Hyponatremia and Hypernatremia: A Practical Guide to Disorders of Water Balance
Author(s): Mohammad Tinawi
Hyponatremia and hypernatremia are disorders of water balance and are very common especially in hospitalized patients. Hyponatremia is defined as serum sodium < 135 mEq/l (mmol/l). Hypernatremia is defined as serum sodium > 145 mEq/l (mmol/l). Most of hyponatremia and hypernatremia cases are mild but they are clinically significant. Even mild hyponatremia is associated with many non-specific symptoms and may quickly evolve into severe hyponatremia. Quick and uncontrolled correction of chronic hyponatremia may lead to severe clinical consequences. Hypernatremia is associated with high mortality due to associated co-morbid conditions even after successful correction. The following review will cover the most salient aspects of hyponatremia and hypernatremia and provide the clinician with a practical guide to the diagnosis and treatment. Complex tables, flow charts and algorithms will be avoided. The review will conclude with clinical cases that apply the discussed principles in diagnosis and treatment.