Acute Flaccid Myelitis Outbreak Warning: What Causes Polio-like Illness, Which Age Group Is Most at Risk?

The U.S. Centers for Disease Control and Prevention (CDC) has warned of a potential peak in cases of a rare but serious polio-like condition known as acute flaccid myelitis (AFM) in the coming fall.

It described the neurologic condition which largely effects children as a medical emergency. Patients thought to have AFM should seek immediate medical care, regardless of if there are high levels of COVID-19 in the area, the CDC said.

On average, patients during the last outbreak in 2018 were aged 5 years old. Limb weakness and paralysis is the most common symptom of the condition which affects the nerve cells in the gray matter of the spinal cord. Others include a fever, pain or numbness in one or more limbs, problems walking normally, a headache, back or neck pain, issues with swallowing or talking, and weakness in the face or neck. Patients may also have had a recent or current respiratory illness.

According to the CDC, the condition has peaked every two years in the U.S. between August and November since 2014.

The cause of AFM is unknown, but it is thought germs known as enteroviruses, especially EV-D68, cause these biennial flare-ups.

In a Vital Signs report, the CDC urged doctors to make sure patients with the condition are hospitalized quickly. If left untreated, the condition can quickly take hold, in a matter of hours or days. Patients can be left permanently paralysis, suffer life-threatening complications from respiratory failure.

In 2018, 35 percent of patients were not hospitalized for two or more days after they first experienced weakness in their limbs.

The CDC said parents and doctors should suspect a person has ASM if limb weakness comes on suddenly, particularly between August and November. They should be more suspicious if they have recently come down with a respiratory illness, and or fever, have neck or back pain, or neurological symptoms.

Dr. Robert Redfield, the director of the CDC, said in a statement: "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.

"Recognition and early diagnosis are critical. CDC and public health partners have strengthened early disease detection systems, a vital step toward rapid treatment and rehabilitation for children with AFM."

In 2018, the U.S. was hit by the third and biggest peak of AFM. Across 42 states, 238 cases were reported, with 94 percent children. Of the total, 98 percent of patients were hospitalized, with 76 percent seeking medical care after a day, and 64 presenting to an ER. More than half (54 percent) were admitted to an intensive care unit, and a quarter needed to be hooked up to a ventilator to breathe.

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Robert Redfield, director of the U.S. Centers for Disease Control and Prevention (CDC) testifies during a House Select Subcommittee on the Coronavirus Crisis hearing on July 31, 2020 in Washington, D.C. The CDC has warned of a potential rise in acute flaccid myelitis cases. Erin Scott-Pool/Getty Images