Merck Manual

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Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

(Chronic Acquired Demyelinating Polyneuropathy; Chronic Relapsing Polyneuropathy)


Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Reviewed/Revised Apr 2022 | Modified Sep 2022
Topic Resources

Chronic inflammatory demyelinating polyneuropathy is a form of polyneuropathy that, like Guillain-Barré syndrome, causes increasing muscle weakness, but the weakness progresses for more than 8 weeks.

  • Chronic inflammatory demyelinating polyneuropathy is thought to be caused by an autoimmune reaction that damages the myelin sheath around nerves.

  • In this disorder, weakness worsens continually over a period of more than 8 weeks.

  • Electromyography, nerve conduction studies, and analysis of cerebrospinal fluid can help confirm the diagnosis.

  • Treatment may include corticosteroids, drugs that inhibit the immune system, and sometimes immune globulin and plasma exchange.

Nerve Cells and Fibers

As in Guillain-Barré syndrome, an autoimmune reaction Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers an autoimmune disorder is not known. Symptoms vary depending... read more , is thought to be involved. The body's immune system attacks the myelin sheath, which surrounds the nerve and enables nerve impulses to travel quickly.

Insulating a Nerve Fiber

Most nerve fibers inside and outside the brain are wrapped with many layers of tissue composed of a fat (lipoprotein) called myelin. These layers form the myelin sheath. Much like the insulation around an electrical wire, the myelin sheath enables nerve signals (electrical impulses) to be conducted along the nerve fiber with speed and accuracy. When the myelin sheath is damaged (called demyelination), nerves do not conduct electrical impulses normally.

Insulating a Nerve Fiber

Symptoms of CIDP

Symptoms of chronic inflammatory demyelinating polyneuropathy are similar to those of Guillain-Barré syndrome: Weakness is more prominent than abnormal sensations (numbness and a pins-and-needles sensation). However, these symptoms worsen for more than 8 weeks. (In Guillain-Barré syndrome, weakness usually worsens over 3 or 4 weeks, then remains the same or starts to return to normal.)

Symptoms may slowly worsen or may lessen or disappear, then worsen or reappear.

Reflexes are usually absent.

In most people with this disorder, blood pressure fluctuates less, abnormal heart rhythms occur less often, and other internal functions are less impaired than in people with Guillain-Barré syndrome. Also, weakness may be more irregular, affecting the two sides of the body differently, and weakness may progress more slowly.

Diagnosis of CIDP

  • Electromyography, nerve conduction studies, and a spinal tap

Doctors suspect chronic inflammatory demyelinating polyneuropathy based on symptoms. It can be distinguished from Guillain-Barré syndrome because it progresses for more than 8 weeks.

Rarely, a biopsy of the nerve is needed to detect demyelination.

Treatment of CIDP

  • Immune globulin

  • Corticosteroids and/or drugs that inhibit the immune system

  • Plasma exchange

Immune globulin (a solution containing many different antibodies collected from a group of donors) may be given by vein (intravenously) or under the skin (subcutaneously). It can relieve symptoms. It has fewer side effects than corticosteroids and is easier to use than plasma exchange Plateletpheresis (platelet donation) In addition to normal blood donation and transfusion, special procedures are sometimes used. In plateletpheresis, a donor gives only platelets rather than whole blood. Whole blood is drawn from... read more (filtering of toxic substances, including antibodies to the myelin sheath, from the blood). However, after treatment is stopped, its beneficial effects may not last as long as those of corticosteroids.

People may need treatment for months or years.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Deltasone, Predone, RAYOS, Sterapred, Sterapred DS
Azasan, Imuran
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