Everything You Need to Know
CIDP (Chronic Inflammatory Demyelinating Polyneuropathy) is a rare disorder of the peripheral nerves characterized by gradually increasing sensory loss and weakness associated with loss of reflexes.
While GBS (Guillain Barré Syndrome) and CIDP share many features, one that separates them is the onset: in GBS, onset to maximum weakness occurs in under 30 days and in most people in under 14 days, while in CIDP, sensory loss and weakness progress beyond those times. The number of new cases per year of CIDP is about 1-2 per 100,000 people, but as the disease can be present in a person for years prior to diagnosis, the prevalence reflecting the accumulation of cases over time may be as high as 9 per 100,000 in some areas.
Like GBS, CIDP is caused by damage to the covering of the nerves, called myelin. It can start at any age and is more frequent in men than women.
Unlike GBS, CIDP is not self-limiting or spontaneous. Left untreated, 30% of CIDP patients will progress to wheelchair dependence. Early recognition and proper treatment can avoid a significant amount of disability.
What causes CIDP?
Current theory holds that the body’s immune system, which normally protects itself, perceives myelin as foreign and attacks it. Myelin is an important part of the peripheral nervous system. It wraps around the nerve axon (the long, wire-like part of a nerve cell) much like insulation around an electrical wire. The nerves extend from the spinal cord to the rest of the body, stimulating muscle contraction and transmitting sensory information back to the nervous system from receptors in the skin and joints. This insulation (myelin) allows electrical impulses to efficiently travel along the nerve axon. When myelin is damaged or removed, these electrical impulses are slowed or lost, and messages transmitted from the brain are disrupted and may never make it to their final destination. What causes this process is not yet clear.
How is CIDP diagnosed?
Diagnosis of CIDP is based on the symptoms of the patient:
- Symptoms such as loss of sensation (numbness), abnormal sensation (tingling and pain), loss of reflexes, and weakness (difficulty walking, foot drop)
- Tests such as nerve conduction and EMG (usually showing a demyelinating neuropathy), spinal fluid analysis (usually showing elevated protein with normal cell count), blood and urine tests (to rule out other disorders that may cause neuropathy and to look for unusual proteins)
How is CIDP treated?
There are three standard or first line treatments in CIDP:
- Corticosteroids (Prednisone, Prednisolone) are similar to naturally occurring anti-inflammatory hormones made by the body, and can be used as an initial treatment. Corticosteroids often improve strength, are conveniently taken by mouth, and are inexpensive. Side effects however can limit long-term use.
- High dose Intravenous Immune Globulins (IVIG) is the only drug that has FDA, Canadian, and European approval for treatment of CIDP. IVIG contains naturally occurring antibodies obtained from healthy volunteers. IVIG is given through a vein over the course of several hours. Newer preparations of higher concentrations that can be given under the skin (subcutaneous) are currently being tested in controlled trials in CIDP patients.
- Plasma Exchange (PE), or Plasmapheresis (PLEX), is a process by which some of the patient’s blood is removed and the blood cells returned without the liquid plasma portion of the patient’s blood. It may work by removing harmful antibodies contained in the plasma.
There are a large number of so-called second line drugs used to treat CIDP. These are used when the above standard treatments fail, cause significant side-effects, or the clinical response is not optimal. These drugs are largely not tested in randomized controlled trials, but their use is supported by case series from the medical literature.
There are a number of so-called third line treatments, usually chemotherapy drugs, but these should be given only in selected circumstances and by those with extensive experience in their use.
There are also ongoing research studies (see www.clinicaltrials.gov)
Treatment of CIDP is an art. An experienced doctor is more likely to have good outcomes than someone treating their first case as is true throughout medicine. That is why we have set up the Centers of Excellence program. If treated early, most CIDP patients respond well to therapy that can limit the damage to peripheral nerves and contribute to improved function and quality of life and at times can cure the disorder altogether.
Typical CIDP is a symmetrical motor and sensory progressive neuropathy affecting proximal and distal muscles with loss of deep tendon reflexes.
Multifocal Motor Neuropathy is a pure motor disorder in which there is asymmetric weakness in the distribution of individual nerves that can be confirmed by diagnostic nerve conduction results.
Lewis-Sumner syndrome is a sensory-motor disorder in which there is sensory loss and weakness in the distribution of individual nerves. Diagnostic nerve conduction studies confirm the focal nerve involvement.
Pure sensory CIDP presents with sensory loss, pain, and poor balance with abnormal gait or walking. There is no weakness but frequently motor nerve conduction studies are abnormal in addition to sensory conduction studies.
Pure motor CIDP presents with weakness and loss of reflexes without sensory loss.
There are other less well established variants most of which would fall into the category of CIDP.
Living with CIDP
Post-treatment life depends on whether the disease was caught early enough to benefit from treatment options. Patients respond in various ways. The gradual onset of CIDP can delay diagnosis by several months or even years, resulting in significant nerve damage that may limit and delay the response to therapy. The chronic nature of CIDP requires long-term care of patients. Accommodations in the home may be needed to facilitate daily living activities.