An Unusual Presentation of Metformin-Associated Lactic Acidosis: A Case Report

Metformin-associated lactic acidosis (MALA) is a rare but serious complication of metformin therapy, typically occurring in patients with underlying risk factors, such as renal impairment. While metformin is commonly prescribed for managing type 2 diabetes, its association with lactic acidosis is infrequent. We present the case of a 73-year-old woman with type 2 diabetes and atrial fibrillation (AFib) who developed MALA following acute kidney injury (AKI). The patient presented with symptoms of malaise, dizziness, abdominal pain, nausea, and vomiting, along with signs of severe metabolic acidosis and elevated lactate levels. Upon further evaluation, she was found to have impaired renal function, which likely reduced the clearance of metformin and lactate, leading to the development of MALA. The patient underwent hemodialysis for four days, which led to a gradual normalization of her acid-base balance and an improvement in renal function. She made a full recovery and was discharged home after two weeks. Metformin can inhibit mitochondrial function, impairing lactate clearance and increasing the risk of lactic acidosis, particularly in patients with compromised renal function. The clinical presentation of MALA is nonspecific, often mimicking other conditions, such as sepsis or gastrointestinal disorders. Early recognition and management, including hemodialysis, are crucial for improving outcomes. This case highlights the importance of monitoring patients with predisposing factors for MALA and providing timely intervention to prevent severe complications.