Importance of timing of risk factors for cerebral oedema during therapy for diabetic ketoacidosis.

Cerebral oedema is the most common cause of mortality and morbidity during the first day of conventional treatment for diabetic ketoacidosis in paediatric patients. It is possible that therapy contributes to its development. Risk factors that predispose to cerebral oedema should lead to an expansion of the intracellular and/or the extracellular fluid compartment(s) of the brain because water normally accounts for close to 80% of brain weight. With respect to the intracellular fluid compartment, the driving force to cause cell swelling is a gain of effective osmoles in brain cells and/or a significant decline in the effective osmolality of the extracellular fluid compartment. Factors leading to an expansion of the intracerebral extracellular fluid volume can be predicted from Starling forces acting at the blood-brain barrier. Some of these risk factors have an early impact, while others have their major effects later during therapy for diabetic ketoacidosis. Based on a theoretical analysis, suggestions to modify current therapy for diabetic ketoacidosis in children are provided.