Kyle Busch's cause of death confirmed as sepsis after NASCAR driver died aged 41

Two-time NASCAR Cup Series champion Kyle Busch's cause of death has been confirmed as sepsis, after his family released a devastating statement.

The family shared the driving legend's cause of death in a statement which read: "The medical evaluation provided to the Busch Family concluded that severe pneumonia progressed into sepsis, resulting in rapid and overwhelming associated complications."

They added: "The family asks for continued understanding and privacy during this difficult time."

In a joint post with NASCAR on Thursday (May 21), his family wrote that they are 'heartbroken' at the loss of 'a giant of the sport'.

They described the 41-year-old as 'a rare talent, one who comes along once in a generation', and someone who 'sparked a deep emotional connection with race fans of every age'.

Busch is survived by his parents, wife Samantha Busch, and their two young children, Brexton and Lennix.

"He was fierce, he was passionate, he was immensely skilled, and he cared deeply about the sport and fans," the statement continued.

A 911 call from General Motors training facility in North Carolina, obtained by NBC News, suggests that the 41-year-old had been 'coughing up blood' on Wednesday (May 20), the day before his death was announced.

"I’ve got an individual that’s, uh, 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 man could be heard saying around 5:30 p.m.

"He’s awake," the man said. "He’s on the bathroom floor right now."

The dad-of-two had been due to compete in the Coca-Cola 600 at Charlotte Motor Speedway in the US on Sunday (May 24), an event that NASCAR officials told the Associated Press will go ahead as planned.

It was reported that Busch called for medical attention during a race at Watkins Glenn on May 10 for a 'substantial cough', and had won a race just less than week before his sudden death.

Speaking after his final victory, words that now hold a very different meaning, Busch said: "You never know when the last one is.

"But, you know, here with the truck stuff right now, it’s awesome just to be a part of Spire Motorsports."

What are the symptoms of sepsis?

Sepsis is a life-threatening medical emergency that occurs when the body has an extreme reaction to an infection, as per Cleveland Clinic.

Symptoms can vary, but common warning signs include a high fever, chills, rapid breathing, confusion, dizziness, extreme pain or discomfort, and a fast heart rate.

Some people may also experience clammy or discoloured skin, slurred speech, or difficulty staying awake.