Chronic inflammatory demyelinating polyneuropathy (CIDP): symptoms, diagnosis and treatment

The peripheral nerves carry signals between the brain and spinal cord and the rest of the body. Many nerve fibres are wrapped in myelin, an insulating layer that helps signals travel quickly. GAIN explains that demyelination is damage to this myelin, and that polyneuropathy means a condition affecting many nerves. In CIDP the immune system is thought to attack the myelin, so signals travel more slowly or fail, and muscles become weak while sensation changes.

GAIN says that although CIDP can occur at any age and in both sexes, it is more common in young adults and in men more than women. Its course varies widely: some people have a single episode followed by spontaneous recovery, while others have several relapses with partial recovery in between. GAIN notes it is a treatable cause of acquired neuropathy and that early treatment is recommended to prevent loss of nerve axons, although some people are left with residual numbness, weakness or abnormal sensations.

GAIN says symptoms usually develop slowly, starting in the feet and legs before progressing to other parts of the body, and that they vary considerably between patients and may be vague and confusing to both the patient and the doctor. Symptoms such as fatigue and sensory disturbance can be hard to communicate. They may remain mild or may become progressively worse over weeks, months or even years, rarely leaving a person bed bound with profound weakness of the arms.

• Numbness and pins and needles.

• Muscle weakness, often in the legs first.

• Fatigue.

• Loss of deep tendon reflexes, which a doctor finds on examination.

GAIN says GBS normally progresses over 2 to 4 weeks, then plateaus, improves over several months and does not usually recur, whereas CIDP has ongoing symptoms for over 8 weeks and usually does not improve unless ongoing treatment is given. Most people with CIDP cannot identify a preceding viral or bacterial infection, in contrast to GBS. The NHS says GBS usually starts within a few weeks of an infection such as flu or a stomach bug.

Early on the two can look alike. GAIN reports that, because of similarity in the early stages, up to 16% of patients with acute-onset CIDP are misdiagnosed with GBS, and that the diagnosis of acute-onset CIDP should be considered when a patient with GBS deteriorates after nine weeks from onset or deteriorates three times or more. The distinction matters because CIDP often needs maintenance treatment.

The NHS advises asking for an urgent GP appointment or contacting NHS 111 if you think you have a condition like Guillain-Barré syndrome, and calling 999 or going to A&E if you have problems with your face muscles such as a drooping face or trouble swallowing, cannot lift one or both arms, or have trouble speaking, because these could be signs of a stroke. The same applies to any rapidly worsening weakness, breathing difficulty or inability to walk.

GAIN says CIDP can be difficult to diagnose because there is no single conclusive test, symptoms are often vague and many conditions can mimic them, so a long period may pass before the diagnosis is made. A diagnosis requires weakness of at least two limbs, complete or partial loss of tendon reflexes, progression or relapse 8 weeks or more after onset, and evidence of myelin damage on nerve conduction studies.

Supporting tests include nerve conduction studies and electromyography (EMG) carried out by a clinical neurophysiologist, a lumbar puncture to check the cerebrospinal fluid, MRI and sometimes nerve biopsy. Doctors also rule out other causes of demyelinating neuropathy, including inherited neuropathy, toxins or drugs, and conditions such as diabetes, alcohol dependency and hepatitis. A neurologist usually leads this assessment.

GAIN says three treatments have proven efficacy in CIDP: intravenous immunoglobulin (IVIg), corticosteroids and plasma exchange. In studies they have been found equivalent to one another, with between 50 and 80% of patients responding to each, and failure of one does not mean the others will not work; about 15% of patients do not respond to any of the three.

IVIg is the most commonly used treatment, particularly for motor-dominant CIDP. It is made from donated blood containing healthy antibodies and is given in hospital; if needed long term, regular infusions are typically given every 6 weeks. In some areas subcutaneous immunoglobulin can be given at home. GAIN says plasma exchange and corticosteroids should be considered in preference to IVIg in non-motor-dominant CIDP, and that a neurologist may add a steroid or another immunosuppressant if very frequent IVIg infusions are needed.

Side effects of IVIg are usually minimal and may include headache, low blood pressure or a rash, and GAIN advises drinking plenty of fluids while receiving it. Corticosteroids may need caution in older people with conditions such as poorly controlled diabetes or osteoporosis.

GAIN says that in CIDP literature a cure has been defined as remission of over 5 years off treatment, reported in about 25% of patients treated with steroids for less than one year, and that up to 40% may be in remission after one year of treatment with steroids or IVIg. Neurologists more often use the word remission, meaning stability without treatment, and advise reviewing the need for treatment annually if symptoms are stable. Many people stay symptom-free after remission, but relapse is always possible.

GAIN's hub covers rehabilitation, physiotherapy and pain management as part of what happens next. GAIN also provides information for carers and for return to work.

On the NHS, CIDP is investigated and treated by neurology services, with nerve conduction tests and immunoglobulin supplied through hospital and home-therapy programmes. GAIN notes that IVIg is given in hospital and that subcutaneous immunoglobulin at home is available in some parts of the country, so treatment is usually organised by a hospital neurology team.