What is the most common cause of an increased anion gap metabolic acidosis?

Diabetic ketoacidosis is the most common cause of an increased anion gap metabolic acidosis due to the production of excess ketoacids as a result of insulin deficiency and increased fat metabolism. In diabetic patients, particularly those with type 1 diabetes, the lack of insulin leads to lipolysis and the subsequent production of ketone bodies, such as acetoacetate and beta-hydroxybutyrate. These ketoacids accumulate in the bloodstream, contributing to a significant increase in the anion gap.

The anion gap is calculated using the formula: Anion Gap = (Na+)-(Cl- + HCO3-). In conditions like diabetic ketoacidosis, as the concentration of unmeasured anions (like ketoacids) rises, the bicarbonate levels decrease, resulting in a higher anion gap. This is a critical aspect to monitor in patients presenting with hyperglycemia and symptoms of metabolic acidosis.

Understanding the underlying mechanisms can also help differentiate it from other conditions associated with increased anion gap. For instance, while renal failure can cause an increased anion gap acidosis due to the accumulation of uremic toxins, it is generally less common than diabetic ketoacidosis, particularly in the context of