A Rare Case of Metformin-Induced Lactic Acidosis and Concomitant Euglycemic Ketoacidosis

Acidemia arises primarily from the accumulation of carbon dioxide or the loss of bicarbonate, leading to a pH decrease within the body, which can be fatal if severe and not promptly addressed. Metabolic acidemia occurs due to a loss of bicarbonate and can manifest through direct losses of bicarbonate via renal or gastrointestinal routes, or through the accumulation of anions such as lactic acid or ketoacids, leading to an anion gap metabolic acidosis. Many common etiologies for lactic acid and ketoacid generation exist, including medication-induced causes. Metformin-induced lactic acidemia is a well-known, yet rare, complication of metformin usage, but metformin-induced ketoacidemia is not well described. This report presents a case involving a patient with end-stage renal disease (ESRD) who, while taking metformin, developed severe anion gap metabolic acidosis with undetectably high levels of lactic acid and ketones, supporting the potential role of metformin in inducing severe lactic acidosis and ketoacidosis.