It’s usually caused by a viral infection but can also result from medication or inflammatory conditions. In severe cases, it can lead to blood clots, stroke, or heart failure. Treatment may include medication, procedures, or surgery.

Just the day before, Bryson had struck out the final batter to secure his team’s championship victory, his 9-year-old teammate Elias Vilfort told WHP-TV.

Bryson was born with a heart condition—coarctation of the aorta and a deformed bicuspid aortic valve—but family members said doctors do not believe those conditions caused his death.

Loved ones say their hearts are “shattered” by the loss. The GoFundMe campaign has raised over $45,000 to support Bryson’s grieving family.

“It’s something no one could have ever imagined happening to such a vibrant, active guy,” Brantner wrote beside “the last picture his parents