What causes transverse myelitis?
Researchers are uncertain of the exact causes of transverse myelitis. The inflammation that causes such extensive damage to nerve fibers of the spinal cord may result from viral infections or abnormal immune reactions. Transverse myelitis also may occur as a complication of syphilis, measles, Lyme disease, and some vaccinations, including those for chickenpox and rabies. Cases in which a cause cannot be identified are called idiopathic.
Transverse myelitis often develops following viral infections. Infectious agents suspected of causing transverse myelitis include varicella zoster (the virus that causes chickenpox and shingles), herpes simplex, cytomegalovirus, Epstein-Barr, influenza, echovirus, human immunodeficiency virus (HIV), hepatitis A, and rubella. Bacterial skin infections, middle-ear infections (otitis media), and Mycoplasma pneumoniae (bacterial pneumonia) have also been associated with the condition.
In post-infectious cases of transverse myelitis, immune system mechanisms, rather than active viral or bacterial infections, appear to play an important role in causing damage to spinal nerves. Although researchers have not yet identified the precise mechanisms of spinal cord injury in these cases, stimulation of the immune system in response to infection indicates that an autoimmune reaction may be responsible. In autoimmune diseases, the immune system, which normally protects the body from foreign organisms, mistakenly attacks the body’s own tissue, causing inflammation and, in some cases, damage to myelin within the spinal cord.
Because some affected individuals also have autoimmune diseases such as systemic lupus erythematosus, Sjogren’s syndrome, and sarcoidosis, some scientists suggest that transverse myelitis may also be an autoimmune disorder. In addition, some cancers may trigger an abnormal immune response that may lead to transverse myelitis.
In some people, transverse myeltis represents the first symptom of an underlying demyelinating disease of the central nervous system such as multiple sclerosis (MS) or neuromyelitis optica (NMO). A form of transverse myelitis known as "partial" myelitis--because it affects only a portion of the cross-sectional area of the spinal cord--is more characteristic of MS. Neuromyelitis optica typically causes both transverse myelitis and optic neuritis (inflammation of the optic nerve that results in visual loss), but not necessarily at the same time. All patients with transverse myelitis should be evaluated for MS or NMO because patients with these diagnoses may require different treatments, especially therapies to prevent future attacks.
Transverse myelitis often develops following viral infections. Infectious agents suspected of causing transverse myelitis include varicella zoster (the virus that causes chickenpox and shingles), herpes simplex, cytomegalovirus, Epstein-Barr, influenza, echovirus, human immunodeficiency virus (HIV), hepatitis A, and rubella. Bacterial skin infections, middle-ear infections (otitis media), and Mycoplasma pneumoniae (bacterial pneumonia) have also been associated with the condition.
In post-infectious cases of transverse myelitis, immune system mechanisms, rather than active viral or bacterial infections, appear to play an important role in causing damage to spinal nerves. Although researchers have not yet identified the precise mechanisms of spinal cord injury in these cases, stimulation of the immune system in response to infection indicates that an autoimmune reaction may be responsible. In autoimmune diseases, the immune system, which normally protects the body from foreign organisms, mistakenly attacks the body’s own tissue, causing inflammation and, in some cases, damage to myelin within the spinal cord.
Because some affected individuals also have autoimmune diseases such as systemic lupus erythematosus, Sjogren’s syndrome, and sarcoidosis, some scientists suggest that transverse myelitis may also be an autoimmune disorder. In addition, some cancers may trigger an abnormal immune response that may lead to transverse myelitis.
In some people, transverse myeltis represents the first symptom of an underlying demyelinating disease of the central nervous system such as multiple sclerosis (MS) or neuromyelitis optica (NMO). A form of transverse myelitis known as "partial" myelitis--because it affects only a portion of the cross-sectional area of the spinal cord--is more characteristic of MS. Neuromyelitis optica typically causes both transverse myelitis and optic neuritis (inflammation of the optic nerve that results in visual loss), but not necessarily at the same time. All patients with transverse myelitis should be evaluated for MS or NMO because patients with these diagnoses may require different treatments, especially therapies to prevent future attacks.
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