Acute Flaccid Myelitis: Outbreak of Polio-Resembling Disease of Unknown Origin Affecting Children in the US
A recently emerging outbreak of symptoms affecting children has been recorded in the United States since September is being referred to as acute flaccid myelitis.
Reports describe cases of acute weakness in one or more limbs with MRI scans showing inflamed non-enhancing lesions in the grey matter of the spinal cord similar to the manifestations of West Nile viruses and enteroviruses. Severity of weakness has been known to vary, with some cases displaying full limb paralysis (Jayne M. Ness, University of Alabama). Jean-Baptiste Le Pichon (neurologist, Children’s Mercy Hospital) reported that the majority of cases have an increased white blood cell count in the cerebrospinal fluid. He also noted all MRI’s showing a signal increase in the ventral horns of the spinal cord in the same area as is shown in polio. It was suggested in an October CDC Morbidity and Mortality Weekly Report that often, symptoms are accompanied by neck, back, or extremity pain.
Aetiology has been speculated upon, and it is generally recognised that Enterovirus 68 is the leading candidate for the cause of the illness. The first cases were mostly from the Denver area (Health Advisory, September 2014), but now 93 reports have been verified in 33 states as of December 3rd 2014. Before October 29th, 80% of the 64 patients meeting the criteria reported a preceding respiratory illness and 75% reported fever in the days leading up to onset of symptoms (American Academy of Pediatrics, November 2014). This suggests that acute flaccid myelitis could be caused as a rare complication to exposure to a common virus.
The CDC is requesting that clinicians remain vigilant and report cases that match the case definition. A correct diagnosis requires an accurate medical history, MRI imaging, and elimination of similar illnesses; namely transverse myelitis and Guillain-Barré syndrome (Neurology News, October 2014).
There is currently no treatment available for this illness. People are advised to follow hand washing procedures and avoid contact with people who show symptoms. The CDC recommend parents stay up to date with vaccinations and consult with a paediatrician if their child begins to show symptoms.