Cause of Death Revealed for 8-Year-Old Girl Who Died After Mid-Flight Medical Emergency

Sydney Weston became unresponsive while on a SkyWest Airlines flight on June 13

An Illinois county coroner has determined Sydney Weston’s cause of death.

Weston, the 8-year-old Missouri girl who experienced a medical emergency while aboard a regional jet en route to a family vacation in Chicago in June, died of “complications of chronic primary adrenalitis in the setting of multiple infections, including Strep and Enterovirus,” Peoria County coroner Jamie Harwood said in a press release.

Harwood said he reached the assessment “after consideration of the circumstances surrounding her death in correlation with a review of the medical records and after a complete autopsy with extensive ancillary studies.”

The Carl Junction girl also had duodenitis (inflammation of the small intestine) and thyroiditis (thyroid gland inflammation), according to the release.

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“The associated diagnoses of chronic adrenalitis, duodenitis and thyroiditis are suggestive of an underlying autoimmune disorder,” Harwood said.

On Thursday, June 13, Weston was traveling on a SkyWest Airlines flight from Joplin to Chicago when she became unresponsive while on board, the coroner's office said in a release on Facebook.

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Officials said Weston’s family notified flight personnel about the medical emergency, and the plane was diverted to Peoria.

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Upon landing, Weston was not breathing nor had a pulse, the coroner's office added. The girl was transported to a local hospital, where she was pronounced dead at 8:05 a.m. local time.

After her death, a SkyWest spokesperson told USA Today that they appreciated "the efforts of our crewmembers who responded quickly to assist and the medical personnel who met the aircraft.”

PEOPLE has reached out to the airline for comment.

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In her obituary, the young girl was remembered for her “infectious joy and vigorous love for life.”

Weston died eight days before her ninth birthday and had “big plans” for a skating party. She also looked forward to her family’s summer vacation, loved the Missouri amusement park Silver Dollar City and the Taylor Swift song "Karma."

“She will forever be remembered for the happiness she brought to every single person she encountered,” her family wrote before her funeral. “Our hearts are heavy. She was our baby girl and we celebrate her beautiful life.”

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