What electrolyte disturbances are common in Addison's disease?

• A. Hyponatremia and hyperkalemia
• B. Hypernatremia and hypokalemia
• C. Hypokalemia and hypochloremia
• D. Hypercalcemia and hypophosphatemia

Answer: (A)

Addison's disease causes a deficiency of aldosterone, and that shift has a clear effect on kidney handling of sodium and potassium. Aldosterone normally promotes sodium reabsorption and potassium excretion in the distal tubules. When it’s lacking, sodium is wasted in the urine, leading to low blood sodium (hyponatremia) and volume depletion, while potassium isn’t excreted as efficiently, causing high blood potassium (hyperkalemia). This combination—hyponatremia with hyperkalemia—is the classic electrolyte pattern in primary adrenal insufficiency. The other pairings don’t fit because they imply sodium or potassium changes opposite to what aldosterone deficiency causes.