Autonomic neural control of the cardiovascular system in patients with Behçet's disease in the absence of neurological involvement

Heart Rate Variability as an Indicator of Autonomic Nervous System Disturbance in Behcet's Disease

Background

Behçet’s disease (BD) is a multisystemic vasculiti where cardiac involvement is not common. Previous studies have shown that the incidence of ventricular arrhythmia and sudden cardiac death (SCD) is higher in patients with BD than in the healthy population. Among various possible explanations, autonomic nervous system (ANS) dysfunction has been suggested. Few studies have evaluated ANS function in patients with BD, and the results obtained are controversial.

Objective

We aimed to assess cardiac autonomic function by heart rate variability (HRV) in patients with BD; to evaluate circadian changes in HRV; and to study the relationship between HRV parameters and disease parameters.

Methods

Thirty-six patients with Behçet’s disease (median age 42 years, 28 men) and 36 age- and sex-matched healthy volunteers were included. HRV analyses were performed in the time and frequency domains for the entire 24-hour period and for the daytime and nighttime periods. BD activity was studied with Behcet’s disease current activity form (BDCAF).

Results

Patients with BD had significantly lower values of SDNN compared to controls. PNN50, RMSSD, and HF components mean values were significantly reduced in patients than in controls implying parasympathetic impairment. LF was comparable between the two groups, whereas LF/HF ratio was significantly higher in BD group. The circadian rhythm of HRV was preserved in patient group. There was no significant correlation of CRP or disease duration with HRV indices in Behçet’s subjects. BDCAF score was found to be negatively correlated with LF/HF.

Conclusion

Patients with BD, despite no cardiovascular involvement, have reduced parasympathetic activity compared with controls. However, circadian rhythms of autonomic function were preserved. As known, there is strong evidence for the role of the ANS in the pathogenesis of ventricular arrhythmias. Thus, being a practical tool, HRV can be an interesting approach for the rhythmic follow-up of BD patients.

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In Vivo Confocal Microscopic Evaluation of Corneal Nerve Fibers and Dendritic Cells in Patients With Behçet's Disease

Central and peripheral nervous system involvement may occur during the course of Behçet’s disease (BD). In vivo corneal confocal microscopy (CCM) can detect corneal small fiber damage and immune cell density. The aim of this study was to assess central corneal sensitivity, corneal subepithelial nerve plexus morphology and dendritic cell (DC) density in patients with BD. Forty-nine consecutive patients with BD and 30 healthy control subjects were included in this cross-sectional study conducted at a tertiary referral university hospital. Central corneal sensitivity was measured using the contact corneal esthesiometer (Cochet-Bonnet; Luneau, France). The laser scanning CCM (Heidelberg, Germany) was used to quantify corneal nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), and DC density. There was a significant reduction in NFD (P = 0.001) and NFL (P = 0.031) and an increase in DC density (P = 0.038) in patients with BD compared to healthy controls, whereas corneal sensitivity (P = 0.066) and NBD (P = 0.067) did not differ significantly. There was no difference in corneal sensitivity, corneal nerve parameters, or DC density between BD patients with [n = 18 (36.7%)] and without a previous history of uveitis (P > 0.05 for all). Disease duration [median (IQR), 6.5 (4.0–14.5) years] correlated with corneal sensitivity (ρ = −0.463; P = 0.001) and NFD (ρ = −0.304; P = 0.034) and corneal sensitivity correlated with NFD (ρ = 0.411; P = 0.003) and NFL (ρ = 0.295; P = 0.039) in patients with BD. CCM demonstrates corneal sub-basal nerve fiber loss and increased DC density, providing a non-invasive ophthalmic means to identify peripheral neuropathy and inflammation in patients with BD.

Epidemiology and management of neuropsychiatric disorders in Behçet's syndrome

Behçet's syndrome (BS) is a systemic, chronic, relapsing vasculitis, typically characterized by recurrent orogenital ulcers, ocular inflammation and skin manifestations; articular, vascular, gastroenteric and neurological involvement may also occur. Besides the other clinical features of BS, it seems relatively frequent that patients with BS develop a neurobehavioural syndrome, characterized by euphoria, bipolar disorders and paranoid attitudes, loss of insight/disinhibition, and indifference to their disease, defined as 'neuro-psycho-BS'. To date, the pathogenetic mechanism underlying neuro-psycho-BS has not been determined. It may be secondary to organic neurological involvement, or it may be related to poor quality of life and the relapsing course of the disease. Another engaging theory suggests that it could be related to the frequent observation of psychiatric symptoms during relapses or, in some cases, in the phases preceding reactivation of the disease; these elements suggest that psychiatric disorders in BS could represent a crucial element, whether a psychiatric subset or a distinct clinical feature of the disease. Moreover, it has been reported that cognitive impairment in BS can be seen with or without central nervous system involvement. Globally, psychiatric symptoms have been described as being multifaceted, ranging from anxiety disorders to depressive-bipolar disorders or to psychotic ones. In addition, some psychological characteristics of BS patients seem to predispose them to maladaptive stress management, which may lead to stress-related disorders, including anxiety and depression. Therefore, the aims of this review are to explore the epidemiology of neuro-psycho-BS by evaluating the relationship between the stress system and the multifaceted psychiatric manifestations in BS, and to summarize the therapeutic strategy used.