American Board of Internal Medicine (ABIM) Certification Practice Exam

For Type 2 Renal Tubular Acidosis, what is the primary treatment approach?

1. Potassium replacement therapy

2. Alkali replacement with thiazide diuretic

3. Fluid restriction

4. Hemodialysis

The correct answer is: Alkali replacement with thiazide diuretic

The primary treatment approach for Type 2 Renal Tubular Acidosis (RTA) involves alkali replacement combined with the use of thiazide diuretics. In Type 2 RTA, there is a defect in bicarbonate reabsorption in the proximal tubule, which results in metabolic acidosis and the loss of bicarbonate in urine. Alkali replacement helps to correct the acidosis by providing bicarbonate that the kidneys are unable to reabsorb effectively. This is crucial for raising blood bicarbonate levels and improving acid-base balance. Thiazide diuretics can be beneficial because they promote the reabsorption of bicarbonate in the distal nephron, despite the proximal tubular dysfunction. Additionally, thiazides can help manage the hyperkalemia (elevated potassium levels) that may occur in Type 2 RTA by promoting potassium excretion, which can be helpful given that these patients may already have impaired potassium handling. Other treatment options like potassium replacement are not the focus in this context since patients usually present with a normal or increased serum potassium. Fluid restriction is not a standard treatment for Type 2 RTA and is generally only indicated in specific scenarios. Hemodialysis is not indicated for Type