A 4-year-old boy went on a couple of roller-coaster rides during a family vacation over the summer and left the amusement park with a torn carotid artery.

Doctors report in the journal Pediatric Neurology that the jerkiness and gravitational forces of the ride appear to be the culprit, and that the tear resulted in a blood clot that traveled to the boy's brain, causing a stroke.

The boy began vomiting the next day, then developed a droop on the left side of his face on the flight home and soon couldn't walk, reports Eureka Alerts.

The doctors say that while several cases of stroke resulting from roller-coaster rides have been documented in adults, this is the youngest known caseā€”in fact, they've identified only two other pediatric cases in medical literature, a 13-year-old and an 11-year-old.

Researchers note that children under 10 possess weak neck muscles and relatively large heads, a "hypermobility" that makes them more vulnerable to such tears, "albeit rarely." Six months after this event, which doctors treated with low-dose aspirin, the boy still has weakness on his left side but is able to move his arm, grip objects, talk normally, perform above average in school, and even take karate lessons, which is part of his therapy, reports CBS News.

(Another 4-year-old boy is fighting a mystery illness that has left him ravaged by strokes.)

This article originally appeared on Newser: Roller Coaster Triggers Stroke in 4-Year-Old

More From Newser