Severe Metformin-Associated Lactic Acidosis Managed Without Dialysis in an Elderly Patient With Multiple Comorbidities: A Case Report

Metformin-associated lactic acidosis (MALA) is a rare but potentially life-threatening adverse effect. Extracorporeal treatment is generally recommended for severe MALA, defined by a lactate concentration >20 mmol/l, arterial pH ≤7.0, shock, or decreased level of consciousness. We report a case of an 84-year-old Japanese man with autoimmune pancreatitis and type 2 diabetes who developed severe MALA while continuing metformin despite prolonged poor oral intake, and was successfully treated without dialysis. On admission, the patient presented with hypothermia, shock, acute kidney injury (serum creatinine 5.93 mg/dl), hyperkalemia (serum potassium 7.7 mEq/l), and lactic acidosis (arterial pH 6.962, lactate 17 mmol/l), which later worsened to a lactate level of 26 mmol/l. While meeting the criteria for emergency dialysis, renal replacement therapy was withheld in accordance with his advance care planning. The patient received intensive supportive therapy, including aggressive intravenous fluid administration, vasopressor support with noradrenaline and vasopressin, hydrocortisone, vitamin B1, and sodium bicarbonate supplementation. Acidosis resolved by 36 hours after admission, and the lactate level decreased to below 5 mmol/l by 44 hours. He was discharged without sequelae on day 31. This case suggests that even in elderly patients with severe MALA, non-dialytic treatment may be effective when intensive and targeted supportive care is provided.