Inflammation of a transverse portion of the spinal cord characterized by acute or subacute segmental demyelination or necrosis. The condition may occur sporadically, follow an infection or vaccination, or present as a paraneoplastic syndrome (see also ENCEPHALOMYELITIS, ACUTE DISSEMINATED). Clinical manifestations include motor weakness, sensory loss, and incontinence. (Adams et al., Principles of Neurology, 6th ed, pp1242-6)