Skip to main content

Fall could bring rare, paralyzing illness in children, CDC warns

A brain MRI.
(Image: © Shutterstock)

As if the COVID-19 pandemic weren't bad enough, health officials say we're due for an outbreak of a rare, polio-like illness in children this fall.

Cases of this disease, known as acute flaccid myelitis (AFM), spiked late in the summer and fall of 2014, 2016 and 2018, and officials expect the trend to continue for 2020, according to a statement from the Centers for Disease Control and Prevention (CDC). AFM is a condition that affects the nervous system and causes muscle weakness, particularly in the arms and legs, which can progress rapidly and lead to permanent paralysis, the CDC said.

Recent data suggest that enteroviruses — particularly a type called enterovirus D68 — are likely the primary cause of AFM outbreaks in the U.S., according to a new CDC report released Tuesday (Aug. 4) in the journal Morbidity and Mortality Weekly Report. (Polio is also caused by an enterovirus.) 

But COVID-19 is a wild card that could affect AFM outbreaks.

"We do not know how COVID-19 and social distancing may affect enterovirus," CDC Director Dr. Robert Redfield said in a news conference. It's possible that social-distancing measures will decrease circulation of enteroviruses, in which case "AFM cases may be fewer this year or the outbreak may be delayed," Redfield said.

On the flip side, the pandemic could make it harder for health care professionals to recognize and respond to AFM cases, Redfield said.

CDC officials aren't taking any chances, and they are calling on doctors and parents to be on the lookout for AFM. The illness should be suspected in children with sudden limb weakness, especially during the peak months of August through November. Limb weakness linked to AFM is often preceded by respiratory illness or fever and the presence of neck or back pain.

"AFM is a medical emergency that requires immediate care," Redfield said. There is no specific treatment for AFM, but since symptoms can progress rapidly and require mechanical ventilation, patients suspected to have the disease should be hospitalized immediately, the report said. What's more, doctors may recommend physical or occupational therapy to help with limb weakness caused by AFM, and this therapy may lead to better outcomes if implemented in the initial phase of illness, according to the CDC.

Related: 28 Devastating Infectious Diseases

Although cases of AFM have increased in recent years, the disease remains very rare. A total of 633 cases of AFM have been confirmed in the U.S. since officials started tracking the disease in 2014, according to the CDC. So far in 2020, 16 cases have been reported as of July 31, and 38 cases are under investigation. In previous years, cases of AFM did not start to rise until August.

The outbreak in 2018 was the biggest yet, with 238 confirmed cases in 42 states. The new report provides a detailed review of these 238 cases to help doctors quickly recognize cases and refer them to appropriate care. 

The report authors found that among cases in 2018, 86% started showing symptoms in August through November, and 92% experienced a fever, respiratory illness or both about a week before symptoms of limb weakness. Other common symptoms in patients were walking difficulty, neck or back pain, limb pain and headache. The most common virus identified in patient samples was enterovirus D68. (Although AFM and polio have similar symptoms, the poliovirus has not been detected in any cases of AFM. Thanks to the polio vaccine, the disease has not turned up in American children since 1979, according to the CDC.)

Nearly all patients (98%) in 2018 were hospitalized, with about half admitted to the intensive care unit and about a quarter requiring mechanical ventilation to help them breathe, the CDC said.

Most patients were hospitalized within one day of their limb weakness, but 25% of patients were not hospitalized until two or three days after, and 10% were not hospitalized until four or more days later. This could suggest delays in recognition in some cases.

There are worries that COVID-19 may make AFM harder to spot this year and that parents may delay taking their children to the doctor.

"We are concerned that in the midst of a COVID pandemic that cases might not be recognized as AFM, or … that parents might be worried about taking their children to the doctor if they develop something as serious as limb weakness," Dr. Thomas Clark, deputy director of CDC's Division of Viral Diseases, said at the news conference. Officials "want parents to understand that many measures have been taken to provide health care safely," Clark said. "Any signs of limb weakness that develop suddenly, [children] need to get to the doctor."

Originally published on Live Science.