Chronic inflammatory demyelinating polyneuropathy

Synonyms

2

Overview

Chronic inflammatory demyelinating polyneuropathy is an acquired immune-mediated inflammatory disorder of the peripheral nervous system. CIDP is a neurological disorder that causes progressive weakness and impaired sensory function in the legs and arms. The disorder is sometimes called chronic relapsing polyneuropathy (CRP) or chronic inflammatory demyelinating polyradiculoneuropathy (because it involves the nerve roots). CIDP is closely related to Guillain-Barr├ę syndrome and it is considered the chronic counterpart of that acute disease. Its symptoms are also similar to progressive inflammatory neuropathy. An asymmetrical variant of CIDP is known as Lewis Sumner-Syndrome. Treatment may include corticosteroids, immunosuppressant drugs, plasma exchange, physiotherapy, and/or intravenous immunoglobulin (IVIG) therapy.

Symptoms

  • Slowly progressive weakness and sensory dysfunction of the legs and arms
  • Tingling in toes and fingers
  • Numbness in toes and fingers
  • Weakness of the arms and legs
  • Aching muscle pain
  • Loss of deep tendon reflexes (areflexia) 
  • Fatigue
  • Abnormal sensations
  • Weakness
  • Paralysis
  • Impaired motor function
  • Sensory loss 
  • Numbness
  • Tingling
  • Prickling sensations

Causes

The exact underlying cause of CIDP is unknown, but there is evidence to support that it is related to the immune system and may have multiple triggers. It is thought to be caused by an abnormal immune response in which the immune system mistakenly attacks and damages the myelin sheath (the covering that protects nerve fibers) of the peripheral nerves. However, no specific provoking antigens or other predisposing factors for CIDP have been identified. In several case reports, treatment with tumor necrosis factor-alpha inhibitors has been associated with the subsequent development of chronic demyelinating neuropathies.

Prevention

CIDP is not known to be inherited and is considered an acquired disorder. No clear genetic predisposition or other predisposing factors for CIDP have been identified.

Diagnosis

Diagnosis is usually made through a clinical neurological examination. Patients usually present with a history of weakness, numbness, tingling, pain and difficulty in walking. They may additionally present with fainting spells while standing up or burning pain in extremities. Some patients may have sudden onset of back pain or neck pain radiating down the extremities, usually diagnosed as radicular pain. These symptoms are usually progressive and may be intermittent.

Autonomic system dysfunction can occur; in such a case, the patient would complain of orthostatic dizziness, problems breathing, eye, bowel, bladder and cardiac problems. The patient may also present with a single cranial nerve or peripheral nerve dysfunction.

On examination the patients may have weakness, and loss of deep tendon reflexes (rarely increased or normal). There may be atrophy (shrinkage) of muscles, fasciculations (twitching) and loss of sensation. Patients may have Multi-Focal Motor neuropathy, as they have no sensory loss.

Most experts consider the necessary duration of symptoms to be greater than 8 weeks for the diagnosis of CIDP to be made.

Typical diagnostic tests include:

  • Electrodiagnostics - electromyography (EMG) and nerve conduction study (NCS). In usual CIDP, the nerve conduction studies show demyelination. These findings include:
    1. a reduction in nerve conduction velocities;
    2. the presence of conduction block or abnormal temporal dispersion in at least one motor nerve;
    3. prolonged distal latencies in at least two nerves;
    4. absent F waves or prolonged minimum F wave latencies in at least two motor nerves. (In some case EMG/NCV can be normal).
  • Serum test to exclude other autoimmune diseases.
  • Lumbar puncture and serum test for anti-ganglioside antibodies. These antibodies are present in the branch of CIDP diseases comprised by anti-GM1, anti-GD1a, and anti-GQ1b.
  • Sural nerve biopsy; biopsy is considered for those patients in whom the diagnosis is not completely clear, when other causes of neuropathy (e.g., hereditary, vasculitic) cannot be excluded, or when profound axonal involvement is observed on EMG.

In some cases electrophysiological studies fail to show any evidence of demyelination. Though conventional electrophysiological diagnostic criteria are not met, the patient may still respond to immunomodulatory treatments. In such cases, presence of clinical characteristics suggestive of CIDP are critical, justifying full investigations, including sural nerve biopsy.

Prognosis

Data are limited regarding the long-term outlook (prognosis) of CIDP and the course and prognosis appear to vary among affected people. Some may have a "bout" of CIDP followed by spontaneous recovery, while others may have many bouts with partial recovery in between relapses. Some people are left with residual numbness or weakness that can lead to reduced quality of life. Complete remission, partial remission, and severe disability have all been documented. Quadriplegia, respiratory failure and death can occur, but are rare.

It has been reported that approximately two-thirds of people with CIDP will initially respond to any single standard therapy (intravenous immune globulin, glucocorticoid, and plasma exchange), while about 10 to 15 percent are resistant to all of these.

Treatment

The standard therapies for CIDP appear to be equally effective and include:

  • Intravenous immune globulin (IVIG) - adds large numbers of antibodies to the blood plasma to reduce the effect of the antibodies that are causing the problem
  • Glucocorticoids - help reduce inflammation and relieve symptoms
  • Plasma exchange - remove antibodies from the blood

The treatment choice is influenced by the preference of the affected person, side effects, treatment cost, duration, ease of administration, and availability. Advantages and disadvantages of standard therapies may include the following:

  • IVIG and plasma exchange may lead to a more rapid improvement in CIDP than glucocorticoid therapy, but are less likely than glucocorticoids to produce a remission
  • IVIG is expensive, and its supply is sometimes limited
  • Glucocorticoids are inexpensive, but chronic use is limited by common and important side effects
  • Plasma exchange is expensive, invasive, and available only at specialized centers

Other medications that suppress the immune system (immunosuppressants) may also be used. Physiotherapy may improve muscle strength, function and mobility.
Approved therapies:
Immune Globulin (Human) (Gamunex) FDA-approved indication: Treatment of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) to improve neuromuscular disability and impairment and for maintenance therapy to prevent relapse 

Resources

Refer to Research Publications.