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Acute Flaccid Myelitis

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Condition Basics

What is acute flaccid myelitis?

Acute flaccid myelitis (AFM) is a rare condition that affects the spinal cord. It causes certain muscles and reflexes in the body to stop working normally. Anyone can get AFM.

What causes it?

Experts are still doing research to find the exact cause of AFM. It may be linked to certain viruses. This includes the West Nile virus and ones that can cause other illnesses, such as colds or rashes.

What are the symptoms?

The main symptom is weakness in one or more arms or legs, with a loss of muscle tone and reflexes. Other symptoms may include:

  • Drooping or weakness in the face or eyes.
  • Trouble swallowing.
  • Slurred speech.
  • Pain in the arms or legs.

Symptoms of acute flaccid myelitis usually come on suddenly.

Severe cases may cause respiratory failure, since the condition may affect muscles used for breathing.

How is it diagnosed?

A doctor will do a physical examination to check for weakness, such as in the arms and legs. The doctor may also do tests such as an MRI or tests to check the spinal fluid.

How is acute flaccid myelitis treated?

There is no specific treatment to cure acute flaccid myelitis. But doctors can give treatment to help manage the symptoms. You may get physiotherapy or occupational therapy to help regain function in your arms and legs.

For severe AFM that causes problems breathing, you will get care in the hospital. This includes treatment that helps you stay hydrated, gives you nutrition, and helps you breathe.

More information about AFM is available from Health Canada. Visit the Health Canada website at to learn more.

How can you protect yourself?

You can take steps to help protect yourself and your family from viruses and infections that may be linked to acute flaccid myelitis.

  • Get vaccinations. Check with your doctor to make sure that you and your family are up-to-date on all vaccinations.
  • Avoid infections transmitted by mosquitoes, such as West Nile virus. To protect yourself:
    • Use insect repellent.
    • Get rid of standing water near your home.
    • Avoid going outside at times when mosquitoes are more likely to be out.
  • Avoid germs that can cause illness or infection. Make sure to:
    • Wash your hands often with soap and water.
    • Avoid contact with sick people if you can.
    • Clean household surfaces with disinfectant.


Current as of: December 13, 2021

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine
Elizabeth T. Russo MD - Internal Medicine