Abstract: SA-PO0604
Metformin-Associated Lactic Acidosis from Unprescribed Use in a Patient with ESRD
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Case Reports - 2
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Authors
- Mehmood, Tahir, Hennepin Healthcare System Inc, Minneapolis, Minnesota, United States
- Nelson, Andrea M., Hennepin Healthcare System Inc, Minneapolis, Minnesota, United States
Introduction
Metformin-associated lactic acidosis (MALA) is a rare but life-threatening condition, most commonly occurring in patients with impaired renal clearance. Diagnosis may be challenging when metformin exposure is unrecognized. We present a case of MALA in a patient not prescribed metformin, highlighting the critical importance of detailed medication reconciliation.
Case Description
A 59-year-old woman with type 2 diabetes mellitus and end-stage kidney disease on peritoneal dialysis presented with two days of nausea, vomiting, diarrhea, and poor oral intake. Initial evaluation demonstrated high anion gap metabolic acidosis with markedly elevated lactate and beta-hydroxybutyrate, raising concern for diabetic ketoacidosis versus starvation ketosis. Despite supportive management, lactate levels and anion gap remained persistently elevated. On further detailed history, the patient disclosed taking multiple doses of metformin that belonged to a family member to control her hyperglycemia, despite not being prescribed the medication herself. Given concern for MALA in the setting of ESRD, she was started on urgent hemodialysis. Following dialysis, lactate rapidly normalized and metabolic acidosis resolved. She was transitioned to a subcutaneous insulin regimen and discharged in stable condition.
Discussion
This case illustrates an uncommon but critical presentation of MALA due to unprescribed metformin use in a high-risk patient with ESRD. In patients presenting with persistent lactic acidosis and renal failure, metformin toxicity should be considered even when the medication is not listed in the chart. Reliance on documented medication lists alone may delay diagnosis and definitive therapy. Thorough, repeated, and nonjudgmental medication history-taking including access to family members’ medications is essential. Early recognition of MALA and prompt initiation of renal replacement therapy can be lifesaving.
Lactate and AGAP values over the early treatment period