Acute Flaccid Myelitis (AFM)

AFM Basics


Disease Description


Acute flaccid myelitis (AFM) is a rare but serious condition affecting the nervous system, specifically the spinal cord. AFM causes weakness in the body’s muscles and reflexes.


  • Symptoms

AFM causes sudden arm and/or leg weakness. AFM also causes loss of muscle tone and reflexes. Someone with AFM might also have:


  • facial droop/weakness
  • difficulty moving the eyes
  • drooping eyelids
  • difficulty with swallowing or slurred speech
  • pain in the arms or legs

Rarely, someone with AFM might have numbness or tingling in limbs, and difficulty passing urine. Some patients might have difficulty breathing due to muscle weakness and need ventilator support. AFM can also cause severe neurologic complications.


If you see potential symptoms of AFM in your child, (for example, if he or she is not using an arm), contact your health care provider right away. AFM can be diagnosed by examining your child’s nervous system, taking an MRI scan, testing the cerebral spinal fluid, and checking nerve conduction. It is important that tests are done as soon as possible after someone develops symptoms. While there is no specific treatment for AFM, doctors may recommend certain interventions on a case-by-case basis.


  • Causes

There is no known single cause of AFM, but the U.S. Centers for Disease Control and Prevention (CDC) believes viruses, including enteroviruses, might be associated with AFM. In the U.S., most patients with AFM occurring since 2014 had symptoms consistent with a viral illness (ex: runny nose, fever, cough), just before their AFM onset.  Sometimes, the cause of a patient’s AFM may not be identified.


  • Prevention

There is no single, specific cause of AFM. However, since AFM can develop as a result of a viral infection, The Georgia Department of Public Health recommends parents and children take basic steps to avoid infections and stay healthy including making sure you and your family are up to date on your vaccinations, protecting yourself from insect bites, and washing your hands often.


Additional Information for Patients and Caregivers


Information for Health Professionals


Reporting


  • Reporting AFM

All individual cases of AFM should be reported to the Georgia Department of Public Health. Find out more about what needs to be reported, who needs to report diseases, which forms to use and where to find out more about the disease.


Clinical Features and Epidemiology


  • AFM in the United States

The Centers for Disease Control and Prevention (CDC) has requested states provide information on suspect AFM cases since the fall of 2014, when clusters of pediatric cases with AFM were identified in Colorado and Kansas. At the same time, there was an ongoing nationwide outbreak of Enterovirus D68 (EV-D68).  States have been reporting suspect AFM cases to CDC and submitting specimens for testing since the fall of 2014. Most cases occurred between August and October, with increases every two years since 2014. At this same time of year, many viruses commonly circulate, including enteroviruses. CDC thinks viruses, including enteroviruses, likely play a role in AFM in the United States. Most reported cases in the U.S. have been in children, but people of any age can get AFM.


  • From August 2014 to December 2014, 120 confirmed AFM cases were reported from 34 states.
  • In 2015, 22 confirmed AFM cases were reported from 17 states.
  • In 2016, 153 confirmed AFM cases were reported from 39 states.
  • In 2017, 37 confirmed AFM cases were reported from 16 states.
  • In 2018, 236 confirmed AFM cases were reported from 41 states.
  • In 2019, 37 confirmed AFM cases were reported nationally. Final 2019 case counts are pending.
  • As of January 30, 2020, there have been no confirmed cases in 2020.
  • AFM in Georgia

Since August 2014, 15 cases of AFM have been reported to the Georgia Department of Public Health, with ages ranging from 6 months – 17 years at weakness onset. Establishing routine surveillance for AFM in Georgia is necessary to determine the burden of this syndrome and establish baseline incidence. Suspect cases of AFM reportable to DPH are classified according to the following criteria:


Case Definition (updated January 1, 2020)


  • Clinical Criteria: An illness with onset of acute flaccid(a) limb weakness

     
  • Laboratory/Imaging Criteria:
    • Confirmatory laboratory/imaging evidence:
      • MRI showing spinal cord lesion with predominant gray matter involvement(b) and spanning one or more vertebral segments
      • Excluding persons with gray mater lesions in the spinal cord resulting from physician diagnosed malignancy, vascular disease, or anatomic abnormalities
    • Presumptive laboratory/imaging evidence:
      • MRI showing spinal cord lesion where gray matter involvement is present, but predominance cannot be determined
      • Excluding persons with gray mater lesions in the spinal cord resulting from physician diagnosed malignancy, vascular disease, or anatomic abnormalities

