Subtle retinal degeneration can be detected on optical coherence tomography (OCT) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), which, according to study results published in Neurology, provides further evidence of central nervous system (CNS) involvement in the autoimmune disease.
While CIDP primarily affects the peripheral nervous system, concomitant CNS involvement has previously been reported. The aim of the current study was to investigate structural retinal changes as markers of CNS degeneration in patients with CIDP using spectral domain OCT.
The prospective cross-sectional study comprised 22 patients with CIDP (mean age 58.27 years; 63.6% men) and 22 age- and gender-adjusted healthy controls (mean age 57.68 years; 59.1% men).
The researchers compared the thickness of the peripapillary nerve fiber layer of the retina and the deeper layers of the retina of the macula.
In patients with CIDP, compared to healthy controls, the mean total volume of the macula was significantly reduced (8.48 mm3 vs. 8.75 mm3; P = 0.018), there was a significant thinning of the ganglion cell layer (1.03 mm3 vs. 1, 07 mm3.). ; P = .037) and the inner plexiform layer (0.83 mm3 vs. 0.88 mm3; P = .015). A slight but significant reduction in the volume of the retinal pigment epithelium (0.38 mm3 vs. 0.40 mm3; P = 0.02) was reported in patients with CIDP compared to healthy controls.
The data suggest relationships between retinal layer volumes and nerve conduction and clinical parameters, including a remarkably positive association between right ulnar nerve motor conduction velocity and ganglion cell layer volume (P = 0.02; B = 0.002).
The study had several limitations, including the limited sample size and exploratory nature of the study.
“[T]The data indicate degenerative processes in the retina and thus in the CNS in CIDP. In particular the changes in the GCIPL [combined ganglion cell inner plexiform layer] could indicate underlying processes that may be functionally and biologically relevant. To consolidate these fascinating results, an independent longitudinal study of a larger patient cohort should be conducted, ”the researchers concluded.
Ingwersen J, Graf J, Kluge J, et al. CNS involvement in chronic inflammatory demyelinating polyneuropathy: subtle retinal changes on optical coherence tomography. Neurol Neuroimmunol Neuroinflamm. Published online October 19, 2021. doi: 10.1212 / NXI.0000000000001099