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Other Primary Demyelinating Diseases
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 Guillain-Barré Syndrome) seems to be a similar disorder of the peripheral nerves.
Adrenoleukodystrophy and adrenomyeloneuropathy 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 often 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. Some boys with adrenoleukodystrophy are totally disabled or die 2 to 3 years after diagnosis. Often, adults with the milder form first notice a problem when their legs become weak and stiff, they lose control of their bladder or bowels (incontinence), and/or erectile dysfunction develops. The diagnosis is confirmed by genetic testing.
No cure for either disorder is known. Dietary supplements with glycerol trioleate and glycerol trierucate (known as Lorenzo’s oil) can be tried in boys when the adrenal gland (but not the brain) is affected. This treatment may slow the progression of the disease slightly. Many experts now recommend bone marrow transplantation if the brain is affected.
Leber hereditary optic neuropathy causes demyelination leading to partial blindness. Some people also have heart problems or muscle symptoms (such as involuntary muscle contractions, muscle weakness, or muscle spasms), which may resemble symptoms of multiple sclerosis. 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 (see Tropical Spastic Paraparesis/HTLV-1–Associated Myelopathy) 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-alpha or immune globulin given intravenously (these drugs help prevent the immune system from attacking myelin sheaths). Muscle relaxants such as baclofen or tizanidine help relieve spasms.
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