Five things you should know about acute flaccid myelitis (AFM)
Between August and December each year, cases of acute flaccid myelitis (AFM) increase nationwide, according to the Minnesota Department of Health. It’s a rare condition. Minnesota has only seen 17 cases since it began tracking the condition in 2014. But parents are still urged to be vigilant.
Mark Schleiss, MD, a pediatric infectious diseases physician with M Health Fairview and a professor at the University of Minnesota Medical School, offers advice on what families should know.
What is AFM?
Acute flaccid myelitis, or AFM, is a condition that causes severe muscle weakness and loss of muscle tone in one or more parts of the body. This profound weakness is caused by inflammation of the spinal cord.
AFM is believed to be caused by certain infections—most of them viral—that attack the spinal cord and damage it. Most of these viruses—known as enteroviruses—are common infections that everyone eventually acquires. No one knows why these viruses affect the spinal cord in only a tiny fraction of the population. Other germs, such as the bacterium that causes Lyme disease, can also cause AFM in some patients. AFM primarily affects children, but adult cases have also been reported.
“A common misconception about AFM is that it’s a muscle problem that causes a child to be unable to move an arm or a leg. But it’s not a disease within the arm muscles or leg muscles. The problem is in the spinal cord. AFM is an inflammatory condition of the grey matter in the spinal cord,” Schleiss said.
The weakness that defines AFM can start anywhere in the body, including a child’s arms or legs, facial muscles and eye muscles. In severe cases, it can also affect the muscles that control swallowing or breathing. The weakness appears random and is often on one side of the body (for example, the right leg might be affected, but not the left leg).
Even though the viruses and germs that may cause it are extremely common, AFM is very rare, affecting less than one in a million people.
What are AFM warning signs?
AFM tends to arrive suddenly. Often, the first symptom is sudden weakness in an arm or leg, followed by the loss of muscle tone in one area of the body. These are signs to seek emergency medical care.
Other signs of AFM can include:
- Sudden weakness in arms and legs
- Loss of muscle tone and reflexes
- Difficulty moving the eyes
- Weakness or drooping in the face or eyelids
- Difficulty in swallowing, speaking, or urination
- Pain in arms or legs, neck, or back
What are the long-term effects of AFM?
Once a virus or other germ damages the spinal cord’s cells, those cells cannot be repaired. There is no known cure for AFM, but medications can help reduce the inflammation associated with the infection that has produced AFM. In another era, the polio virus – which is also an enterovirus – caused myelitis and. AFM has similarities with polio, including injury to the grey matter of the spinal cord and flaccid limb weakness that can result in paralysis. Fortunately, today polio can be prevented by a vaccine. Vaccines for other enteroviruses, including those associated with AFM, are in development, but are not yet available.
However, there is hope. Many children can recover functional abilities and complete daily living activities with the help of physical therapy and occupational therapy, depending on the area affected by AFM.
“Even though the spinal cord does not go back to normal, we have seen amazing things as children adapt and compensate,” Schleiss said.
What should a parent do if they suspect their child may have AFM?
If your child suddenly becomes unable to move a part of his or her body—including an arm, a leg, the face, or the eyes—contact your child’s doctor right away or bring your child to the nearest emergency department.
Children diagnosed with AFM will benefit from a multidisciplinary healthcare team to help regain as much function as possible.
How can people prevent infection?
The steps you can take to prevent AFM are the same steps you should take to prevent any other infection—frequent and careful hand washing. Good hand hygiene is the number one way to avoid infections of all kinds. In order to reinforce good habits, parents may want to supervise their children as they wash their hands. Experts recommend washing with warm water and soap for 30 seconds.
