SHM Converge Scientific Abstract ePoster Gallery-Hidden Acid, High Stakes: Metformin Associated Lactic Acidosis Masquerading as Starvation Ketoacidosis

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This case report describes a 76-year-old woman with type 2 diabetes taking metformin who presented with five days of nausea, vomiting, diarrhea, hypotension, and severe dehydration. She was found to have profound acute kidney injury (BUN 78 mg/dL, creatinine 7.08 mg/dL), severe anion gap metabolic acidosis (bicarbonate 5 mmol/L, anion gap 51), and extreme lactic acidosis (lactate 24 mmol/L) with arterial pH 6.8. Because she also had ketosis, she was initially treated for starvation ketoacidosis with insulin and bicarbonate.<br /><br />However, her lactic acidosis remained far more severe than expected for starvation alone, even after fluid resuscitation and blood pressure improvement. This prompted concern for another cause, and her renal failure was recognized as impairing metformin clearance, leading to metformin-associated lactic acidosis (MALA), a rare but life-threatening form of type B lactic acidosis. Metformin can raise lactate by inhibiting hepatic mitochondrial respiration, and the risk increases sharply when a secondary insult such as acute kidney injury is present.<br /><br />The patient underwent urgent hemodialysis, which produced marked clinical and laboratory improvement. After dialysis, her lactate normalized, the anion gap closed, bicarbonate improved, and arterial pH rose to 7.32. Metformin was discontinued.<br /><br />The report emphasizes the importance of medication reconciliation and considering metformin as a cause of severe lactic acidosis, especially in patients with acute kidney injury and no evidence of tissue hypoxia. Persistent acidosis with lactate above 15 mmol/L should prompt early nephrology consultation and consideration of hemodialysis.

Asset Subtitle

Zoya Khan

Meta Tag

Author List Andrea Rodriguez Jimenez, Camila Villacreses, Joseph Paredes, Umair Ahmed, Zoya Khan

Category Clinical Vignettes

Concept Type A Lactic Acidosis

Concept Type B Lactic Acidosis

Concept Metformin-Associated Lactic Acidosis

Concept Metformin

Concept Acute Kidney Injury

Distinguished Non-Finalist

Presenter Organization Lakeland Regional Health

Presenting Author Zoya Khan

Track Adult

Keywords

metformin-associated lactic acidosis

acute kidney injury

severe lactic acidosis

type 2 diabetes

hemodialysis

anion gap metabolic acidosis

starvation ketoacidosis

metformin toxicity

renal failure

medication reconciliation

Type A Lactic Acidosis

Type B Lactic Acidosis

Metformin-Associated Lactic Acidosis

Metformin

Acute Kidney Injury