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).
In recent cases, most people had a mild respiratory illness or fever (like you would get from a viral infection) before they developed AFM.
Viruses that may cause AFM include
In many cases, it is not possible to identify what caused AFM.
Who is at risk for 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.
If you or your child develops any of these symptoms, you should get medical care right away.
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
Centers for Disease Control and Prevention
- Acute flaccid myelitis (Medical Encyclopedia) Also in Spanish
- 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)
- What Is Acute Flaccid Myelitis?: What Should Parents Watch For? (For Parents) (Nemours Foundation)