To diagnose acute flaccid myelitis, the doctor starts with a thorough medical history and physical exam. The doctor might recommend:

  • Examining the nervous system. The doctor examines the places on the body where you or your child has weakness, poor muscle tone and decreased reflexes.
  • Magnetic resonance imaging (MRI). This imaging test allows the doctor to look at the brain and spinal cord.
  • Lab tests. The doctor might take samples of the fluid around the brain and spinal cord (cerebrospinal fluid), respiratory fluid, blood, and stool for lab testing.
  • A nerve check. This test can check how fast an electrical impulse moves through the nerves and the response of muscles to messages from the nerves.

Acute flaccid myelitis can be hard to diagnose because it shares many of the same symptoms as other neurological diseases, such as Guillain-Barre syndrome. These tests can help distinguish acute flaccid myelitis from other conditions.


Currently, there is no specific treatment for acute flaccid myelitis. Treatment is aimed at managing symptoms.

A doctor who specializes in treating brain and spinal cord illnesses (neurologist) might recommend physical or occupational therapy to help with arm or leg weakness. If physical therapy is started during the initial phase of the illness, it might improve long-term recovery.

The doctor might also recommend treatment with immunoglobulin that contains healthy antibodies from healthy donors, drugs that lower inflammation in the body (corticosteroids) or antiviral drugs. Or the doctor might recommend a treatment that removes and replaces blood plasma (plasma exchange). However, it's not clear whether these treatments have any benefits.

Sometimes nerve and muscle transfer surgeries are done to improve limb function.

Preparing for your appointment

If you have symptoms of acute flaccid myelitis, seek immediate medical care.

Here's some information to help you get ready for your appointment.

What you can do

Make a list of the following:

  • Signs and symptoms, including any that seem unrelated to the reason for the appointment
  • Any medications, including vitamins, herbs and over-the-counter medicines that you or your child is taking, and their dosages
  • Key personal information, including recent illnesses, travel and activities
  • Questions to ask the doctor

For acute flaccid myelitis, some basic questions to ask the doctor include:

  • Will additional tests be needed?
  • What are the treatment options?
  • What are the benefits and risks of each treatment?
  • Is there one treatment you feel is best?
  • Should additional specialists be seen? What will that cost, and will my insurance cover it?
  • Are there brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions that occur to you.

What to expect from your doctor

The doctor is likely to ask you or your child several questions. Be ready to answer them to allow time later to cover other points you want to address. The doctor may ask, for example:

  • When did you or your child first begin experiencing symptoms?
  • Are the symptoms continuous or occasional?
  • How severe are the symptoms?
  • What, if anything, seems to improve the symptoms?
  • What, if anything, appears to worsen the symptoms?
  • Did you or your child have a viral infection in the past month?
Nov. 09, 2021
  1. About acute flaccid myelitis. Centers for Disease Control and Prevention. https://www.cdc.gov/acute-flaccid-myelitis/about-afm.html. Accessed Aug. 7, 2020.
  2. Acute flaccid myelitis. Genetics and Rare Diseases Information Center. https://rarediseases.info.nih.gov/diseases/13142/acute-flaccid-myelitis. Accessed Aug. 7, 2020.
  3. Fatemi Y. Acute flaccid myelitis: A clinical overview for 2019. Mayo Clinic Proceedings. 2019; doi:10.1016/j.mayocp.2019.03.011.
  4. Helfferich J, et al. Acute flaccid myelitis and enterovirus D68: Lessons from the past and present. European Journal of Pediatrics. 2019; doi:10.1007/s00431-019-03435-3.
  5. Greenberg B. Acute flaccid myelitis. https://www.uptodate.com/content/search. Accessed Aug. 7, 2020.
  6. Kidd S, et al. Vital signs: Clinical characteristics of patients with confirmed acute flaccid myelitis, United States, 2018. MMWR Morbidity and Mortality Weekly Report. 2020; doi:10.15585/mmwr.mm6931e3.

Acute flaccid myelitis (AFM)