Transverse myelitis is a neurological disorder caused by inflammation across both sides of one segment of the spinal cord. The term myelitis refers to inflammation of the spinal cord; transverse simply describes the position of the inflammation, that is, across the width of the spinal cord. Attacks of inflammation can damage or destroy myelin, the fatty insulating substance that covers nerve cell fibers. This damage causes nervous system scars that interrupt communications between the nerves in the spinal cord and the rest of the body.
Symptoms of transverse myelitis include a loss of spinal cord function over several hours to several weeks. What usually begins as a sudden onset of lower back pain, muscle weakness, or abnormal sensations in the toes and feet can rapidly progress to more severe symptoms, including paralysis, urinary retention, and loss of bowel control.
The segment of the spinal cord at which the damage occurs determines which parts of the body are affected. Nerves in the cervical (neck) region control signals to the neck, arms, hands, and muscles of breathing (the diaphragm). Nerves in the thoracic (upper back) region relay signals to the torso and some parts of the arms. Nerves at the lumbar (mid-back) level control signals to the hips and legs. Finally, sacral nerves, located within the lowest segment of the spinal cord, relay signals to the groin, toes, and some parts of the legs. Damage at one segment will affect function at that segment and segments below it. In patients with transverse myelitis, demyelination usually occurs at the thoracic level, causing problems with leg movement and bowel and bladder control, which require signals from the lower segments of the spinal cord.
Transverse myelitis occurs in adults and children, in both genders, and in all races. No familial predisposition is apparent. A peak in incidence rates appears to occur between 10 and 19 years and 30 and 39 years. It is estimated that about 1,400 new cases of transverse myelitis are diagnosed each year in North America, and approximately 33,000 North Americans have some type of disability resulting from the disorder.
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:
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 may be either acute (developing over hours to several days) or subacute (developing over 1 to 2 weeks). Symptoms may include:
Depending on which segment of the spinal cord is involved, some patients may experience respiratory problems as well.
From this wide array of symptoms, four classic features of transverse myelitis emerge:
Recovery from transverse myelitis usually begins within 2 to 12 weeks of the onset of symptoms and may continue for up to 2 years. However, if there is no improvement within the first 3 to 6 months, significant recovery is unlikely. About one-third of people affected with transverse myelitis experience good or full recovery from their symptoms; they regain the ability to walk normally and experience minimal urinary or bowel effects and paresthesias. Another one-third show only fair recovery and are left with significant deficits such as spastic gait, sensory dysfunction, and prominent urinary urgency or incontinence. The remaining one-third show no recovery at all, remaining wheelchair-bound or bedridden with marked dependence on others for basic functions of daily living. Research has shown that a rapid onset of symptoms generally results in poorer recovery outcomes.
Although some patients recover from transverse myelitis with minor or no residual problems, others suffer permanent impairments that affect their ability to perform ordinary tasks of daily living. Most patients will have only one episode of transverse myelitis; a small percentage may have a recurrence.
As with many disorders of the spinal cord, no effective cure currently exists for people with transverse myelitis. Treatments are designed to manage and alleviate symptoms and largely depend upon the severity of neurological involvement. Physicians often prescribe corticosteroid therapy during the first few weeks of illness to decrease inflammation. General analgesia will likely be prescribed for any pain the patient may have. And bedrest is often recommended during the initial days and weeks after onset of the disorder.
Following initial therapy, the most critical part of the treatment for this disorder consists of keeping the patient’s body functioning while hoping for either complete or partial spontaneous recovery of the nervous system. This may sometimes require placing the patient on a respirator. Many forms of long-term rehabilitative therapy are available for people who have permanent disabilities resulting from transverse myelitis, including: