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 have numbness or tingling in arms or legs.
The most severe symptoms of AFM are:
- Respiratory failure (when the muscles involved with breathing become weak and require machines to help patients 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 hospitalize patients since AFM can progress rapidly and require urgent medical care, 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: December 29, 2020