Acute Disseminated Encephalomyelitis: Also called parainfectious or postinfectious encephalomyelitis, this rare type of inflammation leads to demyelination of nerves in the brain and spinal cord. (Demyelination is the destruction of the tissues that wrap around nerves, called the myelin sheath.)

This disorder usually develops after a viral infection. Acute disseminated encephalomyelitis is thought to be a misguided immune reaction triggered by the virus. In the United States, this disorder usually results from some types of influenza, hepatitis A or B, or infection with enteroviruses, Epstein-Barr virus, or human immunodeficiency virus (HIV). Measles, chickenpox, and rubella used to be common causes before childhood vaccination became widespread.

Typically, the inflammation develops 1 to 3 weeks after the viral illness begins. It can be treated with corticosteroids given intravenously. Guillain-Barré syndrome (see see Peripheral Nerve Disorders: Guillain-Barré Syndrome) seems to be a similar disorder of the peripheral nerves.

Adrenoleukodystrophy and Adrenomyeloneuropathy: Both are rare hereditary metabolic disorders. Adrenoleukodystrophy affects young boys, usually between the ages of 4 and 8. A milder, more slowly developing form of the disorder can begin in adults in their 20s or 30s. Adrenomyeloneuropathy affects adolescent boys.

In these disorders, widespread demyelination is accompanied by adrenal gland dysfunction. Boys have behavioral problems and problems with hearing and vision. Eventually, mental deterioration, involuntary and uncoordinated muscle contractions (spasticity), and blindness occur.

No cure for either disorder is known. Dietary supplements with glycerol trioleate and glycerol trierucate (known as Lorenzo's oil) have not been shown to slow the progression of the disease. Bone marrow transplantation is an experimental treatment.

Leber's Hereditary Optic Neuropathy: This disorder causes demyelination leading to partial blindness. The disorder is more common among men. Usually, symptoms begin between the ages of 15 and 35. This disorder is inherited through the mother, and the defective genes seem to be located in mitochondria (structures in cells that provide energy for the cell).

No treatments are available. But limiting consumption of alcohol, which may affect the mitochondria, and not using tobacco products may help.

Tropical Spastic Paraparesis: Also called HTLV-associated myelopathy (see Spinal Cord Disorders: Tropical Spastic Paraparesis/HTLV-1–Associated Myelopathy), this disorder causes demyelination in the spinal cord and results from infection with the human T-cell lymphotropic virus (HTLV). The disorder worsens over several years. Gradually, the legs become weak and muscle spasms occur—a condition called spastic weakness. Frequent, strong urges to urinate, urinary incontinence, and bowel dysfunction also develop.

No cure is available, but corticosteroids may help, as may interferon-beta or immune globulin given intravenously (these drugs help prevent the immune system from attacking myelin sheaths). Muscle relaxants such as baclofenSome Trade Names
LIORESAL
or tizanidineSome Trade Names
ZANAFLEX
help relieve spasms.

Neuromyelitis Optica: Also called Devic disease, this disorder causes symptoms similar to those of multiple sclerosis and used to be considered a variant of multiple sclerosis. However, neuromyelitis optica typically affects only the eyes and the spinal cord, and multiple sclerosis also affects the brain.

Neuromyelitis optica causes inflammation of the optic nerve (optic neuritis). One or both eyes may be affected. The disorder causes episodes of eye pain and dim, blurred, or lost vision. Days to weeks (sometimes years) later, the limbs are affected. People may temporarily lose sensation, and the arms and legs may become weak and sometimes paralyzed. People may be unable to control bladder and bowel function.

In some people, the part of the spinal cord that controls breathing is inflamed, leading to difficulty breathing, which is life threatening.

The disorder progresses differently in each person. As the disorder progresses, people may have brief, frequent, painful muscle spasms. Eventually, blindness, loss of sensation and muscle weakness in the limbs, and bladder and bowel dysfunction may become permanent.

To diagnose the disorder, doctors evaluate the nervous system (neurologic examination) during a physical examination (see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: Physical Examination). The optic nerve is examined with an ophthalmoscope (see Diagnosis of Eye Disorders: What Is an Ophthalmoscope?). Tests include magnetic resonance imaging (MRI) and a blood test to detect specific antibodies in people with neuromyelitis optica.

There is no cure. However treatments can stop episodes, control symptoms, and prevent episodes from recurring. A corticosteroid (such as methylprednisoloneSome Trade Names
MEDROL
) and a drug that suppresses the immune system (an immunosuppressant, such as azathioprineSome Trade Names
IMURAN
) are often used to stop and prevent episodes. RituximabSome Trade Names
RITUXAN
, a relatively new drug, may be used to reduce the number of abnormal antibodies and to control disorder. Plasma exchange (plasmapheresis) may help people who do not respond to corticosteroids. For this treatment, blood is removed, then abnormal antibodies are removed, and the blood is returned to the person.

Treatment of symptoms is similar to that for multiple sclerosis (see Multiple Sclerosis (MS) and Related Disorders: Treatment). BaclofenSome Trade Names
LIORESAL
or tizanidineSome Trade Names
ZANAFLEX
may relieve muscle spasms.

Last full review/revision March 2008 by Brian R. Apatoff, MD, PhD