5 questions and answers about acute flaccid myelitis, the polio-like illness confirmed in two Mass. children

The state Department of Public Health is investigating four other suspected cases of the condition.

FILE - In this Oct. 8, 2013, file photo, a sign marks the entrance to the federal Centers for Disease Control and Prevention (CDC) in Atlanta. The canceled federal conference on climate change and health problem is back on but apparently minus the federal government. Former Vice President Al Gore, the University of Washington, the Harvard Global Health Institute and the American Public Health Association are resurrecting a climate change and health conference set for next month that the Centers for Disease Control and Prevention had planned then canceled in December. (AP Photo/David Goldman, File)
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Two children in Massachusetts have contracted a serious, rare illness that causes muscle weakness and paralysis, according to the state’s Department of Public Health.

The state’s first case this year of acute flaccid myelitis, or AFM, was confirmed in August, according to the department, which is investigating four other suspected cases. There is no specific treatment or cure for the illness.

The Centers for Disease Control and Prevention has been actively investigating AFM since 2014 and “monitoring” the activity of the disease. According to the CDC, from August 2014 through September 2018, 386 confirmed cases of AFM have been reported to the federal agency, and the cause for the majority of the cases has not been confirmed. So far in 2018, 62 cases have been confirmed in 22 states.


We spoke with Dr. Leslie Benson, assistant director of the neuro-immunology program at Boston Children’s Hospital, to learn more about the illness, which has been described as being similar to polio

What is acute flaccid myelitis?

It is not “totally clear” what causes AFM, Benson explained.

“Most likely it appears to be a viral infection — specifically a fairly common viral infection,” she said. “But we don’t know why in some patients it may affect the spinal cord. When it does infect the spinal column or parts of the brain stem, it can cause fairly sudden onset weakness and paralysis.”

The effects of AMF range from weakness of the facial muscles to problems with bladder control to weakened breathing.

“It’s not just one virus that can do this. There are a few viruses that can do this,” she said. “And we can’t always detect them in each individual patient for a variety of reasons.”

The vast majority of cases are in children, particularly young kids, Benson said. She said in her experience, four is the average age of the patients, though it is possible in younger children.

“I’ve seen [it in] anyone from one to two, up to teenagers,” she said.  

What is the treatment?


There’s no specific treatment that helps or reverses the effects of the condition.

“The main part of treatment is supportive,” Benson said. “If they can’t breathe, we put them on a ventilator. If they are having pain, we treat their pain. We give them a lot of physical therapy, and they get a lot of rehabilitation.”

While patients can show gradual improvement, she said that many are left with permanent long-term weakness.

Why is it being described as polio-like?

Benson said the polio virus is not the culprit in the AFM cases.

“[AFM is] described as ‘polio-like’ because it sort of acts a lot like polio in the way that we believe it’s a viral infection of the motor nerves in the spinal cord,” she said. “And, really, polio is the classic thing that does that or did that.”

How common is AMF?

“In a general sense, it’s very rare,” she said. “However this year, two years ago, four years ago — so 2014 and 2016 — we definitely saw, along with the rest of the country, clusters of cases where we had multiple patients in the span of a couple of months. And it didn’t feel rare during those clusters on a neurology ward, but in between those clusters, we really don’t see this condition often at all.”

The season for the illness, when it occurs, appears to be August, September, and October, Benson said.

What are the symptoms to watch for?

Benson said she’s hopeful there won’t be a lot more cases in Massachusetts since the season is likely coming to a close.


“The symptoms most often are weakness of an extremity starting in one and sometimes spreading to other extremities,” she said. “And sometimes it’s a shoulder or a hip that are the first sign of weakness. It can also be pain associated in the back or in the limb that’s affected. Those are the biggest, first signs that there’s something going on.”

In addition to the sudden onset of muscle weakness, the state public health department said slurred speech, difficulty swallowing, and difficulty moving the eyes can also be experienced by patients.

“It’s a scary thing, and it’s hard not to be fearful for your own child, but it’s also an extremely rare thing,” Benson said. “The only thing within people’s control is good infection control.”

That includes coughing into your elbow, washing your hands, and taking the precautions you would normally take to avoid the common cold.

“So other than kind of general precautions, there’s not a lot to do,” she said. “But certainly if someone has been sick and starts to notice their child isn’t walking or moving correctly, you should get that checked out as soon as possible.”