Hypernatremia (serum sodium concentration >145 mEq/L) is a common electrolyte disorder with increased morbidity and mortality especially in the elderly and critically ill patients. The review presents the main pathogenetic mechanisms of hypernatremia, provides specific directions for the evaluation of patients with increased sodium levels and describes a detailed algorithm for the proper correction of hypernatremia. Furthermore, two representative cases of hypovolemic and hypervolemic hypernatremia are presented along with practical clues for their proper evaluation and treatment. Accurate diagnosis and appropriate treatment is crucial since undercorrection or overcorrection of hypernatremia are both associated with poor patients' prognosis.
Keywords: Sodium; correction; hypernatremia; hypovolemia; water deficit.