Acute Flaccid Myelitis Update – November 2018

Acute flaccid myelitis (AFM) has reemerged as a polio-like neurologic disease in children and young adults in the United States.   Nationwide clusters have occurred in late summer and early fall in 20141, 20162, and now in 20183.

Table: AFM Cases in US and Texas, with year of illness onset from 2014 to 2018.

Year

Number of States Reporting

Number of Confirmed Cases (US)

Number of Confirmed Cases (TX)

2014

34

120

3

2015

17

22

0

2016

39 (includes DC)

149

19

2017

16

33

5

2018

25

80*

17**

*The case counts are subject to change; Jan-Nov 2;

Note: Table adapted from: https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html and http://www.dshs.texas.gov/IDCU/disease/AFM/AFM-Data.aspx; TX DSHS verbal report on 11/05/2018, Dr. Jennifer Shuford and TX DSHS AFM Epidemiology team.

AFM is not a mandatory reportable condition and numbers are likely higher than reported. The initial cases in 2014 were more common in Colorado and California where there were concurrent outbreaks of “severe lower respiratory illness (LRI)” associated with enterovirus, EV-D68 infection4.  The cause is yet unknown but is likely a post or para infectious condition related to a viral infection.

The presentation is acute onset flaccid limb weakness, commonly with associated limb or neck pain, with a preceding history of fever, respiratory or GI illness, CSF pleocytosis with lymphocytic predominance, and MRI imaging with edema of central gray matter of the spinal cord that can extend through multiple levels of the cord, including extension to brainstem.  Some of these patients have evidence of EV-D68 in the nasopharynx or stool.  Other viruses such as EV A716 (associated with hand foot and mouth disease) and West Nile virus have also been found.  Spinal fluid viral PCR studies are almost always negative.  The neurological outcomes of AFM can be poor, with most having residual weakness one year after diagnosis5.  There is still follow-up data being gathered on cases from 2016.

After the initial wave in 2014, the CDC assembled an expert review panel.7 There was no evidence for benefit of anti-inflammatory treatment. However, if post-infectious process such as transverse myelitis is suspected, there may be benefit to anti-inflammatory treatment.

AFM has been seen across the US including in Texas with all 3 of these events around the same time.  If there are children with suspected or enterovirus-positive severe LRI or neurological presentation such as AFM here in Texas, we should evaluate and report them as recommended by state health department and CDC.

Texas Pediatric Society would like to encourage providers to report cases to their local and state health departments and to send testing.

  • Report cases that meet the clinical picture for AFM to DSHS: Acute onset flaccid weakness. https://www.dshs.state.tx.us/news/releases/2018/HealthAdvisory-10152018.aspx
  • Consider the role of enterovirus in such cases. 
    • Obtain respiratory Viral PCR panel
      • If positive for enterovirus/rhinovirus, send samples through TX DSHS
  • Treatment
    • Although no mode of therapy has been found to be beneficial, some physicians are using anti-inflammatory modalities when the presentation is post infectious.

Texas AFM Research: The Pediatric Infectious Diseases group at Dell Children Medical Center, Austin, Texas has been working to pool Texas cases to better understand presentation, treatments, and outcomes. A total of 6 hospitals have contributed to this database for 2016 cases; 2018 cases are also being collected.  If you are interested in collaborating on this project, please contact Rachel Quick at rdquick@ascension.org

References:

  1. https://www.ncbi.nlm.nih.gov/pubmed/27318332
  2. https://www.ncbi.nlm.nih.gov/pubmed/28796760
  3. https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html
  4. https://www.cdc.gov/non-polio-enterovirus/about/ev-d68.html
  5. https://www.ncbi.nlm.nih.gov/pubmed/27422805
  6. https://www.ncbi.nlm.nih.gov/pubmed/30212441
  7. https://www.cdc.gov/acute-flaccid-myelitis/downloads/Interim-Considerations-AFM.pdf