Update: NASCAR star Kyle Busch death caused by pneumonia, sepsis

Two-time NASCAR Cup Series champ Kyle Busch died on Thursday from pneumonia that progressed into sepsis, after dealing, publicly, for the past couple of weeks with what he thought was a sinus infection.

His family confirmed the diagnosis in a statement released on Saturday.

“The medical evaluation provided to the Busch Family concluded that severe pneumonia progressed into sepsis, resulting in rapid and overwhelming associated complications,” the statement read.

Busch had asked his crew during the Cup Series race at Watkins Glen on May 10 to arrange for a meeting with a medical professional because of a headache; the TV broadcast team noted the issue with a sinus infection, apparently based on conversations with Busch from earlier in the week.

According to Cleveland Clinic, sepsis develops as the body’s “overwhelming response” to an infection that occurs an infection, such as pneumonia, “triggers a serious chain reaction throughout your body.”

The chain reaction leads to the immune system damaging healthy tissues and organs by mistake; without urgent treatment, it can lead to tissue damage, multiple organ failure and death.

Septic shock can cause death in as little as 12 hours.

That seems to be exactly what happened with Busch, who won the May 15 NASCAR Truck Series race at Dover, leading 147 of the 200 laps en route to his second win on the series in 2026, then finished 17th in the Cup Series race at Dover on May 17.

He attended a sponsor event in Durham, N.C., two days later, on Tuesday, and on Wednesday, pictures posted to social media showed him at a meet-and-greet with fans at the Richard Childress Racing team shop in Concord, N.C.

Later on Wednesday, Busch was working at the team shop on a racing simulator when he fell ill, leading to a call to 911 to report that Busch was experiencing shortness of breath, feeling he was very hot, was thinking he was going to pass out and was “coughing up some blood.”

On Thursday morning, RCR put out a news release to announce that Busch would have to miss the Coca-Cola 600 in Charlotte on Sunday due to “severe illness,” which led to the initial reporting in the media about the possible link to his health and the radio traffic from Watkins Glen about the headache.

Later in the day on Thursday, the news had turned tragic.