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:
AFM symptoms: sudden arm or leg weakness

Arm or leg weakness

Loss of muscle tone and reflexes

Some people will also have:
AFM symptoms: difficulty moving the eyes or drooping eyelids

Difficulty moving the eyes or drooping eyelids

AFM symptoms: facial droop or weakness

Facial droop or weakness

AFM symptoms: difficulty with swallowing or slurred speech

Difficulty with swallowing or slurred speech

AFM symptoms: pain in arms or legs

Pain in arms or legs

AFM symptoms: Pain in neck or back

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