Confirmed acute flaccid myelitis (AFM) cases have risen to 158, the highest in any year since tracking began in 2014.
While the disease is extremely rare, health officials have been urging heath care providers to be vigilant for children with sudden limb weakness.
The 158 confirmed cases in 36 states announced by the Centers for Disease Control (CDC) today are up from 134 cases in 33 states a week ago. Officials said last week they expected additional cases but believe the disease has peaked for the year.
AFM cases have spiked every other year since 2014 but have now surpassed the 149 cases confirmed in 2016 and 120 in 2014.
AFM is defined as:
- acute onset of flaccid limb weakness and
- MRI showing spinal cord lesion largely restricted to gray matter spanning one or more vertebral segments (confirmed case) or cerebrospinal fluid with pleocytosis (probable case).
Most cases have been among children who have had a fever or respiratory illness in the weeks leading up to their limb weakness. The CDC has been looking at links between AFM and viruses like enterovirus D68, but these viruses have not been detected in all of the patients. There also are many people who have these common viruses but do not progress to AFM, leading some experts to question whether an autoimmune response also is involved. The CDC has gathered experts from around the country to study AFM causes and treatments.
Physicians should be vigilant for patients with limb weakness, which also may present with facial droop or difficulty swallowing. They should ask whether patients recently experienced respiratory or gastrointestinal illness. Those who suspect a patient has AFM should perform a workup, including MRI, spinal tap and collection of respiratory, stool, serum and spinal fluid samplesfor testing, and report suspected cases to their state or local health department.