Advanced Patient Assessment Practice Exam

What is the most common cause of metabolic acidosis in patients with renal failure?

1. Excessive insulin

2. Lactic acidosis

3. Respiratory failure

4. Diabetes mellitus

The correct answer is: Lactic acidosis

Metabolic acidosis is a condition characterized by a decrease in blood pH due to an accumulation of acids or a loss of bicarbonate. In patients with renal failure, the kidneys are unable to excrete acids effectively, leading to a buildup of metabolic acids in the body. Among the potential causes, lactic acidosis is particularly relevant in this context. Lactic acidosis occurs when there is an increased production of lactic acid, often due to conditions such as severe infections, hypoxia, or shock. In patients with renal failure, the kidneys can no longer eliminate the excess lactic acid effectively, leading to an exacerbation of metabolic acidosis. This is often coupled with the fact that renal failure itself can impair lactate clearance. Therefore, the accumulation of lactic acid is a common cause of metabolic acidosis in these patients. Other options such as excessive insulin can lead to hypoglycemia, which may cause metabolic disturbances, but it is not a direct cause of metabolic acidosis in renal failure. Respiratory failure primarily leads to respiratory acidosis rather than metabolic acidosis, and while diabetes mellitus can contribute to ketoacidosis, it is not as directly related to the metabolic acid buildup seen in renal failure as lactic acidosis is.