CIDP — Chronic Inflammatory Demyelinating Polyneuropathy

Although CIDP can affect both children and adults of any age, it most commonly occurs between the ages of 50 and 60. It is more common in men than in women.

What is Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)?

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is a rare disorder of the peripheral nerves characterized by a gradual loss of sensation and reflexes, as well as the development of muscle weakness.

Although Guillain-Barré syndrome (GBS) and CIDP share many features, the key difference lies in the speed of symptom progression. In GBS, the time from symptom onset to peak weakness is less than 30 days, and in most cases under 14 days. In CIDP, sensory loss and weakness continue to progress beyond this period.

The incidence of CIDP is approximately 1 to 4 cases per 100,000 people. However, because the disease can persist over time in the same individual, its prevalence is estimated to be as high as 9 per 100,000.

Like GBS, CIDP results from damage to the protective covering of the nerves, known as myelin. The disease can occur at any age and is more common in men than in women.

Unlike GBS, the active phase of CIDP is not limited to less than one month. While approximately one-third of patients may enter remission—during which immune therapies are not required—most individuals experience either slow disease progression or relapses over many years.

If left untreated, around 30% of patients may become permanently dependent on a wheelchair. Early recognition and appropriate treatment can prevent significant disability.

What causes CIDP?

According to current understanding, the body’s immune system—which normally protects us—mistakenly identifies myelin as foreign tissue and attacks it.

Myelin is an essential component of the peripheral nervous system. It surrounds the long nerve fiber (part of a nerve cell, similar to a wire), much like insulation surrounds an electrical cable.

Nerves extend from the spinal cord to the rest of the body, stimulating muscle contractions and transmitting sensory information back to the nervous system through receptors in the skin and joints. This insulation (myelin) allows electrical impulses to travel efficiently along the nerve fiber.

When myelin is damaged or destroyed, these electrical impulses slow down or are completely blocked. Signals sent from the brain become delayed or interrupted and fail to reach their intended destination.

The exact cause of this process is still not fully understood.

How is CIDP diagnosed?

Diagnosis of CIDP is based on patient symptoms and diagnostic testing:

Symptoms include:

• loss of sensation (numbness)

• abnormal sensations (tingling and pain)

• loss of reflexes

• muscle weakness (difficulty walking, foot drop)

Diagnostic tests include:

• nerve conduction studies and EMG (typically showing demyelinating neuropathy)

• cerebrospinal fluid analysis (usually elevated protein with normal cell count)

• blood and urine tests (to rule out other conditions causing neuropathy and to detect abnormal proteins)

How is CIDP treated?

There are three standard first-line therapies for CIDP:

• Corticosteroids (Prednisone, Prednisolone)
  These are similar to natural anti-inflammatory hormones produced by the body and may be used as an initial treatment. They often improve muscle strength, are taken orally, and are relatively inexpensive. However, side effects may limit long-term use.

• Intravenous Immunoglobulin (IVIG)
  IVIG is the only therapy approved by regulatory authorities in the United States, Canada, and Europe for the treatment of CIDP. It contains natural antibodies derived from healthy donors and is administered intravenously over several hours. Newer, higher-concentration formulations that can be administered subcutaneously are currently being studied in controlled trials.

• Plasma Exchange (PE or PLEX)
  This procedure involves removing a portion of the patient’s blood, separating and discarding the plasma, and returning the blood cells. It works by removing harmful antibodies from the plasma.

• Subcutaneous Immunoglobulin (SCIg)
  Often used in patients requiring long-term therapy. SCIg can be self-administered at home, usually into the fatty tissue of the abdomen or thigh. It is approved by the FDA in the United States for the treatment of CIDP.

There are also a number of second-line therapies used when standard treatments are ineffective, cause significant side effects, or when the clinical response is suboptimal. These treatments are generally not supported by large randomized controlled trials but are backed by case series in medical literature.

Third-line therapies, often involving chemotherapy-type medications, may be used in specific cases and should only be administered by highly experienced specialists.

Ongoing research and clinical trials are also available (see www.clinicaltrials.gov).

Centers of excellence

Treating CIDP is as much an art as it is a science. An experienced physician is more likely to achieve better outcomes than someone treating their first case—something that applies across all of medicine. That is why the Centers of Excellence program was established.

When treatment is initiated early, most patients with CIDP respond well to therapy. Treatment can limit damage to peripheral nerves, improve function and quality of life, and in some cases even lead to remission.

For more information, visit: gbs-cidp.org/support/centers-of-excellence