Football coaches: watch head injuries.

Young football players who receive blows to the head while on the gridiron can develop potentially deadly brain concussions even if they do not lose consciousness immediately after the injury, cautions a group of Colorado physicians.

In the Nov. 27 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION, neurologist James Kelly and his colleagues at the University of Colorado School of Medicine in Denver report the case of a 17-year-old high school football player who died from severe brain swelling hours after being struck on the helmet during a routine tackle. The physicians later determined that the boy's fatal injury resulted from a stronger blow to the head that he had received during the previous week's game. That concussion had gone undiagnosed because the player never lost consciousness.

Kelly's group warns that lethal brain swelling can develop rapidly in adolescents who experience head trauma, even though they do not always black out after the injury. "This phenomenon is most common in the pediatric age group," the researchers assert.

Kelly says the Colorado Medical Society has responded with new guidelines for determining the severity of head injuries among young football players. The society now advocates removing from the game any player who has received a severe blow to the head, and watching him for at least 20 minutes. If the player remains confused during that time, the society recommends sending him for medical treatment. Players who exhibit no signs of confusion or amnesia during those 20 minutes may return to the game. The society continues to recommend an immediate trip to the hospital for any player who loses consciousness after a play.