• Infectious Diseases A-Z: Keeping perspective on acute flaccid myelitis

a woman taking the temperature of a sick little girl who might have fever, cold or fluThe Centers for Disease Control and Prevention (CDC) says it continues to receive reports of children with acute flaccid myelitis (AFM). "Acute flaccid myelitis is a descriptive term for the primary clinical manifestation of loss of motor function," says Dr. Gregory Poland, director of the Mayo Clinic Vaccine Research Group.

The CDC has been investigating AFM since 2014. "This is not a new issue, AFM has been around a long time," says Dr. Poland. "In the U.S. alone in 2017, 33 confirmed cases were identified, 149 cases in 2016, 22 cases in 2015, and 120 cases in 2014.  Of all these cases, only four have been confirmed to be caused by a virus that could be identified. A host of viruses, diseases and toxins can cause AFM but none has otherwise been identified in these cases."

Dr. Poland says parents who are worried about their children becoming infected should remember that AFM remains a rare condition – affecting less than one   million people – and likely represents a probable genetic predisposition.

"Fortunately, AFM is very rare, albeit scary for everyone," says Dr. Poland. "But we need to keep perspective here. It is rare. Over 90 percent of cases have been in children during the time of the year that respiratory viruses circulate. Most cases have occurred after a respiratory illness. The CDC and other researchers are looking hard for an identifiable cause. Thus far, none has been found."

The complexity of AFM makes it difficult to offer preventive measures. Dr. Poland says his general advice to parents is to ensure all family members are fully immunized, including influenza and polio immunization; avoid mosquito bites; and practice good hand hygiene to help ward off respiratory illnesses.

Symptoms of acute flaccid myelitis include:

  • Weakness and loss of muscle tone and reflexes in the arms or legs
  • Facial droop or weakness
  • Difficulty moving the eyes
  • Drooping eyelids
  • Difficulty swallowing
  • Slurred speech

"Any persistent or worsening neurologic symptoms of weakness would be cause for evaluation by a physician," says Dr. Poland.

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