Acquistapace Giulia, Rossi Marco, Garbi Mara, Cosci Pablo, Canetta Ciro, Manelli Anna, Ricevuti Giovanni
Clin Chem Lab Med. 2014 Oct;52(10):1489-97. doi: 10.1515/cclm-2014-0208.
Background: Metformin is a biguanide antihyperglycemic agent that decreases insulin resistance. It is removed through renal mechanisms and its clearance is reduced in renal failure. Metformin ingestion should always be considered in the differential diagnosis of any patient with metabolic acidosis and increased lactate level. Hemodialysis and continuous veno-venous hemofiltration (CVVH) are both efficient methods to treat metformin intoxication and correct metabolic abnormalities.
Patient 1: A 63-year-old man with type 2 diabetes mellitus presented to emergency department (ED) of Lodi (Italy) for dyspnea. He also reported having diarrhea for 10 days. Initial investigations revealed metabolic acidosis with hyperlactatemia and hypoglycemia (54 mg/dL), metformin concentration was 41 μg/mL (normal value <4 μg/mL). His hemodynamic condition became rapidly unstable and hypotension worsened despite CVVH being performed. Death occurred in 24 h. Patient 2: A 76-year-old man with type 2 diabetes mellitus presented to ED of Lodi for dyspnea. He referred a recent surgery amputation of the left foot's fifth phalanx for osteomyelitis, in levofloxacin therapy. Initial investigations revealed metabolic acidosis with hyperlactatemia and severe hypoglycemia (20 mg/dL). Two hemodialysis sessions were performed with complete normalization of the serum concentration of metformin.
In our two cases the genesis of metformin intoxication was clear, powered by acute renal failure, but less obvious was the etiology of acute renal damage responsible for metformin accumulation. Damage due to renal hypoperfusion or the direct toxic effect of metformin should be considered. Additionally, for the second patient, we can also hypothesize that interstitial nephritis was exacerbated by levofloxacin.
背景：二甲双胍是一种双胍类抗高血糖药物，可降低胰岛素抵抗。它通过肾脏机制清除，在肾衰竭时其清除率降低。对于任何患有代谢性酸中毒和乳酸水平升高的患者，在鉴别诊断时都应始终考虑二甲双胍摄入情况。血液透析和连续性静脉 - 静脉血液滤过（CVVH）都是治疗二甲双胍中毒和纠正代谢异常的有效方法。
病例1：一名63岁的2型糖尿病男性因呼吸困难就诊于意大利洛迪的急诊科。他还报告腹泻10天。初始检查发现代谢性酸中毒伴高乳酸血症和低血糖（54mg/dL），二甲双胍浓度为41μg/mL（正常值<4μg/mL）。尽管进行了CVVH，但他的血流动力学状况迅速不稳定，低血压恶化。24小时内死亡。病例2：一名76岁的2型糖尿病男性因呼吸困难就诊于洛迪的急诊科。他因骨髓炎接受了近期左足第五趾骨截肢手术，正在接受左氧氟沙星治疗。初始检查发现代谢性酸中毒伴高乳酸血症和严重低血糖（20mg/dL）。进行了两次血液透析，二甲双胍血清浓度完全恢复正常。
在我们的两个病例中，二甲双胍中毒的病因明确，由急性肾衰竭引起，但导致二甲双胍蓄积的急性肾损伤病因不太明显。应考虑肾灌注不足或二甲双胍的直接毒性作用所致的损伤。此外，对于第二位患者，我们还可以推测左氧氟沙星加剧了间质性肾炎。
