PSUN265 Metformin-Induced Severe Lactic Acidosis Requiring Urgent Dialysis Associated With Influenza A Infection in a Patient With Previous Preserved Renal Function: Case Report
Authors: Camargos Luisa Campos , da Silva Marina Sousa 
Published: November 2022

Abstract

Background
Although rare, metformin-induced lactic acidosis it's a severe acute condition, that requires immediate recognition and management due to its high lethality.

Clinical case
Female, 70-years-old, presents to the E.R. with generalized malaise, weakness and myalgia for 4 days associated with diarrhea and vomits for 2 days. Denies fever or flu-like symptoms. History of hypertension and T2DM using metoprolol 100mg/day, perindopril 10mg/day, indapamide 2.5mg/day, amlodipine 5mg/day, linagliptin 5mg/day, rosuvastatin 10mg/day, gliclazide 120mg/day, aspirin 100mg/day, clonidine 0.3mg/day and metformin XR 1g/day.
On clinical exam she was dehydrated and tachypneic with no other important findings. Laboratory showed glucose 31mg/dL, severe metabolic acidosis - pH 6,0; HCO3 5,4mmol/L; lactate 11.6mmol/L (n&lt;1.6mmoL/L), acute renal failure KDIGO 3, creatinine 8.08mg/dL eGFR 5mL/min/1.73m2 (patient's baseline 0.9mg/dL), BUN 213mg/dL (n&lt;50mg/dL), potassium 6.8mEq/L (3.5&gt;n&lt;5.1mEq/L), phosphor 14.9mg/dL (2.7&gt;n&lt;4.5mg/dL), chlorine 92mEq/L (98&gt;n&lt;107mEq/L), magnesium 1.7mg/dL (1.6&gt;n&lt;2.6mg/dL), calcium 0.95mmol/L (1.16&gt;n&lt;1.32mmol/L), and normal blood count. She was admitted to the ICU, hemodynamically stable with no need for vasoactive amine, breathing under nasal cannula and proceed with emergency hemodialysis.
Acidosis was corrected after 6h of hemodialysis. Patient turned eupneic in room air and presented renal function improvement (BUN 44mg/dL; Creatinine 2.66mg/dL). She continued under intensive care and daily hemodialysis for another 4 days. The etiological investigation excluded glomerulopathies of rheumatological cause, blood cultures, serology for hepatitis, HIV and Dengue were all negative. However, respiratory viral panel was positive for influenza A.
Although metformin serum dosage was not performed, renal function stability without the need for hemodialysis was only achieved after discontinuation of metformin. The main diagnostic hypothesis was metformin-induced severe metabolic acidosis. Finally, the patient was discharged on day 10, with stable renal function without hemodialysis (creatinine 2.19mg/dL eGFR 22mL/min/1.73m2) and no neurological deficits. The patient was referred to the endocrinologist and nephrologist to follow-up.

Conclusion
Metformin is affordable, safe and widely prescribed since the 50's. Although rare, metformin-induced lactic acidosis is a lethal toxicity, with identifiable risk factors that must be considered by prescribers.

References
Lazarus, Benjamin et al. "Association of Metformin Use With Risk of Lactic Acidosis Across the Range of Kidney Function: A Community-Based Cohort Study." JAMA internal medicine vol. 178,7 (2018): 903-910. doi: 10.1001/jamainternmed.2018.0292
Salpeter, Shelley R et al. "Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus." The Cochrane database of systematic reviews vol. 2010,4 CD002967. 14 Apr. 2010, doi: 10.1002/14651858.CD002967.pub4
Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.