Symptoms of AFM

AFM is an uncommon but serious neurologic condition. Sudden onset of arm or leg weakness, loss of muscle tone, and loss of reflexes are the most common symptoms.

Seek medical care right away if you or your child develops any of these symptoms.

Most people will have sudden onset of:

Arm or leg weakness

Loss of muscle tone and reflexes

Some people will also have:

Difficulty moving the eyes or drooping eyelids

Facial droop or weakness

Difficulty with swallowing or slurred speech

Pain in arms or legs

Pain in neck or back

In uncommon cases, people may also:

The most severe symptoms of AFM are:

Respiratory failure: This happens when the muscles involved with breathing become weak and can require a ventilator (a machine to help them breathe).
Serious neurologic complications such as body temperature changes and blood pressure instability that could be life threatening.

Seek Medical Care Right Away

If you or your child develops any of these symptoms, you should seek medical care right away.
Clinicians should immediately admit patients to the hospital since AFM can progress rapidly and require urgent medical intervention, like assistance with breathing.
Your clinicians should collect information about your symptoms and send this information to their state or local health departments.

Page last reviewed: February 25, 2020