NASCAR champion Kyle Busch died after severe pneumonia progressed into sepsis, resulting in rapid and overwhelming complications, according to a statement from his family.
Busch died on Thursday, a day after he became unresponsive in a racing simulator. The two-time champion was 41 years old.
His family received the medical information Saturday, according to Dakota Hunter, vice president of Kyle Busch Companies.
Sepsis is a life-threatening medical emergency where the body's extreme response to an infection causes the immune system to damage its own tissues and organs, according to the CDC. This overactive response can lead to widespread inflammation, microscopic blood clots, and leaky blood vessels.
Busch had been preparing to race in Sunday’s Coca-Cola 600 at Charlotte Motor Speedway when he collapsed during a test session in a Chevrolet racing simulator in Concord on Wednesday.
He was rushed to a hospital in Charlotte. An emergency call placed that afternoon described an individual with "shortness of breath, very hot, thinks he’s going to pass out, and is producing a little bit of blood, coughing up some blood."
The unidentified caller, whose audio was provided by the Cabarrus County Sheriff’s Office, stated Busch was lying on the bathroom floor but "he is awake," and requested that emergency responders arrive without sirens.
Earlier in May, Busch had reportedly suffered from a sinus cold while racing at Watkins Glen, radioing his team to request a "shot" from a doctor after the race.
He bounced back to win the Trucks Series race at Dover last weekend, and then he finished 17th in the All-Star race on Sunday.
NASCAR driver Brad Keselowski said he knew Busch wasn’t feeling well recently.
“Yes, but I won’t go into any specifics," Keselowski said. “But then when he ran the Truck race last week, those (thoughts) were honestly kind of erased in my mind.”
Keselowski said running multiple races on the same weekend can be difficult on a driver's health — but most don't want to miss a race for fear of being replaced.
“There’s no shortage of drivers that would love to take my seat or anybody else’s seat if we weren’t feeling well, and I think every driver feels that pressure,” Keselowski said. “All athletes do. It’s not unique to NASCAR in that sense. We’re all thinking to ourselves, ‘I don’t wanna be replaced.’ ... So you try to power through it the best you can."
Busch's illustrious career saw him secure 234 victories across NASCAR’s top three series, a record unmatched by any other driver in history. In tribute, all 39 drivers competing in Sunday’s race will display a black No. 8 decal on their cars.
Richard Childress Racing announced it will temporarily retire Busch’s car until Busch's 11-year-old son, Brexton, is old enough to take the wheel himself.
"Kyle Busch was instrumental in the design of RCR’s stylized No. 8 and it has become synonymous with Kyle and an important symbol for his fans and the NASCAR industry,” the team wrote.
“No one can carry it forward to the level that he did. The No. 8 is reserved and ready for Brexton Busch when he is ready to go NASCAR racing."
