Evaluating nerve dysfunction in Behçet's disease: a study using corneal confocal microscopy and electromyography.

PURPOSE: To evaluate peripheral nerves in Behçet's disease (BD) by monitoring the corneal nerves with in vivo corneal confocal microscopy (IVCCM) and measuring sympathetic skin response (SSR) and cutaneous silent period (CSP) with electromyography (EMG).

METHODS

This cross-sectional study included 90 participants: 60 BD patients, divided into Group 1 (n = 30) with uveitis and Group 2 (n = 30) without uveitis, and 30 healthy controls (Group 3). IVCCM assessed the subbasal nerve plexus (SNP), while EMG measured sensory and motor nerve conduction, CSP and SSR. SNP images were analyzed with ACCMetrics software, and dendritic cell (DC) densities were calculated using ImageJ software. In addition, patients under systemic medication were divided by subgroups and analysed separately.

RESULTS

No significant differences in SNP analysis or DC densities were observed across groups (p > 0.05). Patients treated with conventional agents (azathioprine) exhibited significantly lower total DC densities compared to those on colchicine and biological agents (p = 0.003, p = 0.0033). Group 2 demonstrated reduced SSR lower extremity amplitude compared to controls (p = 0.017); nevertheless, no significant differences in CSP durations or SSR latencies were found (p > 0.05).

CONCLUSION

Evidence of small fiber neuropathy in BD was suggested by SSR amplitudes, reflecting autonomic nervous system involvement. The lack of significant differences in CSP and SSR latencies may indicate nerve regeneration due to controlled inflammation. Additionally, lower DC densities in patients on conventional treatments may highlight the mechanism of azathioprine at the in vivo level.