Pathophysiology
Clinical meaning
SIADH: Ectopic or inappropriate AVP release leads to insertion of Aquaporin-2 channels in the collecting duct, causing pure water retention (Euvolemic Hyponatremia). DI: Lack of AVP (Central) or renal resistance (Nephrogenic) prevents water reabsorption, leading to massive dilute urine output. Connect Sodium Disorders: Osmoregulation to bedside cues you will reassess first: vitals trends, work of breathing, perfusion, mentation, and pain or ischemic equivalents when relevant. Boards reward recognizing when subtle instability outweighs reassurance, then selecting nursing actions that protect airway, circulation, and neurologic status before routine tasks.