Postoperative polyuria after pituitary surgery due to ADH deficiency is best described as which hormone deficiency?

Postoperative polyuria after pituitary surgery due to ADH deficiency is best described as which hormone deficiency?

• A. Antidiuretic hormone
• B. Aldosterone
• C. Insulin
• D. Calcitonin

Answer: (A)

Postoperative polyuria after pituitary surgery is best understood as a deficiency of antidiuretic hormone. ADH (vasopressin) is produced in the hypothalamus and stored/released from the posterior pituitary; it acts on the collecting ducts to increase water reabsorption by inserting aquaporin-2 channels. When ADH is lacking, the kidneys cannot concentrate urine, leading to large volumes of dilute urine, excessive thirst, and the risk of hypernatremia—this is central diabetes insipidus. Other choices don’t fit this scenario: aldosterone deficiency would mainly disrupt sodium and potassium balance; insulin deficiency causes hyperglycemia with glycosuria and osmotic diuresis; calcitonin is involved in calcium homeostasis and not acute postoperative polyuria.

Postoperative polyuria after pituitary surgery is best understood as a deficiency of antidiuretic hormone. ADH (vasopressin) is produced in the hypothalamus and stored/released from the posterior pituitary; it acts on the collecting ducts to increase water reabsorption by inserting aquaporin-2 channels. When ADH is lacking, the kidneys cannot concentrate urine, leading to large volumes of dilute urine, excessive thirst, and the risk of hypernatremia—this is central diabetes insipidus. Other choices don’t fit this scenario: aldosterone deficiency would mainly disrupt sodium and potassium balance; insulin deficiency causes hyperglycemia with glycosuria and osmotic diuresis; calcitonin is involved in calcium homeostasis and not acute postoperative polyuria.