I didn’t worry at first when my daughter Elisa, who was then 3, slipped and clunked her head in a museum in Mexico City. She cried, then stopped, and we let her go play. An hour later, she was vomiting and convulsing. Half an hour after that, she was on a gurney in an emergency room while doctors fought to keep her awake, get a line in her arm and race her to a CT-scan machine.
Elisa was lucky: there had been brain swelling but no bleeding. Natasha Richardson, who died after suffering a head bump that seemed no worse than my daughter’s, was not so fortunate. In the wake of Richardson’s death, the question on a lot of minds is what distinguishes one kind of head trauma from another–and how you can tell before it’s too late. (See the top 10 medical breakthroughs of 2008.)
Head injuries are very common–on the order of 1.5 million in the U.S. last year. Most people shake them off, but many don’t. The signs of a serious hit are a headache that gets worse, confusion, disorientation and vomiting. Slurred speech, sleepiness, a droopy eye and clumsiness are also signals, as is any kind of amnesia. And the signs may not be obvious. “They gradually progress,” says Dr. Carmelo Graffagnino, director of the neuroscience critical-care unit at Duke University. “Then suddenly it gets to the critical point that a person can’t be woken up.”
The outlook for a patient depends in part on acting fast: call 911 or drive the victim to the hospital; do not wait to reach your own doctor. The rest turns on the type of injury. Richardson died of an epidural hematoma, an accumulation of blood between the skull and dura, the tough tissue covering the brain. A subdural hematoma is blood between the dura and brain. Both injuries have a mortality rate of about 50%. Intracerebral bleeding, which occurs within the brain, is even more serious. “Patients get redlined to surgery in 15 to 30 minutes” if they have any of these injuries, says Dr. Neil Martin, chairman of the department of neurosurgery at UCLA.
Other head injuries include skull fractures, which can lead to brain bleeding, and concussions, which typically don’t–but which can lead to swelling and potentially permanent brain damage. As a general rule, doctors say that any head injury should be treated within the so-called golden hour after it occurs. In some cases, hospitalization and drugs may resolve the problem. That was what happened with my daughter, who was released after three days. Even then, we realized how close we had come. Now we know better than ever.
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Write to Jeffrey Kluger at jeffrey.kluger@time.com