Patient education: Acute flaccid myelitis (The Basics)

What is acute flaccid myelitis? — Acute flaccid myelitis, or "AFM," is a rare condition that can cause sudden muscle weakness. It typically happens after being sick with a fever or cold. AFM usually affects children.

The cause is not known for sure, but experts think that AFM might be related to certain types of viruses. In 2014, there was an outbreak of a virus called "enterovirus D68" in the US. Around the same time, there was also an outbreak of AFM. Since then, there have been other outbreaks of both enterovirus D68 and AFM. But it is not yet clear whether the virus actually causes AFM.

AFM is very rare. Most people who get infected with enterovirus D68 or another virus do not get AFM.

What are the symptoms of AFM? — In people who get AFM, it usually follows symptoms of a cold. These might include fever, headache, stuffy nose, cough, or stiff neck. Then, AFM symptoms can include:

●Muscle weakness in the arms and legs

●Weakness in the face

The weakness gets worse over several days. In severe cases, it can lead to trouble speaking, swallowing, or breathing. Some people have bowel or bladder problems.

An infection called "polio" can also cause symptoms like these. Polio no longer occurs in the US, because most babies get a vaccine to prevent it.

Is there a test for AFM? — If a doctor thinks that your child might have AFM based on their symptoms, they will do a "neurologic exam." For this exam, the doctor checks how the brain, nerves, and muscles are working.

The doctor will order tests, too, such as:

●MRI – This a type of imaging test. Imaging tests create pictures of the inside of the body. It can show changes in the spinal cord and brain that happen in AFM.

●Lumbar puncture, sometimes called a "spinal tap" – During this procedure, a doctor puts a thin needle into the lower back and removes a small amount of spinal fluid. This is the fluid that surrounds the brain and spinal cord. They will then do lab tests on the spinal fluid.

●Nerve conduction studies or electromyography – These tests can show whether the nerves are carrying electrical signals correctly. They can also show whether the muscles are responding to the signals.

The doctor will also order other tests to figure out what is causing your child's symptoms. These might include tests on samples of blood, bowel movement, urine, or fluid from the nose or throat. These tests can help figure out if your child's symptoms are caused by AFM or something else.

How is AFM treated? — AFM is usually treated in the hospital. There, doctors can monitor the child's breathing and health. Children who cannot breathe on their own need a machine to help them breathe. This is called "mechanical ventilation." In some cases, the machine is only needed for a few days. In other cases, it is needed for longer.

While some children recover completely from AFM, many will have some muscle weakness for months or even years. Following a "rehab" program can help with this. During rehab, doctors, nurses, and therapists help people strengthen their muscles and move their bodies.

Can AFM be prevented? — There is no way to prevent AFM for sure. But you can help prevent enterovirus D68 and other viruses by:

●Making sure that your child washes their hands often with soap and water, especially after using the bathroom

●Staying away from people who are sick, and not sharing cups or eating utensils

While doctors don't know for sure if AFM is caused by a virus, it's still a good idea to take these steps to lower the chances of getting sick.

More on this topic

Patient education: Poliomyelitis (The Basics)
Patient education: Enterovirus D68 (The Basics)