Department of Emergency Medicine, Cleveland Clinic Akron General, Akron, Ohio; Northeast Ohio Medical University, Rootstown, Ohio.
Northeast Ohio Medical University, Rootstown, Ohio.
J Emerg Med. 2024 Apr;66(4):e530-e533. doi: 10.1016/j.jemermed.2023.11.017. Epub 2023 Nov 29.
Metformin is a biguanide hyperglycemic agent used to manage non-insulin-dependent diabetes mellitus. Adverse reactions include mainly mild gastrointestinal adverse effects, but severe complications, such as metformin-associated lactic acidosis (MALA) can occur. Metformin is excreted renally and, therefore, not recommended in patients with renal impairment. The reported incidence of MALA is 3 cases per 100,000 patient-years.
A 79-year-old woman with a complex medical history, including end-stage renal disease on dialysis and type 2 diabetes, presented to the emergency department (ED) for altered mental status. Prior to arrival, she was found to be hypoglycemic. Her laboratory results were significant for creatinine of 6.56 mg/dL and an anion gap of 52 mmol/L. The venous blood gas revealed a venous pH of 6.857 [reference range (7.32-7.43)], pCO of 15.9 mm Hg (40.6-60 mm Hg), HCO of 2.7 mmol/L (21-30 mmol/L), lactate of 27 mmol/L (0.5-2 mmol/L), and ammonia of 233 µmol/L. The patient was dialyzed emergently in the ED; repeat laboratory test results showed blood urea nitrogen of 10 mg/dL, creatinine of 1.65 mg/dL, carbon dioxide of 26 mmol/L, and anion gap of 13 mmol/L. The repeat ammonia was 16 µmol/L. The patient's metabolic encephalopathy resolved, and she was discharged home on hospital day 3. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: MALA has a high mortality rate (36%). Laboratory markers have not been found to be a reliable predictor of mortality. Sodium bicarbonate is controversial, but a pH < 7.15 indicates consideration of its use. A pH < 7.1 and a lactate level > 20 mmol/L indicate the need for emergent hemodialysis. Prompt recognition and management in the ED with early hemodialysis can result in good patient outcomes, with a return to their baseline function despite severe laboratory findings.
二甲双胍是一种用于治疗非胰岛素依赖型糖尿病的双胍类高血糖药物。其不良反应主要为轻度胃肠道不良反应，但也可能发生严重并发症，如二甲双胍相关乳酸酸中毒（MALA）。二甲双胍经肾脏排泄，因此不建议在肾功能损害的患者中使用。据报道，MALA 的发病率为每 10 万患者年 3 例。
一名 79 岁女性，既往病史复杂，包括终末期肾病透析和 2 型糖尿病，因精神状态改变到急诊科就诊。在到达急诊科之前，她被发现低血糖。她的实验室检查结果显示肌酐 6.56mg/dL，阴离子间隙 52mmol/L。静脉血气分析显示静脉 pH 值为 6.857[参考范围（7.32-7.43）]，pCO2 为 15.9mmHg（40.6-60mmHg），HCO3-为 2.7mmol/L（21-30mmol/L），乳酸 27mmol/L（0.5-2mmol/L），氨 233µmol/L。患者在急诊科紧急透析；重复实验室检查结果显示血尿素氮 10mg/dL，肌酐 1.65mg/dL，二氧化碳 26mmol/L，阴离子间隙 13mmol/L。重复氨为 16µmol/L。患者的代谢性脑病得到缓解，并于入院第 3 天出院回家。
为什么急诊医生应该注意这一点？MALA 的死亡率很高（36%）。目前尚未发现实验室标志物可作为死亡率的可靠预测指标。关于碳酸氢钠的使用存在争议，但 pH 值<7.15 表明需要考虑使用。pH 值<7.1 和乳酸水平>20mmol/L 提示需要紧急进行血液透析。在急诊科及时识别和治疗，并早期进行血液透析，可获得良好的患者转归，尽管实验室检查结果严重，但患者可恢复到基线功能。
