In acute primary adrenal insufficiency, which electrolyte pattern is typical?

• A. Hypernatremia and hypokalemia
• B. Hyponatremia and normokalemia
• C. Hyponatremia and hyperkalemia
• D. Hyperchloremia and hypochloremia

Answer: (C)

Aldosterone deficiency in primary adrenal insufficiency disrupts how the kidney handles sodium and potassium. Without enough aldosterone, the distal nephron reabsorbs less sodium and excretes less potassium, so sodium is lost into the urine (hyponatremia) and potassium builds up (hyperkalemia). Cortisol deficiency can further raise ADH, promoting water retention and diluting serum sodium, reinforcing hyponatremia. This combination—low sodium with high potassium—is the classic electrolyte pattern in an acute adrenal crisis. Hypernatremia is unlikely because there’s ongoing sodium loss, and potassium wouldn’t be expected to stay normal. While metabolic changes like acidosis can occur and influence chloride levels, the hallmark is hyponatremia with hyperkalemia.