Cardiac arrest in an infant with congenital adrenal hyperplasia.

We report a 3-month-old boy who suffered an out-of-hospital cardiac arrest. During resuscitation, the medical team was informed that he was receiving hydrocortisone treatment. The possibility of adrenal insufficiency with hyperkalemic cardiac arrest prompted the administration of calcium, which resulted in the return of spontaneous circulation. The infant's diagnosis of congenital adrenal hyperplasia was not spontaneously mentioned by the parents. This case illustrates the importance of obtaining adequate parental information and considering hyperkalemia as a possible cause of cardiac arrest.