(HealthDay News) -- Actress Natasha Richardson died from a blunt impact to the head after falling Monday on a beginner's ski slope in Canada, the New York City medical examiner said Thursday.
The cause of death, which was ruled an accident, was "epidural hematoma due to blunt impact to the head," said medical examiner spokeswoman Ellen Borakove, the Associated Press reported. An epidural hematoma is a blood clot that pools between the brain and the skull.
The 45-year-old, award-winning Richardson, who died Wednesday at a hospital in New York City, reportedly suffered the head injury after falling during a private lesson at a resort in Quebec.
Richardson seemed fine after she fell, but about an hour later, she complained she didn't feel well. She was hospitalized Tuesday in Montreal and later flown to Lenox Hill Hospital in Manhattan, where she died, the AP reported.
Until the autopsy results were released Thursday, many were wondering how Richardson suffered a devastating brain injury after an apparently minor fall on a beginner's ski slope.
"If you take the name Natasha Richardson out of the picture and ask how a neurosurgeon would think of a case where someone has a fall which seems fairly minor and then deteriorates a few hours later, quite a few things would go through the surgeon's differential thinking," Dr. Arno Fried, chairman of neurosurgery at Hackensack University Medical Center in New Jersey, said Wednesday. "It's not an uncommon scenario."
A worse-case scenario would be bleeding either on the surface or deep inside the brain, Fried said.
According to news reports, Richardson fell during a beginner skiing lesson at the Mont Tremblant ski resort north of Montreal. She was not wearing a helmet.
Richardson suffered no immediately apparent injuries and was able to walk and talk right after the accident. "She was awake and alive and laughing and breathing," Catherine Lacasse, the public relations supervisor for Mont Tremblant Resorts, told Bloomberg News. "She refused to see a doctor. She said she was fine, and everything was OK."
But, Richardson complained of a headache about an hour after the mishap and her condition deteriorated. She was taken by ambulance to a nearby hospital, then transferred to Hopital du Sacre-Coeur de Montreal and then flown Tuesday afternoon to New York City, where she reportedly received care at Lenox Hill Hospital before passing away on Wednesday.
Dr. Steven R. Flanagan, director of the Rusk Institute of Rehabilitation Medicine at New York University's Langone Medical Center in New York City, said Wednesday that a diagnosis of hemorrhage would account for the headache that surfaced after the accident.
"It's not terribly common, but someone can be perfectly lucid [after hitting their head], then go rapidly downhill," Flanagan said. "It's not a major surprise. It's clearly reported in the literature."
Fried said that "slow bleeding [could] take a few hours to make itself known."
"The brain is contained within the skull, and the skull is a rigid box. There is no movement [possible]," he added. "Any pressure that builds up will put pressure on the brain, which is very unforgiving and sensitive to pressure."
Dr. Eugene Flamm, chairman of neurosurgery at Montefiore Medical Center and Albert Einstein College of Medicine in New York City, agreed. He stressed that the low-velocity, low-impact type of accident that Richardson experienced would typically not result in a grave outcome.
Such outcomes are "pretty rare," Flamm said. However, he added that it was certainly a possibility that physicians hold in their mind when seeing patients.
"It's quite unusual, but we see a lot of people in the emergency room, and if they have a head injury, and the scan is OK, we send them home but with instructions to 'look out,' " Flamm said. "I don't think any neurologist would say they had never heard of this scenario."
Richardson, who had appeared in several movies and won a 1998 Tony Award for her performance in Cabaret, was married to the actor Liam Neeson. The couple's two sons were reportedly with Richardson on the ski holiday.
Richardson was born into one of the most lauded acting families in Great Britain. She was the daughter of the actress Vanessa Redgrave and film director Tony Richardson, who died in 1991, the niece of the actress Lynn Redgrave, and the granddaughter of Sir Michael Redgrave.
Learn more about traumatic brain injury at the U.S. National Institute of Neurological Disorders and Stroke.
SOURCES: Arno Fried, M.D., chairman, neurosurgery, Hackensack University Medical Center, N.J.; Steven R. Flanagan, M.D., director, Rusk Institute of Rehabilitation Medicine, New York University Medical Center, New York City; Eugene Flamm, M.D., chair of neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, New York City; Bloomberg News; Associated Press