[S2-1B-2] A cluster of acute flaccid myelitis observed in autumn, 2015, Japan
[Introduction] Cluster of acute flaccid paralysis (AFP) cases with spinal cord lesions resembling those of acute flaccid myelitis (AFM) were reported in autumn, 2015, Japan. An increased number of enterovirus D68 (EV-D68) infection was noted from the surveillance data for the same period.
[Methodology] 115 AFP cases were reported following a national AFP surveillance for the period August – December, 2015. 101 cases participated in a subsequent study, with radiological and neurophysiological data submitted for review.
[Results] 59 cases fit in the diagnostic criteria of AFM, including 4 adult cases. Median age was 4.4 years. Types and severity of limb paralysis varied from one to four limbs involvement, most showing asymmetric limb weakness. Prodromal symptoms consisted of fever (88%), respiratory (75%), and gastrointestinal symptoms (19%) were noted. Neurological symptoms of cranial neuropathy, focal paresthesia, neurogenic bladder were noticed in some cases. All except one had longitudinal spinal lesions of predominant grey matter on MRI. Cerebrospinal fluid pleocytosis was observed in 85% of the cases. Despite immunomodulation therapy, residual weakness was noted in 52 cases. 9 cases tested positive for EV-D68 from biological specimens.
[Conclusions] Most cases had spinal MRI lesions and pleocytosis, suggesting AFM as a homogeneous entity with poor motor prognosis. More study should be done to elucidate the pathogenesis of this unknown syndrome for effective intervention.
[Methodology] 115 AFP cases were reported following a national AFP surveillance for the period August – December, 2015. 101 cases participated in a subsequent study, with radiological and neurophysiological data submitted for review.
[Results] 59 cases fit in the diagnostic criteria of AFM, including 4 adult cases. Median age was 4.4 years. Types and severity of limb paralysis varied from one to four limbs involvement, most showing asymmetric limb weakness. Prodromal symptoms consisted of fever (88%), respiratory (75%), and gastrointestinal symptoms (19%) were noted. Neurological symptoms of cranial neuropathy, focal paresthesia, neurogenic bladder were noticed in some cases. All except one had longitudinal spinal lesions of predominant grey matter on MRI. Cerebrospinal fluid pleocytosis was observed in 85% of the cases. Despite immunomodulation therapy, residual weakness was noted in 52 cases. 9 cases tested positive for EV-D68 from biological specimens.
[Conclusions] Most cases had spinal MRI lesions and pleocytosis, suggesting AFM as a homogeneous entity with poor motor prognosis. More study should be done to elucidate the pathogenesis of this unknown syndrome for effective intervention.