C49-01 Consecutive Conventional Hemodialysis Sessions in the Management of Metformin Associated Lactic Acidosis

Abstract Metformin-associated lactic acidosis (MALA) is a known but rare complication of metformin use, with an incidence of 1-9 per 100,000; however, it can be clinically difficult to decipher true causality versus coincidental medication use in the critically ill. We present a case of suspected MALA in a patient with severe metabolic acidosis with shock and an anuric acute kidney injury (AKI) requiring intensive care and urgent hemodialysis. A 57-year-old man with type 2 diabetes on metformin and insulin, hyperlipidemia, and prior diabetic ketoacidosis (DKA) presented with shortness of breath. Workup revealed anuric AKI (creatinine 17.13) and metabolic derangements including profound non-anion and anion gap metabolic acidosis with a pH of 6.95 and bicarbonate of 5. His beta hydroxybutyrate and lactic acid were elevated at 6.1 and 6.5 respectively. Nephrology was consulted for urgent hemodialysis and supportive care initiated with fluids, bicarbonate, norepinephrine, and non-invasive positive pressure ventilation (NIPPV). Despite completion of one full session of hemodialysis, his lactate continued to rise to a peak of 18.9 requiring escalation to 3 vasopressors for hemodynamic support. The severity of his refractory metabolic acidosis prompted an investigation into possible contributing toxins with the leading diagnosis of pre-renal AKI secondary to DKA with subsequent development of MALA. The patient underwent back-to-back sessions of hemodialysis, requiring further augmentation of vasopressor support. He had remarkable improvement after the second hemodialysis session allowing for discontinuation of NIPPV and vasopressors. Initial toxicology panel was unremarkable, however after one week the plasma metformin level returned elevated at 24, confirming MALA diagnosis. This case highlights the importance of early recognition and prompt treatment for suspected MALA, especially in patients presenting with severe acidosis (pH 7) and hemodynamic instability. Renal replacement therapy (RRT) is often urgently required for metabolic correction and drug removal. Hemodialysis is preferred over continuous dialysis for metformin clearance. Consecutive hemodialysis sessions are often needed because metformin has a large volume of distribution and accumulates in both plasma as well as tissues. This creates the potential for rebound elevation of metformin levels and acidosis with redistribution between the intracellular and extracellular space. Despite MALA being a rare complication, a high index of suspicion should be maintained as definitive diagnosis with a plasma metformin level often takes days to result. In patients presenting with suspected MALA, prompt treatment with supportive care and RRT is crucial as mortality rate is high. This abstract is funded by: None