Subtle retinal degeneration may be evident on optical coherence tomography (OCT) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), providing further evidence for a central nervous system (CNS) involvement in the autoimmune disease, according to study findings published in Neurology.
While CIDP primarily affects the peripheral nervous system, concomitant involvement of the CNS was previously reported. The objective of the current study was to investigate structural retinal changes as a marker of CNS degeneration in patients with CIDP using spectral-domain OCT.
The prospective, cross-sectional study included 22 patients with CIDP (mean age, 58.27 years; 63.6% men) and 22 age- and sex-matched healthy controls (mean age, 57.68 years; 59.1% men).
The researchers compared the thickness of the peripapillary retinal nerve fiber layer and the deeper macular retinal layers.
Among patients with CIDP, compared with healthy control individuals, the mean total macular volume was significantly reduced (8.48 mm3 vs. 8.75 mm3; P =.018), there was a significant thinning of the ganglion cell layer (1.03 mm3 vs. 1.07 mm3; P =.037) and of the inner plexiform layer (0.83 mm3 vs. 0.88 mm3; P =.015). Slight but significant volume reductions of the retinal pigment epithelium (0.38 mm3 vs. 0.40 mm3; P =.02) were reported among patients with CIDP, compared with healthy control individuals.
The data suggest relations between the retinal layer volumes and nerve conduction and clinical parameters, including a remarkable positive association between the motor nerve conduction velocity of the right ulnar nerve and the ganglion cell layer volume (P =.02; B =.002).
The study had several limitations, including the limited sample size and the exploratory nature of the study.
“[T]he data suggest degenerative processes in the retina and thus the CNS in CIDP. Particularly, the changes in the GCIPL [combined ganglion cell inner plexiform layer] could point to underlying processes that may be functionally and biologically relevant. To consolidate these intriguing findings, an independent longitudinal study of a larger patient cohort should be conducted,” concluded the researchers.
Ingwersen J, Graf J, Kluge J, et al. CNS involvement in chronic inflammatory demyelinating polyneuropathy: subtle retinal changes in optical coherence tomography. Neurol Neuroimmunol Neuroinflamm. Published online Oct 19, 2021. doi: 10.1212/NXI.0000000000001099