Hypernatremia

#med #disease #y2023

Presentation :

- Most commonly, hypernatremia results from loss of hypotonic fluids (GI, kidney, skin) with inadequate water replacement.

Severe hypernatremia indicates a defective thirst mechanism, inadequate access to water (older patients in nursing homes), a kidney concentrating defect (DI, most commonly caused by lithium), and/or impaired pituitary secretion of ADH (e.g., sarcoidosis).

Treatment is directed at free water replacement and correction of the underlying problem leading to hypotonic fluid loss.
- Free water deficit is calculated as ((Na − 140)/140) × TBW, where TBW = 0.5 × weight (kg) in women or 0.6 × weight (kg) in men.
- Correct the water deficit over 48 to 72 hours.
- In volume depletion, fluid resuscitation with normal saline should precede correction of the water deficit with hypotonic fluids.
Neurogenic (central) DI is treated with intranasal or oral desmopressin.