Brief Summary: Acute Flaccid Myelitis

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Brief Summary: Acute Flaccid Myelitis

Tiffany Henderson, MPH - Epidemiologist Manager - MDHHS 

Acute flaccid myelitis (AFM) is a serious condition that affects the nervous system, specifically an area of the spinal cord called gray matter, causing muscles and reflexes to become weak.  This rare condition is not new, but the number of cases reported since 2014 has increased. Although risk groups vary by year, young children are primarily affected.

Most patients diagnosed with AFM will have a sudden onset of arm or leg weakness, as well as a loss of muscle tone and reflexes. In addition, some individuals may experience facial drooping, difficulty in moving the eyes, and problems with swallowing/speaking. Rarely, there may be pain in the arms or legs. One of the most concerning symptoms is respiratory failure that can occur when there is weakness in the muscles used to breathe.  There are no specific treatments for AFM and interventions are recommended on a case-by-case basis.

Since 2014, cases in the United States have peaked every two years, generally in the late summer and early fall. Although a single cause has not yet been identified, over 90% of patients reported mild respiratory illness or fever prior to developing AFM. Investigators are trying to determine if there is a specific virus that precedes AFM or what differences there may be in those individuals that develop AFM after a mild illness compared to those that do not.

Healthcare providers and public health at the local, state, and federal levels are working together to investigate suspect cases in an attempt to identify specific risk factors.  The reporting of suspect cases by healthcare providers to public health is extremely important.  In Michigan, AFM became a required reportable condition in January 2019.  Clinical information and specimens of patients under investigation (PUIs) are sent to the MDHHS Communicable Disease Division and Bureau of Laboratories, then forwarded to CDC. This information is used to classify cases according to the standard case definition adopted by the Council of State and Territorial Epidemiologists (CSTE).  

In 2018, were been 201 confirmed AFM cases from 40 states, but additional PUIs are still under investigation. Michigan reported 4 of these cases, all of which have been in children.

CDC has recently updated the document “Interim Considerations for Clinical Management of AFM”.  There are currently no targeted therapies or interventions with enough evidence to endorse or discourage their use for the treatment or management of AFM.  Without a known specific cause, AFM prevention is based on reducing the risk of contracting a viral infection and therefore guidance includes, increased hand hygiene, more frequent cleaning of highly-touched surfaces, and avoiding contact with ill individuals.  For more information, please see the CDC AFM website.

To report a suspect case of AFM, contact your local health department or the MDHHS Communicable Disease Division at 517-335-8165.