Which of the following can cause an anion gap to be greater than 16?

Ketoacidosis is a condition characterized by the accumulation of ketone bodies in the blood due to increased fat breakdown, commonly seen in uncontrolled diabetes mellitus, but can also occur in conditions like prolonged fasting or alcoholism. This accumulation leads to an increase in the anion gap, which is a calculated value representing the difference between measured cations (positively charged ions) and measured anions (negatively charged ions) in the serum.

In metabolic acidosis scenarios such as ketoacidosis, the production of excess organic acids results in a significant increase in unmeasured anions in the blood, thus elevating the anion gap beyond the normal range (usually 8-12 mEq/L, with greater than 16 indicating a high anion gap).

On the other hand, conditions like heart failure, hypotension, and dehydration may lead to metabolic imbalances and potentially acidosis, but they typically do not result in a significant increase in unmeasured anions in the same way that ketoacidosis does. Instead, they could lead to non-anion gap metabolic acidosis or mixed acid-base disturbances without the substantial increase in the anion gap seen in ketoacidosis.