CDC expects 2020 outbreak of life-threatening AFM in children

The Centers for Disease Control and Prevention issued a call to action to warn of a potential outbreak between the end of this summer and winter of a rare, but potentially lethal disease that affects young children, where seeking medical attention right away could make all the difference.

Acute flaccid myelitis "is a medical emergency that requires immediate recognition and care," urged CDC director Robert Redfield, on a conference call with the media Tuesday.

AFM is a rare, rapid onset neurological disease affecting the spinal cord leading to paralysis. Symptoms of AFM include sudden arm or leg weakness, difficulty walking, limb pain, back pain or neck pain. AFM can cause paralysis over the course of hours to days, which may require a ventilator for breathing.

It most commonly affects young children. Parents are being asked to seek medical care immediately if a child develops a sudden arm or leg weakness.

Most children with AFM will have a fever or respiratory illness about six days before weakness occurs. For this reason, AFM has been associated with viruses, and specifically one called Enterovirus D68.

But why some children get AFM and some don't isn't yet clear.

"We've learned a lot, but we have a lot to learn about AFM ... We are working at CDC and collaborating with the NIH on a couple of prospective large studies, which will help us better understand risk factors for AFM," said Redfield.

The CDC began tracking cases of AFM in 2014 and a wave of cases has occurred every other year since then. In 2018, the US experienced the third and largest outbreak of AFM with 238 cases in 42 states between August and November.

The average age was just 5 years old.

At least 98% of those children were hospitalized, and over half were admitted to the intensive care unit, while 20% required a ventilator to breathe.

And while most parents sought medical attention within one day of developing AFM symptoms, a concerning 10% were not hospitalized after four days of weakness.

While many children will recover to their usual state of health after AFM, unfortunately, many kids will have permanent disability.

"Early and aggressive physical therapy and occupational therapy can help strengthen the functioning they will retain and go about their lives with the best functioning possible," said Dr. Thomas Clark, a pediatrician and CDC deputy director of the division of viral diseases.

With the 2020 peak season looming, AFM is a priority for CDC as it prepares for an outbreak this year.

"As a parent and a grandparent my heart goes out to the families affected by AFM," Redfield said.

Parents should look out for any sudden weakness of the arms or legs in addition to pain in these areas, the neck or the back. If your child recently had a viral cold or fever, this should heighten your suspicion for AFM.

Clark urged pediatricians and other health care providers to "consider and properly recognize [AFM], hospitalize immediately, take specimens as soon as possible and report [the case] to local health authorities."

If suspecting AFM, health care providers should order an MRI in order to distinguish AFM from other neurological conditions.

"It's vital that all health care providers maintain a high index of suspicion for AFM in children with acute limb weakness or neck or back pain that develops after an upper respiratory illness from late summer through fall," said Dr. Robert Glatter, an Emergency Physician at Lenox Hill in New York City.

"We expect that AFM will likely have another peak in 2020. That said, it's still unclear if or how COVID-19's recommended social distancing measures and attention to mask wearing and hand hygiene will impact how much enterovirus we end up seeing, along with cases of AFM," Glatter said.

The same hygiene precautions for COVID-19 apply to viruses that cause AFM.

As some of the symptoms of COVID-19 may overlap with AFM, parents should be on high alert this season.

Non-COVID-19 emergency room visits dropped off sharply in 2020 due to fear of COVID-19. If this trend continues, parents need to know that time is critical and potentially lifesaving with AFM, so even in the age of COVID-19 seek medical attention immediately if your child has sudden numbness in their arms or legs.

"We are concerned in the midst of a COVID-19 pandemic that cases [of AFM] might not be recognized or that parents might be concerned about taking their kids to the doctor," Clark said.

Molly Stout, M.D. is a dermatology resident at Northwestern in Chicago and a contributor to the ABC News Medical Unit.