Onset and course of chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is clinically heterogeneous. Our purpose was to determine whether initial progression time, clinical features, and distribution of nerve conduction slowing at presentation correlate with clinical course and prognosis. We examined how findings at presentation related to clinical course during an average follow-up time of 4.0 (range 1.0-9.0) years in 44 patients with CIDP. We calculated terminal latency index (TLI), a measure of differential slowing in distal relative to more proximal nerve segments. Patients with acute or subacute onset (progression over less than 8 weeks) had a higher remission rate (P = 0.012) than patients with chronic onset (progression over more than 8 weeks). Patients with proximal weakness had a higher remission rate than patients with the distal phenotype (P < 0.001). All 5 patients with a relapsing course had subacute onset. They had lower TLIs, suggesting a more distal pattern of demyelination, than patients with a monophasic or chronic course. In conclusion, subacute onset and presence of proximal weakness are good prognostic signs that correlate with a high rate of recovery to normal in CIDP. Distal accentuation of conduction slowing at presentation correlates with subacute onset and a relapsing course.