Metformin-associated Lactic Acidosis Successfully Treated with Continuous Renal Replacement Therapy

Metformin-associated lactic acidosis (MALA) is a potentially lethal condition that can result from the use of metformin in the setting of the risk factors such as renal insufficiency or hypoperfusion. We present a case of metformin-associated lactic acidosis incited by pyelonephritis-induced septic shock where use of continuous renal replacement therapy (CRRT) led to good recovery. A 51-year-old female with confusion and abdominal pain was brought to the emergency department (ED). She had a significant past medical history of type ll diabetes mellitus and recurrent urinary tract infections. Prior to the arrival to the hospital, she was conscious but confused and noted to have a low blood glucose level, which was managed with glucose per orally by emergency medical services. While in ED patient was dehydrated and hemodynamically unstable. She failed to respond to intravenous fluids hence vasopressors along with ceftriaxone were initiated. Intubation for mechanical ventilation was performed for respiratory failure and evolving septic shock, sodium bicarbonate for severe metabolic acidosis was started and antibiotics were stepped up to vancomycin and cefepime. The patient was transferred to the medical intensive care unit. Her kidney function continued to worsen, and she remained profoundly acidotic despite aggressive measures. A diagnosis of concomitant MALA was made since vasopressor requirement was less than expected considering the severity of acidosis. Emergent CRRT was initiated, resulting in improvement of acidosis in 24 hours. After she was stabilized vasopressors were stopped, she was extubated, and antibiotics were de-escalated to the oral regimen. MALA is rare but life-threatening complication of metformin use, especially in critically ill patients. CRRT should be considered as the first line in the treatment of metformin-related lactic acidosis, especially in the setting of hemodynamic instability.