Parents and families of children who developed now have a few more answers regarding a recent cluster of cases of acute flaccid myelitis (AFM).

In the report, “Notes from the Field: Six Cases of Acute Flaccid Myelitis in Children – Minnesota, 2018” lead author Heidi Moline, MD, MPH, Chief Resident of Pediatrics at the University of Minnesota Medical School and University of Minnesota Masonic Children’s Hospital, collaborates with experts from the Centers for Disease Control and Prevention (CDC) and the Minnesota Department of Health (MDH), to better understand the course of illness and cause of acute flaccid myelitis. Notably, the team found Enterovirus-D68 (EV-D68) in the cerebrospinal fluid of one affected patient, concluding that, "identification of EV-D68 in the CSF of case 2 is considered the cause of AFM in this patient."

During September 14 through October 1, 2018, MDH was notified of six children hospitalized in the Minneapolis-St. Paul area with symptoms consistent with AFM. 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. All six of these cases were confirmed as AFM by the CDC. This report describes the first 6 cases of AMF identified last fall, though by the end of 2018, there were a total of 10 confirmed cases of AFM in Minnesota.

Other important components of this report include:

  • This AFM cluster—the largest identified in Minnesota—occurred during a period of increased AFM reports nationally
  • The average patient age for this cluster in Minnesota was 6 years old
  • All patients in this cluster live in different counties of Minnesota.
  • All patients experienced fever and upper respiratory signs and symptoms (such as rhinorrhea, cough) beginning an average of eight days prior to weakness onset
  • Magnetic resonance imaging (MRI) showed spinal cord grey matter involvement in all six patients, largely in the anterior horns.

“Acute flaccid myelitis is incredibly scary for patients and families. The fact that we were able to definitively identify the EV-D68 virus as the cause of paralysis in one of our Minnesota patients, does suggest this virus as a probable cause in our other recent AFM cases. We are working with our public health partners to better understand this virus, and how it is affecting children in our community. Clinically, we need to continue efforts to rapidly identify these patients to optimize therapy and improve long term outcome of affected children, ” said Moline.

Following a cluster of three cases in 2014, less than one AFM case per year has been reported to MDH.

During her research, Dr. Moline found an excerpt from a book in 1877 which described polio. She said it was striking, because it was almost identical to what her patients’ parents were describing to her: “A child of two or four years of age is put to bed well, and without the occurrence of any febrile illness in the night, flaccid paralysis of one or more limbs is discovered in the morning.” Essentially, children would go to sleep feeling well, but then wake up unable to brush their hair or walk without assistance.

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. AFM primarily affects children, but adult cases have also been reported.