Transverse myelitis is a rare condition involving inflammation of the spinal cord that can be caused by infectious processes, autoimmune disorders, or toxic agents. Infectious agents include tuberculosis, Lyme disease, and syphilis as well as viruses such as varicella zoster and herpes simplex, especially in immunocompromised patients. Travel to geographically endemic areas may lead to exposure of potential causative infectious agents such as West Nile virus, Zika virus, and human T-cell lymphotropic virus 1 (HTLV-1) (tropical spastic paraparesis / HTLV1-associated myelopathy [TSP/HAM]) and parasites such as angiostrongyliasis, schistosomiasis, and cysticercosis.

Symptoms of myelopathy often develop over a few hours and progress over days. These include weakness or paralysis, numbness or paresthesias, and neck, back, abdominal, or extremity pain. There may be bowel and/or bladder symptoms including incontinence, urinary retention, or constipation. It is important to note associated symptoms such as fevers, weight loss, or rashes, which may help identify the cause and guide specific treatments. There is often a history of preceding respiratory, gastrointestinal, or systemic illness.

Most individuals have only one attack, and one-third have complete recovery. However, transverse myelitis may be the initial presentation of multiple sclerosis, neuromyelitis optica, or other autoimmune conditions.