Hypernatremia occurs when water loss exceeds sodium, leading to increased serum sodium and hyperosmolality, primarily affecting the brain. It often results renal losses, water evaporation, hypodipsia or restricted water intake. Clinical signs range from subtle neurologic changes to severe neurologic impairment. Management requires slow and careful correction of water deficits using hypotonic fluids, with frequent monitoring of serum sodium and osmolality to prevent complications like brain edema. Accurate diagnosis involves assessing water and sodium balance, understanding underlying causes, and implementing a tailored treatment plan, making effective management both challenging and critical for patient safety.