NASCAR legend Kyle Busch died after complications following pneumonia and sepsis

The family of NASCAR legend Kyle Busch has released a statement confirming the initial evaluation of the 41-year-old's sudden death.

The NASCAR world was rocked by the tragic news this week, with Busch confirmed dead at the age of 41 on Thursday evening.

Just hours before, Busch's family had revealed that he was set to miss the Charlotte race weekend, having been hospitalized with severe illness.

Now, the Busch family has released a short statement, confirming the tragic outcome of an initial medical evaluation of the two-time Cup Series champion.

What caused Kyle Busch's death?

On Saturday, the Busch family confirmed that Kyle had suffered from pneumonia, which developed into severe sepsis.

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

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

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What is sepsis?

As per the World Health Organization (WHO), sepsis is "a life-threatening condition that happens when the body’s immune system has an extreme response to an infection, causing organ dysfunction. The body’s reaction causes damage to its own tissues and organs and it can lead to shock, multiple organ failure and sometimes death, especially if not recognized early and treated promptly."

"Sepsis can affect anyone, but people who are older, very young, pregnant or have other health problems are at higher risk.

"Common signs of sepsis include fever, fast heart rate, rapid breathing, confusion and body pain."

As per the CDC, at least 1.7 million adults develop sepsis every year in the United States. Of those, the CDC states that at least 350,000 die during their hospitalization, or are discharged to hospice.