Differential diagnosis of chronic acquired demyelinating polyneuropathies

Abstract

Introduction. The rarity of chronic acquired polyneuropathies (PNP) with the demyelinating nature of peripheral nerve damage causes the difficulties of their differential diagnosis that persist in our country and abroad. Objective: to identify significant clinical, neurophysiological and sonographic differential diagnostic markers in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and non-IgM paraproteinemic demyelinating polyneuropathies (PDP).Material and methods: 80 patients were included in the study: 30 with CIDP, 30 with non-IgM-PDP associated with monoclonal gammapathy of unclear significance (PDP-MGUS), and 20 with non-IgM-PDP associated with lymphoproliferative disease (PDP-LPD). The patients included in the study underwent clinical evaluation of neurological disorders according to the MRC, NIS, VAS, INCAT, IRODS, SARA scales; ENMG and ultrasound studies of peripheral nerves.Results. The predominance of men in all groups was noted (p > 0.05). Compared with patients with CIDP, patients with PDP were significantly older, they were more likely to have neuropathic pain syndrome and trophic disorders (p < 0.05). In patients with PDP-LPD, in contrast to CIDP and PDP-MGUS, there was a predominance of the distal pattern of muscle weakness distribution and a greater severity of sensitive ataxia (p < 0.05). During NCV studies in patients with CIDP, compared with patients with PDP, blocks of conduction and dispersion of M-waves were signifi -cantly more often recorded in the study of motor fibers of the nerves of the hands (p < 0.05); and in the study of motor nerves of the legs, non-excitability of motor fibers was significantly less often noted (p < 0.05). Ultrasound examination of peripheral nerves showed no significant differences between patients (p > 0.05).Conclusion. Clinical phenotype, neurophysiological and sonographic changes in patients with CIDP and PDP do not have highly specific differences. Electrophoresis of serum proteins with immunofixation makes it possible to differentiate CIDP and PDP, and further examination by an oncohematologist with paraproteinemia makes it possible to distinguish MGUS from LPD.