Transverse myelitis

Acute transverse myelitis is a neurological disorder caused by inflammation of the spinal cord that damages or destroys myelin, the fatty insulating substance that covers nerve cells fibers. This results in scarring, which interrupts communications between the nerves in the spinal cord and the rest of the body.

Signs and symptoms can develop over several hours or weeks and may include:

• Muscle weakness or paralysis of the arms or legs or both
• Pain
• Loss of sensation in the toes and feet
• Loss of bladder and bowel control

Causes of transverse myelitis include:

• Abnormal immune system response to a virus, causing the immune system to mistakenly attack the spinal cord. Transverse myelitis often follows a viral infection. It usually occurs as a single episode with no recurrence.
• Autoimmune diseases, such as lupus and Devic disease, a condition that affects the optic nerves and spinal cord. In such cases, transverse myelitis may recur.

Other conditions — such as stroke, blood vessel abnormalities and a tumor of the spinal cord — may cause signs and symptoms that mimic transverse myelitis. Multiple sclerosis (MS) also may affect the spinal cord. But it usually affects other parts of the nervous system as well. When MS does involve the spinal cord, it's more likely to affect only one side of the body and cause only partial paralysis and sensory loss. Fewer than 10 percent of people with acute transverse myelitis ever develop MS.

Some people with transverse myelitis recover with few, if any, long-term problems. Others may have permanent impairments that affect their ability to perform daily tasks. The level of the spinal cord at which the damage occurs determines which parts of the body are affected. Damage at one segment will affect function at that segment and all segments below it. For example, damage in the neck (cervical) region usually affects both the arms and legs; damage in the upper back (thoracic) region usually affects only the legs.

A doctor may make a diagnosis by taking a medical history and performing a thorough neurological exam. Standard treatment is with high doses of corticosteroids. With such treatment, about half of the people with transverse myelitis recover within six months.

Another promising therapy is plasma exchange. In one study, those with transverse myelitis who didn't respond to steroids were treated with a two-week course of plasma exchange within the first three months after onset of the condition. Forty percent of study participants showed dramatic improvement with the plasma exchange treatment.

Typically, if significant recovery doesn't take place by six months after onset of transverse myelitis, it's unlikely to occur. Treatment is then directed at rehabilitation.