Pediatric emergency medicine (PEM) is a medical subspecialty of both pediatrics and emergency medicine. It involves the care of undifferentiated, unscheduled children with acute illnesses or injuries that require immediate medical attention. While not usually providing long-term or continuing care, pediatric emergency doctors undertake the necessary investigations and interventions to diagnose patients in the acute phase, to liaise with physicians from other specialities, and to resuscitate and stabilize children who are seriously ill or injured. Pediatric emergency physicians generally practice in hospital emergency departments.