Kyle Busch dies at 41: NASCAR legend's cause of death

Two-time NASCAR Cup Series champion Kyle Busch passed away unexpectedly on May 21. He was 41 years old.

Busch's family made a joint statement with NASCAR and Richard Childress Racing the day of his passing: "Our entire NASCAR family is heartbroken by the loss of Kyle Busch. A future Hall of Famer, Kyle was a rare talent, one who comes along once in a generation. He was fierce, he was passionate, he was immensely skilled and he cared deeply about the sport and fans."

Busch's death was a shock to the racing community.

Here's what to know about Kyle Busch's passing:

Kyle Busch cause of death

It has been confirmed that Busch died due to pneumonia, leading to sepsis.

Sepsis occurs when the body inappropriately responds to an infection, causing the organs to operate poorly. Busch's body went into sepsis in response to his pneumonia.

Had Kyle Busch experienced any medical issues prior?

On May 16, Busch did an interview in which he spoke on his symptoms. He said, "I’m still not great. But the cough was pretty substantial last week."

On May 10, Busch made a radio call requesting assistance during a race.

In the clip, Busch expresses that he's been dealing with a "sinus cold."

Finally, on May 20, Busch experienced serious issues. Not only did he become unresponsive while testing in a Chevrolet racing simulator, but a 911 call made later that day revealed that Busch had coughed up blood and was lying on the bathroom floor before calling for help.