Information on the following diseases can be found in the Related Disorders section of this report:

• Dejerine-Sottas disease
• Guillain-Barre syndrome
• Lewis-Sumner syndrome
• Multifocal motor neuropathy
• Multiple sclerosis

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a disorder in which there is inflammation of nerve roots and peripheral nerves nerve roots destroying the covering (myelin sheath) of nerves. Most patients cannot identify a preceding viral infection for prior to the appearance of CIDP.

The chief symptoms of CIDP are slowly progressive (over at least 2 months) muscle weakness and sensory dysfunction affecting the arms and legs. Weakness and sensory dysfunction usually becomes apparent during a period of several weeks or a few months. Nerve signals become altered causing impairment in motor function and/or abnormal, or loss of, sensation. The course of CIDP as well as the severity of impairment can vary from case to case. In some affected individuals, the disorder may progress slowly while others may have symptoms that worsen, get better, and then recur. In some people, the disorder becomes more obvious and/or severe as it progresses over many months.

Symptoms and signs of CIDP may include fatigue; burning, numbness, and/or tingling sensations affecting the hands and feet or arms and legs; weakened or absent reflexes (areflexia); facial weakness; weakness of the arms and/or legs; paralysis of the arms and/or legs; weakness of the muscles between the ribs; aching pains affecting various muscles; respiratory problems; loss of feeling; and/or difficulty walking.

The exact cause of chronic inflammatory demyelinating polyneuropathy is unknown. Unlike similar disorders, such as Guillain-Barre syndrome, CIDP rarely is preceded by a viral infection.

It is thought that a defect in the immune system may be the cause of CIDP but this has not yet been proven. However, many researchers believe that CIDP is an autoimmune disorder. Autoimmune disorders occur when the body's natural defenses (antibodies and lymphocytes) against invading organisms suddenly begin to attack perfectly healthy tissue. The cause of autoimmune disorders is unknown.

Chronic inflammatory demyelinating polyneuropathy is a rare disorder that can affect any age group and the onset of the disorder may begin during any decade of life. CIDP affects males twice as often as females (M2:F1) and the average age of onset is 50. One study estimates the prevalence of CIDP as one in 100,000 individuals in the United States.

Symptoms of the following disorders can be similar to those of chronic inflammatory demyelinating polyneuropathy. Comparisons may be useful for a differential diagnosis:

Lewis-Sumner syndrome is a rare neurological disorder characterized by asymmetric or multifocal weakness and sensory dysfunction affecting the arms and legs (limbs). In some cases, weak responses of the tendon reflexes may be present. Some researchers believe that Lewis-Sumner syndrome is a variant of CIDP. Others believe it, along with multifocal motor neuropathy, represents part of a disease spectrum. The exact cause of Lewis-Sumner syndrome is unknown.

Multifocal motor neuropathy (MMN) is a rare disorder characterized by asymmetric or multifocal weakness of the arms and legs without sensory signs or symptoms. MMN usually affects one side of the body (asymmetric) and affects the arms more often than the legs. Degeneration (atrophy) of the muscles of the arms and legs is also often present. The disorder is usually slowly progressive over several years. The exact cause of MMN is unknown.

Dejerine-Sottas disease is an inherited neurological disorder that progressively affects movement (mobility). Peripheral nerves become enlarged or thickened causing an irregular progression of muscle weakness. Pain, weakness, numbness, and a tingling, prickling or burning sensation can occur in the legs of individuals with this disorder. Additional symptoms may include weak response of reflexes (hyporeflexia), eye abnormalities, and abnormal curvature of the spine (kyphoscoliosis). The term Dejerine-Sottas Disease implies that the disorder begins early in childhood and that the child never walked normally. A number of genetic disorders, both dominantly and recessively inherited, can cause this. (For more information on this disorder, choose "Dejerine-Sottas" as your search term in the Rare Disease Database.)

Guillain-Barre syndrome (acute idiopathic polyneuritis) is a rare, rapidly progressive disorder causing inflammation of the nerves (polyneuritis) and paralysis. Although the precise cause of Guillain-Barre syndrome is unknown, a viral or respiratory infection precedes the onset of the syndrome in about half of the cases. This has led to the theory that Guillain-Barre syndrome may be an autoimmune disease (caused by the body's own immune system). Damage to the covering of nerve cells (myelin) and nerve axons (the extension of the nerve cell that conducts impulses away from the nerve cell body) results in delayed nerve signal transmission. There is a corresponding weakness in the muscles that are supplied with nerve impulses (innervated) by the affected nerves. Guillain-Barre syndrome is similar to CIDP, but the course of the disorder begins quickly (acute), progresses for two to three weeks and then becomes stationary (plateaus) with a slow recovery. Patients can become completely paralyzed but can still have full recovery over weeks to months. Unlike CIDP, individuals with Guillain-Barre syndrome rarely have signs of sensory loss. Some researchers consider CIDP a subdivision of Guillain-Barre syndrome. (For more information on this disorder, choose "Guillain-Barre" as your search term in the Rare Disease Database.)

Multiple sclerosis is a chronic disease of the brain and spinal cord (central nervous system) that may be progressive, relapsing and remitting, or stable. The pathology of MS consists of small lesions called plaques that may form randomly throughout the brain and spinal cord. These patches prevent proper transmission of nervous system signals and thus result in a variety of symptoms including eye abnormalities, impairment of speech, and numbness or tingling sensation in the limbs and difficulty walking. The exact cause of multiple sclerosis is unknown. (For more information on this disorder choose "Multiple Sclerosis" as your search term in the Rare Disease Database.)

Diagnosis
Chronic inflammatory demyelinating polyneuropathy can be difficult to diagnose. The symptoms must be present for at least two months and typically there is no preceding ailment (e.g., viral infection). Extensive destruction of the covering (myelin sheath) of peripheral nerves is present. The reflexes of the tendons may be absent or reduced and the progression of the disorder may vary from a slow, gradual onset eventually waxing and waning to a course where the disorder becomes more obvious and severe as it progresses. Motor and sensory loss is present in individuals with CIDP and there typically is no family history of a related disease.

Treatment
Glucocorticoid drugs such as prednisone have proven effective in treating individuals with CIDP. In many cases, individuals with CIDP may respond to corticosteroid treatment alone. However, individuals requiring high doses of corticosteroid drugs may experience side effects that deter long-term therapy. Corticosteroids may also be used in conjunction with other drugs such as those that suppress the immune system (immunosuppressive drugs). Azathioprine and cyclophosphamide are immunosuppressive drugs that have been used to treat CIDP.

Intravenous immunoglobulin (IVIG) has also been proven to be effective and is often used as a treatment for chronic inflammatory demyelinating polyneuropathy. IVIG can enhance the immune system. Very high doses are usually used for initial treatment of CIDP and most patients require continued intermittent treatments.

Plasmapheresis has also been shown to be of benefit in chronic inflammatory demyelinating polyneuropathy. This procedure is a method for removing unwanted substances (toxins, metabolic substances and plasma parts) from the blood. Blood is removed from an affected individual and blood cells are separated from plasma. The plasma is then replaced with other human plasma and the blood is transfused back into the affected individual.

There is a great deal of interest in using monoclonal antibodies to treat chronic inflammatory demyelinating polyneuropathy. Clinical trials are being developed to use rituximab, a monoclonal antibody against immune forming lymphocytes (B cells). Another monoclonal antibody under consideration is alemtuzumab which acts on both B cells and T cells, providing a broader attack on the immune system.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

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