The exact cause of transverse myelitis and extensive damage to the bundles
of nerve fibers of the spinal cord is unknown in many cases. Cases in which a cause cannot be identified are called idiopathic. Viral, bacterial, and fungal infections affecting the spinal cord may cause the disorder.
A number of conditions appear to cause transverse myelitis, including:
Immune system disorders appear to play an important role in causing damage to the spinal cord. Such disorders are:
aquaporin-4 autoantibody associated neuromyelitis optica. Neuromyelitis optica is a disorder that affects the eye nerves and spinal cord. Aquaporin-4 is a channel on the cell membrane that lets water enter the cell and helps maintain the chemical balance for processes to take place within the central nervous system. An antibody is a protein that binds to foreign substances that can attack the host organism.
multiple sclerosis, a disorder in which immune system cells that normally protect us from viruses, bacteria, and unhealthy cells mistakenly attack the protective coating of myelin in the brain, optic nerves, and spinal cord
post-infectious or post-vaccine autoimmune phenomenon, in which the body’s immune system mistakenly attacks the body’s own tissue while responding to the infection or, less commonly, a vaccine
an abnormal immune response to an underlying cancer that damages the nervous system; or
other antibody-mediated conditions that are still being discovered.
Viral infections including herpes viruses such as varicella zoster (the virus that causes chickenpox and shingles), herpes simplex, cytomegalovirus, and Epstein-Barr; flaviviruses such as West Nile and Zika; influenza, echovirus, hepatitis B, mumps, measles, and rubella. It is often difficult to know whether direct viral infection or a post-infectious response causes the transverse myelitis.
Bacterial infections such as syphilis, tuberculosis, actinomyces, pertussis, tetanus, diphtheria,and Lyme disease. Bacterial skin infections, middle-ear infections, campylobacter jejuni gastroenteritis, and mycoplasma bacterial pneumonia have also been associated with the condition.
Fungal infections in the spinal cord, including aspergillus, blastomyces, coccidioides, and cryptococcus.
Parasites, including toxoplasmosis, cysticercosis, shistosomiasis, and angtiostrongyloides.
Other inflammatory disorders that can affect the spinal cord, such as sarcoidosis, systemic lupus erythematosus, Sjogren’s syndrome, mixed connective tissue disease, scleroderma, and Bechet’s syndrome.
Vascular disorders such as arteriovenous malformation, dural arterial-venous fistula, intra-spinal cavernous malformations, or disk embolism.
In some people, transverse myelitis represents the first symptom of an autoimmune or immune-mediated disease such as multiple sclerosis or neuromyelitis optica.“Partial” myelitis—affecting only a portion of the cord cross-section—is more characteristic of multiple sclerosis. Neuromyelitis optica is much more likely as an underlying condition when the myelitis is “complete” (causing severe paralysis and numbness on both sides of the spinal cord). Myelitis attacks with neuromyelitis optica spectrum disorder (NMOSD) tend to be more severe and are associated with less recovery than attacks with multiple sclerosis.