2016 Acute Flaccid Myelitis Outbreak in Texas: Promising Outcomes
In 2014, the United States saw an unprecedented rise in cases of acute flaccid myelitis (AFM). Causes and treatment of AFM are unknown, though it has been linked to enterovirus D68 (EV-D68). Poor outcomes were observed in 2014, with only 5% showing complete recovery of symptoms.
During the year 2016, a new outbreak of AFM occurred that surpassed that of 2014. In this outbreak we saw a larger portion of cases in Texas and the disease did not coincide temporally with an EV-D68 outbreak as it did in 2014.
We reviewed cases of AFM in Central Texas during 2016 to describe presentation, possible causes, treatments, and outcomes.
Cases of AFM, defined as sudden onset limb weakness and abnormal spinal magnetic resonance imaging involving grey matter, were manually reviewed May 2016-April 2017. Information included extensive review of presentation, imaging, laboratory values, treatment and response, and neurology follow up and outcomes.
AFM was identified in 7 cases. Median age was 4.4 years. Cervical spinal involvement and cerebrospinal fluid pleocytosis (>5 white blood cells/mm3) were present in all cases. Fever and respiratory illness were the most common prodromal symptoms (71% each). Medical treatments varied; use and response are represented in figure 1. All children received physical/occupational therapy.
A possible etiology was found in 4 cases; one with EV-D68. The remaining 3 cases tested positive for enterovirus A71 and human parechovirus (HPeV), HPeV alone, and human herpesvirus-6 (HHV-6). Three of the 7 cases regained full function at 9-30 weeks after onset of illness, including the cases diagnosed with HHV-6 and HPeV only; the remaining 4 all showed improvement with residual functional impairment at 4.5-9 months. Neither case with concomitant enterovirus has recovered fully; the case with EV-D68 suffered the most severe disease.
AFM continues to be a complex, poorly understood disease. Although there are no treatment standards, our data show promising symptom improvement. One case (14%) was diagnosed with EV-D68 compared with 22% of cases tested in the U.S. in 2014.
Figure 1. Treatments and Symptom Response in 7 Cases with AFM
B. Patel, None
A. Bailey, None
D. Murphey, None
M. Fernandez, None
J. Kane, None
S. Hauger, None