Peer-review started: June 16, 2016
First decision: July 27, 2016
Revised: October 17, 2016
Accepted: November 1, 2016
Article in press: November 2, 2016
Published online: January 6, 2017
Processing time: 198 Days and 4.2 Hours
Hypertonicity causes severe clinical manifestations and is associated with mortality and severe short-term and long-term neurological sequelae. The main clinical syndromes of hypertonicity are hypernatremia and hyperglycemia. Hypernatremia results from relative excess of body sodium over body water. Loss of water in excess of intake, gain of sodium salts in excess of losses or a combination of the two are the main mechanisms of hypernatremia. Hypernatremia can be hypervolemic, euvolemic or hypovolemic. The management of hypernatremia addresses both a quantitative replacement of water and, if present, sodium deficit, and correction of the underlying pathophysiologic process that led to hypernatremia. Hypertonicity in hyperglycemia has two components, solute gain secondary to glucose accumulation in the extracellular compartment and water loss through hyperglycemic osmotic diuresis in excess of the losses of sodium and potassium. Differentiating between these two components of hypertonicity has major therapeutic implications because the first component will be reversed simply by normalization of serum glucose concentration while the second component will require hypotonic fluid replacement. An estimate of the magnitude of the relative water deficit secondary to osmotic diuresis is obtained by the corrected sodium concentration, which represents a calculated value of the serum sodium concentration that would result from reduction of the serum glucose concentration to a normal level.
Core tip: States of hypertonicity cause transfer of fluid from inside the body cells into the fluid compartment surrounding the cells. The shrinking of the brain cells in hypertonicity causes severe manifestations and even death. The management of hypertonicity requires administration of intravenous solutions. The volume and the composition of the administered solutions are calculated by various equations. Close monitoring of the condition of the patient and frequent measurements of appropriate blood chemistries during treatment are critical steps for a favorable outcome. The two major states of hypertonicity are hypernatremia, an elevation of the concentration of sodium in the blood, and hyperglycemia, an elevation of the concentration of glucose in the blood. The management of severe hypertonicity in hypernatremia and hyperglycemia encounters different obstacles and requires different equations for the quantitative replacement of body fluid deficits.