If a patient has hypercortisolism and edema, which electrolyte change is commonly observed?

If a patient has hypercortisolism and edema, which electrolyte change is commonly observed?

• A. Serum sodium 155
• B. Serum potassium 2.9
• C. Serum calcium 11.0
• D. Serum bicarbonate 18

Answer: (A)

In hypercortisolism, the excess cortisol can act like a mineralocorticoid in the kidney, increasing sodium reabsorption in the distal tubules and collecting ducts. This sodium retention pulls water along with it, expanding the extracellular fluid and producing edema. The same mechanism often leads to elevated serum sodium (hypernatremia), which is the most characteristic electrolyte change in this setting. Potassium can be wasted and may drop, but the edema and hypernatremia reflect the predominant effect. A bicarbonate of 18 would indicate metabolic acidosis, which is not typical here ( mineralocorticoid excess more commonly associates with metabolic alkalosis). Calcium elevation is not a defining feature of hypercortisolism. So the high sodium level best fits the scenario.

In hypercortisolism, the excess cortisol can act like a mineralocorticoid in the kidney, increasing sodium reabsorption in the distal tubules and collecting ducts. This sodium retention pulls water along with it, expanding the extracellular fluid and producing edema. The same mechanism often leads to elevated serum sodium (hypernatremia), which is the most characteristic electrolyte change in this setting. Potassium can be wasted and may drop, but the edema and hypernatremia reflect the predominant effect. A bicarbonate of 18 would indicate metabolic acidosis, which is not typical here ( mineralocorticoid excess more commonly associates with metabolic alkalosis). Calcium elevation is not a defining feature of hypercortisolism. So the high sodium level best fits the scenario.