Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

What happens in CIDP

Peripheral nerves carry signals between the spinal cord and the muscles and skin. Myelin wraps around nerve fibers and lets signals travel quickly. In CIDP, the immune system attacks the myelin, slowing or blocking signals. Over time, if inflammation continues, the nerve fibers themselves (axons) can be damaged, which is harder to reverse.

CIDP is considered the chronic counterpart of Guillain-Barre syndrome (GBS).

CIDP vs Guillain-Barre syndrome

About 1 in 20 people first diagnosed with GBS turn out to have CIDP that started acutely, especially if they deteriorate again after 8 weeks or have three or more relapses.

Symptoms

• weakness of the arms and legs, both close to the body (difficulty climbing stairs, getting up from a chair, lifting arms) and far from the body (weak grip, foot drop)
• numbness, tingling or pins and needles, usually starting in the feet and hands
• loss of balance and unsteadiness, especially in the dark, from loss of position sense
• loss of reflexes
• fatigue
• tremor in some people
• pain, less common than in many other neuropathies

The involvement of muscles close to the body as well as in the hands and feet helps distinguish CIDP from the common length-dependent neuropathies caused by diabetes or alcohol.

Variants

• Typical CIDP: symmetric, motor and sensory, near and far muscles.
• Distal CIDP: mainly hands and feet.
• Multifocal CIDP (Lewis-Sumner syndrome): patchy, asymmetric involvement of individual nerves.
• Focal CIDP: affects one limb.
• Motor or sensory predominant CIDP.

Conditions that resemble CIDP include multifocal motor neuropathy, anti-MAG neuropathy linked to an IgM paraprotein, POEMS syndrome and autoimmune nodopathies. They respond differently to treatment, so accurate diagnosis matters.

Causes and associations

The trigger is usually unknown. CIDP is more common, or may coexist, with:

• diabetes
• MGUS and other paraproteins
• HIV and hepatitis C
• other autoimmune diseases, such as lupus and inflammatory bowel disease
• certain medicines, such as immune checkpoint inhibitors used in cancer treatment

Diagnosis

The 2021 EAN/PNS guideline bases diagnosis on clinical features plus:

• Nerve conduction studies and EMG: show slowed conduction, conduction block and other signs of demyelination in multiple nerves. This is the key test.
• Lumbar puncture: raised protein with a normal cell count in the spinal fluid.
• Nerve ultrasound or MRI: may show enlarged nerve roots or plexuses.
• Blood tests: glucose, B12, thyroid, kidney and liver function, HIV and hepatitis, serum protein electrophoresis and immunofixation for paraproteins, and antibodies for nodopathy.
• Response to treatment: objective improvement supports the diagnosis.
• Nerve biopsy: occasionally, in uncertain cases.

Misdiagnosis is common in both directions, so diagnosis and treatment are best overseen by a neuromuscular specialist.

Treatment

First-line treatments are similarly effective. The choice depends on side effects, other medical conditions, cost and convenience.

• Immunoglobulin (IVIG or subcutaneous SCIG): antibodies pooled from blood donors, given as infusions every few weeks. Works within weeks in most responders. SCIG can be given at home for maintenance.
• Corticosteroids: daily prednisone or pulsed high-dose dexamethasone or methylprednisolone. Inexpensive but long-term side effects include weight gain, diabetes, bone thinning and cataracts.
• Plasma exchange: filtering antibodies from the blood. Effective but requires specialized equipment, usually used short-term.
• Efgartigimod: a newer drug that lowers IgG antibody levels, approved in the US for CIDP.
• Other immunosuppressants: azathioprine, mycophenolate, cyclophosphamide or rituximab may be used for treatment-resistant cases or to reduce steroid doses.

Treatment is usually continued and then gradually reduced to the lowest effective dose, with regular objective strength and disability measurements. Some people can eventually stop treatment.

Rehabilitation

Physical and occupational therapy, ankle-foot orthoses for foot drop, fall prevention and fatigue management are important at every stage.

Outlook

Most people with CIDP, around 70 to 80%, improve with treatment. Many achieve good function, and some go into lasting remission. Others need long-term treatment, and a minority are left with significant disability, particularly if diagnosis was delayed and axonal damage occurred. Life expectancy is generally not reduced.

Frequently asked questions

What is CIDP?

CIDP is a rare autoimmune disorder in which the immune system damages the myelin coating of the peripheral nerves. It causes gradually worsening or relapsing weakness and numbness in the arms and legs over more than 8 weeks, along with loss of reflexes and balance problems.

What is the difference between CIDP and Guillain-Barre syndrome?

Both attack peripheral nerve myelin. Guillain-Barre syndrome develops over days to 4 weeks, peaks and then recovers. CIDP develops over 8 weeks or more and is progressive or relapsing. CIDP responds to steroids, while GBS does not, and CIDP often needs long-term treatment.

Is CIDP curable?

CIDP is not always curable, but it is very treatable. Most people improve with immunoglobulin, steroids or plasma exchange, and some go into long-term remission and can stop treatment. Others need ongoing maintenance therapy to keep symptoms controlled.

What are the first symptoms of CIDP?

Early symptoms often include tingling or numbness in the feet and hands, weakness when climbing stairs or rising from a chair, a weak grip, tripping over the toes, and unsteadiness. These develop gradually over weeks to months.

How is CIDP diagnosed?

Diagnosis combines the pattern of symptoms with nerve conduction studies that show demyelination. A lumbar puncture showing raised protein, nerve imaging, blood tests to exclude other causes, and a clear response to treatment support the diagnosis.