I would like to know more about a condition called chronic inflammatory demyelinating polyneurapathy (CIDP). My husband has been suffering with this disease for seven years. We are so confused: One doctor says one thing, another says another. Our general practitioner hasn't bothered to explain it to us, saying he doesn't have the time and is "not familiar" with this disease. We receive some information from the Internet, but it is not enough. C.H., via e-mail
Prof. Zohar Argov, senior expert on neuromuscular diseases in the neurology department at Hadassah University Medical Center, replies:
CIDP is a chronic disease of the peripheral nerves and their roots in the spinal canal. It is an autoimmune disorder, in which the immune system of the body "attacks" a self organ mistakenly identifying it as foreign (such as type 1 diabetes and multiple sclerosis). This abnormal immune response is carried out as an invasion of the nerve by cells that are part of the immune "counterattack" system and by producing antibodies against nerve components.
As the name implies, the attack is mainly against the myelin sheath of the nerve fibers that is produced by non-neuronal cells called Schwan cells. When the myelin is damaged, the electrical conduction along the nerve is either slowed or blocked, leading to the classical signs of this neuropathy - muscle weakness and reduced sensation.
The disease usually starts in the legs and progresses to the upper limbs. It does not affect the nerves of the inner organs (such as the intestines, heart or bladder) and does not impair the central nervous system function. On rare occasions, CIDP is associated with other autoimmune conditions. It is even rarer for the condition to be linked to a malignancy. This combination is usually identified within a year or two of the onset of CIDP, so it is not relevant to your husband's case.
The disease is diagnosed at the onset by its peculiar clinical behavior affecting the motor nerves more than the sensory nerves and with the help of two major important laboratory tests. A lumbar puncture shows increased protein levels in the cerebrospinal fluid that bathes the nerve roots in the spinal canal. The patient also undergoes nerve-conduction studies, an electrical test (sometimes called electromyography) that demonstrates the slowing or blockage of nerve conduction. As in many other diseases, some CIDP patients do not fulfill all the above diagnostic criteria.
By its nature CIDP is a progressive disorder; if untreated, it can lead to marked disability because of the weakness or sensory loss or both. Rarely, if the disease continues to progress, the increase in the nerve sheath size by a continuous self-repair attempt may lead to blockage of the spinal canal and strangulation of the nerve roots or to secondary damage to the nerve cell extension in the peripheral nerves. These are usually irreversible.
Thus, CIDP should be treated vigorously as soon as possible. Conventional treatment includes high-dose steroids that reduce the inflammatory response and partly suppress the immune system. In general, treatment should start at high doses and remain at this level until a maximal therapeutic effect is achieved. Only then can steroids be slowly reduced over several months, but many patients will have to continue taking low-dose steroids for very long periods (years).
The exact starting dose and mode of steroid administration are a bit controversial. Prolonged usage of steroids is associated in many patients with marked side effects. Thus use of "steroid sparing" medications is highly recommended. These are drugs that suppress the immune response (such as azathioprine, cyclophophamide, methotrexate). Each has also side effects, but those may be less than the steroids' complications. There are also various views about how long to give medications and which ones to use.
More modern (and much more expensive) treatment modalities are plasmapheresis ("cleaning" the blood of antibodies) and giving high-dose immunoglobulins intravenously (IVIG). Plasmapheresis has been shown to be as effective as steroids, but it requires special machines and expertise. IVIG is also effective, but its long-term effectiveness in treating CIDP has not yet been proven. Overall, the success rate in treating CIDP is high and at times complete remissions can be achieved. However most patients need continuous treatment of some sort and may be left with residual damage.
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