Chronic prostatitis (CP) / chronic pelvic pain syndrome (CPPS) are common debilitating conditions which effect 35-50% of men (1). The ICS defines CP/CPPS as ‘Persistent or recurrent prostate and/or pelvic pain, associated with symptoms suggestive of urinary tract and/or sexual dysfunction’ (2). 

The National Institutes of Health (NIH) has four classifications of prostatitis (2):

1.	Acute bacterial prostatitis (CP/CPPS associated with bacterial urinary tract infection requiring hospitalisation). 
2.	Chronic bacterial prostatitis (CBP) (CP/CPPS symptoms associated with recurrent bacterial urinary tract infections caused by the same bacterial strain). 
3.	CPPS in the absence of bacterial urinary tract infection.
4.	Asymptomatic inflammatory prostatitis (usually incidental finding of PSA).  
A recognised cause of bacterial and abacterial CP/CPPS is intra-prostatic reflux (PR) (3).

PR can occur when there is increased urethral resistance distal to the prostatic ducts during periods of raised detrusor pressure. Underlying aetiologies can be functional or anatomical. Functional pathologies include inappropriate relaxation of the external urethral sphincter (EUS) during voiding (known as detrusor sphincter dyssynergia (DSD) or dysfunctional voiding (DV) depending on if the patient has a known neurological diagnosis or idiopathic respectively) or guarding against detrusor overactivity (DO). Anatomical pathologies include urethral stricture, which can be idiopathic or iatrogenic post-surgery to de-obstruct the prostate. Video urodynamics (VUDS) can be used to identify PR and delineate the aetiology. 

The aim of this original study is to determine the aetiology of PR identified during VUDS and whether this finding is associated with CP/CPPS symptoms.

We retrospectively assessed the VUDS of 22 male patients referred due to bothersome LUTS, during which PR was observed. We determined the aetiology of the PR and whether this correlated with CP/CPPS symptoms. All urodynamic studies were conducted in accordance with the ICS good Urodynamics Practice Document.

The mean (±SD) age of participants was 57.9(±15) years. Results are illustrated in Figure 1, 64% of patients with PR were symptomatic with CP/CPPS. All patients with CP/CPPS symptoms had PR secondary to reduced bladder compliance, DO or DV. 
8 non-neurogenic patients were asymptomatic, 4 had DO, 4 had PR during the voiding phase (one anuric patient, 3 having previous benign prostatic obstruction surgery). There was no difference in DO onset, desire to void or DO PP between symptomatic and asymptomatic patients with PR resulting from DO.

64% of patients with PR identified during VUDS were symptomatic for CP/CPPS. The aeitiology of symptomatic PR is distension of the prostatic urethra either due to guarding against raised detrusor pressure during storage or inappropriate relaxation of the EUS during voiding (DV or DSD). 
5/8 of patients who demonstrated PR without reporting CP/CPPS symptoms either had previous benign prostatic obstruction (BPO) surgery or were anuric with a bulbar stricture(n=1).

64% of patients with PR reported symptoms consistent with prostatitis. The cause for symptomatic PR appears to be distension of the prostatic urethra either due to guarding against raised detrusor pressure during storage or inappropriate relaxation of the external urinary sphincter during voiding (DV or DSD). This finding suggests patients with symptoms consistent with prostatitis would benefit from VUDS. Patients with PR secondary to BPH surgery did not present with prostatitis symptoms (potentially due to the lower voiding pressures).

Pavone-Macaluso M. Chronic prostatitis syndrome: A common, but poorly understood condition. part I. EAU-EBU Update Series. 2007;5(1):1-15. doi:10.1016/j.eeus.2006.10.002
Kocjancic E, Chung E, Garzon JA, et al. International Continence Society (ICS) report on the terminology for sexual health in men with lower urinary tract (LUT) and pelvic floor (PF) dysfunction. Neurourology and Urodynamics. 2022;41(1):140-165. doi:10.1002/nau.24846
KIRBY RS, LOWE D, BULTITUDE MI, SHUTTLEWORTH KE. Intra-prostatic urinary reflux: An aetiological factor in abacterial prostatitis. British Journal of Urology. 1982;54(6):729-731. doi:10.1111/j.1464-410x.1982.tb13635.x