Acute flaccid myelitis (AFM) is a rare, polio-like condition that affects the body’s nervous system, specifically the spinal cord. It affects the spinal cord, the part of the nervous system that carries messages to and from the brain. AFM can lead to paralysis. Though, most cases of AFM have been in children, it can develop in adults too.
The exact cause of the illness is not known, though scientists think it is most likely the result of a viral infection. A leading candidate for the cause of the condition is enterovirus 68, a member of the enterovirus genus and thus related to poliovirus. Other variety of possible causes of AFM may include environmental toxins and genetic disorders.
Although the illness is not new, its increased incidence since 2014 is new; the existing information about it is tentative and should not be taken as established medical opinion.
Signs and Symptoms
Most people will have sudden onset of arm or leg weakness and loss of muscle tone and reflexes. Some people, in addition to arm or leg weakness, will have:
difficulty moving the eyes,
drooping eyelids, or
difficulty with swallowing or slurred speech.
Numbness or tingling is rare in people with AFM, although some people have pain in their arms or legs. Some people with AFM may be unable to pass urine (pee).
The most severe symptom of AFM is respiratory failure that can happen when the muscles involved with breathing become weak. This can require urgent ventilator support (breathing machine).
In some cases, the paralysis has been permanent. And in very rare cases, it is possible that the process in the body that triggers AFM may also trigger other serious neurologic complications that could lead to death.
When to Seek Medical Help
Seek treatment as soon as possible if you see any symptoms of AFM. If you notice your child is not using his/her arm, call your pediatrician or go to the emergency room.
AFM is diagnosed by examining a patient’s nervous system in combination with reviewing images of the spinal cord. A doctor can examine a patient’s nervous system and the places on the body where he or she has weakness, poor muscle tone, and decreased reflexes.
In addition, a doctor can do an MRI (magnetic resonance imaging) to look at a patient’s brain and spinal cord, do lab tests on the cerebrospinal fluid (the fluid around the brain and spinal cord), and may check nerve conduction (impulse sent along a nerve fibre) and response.
There is no specific treatment for AFM. Techniques such as corticosteroids, plasmapheresis, intravenous immunoglobulin and experimental antiviral drugs have been attempted on a trial basis, but have not been established to be effective. Plasmapheresis is specifically not recommended because the potential for harm is significant in the absence of any evidence of benefit.
Transplantation of nerves from the ribs and diaphragm, done within 8-12 months after onset of paralysis, has been reported.
Other treatment is supportive and depends on the symptoms. A doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend certain interventions on a case-by-case basis. For example, neurologists may recommend physical or occupational therapy to help with arm or leg weakness caused by AFM. Physical therapy and occupation therapy are especially important during recovery. The extent of recovery varies. Although some people may make a full recovery, most have continued muscle weakness even after a year. Long term outcomes are not known.
Poliovirus and West Nile virus may sometimes lead to AFM.
You can protect yourself and your children from poliovirus by getting vaccinated.
You can protect against bites from mosquitoes, which can carry West Nile virus, by using mosquito repellent, staying indoors at dusk and dawn (when bites are more common), and removing standing or stagnant water near your home (where mosquitoes can breed).
While hand washing is not known to be effective in preventing AFM, washing your hands often with soap and water is one of the best ways to avoid getting sick and spreading germs to other people.
It is advised that in preventing infections generally, people should stay home if they are ill, avoid close contact (such as touching and shaking hands) with those who are ill, also clean and disinfect frequently touched surfaces.
Unlike polio, acute flaccid myelitis cannot currently be prevented with a vaccine.