Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired polyneuropathy associated with considerable long-tern disability. CIDP has been attributed to an immune-mediated attack on peripheral nerves with inflammation and demyelination. In contrast to Guillain-Barré Syndrome, the course may be relapsing or progressive. Although the broad clinical features of CIDP are well described, a recent report by Gorson and colleagues provides new information on the clinical heterogeneity of the disorder and response to treatment. Sixty-seven consecutive patients fulfilled clinical and electrodiagnostic criteria for CIDP (the largest series to date to fulfill both research criteria). A number of variant presentations were identified, including patients with a pure motor syndrome, a pure sensory variant with incoordination (ataxia), regional patterns with weakness and sensory loss restricted to only the arm or legs, and a relapsing acute Guillain-Barré syndrome. The authors also found that pain (noted in 42% of their patients) was more frequent than previously reported. Electrodiagnostic studies showed that the majority of patients had axonal loss, suggesting that EMG studies must be extensive to establish the presence of demyelination. One-quarter of the patients has an abnormal serum protein (monoclonal gammopathy) associated with CIDP. This group has more sensory findings compared to patients without monoclonal gammopathy but most responded to plasma exchange.
Only 39% of patients with CIDP improved with initial treatment, and the response rates were the same among plasma exchange, IVIG and steroids. Importantly, when patients who failed to improve or relapsed after initial therapy were treated with an alternative second or third therapy, one-third improved with each treatment modality, increasing the overall response rate to 66%. Gorson and associates emphasized that although fewer than one-half of patients with CIDP respond to the first treatment, the majority will improve if alternative therapies are used.
For further information, contact Dr. Kenneth C. Gorson, Neurology Service, St. Elizabeth’s Medical Center, 736 Cambridge Street, Boston, MA 02135. Phone (617) 789-2375