会诊确认肌酐是用碱性苦味酸法测定的，并建议用酶法重复测定肌酐，结果在正常范围内。患者仍住院接受进一步评估，这使得能够在3天内对其碱性苦味酸法测定的肌酐进行肌酐进行跟踪。碱性苦味酸法测定的肌酐呈逐渐下降趋势；重复的酶法测定的肌酐仍在正常范围内。
该儿科患者碱性苦味酸法测定的肌酐下降与硝基甲烷的一级清除一致，这在成人接触中已有描述。本病例表明，在儿科人群中，碱性苦味酸法测定的血清肌酐可能有助于确定、量化和跟踪硝基甲烷暴露情况，同时必须结合酶法测定来确定实际肌酐水平。
