What Is Acute Flaccid Myelitis?

Attempting to answer some questions about this mysterious illness suddenly striking U.S. children

As of this week, almost 200 children across 39 different states have been diagnosed with acute flaccid myelitis (AFM), a condition that affects the nervous system, especially in the area of spinal gray matter, weakening muscles and reflexes.

Although AFM affects less than one in 500,000 U.S. children, diagnoses have shown a steady increase since 2014 leading up to the relative explosion of this past fall.

Thus far, the CDC has established that over 90 percent of confirmed cases are present in children, and in those case, the vast majority of patients present with fever consistent with a viral infection or some sort of respiratory virus before developing AFM.

Onset tends to increase between August and October of each year, as with many viruses. Thus far, all tested cases have proven negative for poliovirus, and the singular cause of AFM remains a mystery.

According to the CDC, Most people with AFM will suddenly have arm or leg weakness and a loss of muscle tone and reflexes. Some people also have other symptoms, including

  • Facial drooping/weakness
  • Trouble moving the eyes
  • Drooping eyelids
  • Trouble swallowing
  • Slurred speech

Sometimes AFM can weaken the muscles that you need for breathing. This can lead to respiratory failure, which is very serious. If you get respiratory failure, you may need to use a ventilator (breathing machine) to help you breathe.

If you or your child develops any of these symptoms, you should get medical care right away.