         
  • Case Classification(c):
    • Confirmed:
      • Clinically compatible case with confirmatory laboratory/imaging evidence AND absence of a clear alternative diagnosis attributable to a nationally notifiable condition
    • Probable:
      • Clinically compatible case with presumptive laboratory/imaging evidence AND absence of a clear alternative diagnosis attributable to a nationally notifiable condition
    • Suspect:
      • Clinically compatible case AND available information is insufficient to classify case as probable or confirmed

(a) Low muscle tone, limp, hanging loosely, not spastic or contracted


(b) Terms in the spinal cord MRI report such as “affecting gray matter,” “affecting the anterior horn or anterior horn cells,” “affecting the central cord,” “anterior myelitis,” or “poliomyelitis” would all be consistent with this terminology.


(c) Assignment of final case classification for all suspected AFM cases is done by experts in national AFM surveillance


Laboratory Testing


Specimens should be collected from patients suspected of having AFM as soon as possible, ideally on the day of limb weakness onset. Requested specimens include:


  • Cerebrospinal Fluid (CSF)
  • Blood serum
  • A nasopharyngeal swab
  • Stool
    • Two stool specimens collected as soon after onset of limb weakness as possible and separated by 24 hours

For detailed instructions visit the CDC’s webpage on AFM specimen collection. DO NOT ship specimens directly to CDC, call your local health department to coordinate shipment to the Georgia Public Health Laboratory, who will then coordinate testing and shipping with CDC.


Case Investigations


These are the steps to AFM investigations: 


  1. Doctors report suspect AFM cases to the Georgia Department of Public Health (DPH) or their patient’s local public health office. Public health and DPH work with doctors to collect case medical information and specimens. DPH shares information with the U.S. Centers for Disease Control and Prevention (CDC) to complete AFM investigations. 
  2. CDC may do enterovirus testing with specimens from suspect AFM cases. Any available test results will be sent to the reporting doctor. CDC may also do research or additional testing with specimens to look for possible causes of AFM 
  3. After identifying information (ex: name and home address) is removed, case information is sent securely to CDC. Neurologists at CDC review the medical information and classify cases as confirmed AFM, probable AFM, or not AFM.  
  4. Case classifications are reported back to public health by CDC and then provided to cases’ doctors. It may take a few weeks for case classifications to become available. This is because in depth review of all of the medical information is needed. Since this can take time, doctors should not wait for the case classification to provide a diagnosis. The case classification might be different from the diagnosis made by a patient’s doctor. Patients should always refer to their doctor for information on their medical care. 
    • At this time, there are no specific recommended treatments for people diagnosed with AFM. As we learn more about AFM, suspect cases’ diagnosis and recommended treatments might change. 
  5. To help us learn more about how long-term effects of AFM, Public Health will contact confirmed and probable AFM cases. Public Health will call to do a short interview at three time points: 60 days, 6 months, and 12 months after the AFM illness began. 

Provider Resources


 


Case Counts









Report Year Number of AFM Cases*
Reported AFM Cases in Georgia
2014 1
2015 1
2016 5
2017 1
2018 6
2019** 1

*Includes Confirmed or Probable AFM cases


**Preliminary Case Count



References


  1. Revision to the Standardized Case Definition, Case Classification, and Public Health Reporting for Acute Flaccid Myelitis [Internet]. Council of State and Territorial Epidemiologists; 2019. Retrieved from: https://cdn.ymaws.com/www.cste.org/resource/resmgr/2019ps/final/19-ID-05_AFM_final_7.31.19.pdf [Accessed February 17, 2020]
  2. About Acute Flaccid Myelitis [Internet]. Centers for Disease Control and Prevention; 2018. Retrieved from: http://www.cdc.gov/acute-flaccid-myelitis/about-afm.html [Accessed August 10, 2018]
  3. Standardized Case Definition for Acute Flaccid Myelitis [Internet]. Council of State and Territorial Epidemiologists; 2015. Retrieved from: http://c.ymcdn.com/sites/www.cste.org/resource/resmgr/2015PS/2015PSFina… [Accessed August 10, 2018]
  4. AFM Investigation [Internet]. Centers for Disease Control and Prevention; 2018. Retrieved from: https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html [Accessed August 10, 2018]

Additional Resources