National Institutes of Health

The primary NIH organization for research on Acute Flaccid Myelitis is the National Institute of Neurological Disorders and Stroke

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Acute Flaccid Myelitis

Also called: AFM

Summary

What is acute flaccid myelitis (AFM)

Acute flaccid myelitis (AFM) is a neurologic disease. It is rare, but serious. It affects an area of the spinal cord called gray matter. This can cause the muscles and reflexes in the body to become weak. Because of these symptoms, some people call AFM a "polio-like" illness.

What causes acute flaccid myelitis (AFM)?

There are a variety of possible causes of AFM, including viruses and environmental toxins (harmful substances in the environment).

Viruses that may cause AFM include

Poliovirus and non-polio enteroviruses
West Nile virus (WNV)
Adenoviruses

In many cases, it is not possible to identify what caused AFM.

Who is at risk of getting acute flaccid myelitis (AFM)?

Anyone can get AFM, but most of the recent cases have been in children.

What are the symptoms of acute flaccid myelitis (AFM)?

Most people with AFM will suddenly have arm or leg weakness and a loss of muscle tone and reflexes. Some people also have other symptoms, including

Facial drooping/weakness
Trouble moving the eyes
Drooping eyelids
Trouble swallowing
Slurred speech
Pain in the arms or legs

Sometimes AFM can weaken the muscles necessary for breathing. This can lead to respiratory failure, which is very serious. A ventilator (breathing machine) may be needed.

How is acute flaccid myelitis (AFM) diagnosed?

AFM causes many of the same symptoms as other neurologic diseases, such as transverse myelitis and Guillain-Barre syndrome. This can make it difficult to diagnose. To make a diagnosis, a doctor will

Do a neurologic exam, including looking at where there is weakness, poor muscle tone, and decreased reflexes
Look at pictures of the spinal cord and brain. This may include images from an MRI
Do lab tests on the cerebrospinal fluid (the fluid around the brain and spinal cord)
Check nerve speed (nerve conduction velocity) and the response of muscles to the messages from the nerves (electromyography)

It is important that the tests are done as soon as possible after the symptoms start.

What are the treatments for acute flaccid myelitis (AFM)?

There is no specific treatment for AFM. A doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend treatments for specific symptoms. For example, physical and/or occupational therapy may help with arm or leg weakness. Researchers do not know the long-term outcomes of people with AFM.

Can acute flaccid myelitis (AFM) be prevented?

You can take steps to help prevent infections of some of the viruses that may cause AFM:

Make sure that you and your children are up to date on polio vaccinations
Protect yourself and your children against bites from mosquitoes, which can carry West Nile virus

Learn More

Acute Flaccid Myelitis (Genetic and Rare Diseases Information Center)Also in Spanish
Acute Flaccid Myelitis (Centers for Disease Control and Prevention)
Acute Flaccid Myelitis in U.S. Children (Centers for Disease Control and Prevention)