The clinical signs are caused by an interruption in ascending and descending neuroanatomical pathways in the transverse plane of the spinal cord, and a resulting sensory level is characteristic of the syndrome.
The transverse myelitis syndrome may arise from various causes, but it most often occurs as an autoimmune phenomenon after an infection or vaccination (accounting for 60% of the cases in children) or as a result of a direct infection, an underlying systemic autoimmune disease, or an acquired demyelinating disease such as multiple sclerosis or the spectrum of disorders related to neuromyelitis optica (Devic's disease, a demyelinating disease that is defined by transverse myelitis and optic neuritis).
However, after detailed evaluation, 15 to 30% of the cases of transverse myelitis are ultimately categorized as idiopathic.