After finding a picture of her son engaging in a dangerous activity known as "the choking game", Michele Mansfield kept her eyes open for additional warning signs that her son was putting his life at risk.
But ultimately, her diligence could not save her son's life.
"No one ever talked about it," said Mansfield of Phoenix, adding that at the time her son Nick Serna likely engaged in the practice -- from 2004 to 2005 -- there was little information available on the deadly game.
"Sometimes he would be in his room, and he would come out kind of dazed and confused," she said. "I would check his eyes for redness, but I never checked his pupil size. You do not always see redness unless they do it for a long, extended period of time."
On Jan. 29, 2005, Mansfield's suspicions were confirmed.
"We called him for dinner and he didn't come," she recalled. "I had been in the room 15 minutes earlier."
Nick had strangled himself using an ace bandage tied to his bed. Mansfield believes that her son had no intention of killing himself, but that a strip of Velcro had caused the bandage to remain around his neck even after he released it.
"He was blue, and it was awful."
Now, new research suggests that doctors, as well as parents, may be less aware than they should be of the warning signs that a child is engaging in this dangerous practice.
The report, titled "The Choking Game: Physician Perspectives," will be published in the January issue of the journal Pediatrics. It details the results of a survey issued to 163 pediatricians, in which nearly a third of the doctors -- 32 percent -- had never even heard of the choking game. A quarter of those who responded could not identify a single physical warning sign of a child's participation in the game, such as bruising around the neck, headaches and bloodshot eyes.
The choking game is an activity usually practiced by children and adolescents, either alone or in groups. Sometimes the "players" choke each other; other times they use improvised nooses to accomplish the goal of the activity -- depriving the brain of needed oxygen -- which leads to possible loss of consciousness and a temporary high.
Mansfield said the report confirmed to her something which she had long suspected.
"Doctors don't look for this in kids because it's not something that's talked about; it's not common knowledge," she said. "I don't think doctors are very educated about it."
Mansfield said that after this realization, she began to talk to doctors about the practice in the first year after her son died.
"Even when I want out there and started talking about it, most of them were skeptical," she said. "Some of them listened to me, but some of them blew me off."
Judith Myers-Walls, an associate professor and extension specialist of Child Development and Family Studies at Purdue University in West Lafayette, Ind., agreed that doctors should know more about the practice.
"I can tell you that I came in contact with this more than 30 years ago when I was a houseparent with 'pre-delinquent' teens," she said. "One of the teens fell and had a knot on his head. He said it was because he was standing on something and fell, but we discovered he was playing with anoxia -- it wasn't called the choking game then.