Classifications and treatment responses in chronic immune-mediated demyelinating polyneuropathy

Background: Chronic immune- mediated demyelinating polyneuropathy (CIP) represents a heterogeneous pool of motor, sensory, sensorimotor, symmetric, or asymmetric syndromes. Objective: To evaluate published diagnostic classifications and characterize predictors of treatment response. Methods: One hundred two of 158 patients with a working diagnosis of CIP were included and clinically characterized because they had electrophysiologic and/ or histologic evidence of demyelination. The biostatistical profile of patients with symmetric clinical manifestation was analyzed using three proposed classifications (American Academy of Neurology [AAN] criteria, modified AAN criteria, European Federation of Neurological Societies/ Peripheral Nerve Society [EFNS/ PNS] criteria). Treatment responses to IV immunoglobulins (IVIg) and their positive predictors were investigated. Results: Sensitivities (0.52 [AAN] vs 0.83 [modified AAN] vs 0.95 [EFNS/ PNS]) and negative predictive values (0.68 vs 0.85 vs 0.92) differed markedly, whereas specificities (0.94 vs 0.90 vs 0.96) and positive predictive values (0.89 vs 0.89 vs 0.97) were similar. In CIP patients treated with IVIg, a positive response was found in 62 of 76 (82%). Patients with a monophasic or relapsing - remitting course or a more than twofold CSF protein increase had the highest probability to respond to IVIg, most evident when using the modified AAN criteria. Conclusions: The European Federation of Neurological Societies/ Peripheral Nerve Society criteria for chronic inflammatory demyelinating polyneuropathy improve treatment of patients with chronic immune- mediated demyelinating polyneuropathy, particularly with respect to diagnostic issues. To predict IV immunoglobulin treatment response, the modified American Academy of Neurology criteria are the most valuable classification provided an increased CSF protein level.