ITE Nephrology Practice Test

The key idea is to correct both the volume deficit and the high sodium in a controlled sequence. Start by restoring intravascular volume with isotonic saline (0.9% NaCl). This expands the circulating blood volume, improves tissue perfusion, and supports kidney function without rapidly changing the serum sodium. After the patient is euvolemic, switch to hypotonic fluids or free water to gradually lower the serum sodium and correct the water deficit.

Hypertonic saline would worsen the hypernatremia, so it’s not appropriate as initial therapy. Water restriction would worsen the volume depletion. Rapid IV dextrose provides free water but does not reliably correct volume status and can lead to unpredictable changes in sodium. Aim for a careful correction rate to avoid osmotic shifts, typically slowing the Na decline to a safe range over 24 hours.