OBJECTIVETo explore the development and prognosis of the acute flaccid paralysis (AFP) associated with enterovirus 71 (EV71) infection through clinical follow-up study for clinical and magnetic resonance imaging (MRI) features based on the research progress of virology and pathology.

METHODSixteen children with HFMD associated with AFP in hospital from May 1, 2011 to August 31, 2011 were investigated and the patients received intensive rehabilitation training. The 16 cases were divided into two groups (the recovery or the sequela) by if the muscle strength recovered to level 4 after intensive rehabilitation. The MRI findings of 15 children were analyzed and among them, 6 patients were reexamined after one month. The clinical markers were compared between groups including course of disease, WBC, WBC in cerebrospinal fluid (CSF), ventilator support, therapy, the worst muscle strength, the initial tendon reflex, the muscle atrophy, and multi-limb paralysis. The data were analyzed by t test and χ2 test with SPSS10.0.

RESULTAll the 16 children were infected with enterovirus 71 (EV71). The myodynamia of 7 children were level 0, 4 children had serious upper limbs paralysis. The neck muscle in 3 cases and the brain stem motor ruckus in 4 cases were involved. The ankle clonus of non-completely paralyzed limbs in 14 cases occurred during rehabilitation. Eight children had the better prognosis, the other 8 children had sequela. 0 level muscle strength (0 case vs. 7 cases, χ2=12.4), the initial tendon reflex (2 cases vs. 8 cases, χ2=9.6), obvious muscle atrophy (0 case vs. 8 cases, χ2=16), were significantly different in the children with the recovery when compared to the sequela (P<0.01). The severe upper limbs paralysis had the worse prognosis than the severe lower limbs paralysis. MR imaging showed signs of spinal nerve root inflammation and the bilateral hyperintense lesions, symmetrical in the posterior portions of the medulla, pons, and asymmetrical in the ventral horns of cervical spinal cord. Signal enhancement occurred only in the early MRI examination.

CONCLUSIONIn the evolution of AFP due to EV71 infection, the upper motor neuron damage is common, the prognosis is related with the severity of early paralysis and neuron damage. MR imaging is helpful to understand the pathological mechanism of AFP.