THURSDAY, April 2, 2020 (HealthDay News) -- The woman worked in the airlines industry and was in her late 50s. She arrived at Henry Ford Health System in Detroit with a cough, fever and mental confusion that had arisen over the prior three days.

A nasal swab test showed she was infected with the new coronavirus. And as doctors tried to track down the cause of her "altered mental status," brain scans revealed an encephalopathy -- swelling in some areas of the brain -- as well as small areas of brain cell death.

It's a condition that's relatively rare in adults and potentially deadly, according to a team led by Henry Ford radiologist Dr. Brent Griffith.

"While [COVID-19] patients typically present with fever, shortness of breath and cough, neurologic manifestations have been reported, although to a much lesser extent," the woman's doctors wrote in the April 2 issue of the journal Radiology.

Their diagnosis: "COVID-19-associated acute necrotizing hemorrhagic encephalopathy, a rare encephalopathy that has been associated with other viral infections."

It's believed the brain can be damaged by viral infection whenever a patient's immune system overreacts to the virus. This immune system hyperactivity triggers a "cytokine storm" -- an overproduction of immune cells and their activating compounds, known as cytokines.

In the Detroit woman's case, it's thought that an "intracranial" cytokine storm occurred. That led to a breakdown of the blood-brain barrier that would normally shield the brain.

In an interview with the New York Times, Henry Ford neurologist Dr. Elissa Fory said the quick progression of the woman's illness "may indicate the virus can invade the brain directly in rare circumstances." She added that the woman remains in critical condition at the hospital.

Dr. Anthony Geraci directs neuromuscular medicine at Northwell Health in Great Neck, N.Y. Reading over the woman's case, he said the cytosine storm theory appears to be correct.

"Cytokines are chemicals that, among other functions, can cause small blood vessels to leak, and this can lead to small hemorrhages in many organs including the brain -- this is well-known to occur as a consequence of several viral infections, including influenza," Geraci said.