Behcet’s disease (BD) is a chronic multisystemic inflammatory disorder of unknown etiology. The most common manifestation of BD is oral aphthous ulcers (1,2,3). Other symptoms of BD include mucous membrane involvement such as genital ulcers, eye and skin lesions, gastrointestinal, cardiac, vascular, neurologic and pulmonary system involvements. Genitourinary tract involvement is encountered not only with genital aphthous ulcers but also with the urological problems such as epididymitis and sterile urethritis (4). Studies regarding the lower urinary tract involvement of BD are rare in the literature. The most common symptoms of lower urinary tract are filling symptoms and urinary incontinence. However, voiding symptoms and urinary retention may also be observed (5). In this study, we aimed to determine the relationship between BD and lower urinary tract symptoms.

This study was approved by the ethics comittee of the faculty of medicine of our university. Informed consent were obtained from all of the patients participated in the study.
From January to Deecember 2018, we determined 189 patients who admitted to rheumatology and dermatology clinics and diagnosed as BD according to the criteria of International Behcet Study Group. We included 55 patients who accepted to participate and were eligible according to the inclusion and exclusion criteria in this study.
Inclusion criteria:
•	Diagnosis of Behcet’s Disease
•	18-60 years of age
Exclusion Criteria:
•	Diagnosis of benign prostate hyperplasia
•	Urinary cancer
•	Urinary tract infection
•	Pelvic organ prolapse
•	History of urological surgery
•	Pregnancy
Patients were requested to complete a questionnaire including BD Current Activity Form which was validated in Turkish and had a minimal score 0 and maximal score 12. International Prostate Symptom Score Questionnaire (IPSS), International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF) and Overactive Bladder Questionnaire (OAB-V8) were also filled in by the patients. Uroflowmetry and post-void residual urine tests were performed. Demographic and clinical characteristics of patients were recorded.
In statistical analysis, the tests for comparisons were analyzed according to Central Limit Theory. SPSS 22.0 software package descriptive statistics (amount, percentage, mean, standard deviation) and analysis tests (Mann-Whitney U Test and Pearson correlation tests) were used when necessary. P<0.05 was considered as statistically significant.

The mean age of the patients (27 male, 28 female) was 42.6 ± 9.4 (20-59). The mean activity scores of BD were found to be 4.6 ± 3.2 (3.8 ± 2.8 in males and 5.5 ± 3.3 in females). The IPSS scores were 7.3 ± 7.3 (7.0 ± 7.0 for males and 7.7 ± 7.6 for females). According to the IPSS score, 60% of the patients had mild, 14.5% had moderate, and 15.5% had severe symptoms. The frequency of daytime urination was 5.0 ± 4.1 times (3.6 ± 2.3 in males and 6.4 ± 5.0 in females). The mean frequency of nocturia was 1.5 ± 1.4 (1.1 ± 1.3 in males and 2.0 ± 1.5 in females). The mean value of peak flow rate for all patients were 13.4 ± 8.5 ml/sec (11.3±7.0 ml/sec in men and 5.5 ± 9.6 ml/sec in women) and the mean volume of voided urine was 315.1±189.1 ml (315.5 ± 178.7 ml for males and 314.8 ± 202.8 ml for females). The mean postvoiding residual urine volume was 22.4 ± 54.2 ml (18.9 ± 33.6 ml for males and 26.1 ± 70 ml for females). The effect of gender on the BD Current Activity Score was not significant (P=0.057). 
The presence and the severity of lower urinary tract symptoms such as pollakuria, nocturia, urge incontinence, frequency of urinary incontinence and the effect of urinary incontinence for daily life are shown in Table-1. The correlation between the BD Current Activity score and urinary symptoms and the other study parameters are given in Table-2. None of the patients received any treatment for lower urinary tract symptoms and none of the male patients had epididymitis in their past medical history.

Studies on the urological aspect of BD are limited. In previous studies genital aphthous ulcers, epididymitis, urethritis, and cystitis were  encountered commonly in patients with BD (4,6). BD was postulated to affect neurological system of the lower urinary tract and leading to various filling and voiding dysfunction, therefore urodynamic evaluation is required in patients with BD (7,8). In another study by Cetinel et al.,104 BD patients and 44 controls were compared in terms of irritative and obstructive symptoms, the patients of BD group were found to have  more irritative symptoms than control group but obstructive symptoms were not significantly  different in both groups (9). In our study, we found a significant correlation between BD Activity Score and IPSS score and also particularly in the frequency of daytime urination, nocturia, urgency, and the presence of urinary incontinence, however there was no significant relationship with urine peak flow rate, voided volume and post-void residual urine.

Although the studies on the bladder involvement of BD and the relationship between lower urinary tract symptoms and BD suggest neurological involvement as the underlying cause, we showed that BD patients without neurological involvement had also lower urinary tract symptoms, therefore the main cause might be the systemic vasculitis  and chronic systemic inflammation in BD that would affect many organs and the urinary symptoms was correlated to the severity of the disease which was also valid in patients without any neurological involvement.

Dongsik Bang. Clinical Spectrum of Behçet’s Disease, The Journal of Dermatology Vol. 28: 610–613, 2001
Davatchi F. Behçet's disease. Int J Rheum Dis. 2018 Dec;21(12):2057-2058.
International Team for the Revision of the International Criteria for Behc_et’s Disease (ITR-ICBD): Davatchi F, Assaad-Khalil S, Calamia KT et al. (2014) The International Criteria for Behcet’s Disease (ICBD): a collaborative study of 27 countries on the sensitivity and specificity of the new criteria. J Eur Acad Dermatol Venereol 28, 338–47.