A nurse is providing care for a client who is postoperative for removal of a pituitary tumor. Which of the following priority developments should the nurse anticipate?

Surgical excision of pituitary lesions via a transsphenoidal approach frequently disrupts the hypothalamo-neurohypophyseal tract or the posterior pituitary gland. This mechanical trauma causes a sudden cessation of antidiuretic hormone synthesis, storage, and release into systemic circulation. The acute hormonal deficiency prevents renal water conservation, precipitating severe polyuria and profound volume depletion. A. Diabetic ketoacidosis (DKA): This acute metabolic crisis stems from absolute insulin deficiency and uninhibited ketogenesis, typically seen in type 1 diabetes mellitus. Pituitary surgery does not damage pancreatic beta cells or alter insulin production. It is not a consequence of neurosurgical interventions. B. Hyperosmolar hyperglycemic syndrome (HHS): This condition arises from severe relative insulin deficiency and profound dehydration in type 2 diabetes mellitus. While transient stress hyperglycemia can occur postoperatively, primary pancreatic exhaustion is not a direct anatomical risk of hypophysectomy. It is etiologically distinct. C. Diabetes insipidus (DI): Surgical manipulation or edema near the posterior pituitary stalls vasopressin release, causing rapid excretion of vast amounts of dilute urine. Monitoring urine output and specific gravity is vital to catch this expected neurosurgical complication. It represents the primary direct hormonal risk. D. Pheochromocytoma: This catecholamine-secreting neuroendocrine tumor originates within the adrenal medulla, driving severe paroxysmal hypertension. It is anatomically and pathophysiologically unrelated to the pituitary gland or the cranial vault. Surgical hypophysectomy does not trigger adrenal medullary neoplasia.