What is a potential cause of a normal anion gap?

A normal anion gap refers to the measurement of the difference between the measured cations (positively charged ions) and the measured anions (negatively charged ions) in serum. It typically ranges from 8 to 12 mEq/L. When this gap is normal, it is often associated with certain conditions that do not significantly alter the balance of these electrolytes.

One potential cause related to a normal anion gap is the presence of gastrointestinal losses or conditions affecting the absorption of electrolytes, such as an ileostomy. In this situation, the loss of bicarbonate from the intestinal tract can lead to a non-anion gap metabolic acidosis. The loss occurs due to the secretion of bicarbonate into the intestine, which when lost, is not compensated by an increase in other anions, thus maintaining a normal anion gap while presenting with metabolic acidosis.

This differs from conditions such as diabetic ketoacidosis or lactic acidosis, which typically result in an increased anion gap due to the accumulation of ketoacids or lactic acid, respectively. Severe dehydration can lead to a number of electrolyte imbalances and may affect overall metabolic status but does not inherently lead to a normal anion gap acidosis. Therefore, in the