What endocrine imbalance in a brain-dead donor is characterized by excessive urine output and requires treatment with antidiuretic hormone?

The endocrine imbalance characterized by excessive urine output in a brain-dead donor and requiring treatment with antidiuretic hormone is Central Diabetes Insipidus. This condition results from an insufficient production or release of antidiuretic hormone (ADH), also known as vasopressin. ADH is a hormone synthesized in the hypothalamus, a region of the brain, and then released into the bloodstream by the posterior pituitary gland, which is located at the base of the brain. The primary function of ADH is to regulate water balance in the body by signaling the kidneys to reabsorb water from the filtered blood back into the body, thereby concentrating urine and preventing dehydration. In a brain-dead donor, the severe damage to the brain, particularly the hypothalamus or the posterior pituitary gland caused by trauma or lack of blood flow, disrupts the normal synthesis or release of ADH. Without adequate ADH, the kidneys are unable to reabsorb sufficient water. This leads to the characteristic symptom of excessive urine output, known as polyuria, where large volumes of very dilute urine are continuously produced. To manage this imbalance and prevent severe dehydration and electrolyte abnormalities, treatment with synthetic antidiuretic hormone is necessary. This synthetic hormone replaces the missing natural ADH, allowing the kidneys to resume proper water reabsorption and reduce urine production.