Sudden Paralysis and Acute Flaccid Myelitis in Children

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If you are like most people, there's a good chance you have never heard of acute flaccid myelitis (AFM). It's an extremely rare condition that can lead to paralysis and affects fewer than one in 1 million people in the United States.

However, although AFM is rare, a substantial increase in the number of cases diagnosed in both 2014 and 2016 was noted. Interestingly, diagnosed cases were low in 2015. Because this condition is so unpredictable and the exact causes are unknown, we need to stay on top of it and know what to watch for.

Young girl in hospital.
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If this condition is so rare, you may wonder why you need to know about it at all. The concern here is that cases are increasing and we don't know why. We don't know what causes acute flaccid myelitis and we don't know how to prevent it.

This condition has affected primarily children, although some adults have been diagnosed as well. Educating yourself about the symptoms and what to expect will help if you, your child, or someone you know is diagnosed with AFM.


Not everyone with acute flaccid myelitis experiences the same symptoms. The symptoms that typically occur with AFM include:

  • Sudden weakness of the limbs
  • Loss of muscle tone and reflexes
  • Facial droop/weakness
  • Difficulty moving the eyes
  • Drooping eyelids
  • Difficulty speaking or slurred speech

Some people may experience numbness, tingling, or pain in the arms and legs, but these symptoms are rare.

Respiratory failure may occur if the muscles that aid in breathing are affected. In these cases, mechanical ventilation may be necessary, often referred to as a breathing machine or life support. Other people may have trouble passing urine. The severity of these symptoms varies on a case by case basis.


If your child has the symptoms listed above and her doctor suspects that she may have acute flaccid myelitis, there are a number of tests that could be performed. Your child's pediatrician will test her nervous system checking her reflexes, muscle tone, and weakness. An MRI is often ordered to aid in diagnosis.

It is also possible that your child may need to have a lumbar puncture—or spinal tap—performed to test the cerebrospinal fluid (CSF) for germs that could be causing the symptoms.

All of these tests together help the healthcare team make a diagnosis and figure out treatment.

There are several viruses (germs) that can cause AFM-like symptoms. The most common that have been identified include:

  • Enteroviruses (like polio)
  • West Nile Virus
  • Adenovirus

Unfortunately, more often than not, an exact cause for AFM cannot be identified.

In 2014, there was an outbreak of an enterovirus known as EV-68. There was speculation that this new type of enterovirus could have been the cause of the increase in AFM cases that year. According to the CDC:

"EV-D68 has been previously identified in clinical specimens from a few patients with AFM. In those cases, however, it is not clear whether the presence of EV-D68 was a coincidence or whether it was the cause of the AFM. Regardless, extensive testing of clinical specimens from AFM cases in 2014 did not find a clear and consistent pathogen."


There is no specific treatment or cure for acute flaccid myelitis. The symptoms often resolve on their own but can be permanent or even life-threatening.

People that are diagnosed with AFM will likely need to treated by a team of doctors that may include a neurologist and possibly—if an infectious cause is identified—an infectious disease specialist. The doctors will determine which treatments could be effective in minimizing the symptoms and regaining function. Many people who have AFM need at least some physical therapy or rehabilitation.

Other Paralytic Conditions

There are many diseases and conditions that cause sudden onset or gradual paralysis in children and adults. AFM may initially be misdiagnosed or confused with a similar condition called Guillain-Barré syndrome (GBS).

Although the symptoms are similar, distinct differences between AFM and GBS can be seen on MRI and through other tests that neurologists may perform. If your child's Pediatrician suspects one of these conditions, he should refer you to a pediatric neurologist as soon as possible for more definitive testing and diagnosis.

Taking Action

The fact that we don't know what causes acute flaccid myelitis or how to treat it can be frightening for many parents and healthcare providers. It's hard to know what to do or how to prevent it. The US Centers for Disease Control and Prevention (CDC) do have some guidelines for trying to protect yourself and your children:

  • Get vaccinated
  • Protect yourself from mosquitoes
  • Wash your hands

Although doing these things won't guarantee that your children will not get AFM, these steps will protect them from many diseases and illnesses that could potentially cause it. Mosquitoes carry West Nile virus, so using mosquito protection is essential for avoiding it.

It isn't known if proper handwashing will prevent AFM or not, but it certainly can't hurt. Ensuring that your children are washing their hands correctly is so important. Make sure everyone in the family washes their hands before eating, after using the bathroom, before and after preparing food, and after changing diapers.

A Word From Verywell

Acute flaccid myelitis is a very rare condition. Although the fact that we don't know what causes it and we can't treat it is concerning, there is no need for parents to be overly alarmed. CDC researchers are working hard to get more information about this condition.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gavin M. What Is Acute Flaccid Myelitis?. [internet]. 2018.

  2. AFM Investigation. Centers for Disease Control and Prevention [internet]. 2019.

  3. Fatemi Y, Chakraborty R. Acute Flaccid Myelitis: A Clinical Overview for 2019. Mayo Clin Proc. 2019;94(5):875-881. doi:10.1016/j.mayocp.2019.03.011

  4. Acute flaccid myelitis (AFM). Virginia Department of Health [internet]. 2018.

  5. Millichap JG. Acute Flaccid Myelitis OutbreakPediatr Neurol Briefs. 2015;29(12):96. doi:10.15844/pedneurbriefs-29-12-7

Additional Reading
  • Acute Flaccid Myelitis. US Centers for Disease Control and Prevention.
  • Acute Flaccid Myelitis | AFM Surveillance | CDC. 
  • Acute Flaccid Myelitis | Frequently Asked Questions | CDC. 
  • Meissner, H. Cody MD, FAAP. Is EV-D68 Infection a Cause of Acute Flaccid Myelitis in Children? American Academy of Pediatrics.

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.