**Question:** All of the following cause high anion gap acidosis EXCEPT

A. Diabetic ketoacidosis
B. Hypokalemic alkalosis
C. Hypercalcemia
D. Acidosis due to increased lactate production

**Core Concept:**
High anion gap acidosis is a condition characterized by an elevated anion gap, which represents the difference between the measured and expected anion concentration in the blood. The anion gap is calculated as follows:

Anion Gap = Na+ (mEq/L) + Gluconate (mEq/L) - Cl- (mEq/L) - Lac-(mEq/L)

The anion gap is influenced by various substances, such as glucose, lactate, and bicarbonate ions. A normal anion gap is typically between 10-16 mEq/L.

**Why the Correct Answer is Right:**
Option D, "Acidosis due to increased lactate production," is the correct answer because an increase in lactate levels leads to an increase in anion gap acidosis. However, in this case, the anion gap is reduced because lactate ions are considered anions (negatively charged molecules) while glucose, gluconate, and chloride ions are not.

**Why Each Wrong Option is Incorrect:**
A. Diabetic ketoacidosis (DKA) is a condition characterized by high blood glucose, ketones, and a decreased pH, leading to a high anion gap acidosis.
B. Hypokalemic alkalosis is a type of alkalosis characterized by elevated potassium levels and a low anion gap.
C. Hypercalcemia is a condition characterized by high calcium levels and a low anion gap.

**Clinical Pearl:**
Diabetic ketoacidosis (DKA) is a critical complication of uncontrolled diabetes mellitus that requires prompt diagnosis and treatment. It is typically seen in patients with poorly controlled type 1 diabetes, but can also occur in type 2 diabetes mellitus. DKA is characterized by acidosis, hyperglycemia, and ketonemia. If you suspect a patient is suffering from DKA, initiate treatment immediately and refer them to a specialist for further evaluation.

**Why DKA is an exception:**
DKA has a unique characteristic regarding its anion gap. While it is a high anion gap acidosis, the increased lactate levels in DKA lead to a decreased anion concentration, contributing to the high anion gap acidosis. This helps differentiate DKA from other causes of high anion gap acidosis, such as other types of ketoacidosis (e.g., starvation ketoacidosis) or organic acidosis (e.g., lactic acidosis).