Metformin, a cornerstone therapy for type 2 diabetes mellitus, is highly effective but poses a risk of metformin-associated lactic acidosis (MALA), a rare yet potentially fatal complication, particularly in patients with impaired renal function. This case report details an 88-year-old female with type 2 diabetes and chronic kidney disease (CKD) stage III who presented with severe lactic acidosis and encephalopathy amid acute kidney injury and a recent infection.
Initial management with broad-spectrum antibiotics and hemodynamic support failed to halt her rapid clinical deterioration, characterized by profound metabolic acidosis (pH < 7.0, lactate > 15 mmol/L) and neurological impairment. The differential diagnosis required careful exclusion of other lactic acidosis causes, such as sepsis or hypoperfusion, which can mimic MALA. Laboratory findings and clinical context strongly suggested MALA, prompting emergent hemodialysis.
This intervention rapidly corrected the metabolic derangements, reduced lactate levels, and improved the patient’s mental status, confirming the diagnosis. The pathophysiology of MALA involves metformin accumulation in renal impairment, leading to impaired mitochondrial function and lactate overproduction. Risk factors include acute or chronic renal dysfunction, as seen in this patient, compounded by infection-induced acute kidney injury. Diagnostic challenges include distinguishing MALA from other causes of lactic acidosis, necessitating a thorough clinical and biochemical evaluation. Management hinges on early recognition and prompt initiation of renal replacement therapy, typically hemodialysis, to clear metformin and lactate while addressing underlying triggers such as infection.
This case highlights the vulnerability of elderly patients with CKD to MALA and the importance of vigilant monitoring of renal function in metformin users. It also underscores the critical role of timely dialysis in reversing life-threatening metabolic derangements. Clinicians should maintain a high index of suspicion for MALA in diabetic patients with renal compromise presenting with acidosis, ensuring rapid intervention to optimize outcomes. Further research is needed to refine risk stratification and preventive strategies for MALA in at-risk populations.
