Federal health officials are investigating a spike in cases of acute flaccid myelitis (AFM) and asking clinicians to remain vigilant.
There have been 108 confirmed cases in 36 states this year through October, most of which have been children under 18. However, the cause of the uptick is unknown, according to the Centers for Disease Control and Prevention (CDC). The illness is rare but serious.
“You have a normal healthy child over the course of a few hours to weeks develop weakness and in some cases paralysis and in even more rare instances they need to be on a ventilator,” said Manisha Patel, M.D., M.S., a pediatrician and the CDC’s team lead on AFM. “It’s incredibly heartbreaking to see this.”
AFM is defined as
- acute onset of focal limb weakness and
- MRI showing spinal cord lesion largely restricted to gray matter or cerebrospinal fluid (CSF) with pleocytosis.
Some patients will present with facial droop, difficulty moving their eyes, ptosis or slurred speech. They also may have limb pain, but numbness and tingling are rare, according to Mary Anne Jackson M.D., FAAP, an ex officio member of the AAP Committee on Infectious Diseases. Some patients experience respiratory failure.
Clinicians should keep in mind AFM is rare and rule out other diagnoses with similar symptoms.
“There are other things that can look like (acute) flaccid myelitis so (take) care in defining the patients’ clinical presentation, associating it with MRI findings and then correlating it with CSF findings,” Dr. Jackson said.
Enteroviruses, West Nile virus and adenoviruses all can cause AFM, but this year’s cases haven’t had a common link, according to Dr. Patel.
In 2014, an outbreak of 120 cases of AFM in 34 states coincided with an outbreak of enterovirus D68 (EV-D68). However, the CDC has not been able to determine whether the virus was causing the AFM outbreak.
“At this point, we just need the epidemiologic link, but we’ve tested hundreds of specimens and we have not been able to consistently identify a pathogen,” Dr. Patel said.
In 2015, there were 21 cases of AFM but no EV-D68. This year, there have been 108 AFM cases and only “limited sporadic cases” of EV-D68, according to the CDC.
Because a single pathogen hasn’t been linked consistently to this year’s cases, the CDC is providing general disease-prevention strategies, advising people to wash their hands often, stay up-to-date on vaccines, protect themselves from mosquito bites and avoid contact with people who are sick.
During the 2014 outbreak, experts from the CDC, Academy and other groups crafted guidance on clinical management of AFM but “found no concrete evidence for indication of corticosteroids, IVIG (intravenous immune globulin), plasmapheresis, interferon, antivirals, or other immunomodulatory agents,” according to the report.
“Most of the interventions, really we don’t have evidence that they hasten improvement or result in a better outcome so management is predominantly supportive care and in terms of recovery, focusing on aggressive physical and occupational therapy,” said James J. Sejvar, M.D., a CDC neuroepidemiologist on the AFM team.
Dr. Sejvar is reconvening the expert group this winter to see if the guidance needs to be updated and hopes to release any revisions in late January or early February. The Academy again will be providing input.
Clinicians should report cases of AFM to their state or local health department.
“We are working really hard to better understand this,” Dr. Patel said. “And we hope as providers continue to report to us, we’ll get more robust data to get a better handle on what’s going on with AFM.”