**Question:** The following condition is not associated with an increased anion-gap type of
metabolic acidosis:

A. Diabetic ketoacidosis
B. Hepatic encephalopathy
C. Acute fatty liver of pregnancy
D. Acidosis due to respiratory failure

**Core Concept:**
Anion-gap acidosis is a type of acid-base imbalance characterized by increased anion gap (the difference between the measured and calculated anions in plasma). Normally, anion gap is determined by the difference between measured anions (such as chloride, bicarbonate, and lactate) and calculated anions (such as phosphate, sulfate, and glycerol). An increase in anion gap indicates the presence of unmeasured anions, which are typically due to organic acids. Common causes of anion-gap acidosis include diabetic ketoacidosis, hepatic encephalopathy, and respiratory acidosis.

**Why the Correct Answer is Right:**
The correct answer, C. Acute fatty liver of pregnancy, is not associated with an increased anion-gap type of acidosis. Acute fatty liver of pregnancy is a liver disease that occurs in pregnant women, usually during the third trimester or early postpartum period. Although it can cause liver dysfunction, it does not typically lead to significant release of unmeasured anions that would result in an increased anion gap.

**Why Each Wrong Option is Incorrect:**
A. Diabetic ketoacidosis (DKA) is a known cause of anion-gap acidosis due to the presence of ketoacids, which are unmeasured anions.
B. Hepatic encephalopathy (HE) is characterized by impaired liver function and may lead to increased production of unmeasured anions, causing anion-gap acidosis.
D. Respiratory acidosis (RA) is a type of acid-base imbalance resulting from respiratory alkalosis, which is characterized by an increased partial pressure of carbon dioxide (PaCO2) and decreased bicarbonate (HCO3-) levels. Respiratory acidosis does not contribute to anion-gap acidosis.

**Clinical Pearl:**
In clinical practice, it is crucial to differentiate between different types of acid-base disorders to guide appropriate management and prognosis. Acid-base imbalances may be due to various causes, including respiratory, renal, and mixed acid-base disorders. Understanding the underlying pathophysiology and treatment implications is essential when managing patients presenting with acid-base abnormalities.