British actress Natasha Richardson died from bleeding on the brain caused when she fell and hit her head while skiing, the New York City Medical Examiner's Office said today.
Medical examiners ruled Richardson's death accidental, and as the direct result of a condition known as an epidural hematoma in which damage to a blood vessel in the lining of the brain causes blood to collect between the brain and the skull. The bleeding would have put increasing pressure on Richardson's brain after her Monday accident, eventually leading to her symptoms and death.
On Wednesday night, Alan Nierob, a spokesman for Richardson's husband, actor Liam Neeson, issued a statement revealing that Richardson had died from her injury.
"Liam Neeson, his sons, and the entire family are shocked and devastated by the tragic death of their beloved Natasha," the statement read. "They are profoundly grateful for the support, love and prayers of everyone, and ask for privacy during this very difficult time."
Details of Richardson's condition had remained scarce -- though initial reports suggested the Tony award-winning actress appeared fine up to an hour after a seemingly minor tumble on a beginner's ski slope at Mont Tremblant ski resort in Quebec, Canada, before her condition rapidly worsened and her family sought medical care.
Doctors remain split on the question of whether immediate medical attention may have been able to save Richardson.
Dr. Alan Faden, professor of neuroscience at Georgetown University and a traumatic brain injury expert, said that while he was not familiar firsthand with Richardson's case, he believes that in many cases, prompt medical attention can save these patients.
"If it is a bleed on the brain ... then it is absolutely a neurosurgical emergency and needs rapid diagnosis and treatment," Faden said. "You can go in and evacuate the blood. If you can stop the bleeding, these people can be completely salvageable, with no long-term effects."
However, Dr. Eugene Flamm, chairman of neurosurgery at Montefiore Medical Center in New York, disagreed that early treatment would necessarily have changed the outcome.
"We all bump our heads, and people come into the emergency department all the time after hitting their heads," he said. "People fall during skiing; it is not an uncommon thing."
If there is no loss of consciousness, Flamm said, these common bumps and knocks are often deemed nonserious by doctors upon examination. He added that even when doctors decide to perform a scan on the head, many bleeds in the brain are hard to see or remain undetectable in their early stages.
"The scan may have been normal, and then how would it have changed anything?" Flamm asked.
Richardson was transferred from a Montreal hospital Tuesday and was being cared for in Lenox Hill Hospital on Manhattan's Upper East Side before her death was announced.
Anatomy of a Brain Bleed
The details that emerged about Richardson's accident suggested early on that a head injury led to a slow bleed that put increasing pressure on her brain. Flamm said that it appeared Richardson went through a period called a "lucid interval," during which she seemed to be unhurt while her health gradually worsened.
Flamm's guess seemed to be supported by a statement released by Mont Tremblant ski resort regarding her accident:
"Natasha Richardson fell in a beginners trail while taking a ski lesson at Station Mont Tremblant," the statement said. "She was accompanied by an experienced ski instructor who immediately called the ski patrol. She did not show any visible sign of injury, but the ski patrol followed strict procedures and brought her back to the bottom of the slope and insisted she should see a doctor.
"As an additional precautionary measure, the ski instructor as well as the ski patrol accompanied Mrs. Richardson to her hotel," the statement continued. "They again recommended she should be seen by a doctor. The ski instructor stayed with her at her hotel. Approximately an hour after the incident Mrs. Richardson was not feeling good. An ambulance was called and Mrs. Richardson was brought to the Centre Hospitalier Laurentien in Ste-Agathe and was later transferred to Hôpital du Sacre-Coeur."
A spokesperson for the resort noted Richardson was not wearing a helmet while skiing and didn't collide with anything when she fell.
But even absent an external injury, Flamm said, a tear in a blood vessel near the brain would be a prime candidate for the worsening headaches and, eventually, the loss of consciousness that Richardson experienced.
When bleeding occurs in the tissues surrounding the brain, the blood may become trapped between this covering and the brain itself. As the amount of blood in this space increases, so, too, does the pressure on the brain.
"Though the patient does not necessarily appear impaired at the beginning, as pressure builds up in the brain you can have a coma," Flamm said.
Faden agreed that, although unusual, these types of traumatic brain injury have been known to occur.
"With some cases of TBI, there is an immediate, significant period of unconsciousness, then a slow recovery," he said. "But this particular presentation does happen, even in milder forms of head injuries, though particularly in the elderly.
"You can imagine what happens when you compress the brain."
Staying Safe From Brain Injury
Faden said that Richardson's death should serve as a reminder to the public to take precautions against head injuries whenever possible.
"People don't realize how common this is," he said. "Every year, there are at least 2 million head injuries in the United States, and about 500,000 of these are serious enough for the emergency room."
He said that he believes the use of a helmet may have helped lessen the likelihood of a traumatic brain injury. Still, Flamm said there is little evidence in this case that a helmet would have warded off Richardson's injury.
"You can't be 100 percent safe in anything," he said.
To learn more about how to recognize serious head injuries, visit the Web site of the Brain Injury Association of America.
ABC News' Sharyn Alfonsi, Emily Friedman, Lindsay Goldwert and Luchina Fisher contributed to this report.