Pediatric Acute Flaccid Myelitis

Acute flaccid myelitis (AFM) is a rare – but serious – condition that affects the nervous system. Specifically, it targets the area of the spinal cord called gray matter and causes the body’s muscles and reflexes to become weak. It can lead to paralysis which is sometimes permanent.

Most acute flaccid myelitis cases have been in young children (the average age is five). Many children recover from the disease but others are left with a permanent disability. Prompt recognition and immediate action are critical to achieving the best possible outcomes.

Although acute flaccid myelitis is sometimes referred to as a “polio-like” condition, it is not caused by poliovirus . Instead, experts believe it is usually caused by enteroviruses , particularly D68, or EV-D68. The virus typically strikes between August and November.

Acute flaccid myelitis cases have been increasing in the United States every other year since 2014. The last outbreak, in 2018, resulted in 238 cases in 42 states. The virus tends to come in two-year cycles. Fortunately, acute flaccid myelitis itself is not contagious, and only a few people who get the EV-D68 virus will get acute flaccid myelitis.

The most common symptoms of acute flaccid myelitis are sudden onset of arm or leg weakness, loss of muscle tone and loss of reflexes. This often follows a fever or respiratory illness.

Other symptoms include:

• Drooping eyelids or difficulty moving the eyes
• Facial droop or weakness
• Difficulty talking or swallowing
• Severe pain or numbness in arms or legs
• Pain in neck or back
• Difficulty breathing

You should seek medical care right away if your child develops these symptoms.

Doctors typically diagnose acute flaccid myelitis by reviewing a patient’s medical history, examining their nervous system and performing an MRI to view pictures of the spinal cord. They may also need to collect some cerebrospinal fluid (the fluid around the brain and spinal cord) to look at it in the laboratory.

Acute flaccid myelitis can be difficult to diagnose because it shares many of the same symptoms as other neurologic diseases, such as stroke and Guillain-Barre syndrome , which also need prompt treatment. Children’s National Hospital has an acute flaccid myelitis taskforce consisting of neurologists, infectious disease experts, physical medicine and rehabilitation experts and radiologists, as well as a diagnostic pathway to ensure a fast and thorough evaluation.

Currently, there is no specific treatment for acute flaccid myelitis, but doctors may recommend different treatments based on each patient. Physical and occupational therapy helps with arm or leg weakness, and antivirals or immunoglobulin can help the body fight off the virus and reduce neuroinflammation. Often treatment in an intensive care unit is needed. Research is underway to improve understanding of acute flaccid myelitis and develop better treatments.

Because experts believe acute flaccid myelitis is caused by a virus, the same preventive actions that reduce a person's risk for COVID-19 infection — frequent handwashing, physical distancing, mask wearing and cleaning and disinfecting high-touch surfaces — can also help prevent acute flaccid myelitis.