Prehospital cardiac arrest in diabetic ketoacidemia: why brain swelling may lead to death before treatment.

An adolescent is reported with type 1 diabetes mellitus and diabetic ketoacidemia (DKA) who died from brain herniation prior to treatment with intravenous fluids and intravenous insulin. The pathophysiology of raised intracranial pressure (ICP) and water intoxication is discussed. As DKA evolves, water and electrolyte losses are replaced by very hypotonic fluids taken orally, leading to a physiologic excess of free water that would cause brain swelling prior to treatment. Central nervous system acidosis may interfere with normal compensatory mechanisms that help prevent small increases in ICP. The pathophysiology of pre-treatment brain swelling has important implications for rehydration with intravenous fluids and treatment with insulin. Prevention of DKA is paramount as well as complete postmortem evaluation of patients who die from this disease.