In Addison's disease, which replacement is primarily required to maintain sodium balance?

In Addison's disease, which replacement is primarily required to maintain sodium balance?

• A. Glucocorticoids
• B. Mineralocorticoids
• C. Thyroid hormone
• D. Insulin

Answer: (B)

Mineralocorticoids are needed to maintain sodium balance because aldosterone, the mineralocorticoid hormone, directly increases sodium reabsorption in the distal tubules of the kidney. In Addison’s disease, aldosterone deficiency leads to sodium wasting, hyponatremia, and fluid depletion, so replacing mineralocorticoids helps restore Na retention and extracellular fluid volume. Hydrocortisone (a glucocorticoid) is also used for adrenal replacement because cortisol is missing, but its primary role is not to control sodium balance. It provides some mineralocorticoid activity, yet the key driver of sodium homeostasis in this condition is mineralocorticoid replacement. Therefore, the appropriate choice is mineralocorticoids, typically given as fludrocortisone to promote sodium reabsorption and correct sodium imbalance.

Mineralocorticoids are needed to maintain sodium balance because aldosterone, the mineralocorticoid hormone, directly increases sodium reabsorption in the distal tubules of the kidney. In Addison’s disease, aldosterone deficiency leads to sodium wasting, hyponatremia, and fluid depletion, so replacing mineralocorticoids helps restore Na retention and extracellular fluid volume. Hydrocortisone (a glucocorticoid) is also used for adrenal replacement because cortisol is missing, but its primary role is not to control sodium balance. It provides some mineralocorticoid activity, yet the key driver of sodium homeostasis in this condition is mineralocorticoid replacement. Therefore, the appropriate choice is mineralocorticoids, typically given as fludrocortisone to promote sodium reabsorption and correct sodium imbalance.