Motor chronic inflammatory demyelinating polyneuropathy (CIDP) in 17 patients: clinical characteristics, electrophysiological study, and response to treatment.

: Motor chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and poorly described subtype of CIDP. We aimed to study their clinical and electrophysiological characteristics and response to treatment. From a prospective database of CIDP patients, we included patients with definite or probable CIDP with motor signs and without sensory signs/symptoms at diagnosis. Patients were considered to have pure motor CIDP (PM-CIDP) if sensory conductions were normal or to have motor predominant CIDP (MPred-CIDP) if ≥2 sensory nerve action potential amplitudes were abnormal. Among the 700 patients with CIDP, 17 (2%) were included (PM-CIDP n = 7, MPred-CIDP n = 10); 71% were male, median age at onset was 48 years (range:13-76 years), 47% had an associated inflammatory or infectious disease or neoplasia. At the more severe disease stage, 94% of patients had upper and lower limb weakness, with distal and proximal weakness in 4 limbs for 56% of them. Three-quarters (75%) responded to intravenous immunoglobulins (IVIg) and 4/5 patients to corticosteroids including 3/3 patients with MPred-CIDP. The most frequent conduction abnormalities were conduction blocks (CB, 82%) and F-wave abnormalities (88%). During follow-up, 4/10 MPred-CIDP patients developed mild sensory symptoms; none with PM-CIDP did so. Patients with PM-CIDP had poorer outcome (median ONLS:4, range:2-5) compared to MPred-CIDP (2, range:0-4;P = 0.03) at last follow-up. The present study found a progressive clinical course in the majority of patients with motor CIDP as well as frequent associated diseases, CB, and F-wave abnormalities. Corticosteroids might be considered as a therapeutic option in resistant IVIg patients with MPred-CIDP. This article is protected by copyright. All rights reserved.