About Acute Flaccid Myelitis

  • Acute flaccid myelitis (AFM) is an uncommon but serious neurologic condition. It affects the nervous system, specifically the area of the spinal cord called gray matter, which causes the muscles and reflexes in the body to become weak.
  • We have seen increases in AFM cases in the U.S. every other year starting in 2014.
  • Most AFM cases (more than 90%) have been in young children.
  • You may hear AFM referred to as a “polio-like” condition, but all the stool specimens from AFM patients that we received tested negative for poliovirus. The cases of AFM since 2014 are not caused by poliovirus.
The nervous system: brain, spinal cord, and nerves

Man holding his wrist

Sudden arm or leg weakness, loss of muscle tone, and loss of reflexes are the most common symptoms.

Mother helping child wash her hands

Most children had a respiratory illness or fever before they developed AFM. Learn how to decrease risk of getting viral infections.

Doctor examining little girl's elbow

Clinicians diagnose AFM by taking a careful medical history, doing a physical exam of the patient, and performing an MRI to review pictures of the spinal cord.

Page last reviewed: February 25, 2020