What is the ‘Polio-Like’ Illness, Acute Flaccid Myelitis?

A child with epilepsy during a seizure

Sick child. | Martinbowra/Getty Images

While rare, a polio-like illness called Acute Flaccid Myelitis (AFM) can cause weakness in the arms and legs. Recently six children in Minnesota were diagnosed with the illness, according to CNN.  The state typically sees less than one case per year.

Cases sharply increased in the U.S. from 2014 until 2018. The Centers for Disease Control (CDC) tracked  362 cases of AFM, with most in children. Although cases have increased, the CDC asserts the condition is still rare. “Less than one in a million people in the United States get AFM each year,” the CDC states.

But how do you identify if you have AFM? Also, how is it contracted and is there a treatment?

What is AFM?

According to the Transverse Myelitis Association, AFM is, “inflammation of the spinal cord and generally presents with unique clinical and MRI features that are not typical of classical transverse myelitis.  AFM abnormalities noted on MRI are predominantly found in the gray matter of the spinal cord.”

Symptoms include limb, facial, oral or eye weakness. Weakness may vary from subtle to severe. AFM may also result in total or partial paralysis too. Limbs appear weak or limp, rather than being spastic, which is seen in classic cases of transverse myelitis.

While numbness is rare, people with AFM may experience pain in their extremities. Some people may be unable to urinate. In the most severe form, respiratory failure is possible.

How do you contract AFM?

Researchers are not entirely sure how AFM is contracted. However, the CDC suggests it can be contracted through the polio virus, non-polio enteroviruses, West Nile virus and adenovirus. The CDC notes the adenovirus can cause cold-like symptoms, sore throat and bronchitis. Non-polio viruses can produce the same symptoms as the adenovirus. While polio was eradicated from the U.S., it is still spread in countries like Afghanistan, Pakistan, and Nigeria.

West Nile virus is spread through mosquito bites. AFM may come from the Japanese encephalitis virus and Saint Louis encephalitis virus.

AFM prevention

Getting the polio vaccine is one level of protection, according to the CDC. But you can also protect yourself from the West Nile virus. Use mosquito repellent and avoid being outdoors at dusk and dawn. Also, avoid standing water, which is where mosquitos congregate.

The CDC also suggests good hand washing techniques. That means using soap an water to avoid spreading germs to other people.

How is AFM diagnosed?

AFM is challenging to diagnose because it mimics other neurologic diseases, the CDC reports. However, the physician will examine the patient’s nervous system. Some tests focus on reflexes, muscle tone, and limb weakness. The doctor will also use an MRI (magnetic resonance imaging) to examine the patient’s brain and spinal cord. Tests are also performed on cerebrospinal fluid (the fluid around the brain and spinal cord). Testing should be done as soon as possible once symptoms appear.

Is there a treatment?

No specific treatment exists for AFM, the CDC reports. Specialists will examine individual cases to recommend treatment.  Some treatments include high dose IV steroids, IVIg, and plasma exchange, according to the Transverse Myelitis Association. IV fluids are designed to reduce swelling in the spinal cord.  As of now, long-term prognosis is unknown.

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