American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the appropriate dietary restriction for managing hyperkalemia in Type 4 Renal Tubular Acidosis?

1. Restriction to 1000 mg/d

2. Restriction to 2000 mg/d

3. Increase potassium intake

4. No dietary restrictions necessary

The correct answer is: Restriction to 2000 mg/d

In the management of hyperkalemia related to Type 4 Renal Tubular Acidosis (RTA), dietary potassium restriction is essential. Type 4 RTA is characterized by impaired renal potassium excretion, leading to elevated serum potassium levels. The kidney's inability to sufficiently excrete potassium, particularly in the setting of aldosterone deficiency or resistance, makes dietary management a critical aspect of treatment. Restricting potassium intake to approximately 2000 mg/d is typically appropriate because it allows for better control of serum potassium levels, helping to mitigate the risks associated with hyperkalemia, such as cardiac arrhythmias and muscle weakness. A target of 2000 mg/day strikes a balance between providing enough potassium for normal bodily functions and preventing excess accumulation in the bloodstream. This intervention is foundational in the dietary management of patients with hyperkalemia due to Type 4 RTA and helps optimize their overall clinical care while potentially addressing the underlying disorder. In consideration of other options, more stringent restrictions or no restrictions at all may not adequately address the risks associated with this condition, whereas increasing potassium would be contraindicated.