Acute Flaccid Paralysis — Cause Unknown

Stephen G. Baum, MD

The etiology of 23 cases of acute flaccid paralysis with anterior myelitis, identified in California over the last 2 years, is unknown.

Acute flaccid paralysis (AFP) is not a reportable condition unless it is associated with an unusual disease. Viruses are suspected in most cases; enteroviruses, flaviviruses, and adenovirus are among those implicated in the past.

In August 2012, the California Department of Public Health received a report of AFP with anterior myelitis in a 29-year-old man who had not been vaccinated against polio. Two additional cases followed shortly. Testing did not reveal evidence of enteroviruses or any other known pathogen. Alerts to clinicians in California between December 2012 and February 2014 yielded 23 similar cases. Although poliovirus was not found, and no other virus was consistently isolated, two of the patients had enterovirus D68 (EV-D68) isolated from respiratory tract specimens.

Fifty-six percent of those affected were male (median age, 10 years), with patient race/ethnicity mirroring that of the population. There was no geographic clustering in California and no history of foreign travel. Most patients had a respiratory or gastrointestinal prodrome <10 days before AFP onset, and 83% had lymphocytic cerebrospinal fluid pleocytosis. Although sensory deficits were absent in most patients, mental status changes were seen in 10 (8 of whom reverted to normal) and cranial nerve abnormalities in 8. Of 13 patients with available information, all had paralysis persisting at 60 days, and 5 were ventilator-dependent. One patient — an adult — died.

Citation(s):

Ayscue P et al. Acute flaccid paralysis with anterior myelitis — California, June 2012–June 2014. MMWR Morb Mortal Wkly Rep 2014 Oct 3 (early release); 63:1.