Bilateral choroid plexus enlargement in patients with postherpetic neuralgia

Background The choroid plexus contributes to cerebrospinal fluid regulation, barrier function, and neuroimmune homeostasis. We investigated choroid plexus volume in patients with postherpetic neuralgia (PHN) and its relationships with clinical characteristics and the side of herpes zoster involvement. Methods This cross-sectional analysis of a prospectively recruited neuroimaging cohort included 42 patients with PHN and 41 healthy controls selected to achieve comparable age and sex distributions. Choroid plexus volumes were measured from three-dimensional T1-weighted MRI using the chp_seg pipeline and normalized to the estimated total intracranial volume. Group differences were assessed using age- and sex-adjusted linear regression. Sensitivity analyses assessed absolute volume with intracranial volume adjustment and used heteroscedasticity-robust confidence intervals. Associations with pain intensity, neuropathic symptoms, functional interference, disease duration, and the side of herpes zoster involvement were also examined. Results Normalized total choroid plexus volume was greater in patients with PHN than in healthy controls (0.2334 ± 0.0608% vs. 0.1590 ± 0.0383%; p < 0.001). The difference remained significant after adjustment for age and sex (adjusted mean difference, 0.0729 percentage points; 95% confidence interval, 0.0544–0.0914; p < 0.001). Right and left choroid plexus volumes were also greater in patients with PHN. Sensitivity analyses supported the principal finding. No statistically significant associations were detected with the measured clinical characteristics or the side of herpes zoster involvement. Conclusion Patients with PHN had greater normalized choroid plexus volume in both hemispheres than healthy controls. No significant clinical or laterality associations were detected. The specificity of this morphologic difference to PHN, its temporal origin, and its biological significance remain unresolved.