Overview
Introduction
A sudden drop in serum sodium after a brain bleed, head trauma, or neurosurgery can signal two very different pathophysiologic pathways.
A sudden drop in serum sodium after a brain bleed, head trauma, or neurosurgery can signal two very different pathophysiologic pathways. One, the syndrome of inappropriate antidiuretic hormone secretion (SIADH), traps water while total body sodium stays normal. The other, cerebral salt wasting (CSW), is a true loss of sodium and water through the kidneys, producing hypovolaemia. Distinguishing the two is a bedside priority because the treatments are opposite: CSW needs aggressive salt and volume replacement, SIADH demands fluid restriction. What follows covers the why, how, and what‑now for the nurse caring for a patient with CSW in the Canadian acute‑care setting.