Officials disclose cause of death for 8-year-old girl who died mid-flight

A Missouri coroner recently revealed how an 8-year-old girl died during a SkyWest flight earlier this summer.

Carl Junction, Missouri, resident Sydney Weston suffered a medical emergency on SkyWest Flight 5121 from Joplin, Missouri to Chicago. The flight, which operated as United Express, departed from Joplin on June 13.

In a statement released at the time, the Peoria County Coroner's Office said that Weston's family "immediately notified the flight personnel of her condition, and they began rapidly rendering aid."

"Upon landing in Peoria, she was not breathing and had no pulse," the office added.

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In a press release published on Friday, Peoria County Coroner Jamie Harwood announced that Weston's cause of death was due to complications of "chronic primary adrenalitis." Adrenalitis refers to the inflammation of adrenal glands, which are located on top of the kidneys.

"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 cause of death has been determined to be complications of chronic primary adrenalitis in the setting of multiple infections, including strep and enterovirus," the coroner's statement read.

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"Infections can be associated with precipitating an acute adrenal insufficiency crisis in the presence of chronic adrenal disease," Harwood added. "Little Weston also had duodenitis (inflammation in the first part of your small intestine) and thyroiditis (a general term for thyroid gland inflammation)."

Harwood said that the findings of the autopsy suggest that the young girl suffered from an autoimmune disorder.

"The associated diagnoses of chronic adrenalitis, duodenitis, and thyroiditis are suggestive of an underlying autoimmune disorder," the statement added. "An autoimmune disorder is when your immune system mistakenly attacks the healthy cells of your organs and tissues, disrupting their normal operating function."

In June, SkyWest told FOX Business that the flight was diverted to Peoria, Illinois, in order to assist the young girl.

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"We appreciate the efforts of our crewmembers who responded quickly to assist and the medical personnel who met the aircraft," the airline added.

Fox News Digital's Greg Norman contributed to this report.