CNS Involvement in Chronic Inflammatory Demyelinating Polyneuropathy

Abstract

Background and Objectives Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease primarily affecting the peripheral nervous system. However, several noncontrolled studies have suggested concomitant inflammatory CNS demyelination similar to multiple sclerosis. The aim of this study was to investigate an involvement of the visual pathway in patients with CIDP. Methods In this prospective cross-sectional study, we used high-resolution spectral-domain optical coherence tomography to compare the thickness of the peripapillary retinal nerve fiber layer and the deeper macular retinal layers as well as the total macular volume (TMV) in 22 patients with CIDP and 22 age-matched and sex-matched healthy control (HC) individuals. Retinal layers were semiautomatically segmented by the provided software and were correlated with clinical measures and nerve conduction studies. Results In patients with CIDP compared with healthy age-matched and sex-matched controls, we found slight but significant volume reductions of the ganglion cell/inner plexiform layer complex (CIDP 1.86 vs HC 1.95 mm3, p = 0.015), the retinal pigment epithelium (CIDP 0.38 vs HC 0.40 mm3, p = 0.02), and the TMV (CIDP 8.48 vs HC 8.75 mm3, p = 0.018). The ganglion cell layer volume and motor nerve conduction velocity were positively associated (B = 0.002, p = 0.02). Discussion Our data reveal subtle retinal neurodegeneration in patients with CIDP, providing evidence for visual pathway involvement, detectable by OCT. The results need corroboration in independent, larger cohorts. CIDP= : chronic inflammatory demyelinating polyneuropathy; ETDRS= : early treatment of diabetic retinopathy study; GCIPL= : ganglion cell IPL; GCL= : ganglion cell layer; GEE= : generalized estimation equation; HC= : healthy control; INL= : inner nuclear layer; IPL= : inner plexiform layer; mfVEP= : multifocal visual evoked potential; MNCV= : motor nerve conduction velocity; MS= : multiple sclerosis; OPL= : outer plexiform layer; PNS= : peripheral nervous system; pRNFL= : peripapillary retinal nerve fiber layer; SD-OCT= : spectral-domain optical coherence tomography