(NBC News) – Acute necrotizing encephalopathy is deadly in more than a quarter of kids diagnosed with the inflammatory brain disease.

Severe flu seasons in recent years have brought to light a little-known danger of influenza infections in kids: a rare brain disease called acute necrotizing encephalopathy, or ANE.

It’s a fast-moving condition usually triggered by the flu, causing sudden brain swelling. It’s thought that the virus prompts the immune system to go haywire.

Affected children can go from having mild flu symptoms to seizures, coma or even death within days. Most are kids without any other health problems. (Read More)