National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Acute flaccid myelitis

Acute flaccid myelitis (AFM) is a rare disease that affects the spinal cord, the part of the nervous system that carries messages to and from the brain. Symptoms of AFM include sudden (acute) weakness in the arm(s) or leg(s), along with loss of muscle tone and decreased or absent reflexes. Some people with AFM report pain.[1][2] In some cases, AFM can affect the nerves controlling the head and neck, causing facial weakness, drooping of the eyelids, and difficulty swallowing, speaking, or moving the eyes.[1] The most serious complication of AFM is respiratory failure if the muscles involved with breathing become weakened.[1][2][3] Most cases of AFM have been in children, but it can develop in adults.[1][2]  

Many times symptoms of AFM develop after a viral infection, such as poliovirus, West Nile virus, and adenovirus.[1][2][4] In some cases no clear possible cause is found.[1] In addition, even when associated with a viral infection, it is not known how the infection triggers AFM, and it is not clear why some people develop AFM after an infection and others do not.[1][4]

AFM can be difficult to diagnose because the symptoms are similar to other neurological diseases, such as Guillain-Barre syndrome (GBS), acute disseminated encephalomyelitis (ADEM), and transverse myelitis. Diagnosis may include a physical exam, an MRI of the spine, testing of the cerebral spinal fluid (CSF), and tests checking nerve speed (nerve conduction velocity; NCV) and the response of muscles to the messages from the nerves (electromyography; EMG).[1][2][3][4]

To prevent infections by AFM-related viruses , specialists recommend staying up-to-date with polio vaccines and to minimize exposure to mosquitoes. There is no specific treatment for AFM.[1] Treatments that have been tried include immunoglobulin, corticosteroids, plasma exchange, and antiviral therapy, but there is no clear evidence that any of these treatments affect recovery. Other treatment is supportive and depends on the symptoms. Physical therapy and occupation therapy are especially important during recovery.[2][3][4] The extent of recovery varies. Although some people may make a full recovery, most have continued muscle weakness even after a year.[2][4] Long term outcomes are not known.[1]

For more detailed information about acute flaccid myelitis, you may visit the Centers for Disease Control and Prevention (CDC) webpage.
Last updated: 10/9/2018

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • CAPTURE: Collaborative Assessment of Pediatric Transverse Myelitis; Understand, Reveal, Educate invites children with transverse myelitis or acute flaccid myelitis between the ages of 0 to 18 years of age to participate in their multicenter research program. Click on the link above to visit the Transverse Myelitis Association Web site and read more about the study. 
  • ClinicalTrials.gov lists trials that are related to Acute flaccid myelitis. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • You can obtain information on this topic from the Centers for Disease Control and Prevention (CDC). The CDC is recognized as the lead federal agency for developing and applying disease prevention and control, environmental health, and health promotion and education activities designed to improve the health of the people of the United States.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.

In-Depth Information

  • PubMed is a searchable database of medical literature and lists journal articles that discuss Acute flaccid myelitis. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

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  1. Acute flaccid myelitis. Centers for Disease Control and Prevention. 2016; http://www.cdc.gov/acute-flaccid-myelitis/about-afm.html.
  2. Messacar K, Schreiner TL, Van Haren K, et al. Acute flaccid myelitis: A clinical review of US cases 2012-2015. Ann Neurol. September, 2016; 80(3):326-338. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5098271/.
  3. Nelson GR, Bonkowsky JL, Doll E, Green M, Hedlund GL, Moore KR, Bale JF Jr. Recognition and Management of Acute Flaccid Myelitis in Children. Pediatr Neurol. February, 2016; 55:17-21. https://www.ncbi.nlm.nih.gov/pubmed/26621554.
  4. Hopkins SE. Acute Flaccid Myelitis: Etiologic Challenges, Diagnostic and Management Considerations. Curr Treat Options Neurol. November 28, 2017; 19(12):48. https://www.ncbi.nlm.nih.gov/pubmed/29181601.