Acute Flaccid Myelitis (AFM): Symptoms, Causes and Care

What it is

Acute flaccid myelitis (AFM) is a rare but serious neurologic disease affecting the spinal cord's gray matter, which can make the body's muscles and reflexes weak. Because of this, some people call it a "polio-like" illness — but it is not polio and isn't caused by polioviruses.

Causes

Several viruses can cause AFM. Researchers think enteroviruses are behind the recent rise in cases in children; flaviviruses, herpesviruses and adenoviruses can cause it too. Most people with AFM had a mild respiratory illness or fever, like an ordinary viral infection, beforehand.

Who gets it: anyone can, but more than 90% of cases have been in young children.

Symptoms

Most people with AFM suddenly develop:

• arm or leg weakness;
• loss of muscle tone and reflexes.

Some also have:

• facial drooping or weakness;
• trouble moving the eyes or drooping eyelids;
• trouble swallowing or slurred speech;
• pain in the arms, legs, back or neck.

AFM can weaken the muscles used for breathing, leading to respiratory failure, which is very serious and may require a ventilator. If you or your child develops any of these symptoms, get medical care right away.

Diagnosis

AFM shares many symptoms with other neurologic diseases, such as transverse myelitis and Guillain-Barré syndrome, which makes it hard to diagnose. Doctors may use:

• a neurologic exam — where the weakness is, muscle tone and reflexes;
• an MRI of the spinal cord and brain;
• lab tests of the cerebrospinal fluid around the brain and spinal cord;
• nerve conduction and electromyography (EMG) studies, which check how fast nerves carry signals and how muscles respond.

Tests should be done as soon as possible after symptoms start.

Treatment

There's no specific treatment. A neurologist may recommend care for particular symptoms — for example, physical or occupational therapy for arm or leg weakness. The long-term outcomes of AFM aren't known.

Prevention

There's no specific way to prevent AFM, but you can lower the chance of catching a virus:

• wash your hands often with soap and water;
• don't touch your face with unwashed hands;
• avoid close contact with people who are sick;
• clean and disinfect often-touched surfaces, including toys;
• cover coughs and sneezes with a tissue or your upper sleeve, not your hands;
• stay home when sick.

Sources

Based on "Acute Flaccid Myelitis," MedlinePlus, National Library of Medicine, drawing on the Centers for Disease Control and Prevention; a work of the United States government in the public domain.