CDC fears resurgence of rare, polio-like disease in children

Acute flaccid myelitis causes limb weakness that could lead to permanent paralysis

An outbreak of acute flaccid myelitis, a polio-like condition that causes limb weakness and can cause paralysis, has occurred every other year in the United States since 2014.
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The United States could face an outbreak of acute flaccid myelitis this fall – on top of the ongoing coronavirus pandemic, the Centers for Disease Control and Prevention warned Tuesday. 

The rare, polio-like illness causes limb weakness and can lead to paralysis, respiratory failure and death. It mostly affects children. 

Since 2014, there has been an AFM outbreak every two years in the U.S. between August and November.If this trend continues, the next outbreak will occur this fall. 

It is unclear whether COVID-19 mitigation efforts will help reduce the number of AFM cases.

The largest AFM outbreak occurred in 2018, when there were 238 cases in 42 states. More than half of the patients were admitted to the intensive care unit and one-fourth were put on a ventilator, according to CDC data. The average age of the children was 5 years old.

AFM is believed to be caused by a virus, most likely an enterovirus, the West Nile virus or an adenovirus. The illness typically begins with symptoms similar to the common cold, influenza or COVID-19. But a week after developing a runny nose, cough and fever, the patient develops weakness in one or more limbs and has difficulty walking. 

Early diagnosis is important because a child's condition can deteriorate within hours or days of the initial limb weakness. In 2018, 35% of AFM patients weren't hospitalized until a few days after the limb weakness set in, according to a CDC Vital Signs report

This year, there have been 16 cases and one death. The patient who died was an adult.

"As we head into these critical next months, CDC is taking necessary steps to help clinicians better recognize signs and symptoms of AFM in children," said CDC Director Dr. Robert Redfield.

With the common cold, the flu and the coronavirus expected to be circulating this fall, the CDC said parents and doctors should suspect AFM in any patient who exhibits sudden limb weakness – especially after a recent viral illness. AFM also can cause a headache, neck or back pain and neurological symptoms.

"We have seen a decline in emergency room visits and even parents taking children to pediatric visits," Dr. Janell Routh, the AFM team lead in the CDC's Division of Viral Diseases, said during a conference call with reporters. "With COVID on everyone's mind, it's particularly important to get this message out now."

Early hospitalization and treatment offers the best prognosis for patients with AFM. Diagnosis can be confirmed with an MRI, which will show lesions on the spinal cord.

There isn't a proven treatment for AFM, but intravenous immunoglobulin along with physical and occupational therapy can improve patient outcomes.

Dr. Thomas Clark, deputy director of CDC's Division of Viral Diseases, emphasized that vigilance for AFM must stay strong amid the current public health crisis. 

"During the COVID-19 pandemic, this may require adjusting practices to perform clinical evaluations of patients by phone or telemedicine," he said. "However, clinicians should not delay hospitalizing patients when they suspect AFM."