Pituitary Disorders & SIADH / Diabetes Insipidus

SIADH (syndrome of inappropriate antidiuretic hormone) causes the body to retain too much water, producing dilutional hyponatremia (low sodium from excess water, not true sodium loss), concentrated urine, and — if severe or rapid — confusion and seizures; treatment centers on fluid restriction and, in some cases, careful sodium correction, watched closely to avoid correcting too fast. Diabetes insipidus (DI) is nearly the opposite problem: insufficient antidiuretic hormone effect causes the kidneys to excrete excessive dilute urine, leading to dehydration and hypernatremia despite an intact or even increased thirst response — recognizing these as inverse conditions (water retention vs. water loss) is the fastest way to keep them straight.