Acute Flaccid Myelitis

AFM can be caused by viruses. Specimens collected from patients with AFM have detected coxsackievirus A16, enterovirus A71 (EV-A71), enterovirus D68 (EV-D68) and antibodies specific to enteroviruses. These viruses generally cause mild illness and it is unclear why a small number of individuals develop AFM after viral infection.

Symptoms can progress rapidly and be life threatening. If you see potential symptoms of AFM, contact your health care provider right away. 

Most patients with AFM will have sudden onset of arm or leg weakness and loss of muscle tone and reflexes. Some patients may also experience:

• Difficulty moving the eyes
• Drooping eyelids
• Facial droop or weakness
• Difficulty swallowing or slurred speech
• Pain in arms or legs
• Pain in neck or back

Uncommonly, patients with AFM may experience numbness or tingling in arms or legs. The most severe symptoms of AFM include difficulty breathing due to muscle weakness and serious neurologic complications such as body temperature changes and blood pressure instability.

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

There is no specific treatment for AFM, but a neurologist may recommend certain interventions on an individual basis. If your clinician suspects your child has AFM, they should hospitalize your child immediately; AFM can progress rapidly and sometimes requires machines to help patients breathe.

Since AFM can develop after a viral infection, basic steps to avoid becoming infected with or spreading a virus includes:

• Staying home when sick
• Covering coughs and sneezes
• Avoiding contact with individuals who are sick
• Frequent hand washing with soap and water for a minimum of 20 seconds
• Cleaning and disinfecting frequently touched surfaces

National surveillance for AFM began in 2014 with an increase in reports in the U.S. This surveillance has helped identify increases every other year in 2014, 2016, and 2018. Surveillance has also shown a seasonal pattern, with most cases developing AFM in late summer or early fall. This time period coincides with increased circulation of many viruses, including enteroviruses.

Florida Data

* Numbers reflect confirmed and probable AFM cases; CDC reports only confirmed cases, so numbers may differ.

Reporting AFM

Florida participates in enhanced AFM surveillance through the CDC to provide a better understanding of the spectrum of AFM illness, including all possible causes, risk factors, and outcomes.

The Florida Department of Health asks clinicians to provide information for patients who meet the clinical criteria for AFM (sudden onset of flaccid limb weakness) to their local health department regardless of any laboratory results or magnetic resonance imaging (MRI) findings.

Requested Information and Documents

Information should be sent to the local county health department regardless of any laboratory and MRI results.

1. Order a spinal MRI and collect the following specimens for potential public health testing as soon as possible:
   • Cerebrospinal fluid (CSF)
   • Serum (collected at same time or within 24 hours of CSF if possible)
   • Two stool samples (collected at least 24 hours apart)
   • Respiratory–nasopharyngeal or oropharyngeal swab

Provider Guidance

2. Contact the local county health department and work with them to:
   • Complete the AFM Patient Summary
   • Send MRI reports and images (spinal cord lesions may not be present on initial MRI; a negative or normal MRI performed within the first 72 hours after onset of limb weakness does not rule out AFM)
   • Send neurology consult notes
   • Coordinate specimen shipment

3. Additionally, please report:
   • Any person whose death certificate lists acute flaccid myelitis as a cause of death or a condition contributing to death.
   • Autopsy findings that include histopathologic evidence of inflammation largely involving the anterior horn of the spinal cord spanning ≥1 vertebral segment.

Council of State and Territorial Epidemiologists (CSTE) AFM case definitions will be used to assign a classification after review by a team of neurologists at CDC. This patient classification will be given to the health department which will relay this information to the clinician. The case classification should not be used to decide whether to report a patient.

Long-Term Follow-up

Patients with confirmed or probable AFM will be contacted by the health department at 2 months after the onset of limb weakness to collect information on outcomes after their AFM illness.