This rare flu complication is on the rise in otherwise healthy children

Doctors are warning that a rare and serious complication from the flu is on the rise among otherwise healthy children in the U.S.

Acute necrotizing encephalopathy is a severe neurologic condition that can result in brain damage and swelling following a viral infection — and particularly during influenza. Over this past flu season, researchers said pediatric doctors reported an increased number of children with the condition tied to flu.

“Flu is notoriously dangerous for kids; it always has been,” Dr. Keith Van Haren, an associate professor of neurology and pediatrics at Stanford University, said in a statement.

The precise reasons for the surge remain unclear but the findings come on the heels of America’s worst flu season in 15 years.

There were up to 82 million flu cases from October to mid-May, and between 27,000 and 130,000 flu deaths, according to the Centers for Disease Control and Prevention. The agency provides a lower and higher estimate for the season’s deaths because its influenza data cannot capture the full burden of flu.

There have been 266 pediatric flu deaths to date, the highest tally in a non-pandemic flu season since the agency began reporting in 2004, the American Hospital Association said.

Until this year, there had been no official count of acute necrotizing encephalopathy cases when federal health authorities started to track them in February.

In more than 1,800 reported pediatric flu deaths in the past 15 years, 166 had flu-linked acute necrotizing encephalopathy. This year, CDC preliminary data indicated that nine of the 68 reported deaths had the complication.

Doctors have identified 41 cases of acute necrotizing encephalopathy in children at 23 hospitals over the past two flu seasons. Most of those children had been healthy, with no significant medical history, before contracting the flu.

Of those children, 11 died within three days of the complication’s onset. For the 30 who survived, 63 percent had moderate to severe disability 90 days after diagnosis, including problems walking, eating and seizures.

“It’s like the immune system is going into a panic attack,” Van Haren said.

Doctors found that children under the age of five are at highest risk of serious illness or death from acute necrotizing encephalopathy. While there is no specific treatment for the condition, most of the children were treated with steroids, antiviral medications, an IV with antibodies, or a procedure called plasma exchange, which is somewhat like dialysis.

The physicians noted that only one patient who had died had received a flu vaccine.

“Flu causes all kinds of complications, including other forms of brain swelling, as well as pneumonia and respiratory failure. Vaccines really do help protect wonderfully against all those complications,” Van Haren said.

Notably, of the reported pediatric deaths this flu season, 90 percent were in children who were not fully vaccinated against the flu.

The decline in child vaccination rates have also been associated with this year’s outbreak of measles in West Texas, which saw more than 760 cases and two deaths of unvaccinated children in the state.

Children can get a flu vaccine starting at six months old.

Van Haren and doctors across the country are stressing that flu vaccination is a key protective strategy against acute necrotizing encephalopathy. The vaccines greatly reduce the chance of a child becoming seriously ill with flu.

“For doctors, our message is that these kids can recover remarkably well, even if they appear gravely ill early in their course. Don’t give up,” Van Haren said. “And for parents, it’s: Vaccinate!”