American Board of Internal Medicine (ABIM) Certification Practice Exam

In the management of Type 4 (Hyperkalemic) Renal Tubular Acidosis, which intervention is crucial?

1. Discontinuation of offending medications

2. Increased potassium intake

3. Immediate dialysis

4. Calcium supplementation

The correct answer is: Discontinuation of offending medications

Discontinuation of offending medications is crucial in the management of Type 4 (Hyperkalemic) Renal Tubular Acidosis (RTA) because this condition is often associated with impaired renal potassium excretion, leading to hyperkalemia. Certain medications, particularly those that antagonize renal potassium secretion such as potassium-sparing diuretics, angiotensin-converting enzyme (ACE) inhibitors, and nonsteroidal anti-inflammatory drugs (NSAIDs), can exacerbate the potassium retention. When these medications are stopped, it allows the kidneys to regain their ability to excrete potassium more effectively, thereby helping to normalize serum potassium levels. This approach directly addresses the underlying cause of hyperkalemia in Type 4 RTA. Increased potassium intake is counterproductive, as the goal in managing hyperkalemia is to reduce potassium levels, not elevate them further. Immediate dialysis is usually considered in cases of severely elevated potassium levels or other life-threatening complications, but it is not a first-line intervention specifically for Type 4 RTA without other indications. Calcium supplementation can be beneficial in managing cardiac effects of hyperkalemia, but it does not address the root cause of potassium retention in renal tubular acidosis.