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
  • Be unable to pass urine (pee)
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