Elrich et al reported a definition for acute flaccid myelitis (AFM) that is more restrictive than a CDC definition reported in 2014.
Features:
(1) prodromal fever or viral syndrome
(2) weakness in a lower motor neuron pattern
(2a) involve limbs, face and/or bulbar muscles
(2b) limb weakness accompanied by decreased muscle tone and decreased or absent deep tendon reflexes (DTR)
(3) one or more of the following:
(3a) gray matter predominant T2 hyperintense lesions on MRI of the spinal cord, spanning multiple levels, with or without ventral nerve root enhancement
(3b) motor neuropathy with intact sensory nerve conduction by EMG and nerve conduction studies
(3c) pleocytosis in the CSF (>= 5 white blood cells per µL)
(4) all of the following:
(4a) absence of objective sensory deficits
(4b) absence of supratentorial white matter or cortical lesions > 1 cm in diameter
(4c) absence of encephalopathy that cannot be explained by fever, respiratory distress, metabolic abnormalities or illness
(4d) absence of elevated CSF protein > 2 times ULN in the absence of CSF pleocytosis
(4e) absence of an alternative diagnosis that can explain the findings better
