CDC: What To Look For in Acute Flaccid Myelitis
As the number of confirmed cases in the US continues to rise, a new report from the CDC details common signs and symptoms associated with acute flaccid myelitis (AFM).
Those patients who meet the clinical case criteria for AFM—defined as acute flaccid limb weakness—are classified as “confirmed,” “probable,” or “not a case.”
Among 106 patients with flaccid limb weakness between January 1 and November 2, 2018, 80 cases of AFM were classified as “confirmed,” 6 as “probable,” and 20 as noncases—a 3-fold increase in confirmed cases compared with the same period in 2017.
Among confirmed cases, the median age was 4 years, 59% were male, and 56 of 65 patients with available information on race were white. In the 4 weeks preceding limb weakness, signs and symptoms consistent with viral illness were present in 99% of confirmed cases. These symptoms included fever (81%), respiratory symptoms (78%), and gastrointestinal symptoms (38%). Overall, 47.5% reported upper limb involvement only, 8.8% reported lower limb involvement only, 15% reported two to three upper and lower limbs, and 28.8% reported all 4 limbs.
Among the 78 confirmed cases with available cerebrospinal fluid (CSF) results, 65 (83%) had pleocytosis, with a median cell count of 103 cells per mm3. Among 71 patients who were tested for enterovirus/rhinovirus, 38 patients had positive test results by EV/RV real-time reverse transcription-polymerase chain reaction testing, including 11 (29%) for EV-A71, 14 (37%) for EV-D68, and 13 (34%) for other viruses, primarily from nonsterile sites.
“Almost all patients with AFM have reported signs and symptoms consistent with viral illness in the weeks preceding limb weakness. Clinical, laboratory, and epidemiologic evidence to date suggest a viral association. CDC and collaborators continue to investigate risk factors for AFM and to study the causes and mechanisms of AFM.”
—Michael Potts
Reference:
McKay SL, Lee AD, Lopez AS, et al. Increase in acute flaccid myelitis — United States, 2018 [published online November 13, 2018]. MMWR Morb Mortal Wkly Rep. doi:http://dx.doi.org/10.15585/mmwr.mm6745e1