Polio-like disease sparks new sense of urgency

(Reuters Health) - Back in 2014, as Dr. Riley Bove’s family was just getting over a respiratory virus, her 4-year-old son suddenly developed some very scary symptoms. “He woke up with a paralyzed arm, neck and shoulder,” said Bove, an assistant professor of neurology at the University of California, San Francisco. “I got him right into care. Over the course of the next eight days he continued to get worse and was eventually paralyzed from the face down to his toes.”

It got so bad that the little boy needed help breathing, but after a stint in acute care and then two months in rehab, Bove’s son was finally able to walk on his own. He still has lingering issues from his experience with the polio-like illness called acute flaccid myelitis - a paralyzed right shoulder and a weak neck that requires him to wear a brace - but “he certainly had an amazing recovery,” Bove said.

The experience, along with stories she heard from other parents of children struck by the condition, called acute flaccid myelitis (AFM), prompted Bove and two other health care professionals to write an article they hope will sound an alarm that will spur the Centers for Disease Control and Prevention and scientists from around the country to make a bigger push to better understand the condition.

Bove’s article appears today in JAMA Pediatrics along with two others that grapple with AFM, exploring ways that physicians could more quickly diagnose a disease that currently is so rare that few have any experience with it. Though its symptoms look almost exactly like those of polio, that disease was eradicated in the US decades ago, so “there was no one on the lookout for that kind of weakness,” Bove said. “Kids weren’t being examined properly. Some were told it was all in their kids’ heads or they were lethargic because they were sick. Because the medical community wasn’t aware of it, they weren’t finding it.”

The disease has been seen in previous years, and it is still quite rare. But publication of the three papers on AFM in a special issue of the journal underscores the urgency with which experts are starting to view it. The most recent data from the CDC shows 116 confirmed cases among the total of 286 reports under investigation.

The problem for doctors now is that little is known about the disease: why just one child in a family will get it even though all got sick with the same virus thought to be at its root; why it may be on the rise now; what can be done to prevent it.

One of the two other studies published alongside Bove’s sought to narrow the definition of the disease so that it could be distinguished from other neurologic diseases that have overlapping symptoms, such as spinal cord stroke, Guillain-Barre syndrome, and meningitis. “Our main goal was to prepare ourselves for future research studies that are going to be needed to get an understanding of the causes, diagnoses and treatment,” said the study’s lead author Dr. Matthew Elrick, a fellow in neuromuscular medicine and pediatric neurology at the Johns Hopkins School of Medicine.

The description used by the CDC is good enough as a screening tool, Elrick explained, but to really unravel the details of the disease, you need a much more restrictive set of diagnostic criteria to make sure you are only looking at cases of AFM. One of the signs that distinguishes AFM from other paralyzing diseases is that it doesn’t cause a loss of sensation in affected limbs, Elrick said. AFM also appears to affect limbs on one side of the body more severely than the other.

What is known so far is that AFM’s symptoms “are almost identical to those of polio,” Elrick said. “In fact it’s almost indistinguishable from polio, except for some subtle differences.”

The disease is thought to be caused by viruses from the same family - the enteroviruses - as the polio virus. What scientists know from polio is that certain viruses can kill nerve cells, Elrick said. When kids go through rehab and recover function it’s not because new nerve cells have been made, but because the surviving ones have stepped in and taken over the jobs that the dead ones used to do.

Having a more restrictive definition for AFM will help researchers look for possible genetic vulnerabilities that allow the virus to damage the spinal cord in some children, but not others. It’s thought that about 1 percent of children who catch the viruses associated with AFM will develop paralysis, Elrick said.

Elrick coauthored the third article, which lays out ways that primary care physicians, ER doctors and parents can spot the signs of AFM earlier, which might improve children’s prognoses. “The key point is that a lot of times when children first present to medical professionals, they initially attribute the children’s weakness to lethargy and the children just feeling awful. We want both parents and physicians to make sure the child can at least lift up all four limbs against gravity.”

Children who can’t do that need to be brought in for evaluation for AFM, Elrick said. “In many cases there is a delay of a day or two from when people first start thinking something is wrong,” he added.

Dr. Larry Kociolek welcomed the new articles.

“I think they are largely a call for heightened action,” said Kociolek, associate medical director of infection prevention and control at the Ann & Robert H. Lurie Children’s Hospital of Chicago and an assistant professor of pediatrics at Northwestern University’s Feinberg School of Medicine. “There’s nothing we’ve seen to suggest this is going away. And because of the profound (complications) associated with this diagnosis, we do need to escalate our public health response.”

The biggest challenge right now is pinpointing the cause of AFM, Kociolek said. “Unlike polio where it was found to be caused by one particular virus, many children have not had either clinical or microbiologic evidence of infection and the vast majority have not had any virus identified in their cerebrospinal fluid.”

The good news is that “healthcare providers are becoming increasingly aware of this,” Kociolek said. “And there’s been an increase in partnerships between health care providers and public health officials. I think the response is improving.”

SOURCE: JAMA Pediatrics, online November 30, 2018.