Factors implicated in pathogenesis of urinary tract infections in neurogenic bladders: some revered, few forgotten, others ignored

Abstract

In order to address the issue of urinary tract infection in patients with neurogenic bladders, multiple factors need to be looked into and corrected. Further research is required, especially in the area of compromised host defence mechanisms. An individualized approach, which attempts to optimize each factor is recommended.

Gentamicin bladder instillations decrease symptomatic urinary tract infections in neurogenic bladder patients on intermittent catheterization

“…2 Risk factors for UTI in the NGB population are poorly understood; however, decreased bacterial washout due to inefficient voiding, vesicoureteral reflux, and altered hydrokinetics, as well as alterations in protective flora or the urothelium itself are potential contributors to increased rates of infection. 3 Non-sterile intermittent self-catheterization (ISC), unfortunately does violate the main defense mechanisms of the bladder by introducing bacteria into the system, but is the standard of care for bladder management in NGB with chronic retention, with advantages over indwelling catheters and no proven disadvantages when compared to sterile catheterization. 4 Strategies for preventing UTI in NGB patients on ISC are lacking in evidence.…”

Recurrent urinary tract infections in patients with incomplete bladder emptying: is there a role for intravesical therapy?

“…Immunological impairment has also been postulated, with studies demonstrating deficient mucosal immunity, impaired NK cell, B and T cell function, and defective urothelium that may result in absent apoptosis in response to intercellular signaling (9-11). Bladder ischemia from either over-distension or poor compliance may result in increased risk of infection as adequate blood flow is necessary for host defense mechanisms to function (12). From a mechanical standpoint, impaired washout also increases the risk of UTI.…”

“…Firstly, they negate the protective effect of urethral length on prevention of UTI, specifically in the male. Secondly, they produce chronic inflammation, which may contribute to alterations in defense mechanisms such as the GAG layer (12). Finally, bacterial biofilms may form even in the absence of indwelling catheters (17).…”

Urinary Tract Infection and Neurogenic Bladder

“…Evidence suggests that increased intravesical pressure results in bladder ischemia, which in turn may result in delayed or deficient immune response to pathogens. 10,11 Animal and human studies have found that increased intravesical pressure significantly reduces blood flow, in both the distended and empty bladder, suggesting global dysfunction. 12,13 Although most patients with NGB have abnormal urodynamic studies, many of these parameters can be mitigated successfully with medications or surgery.…”

“…10 Animal studies have shown that 99.9% of bacteria injected into the bladder are removed by voiding. 14 Based on these studies, inefficient voiding with residual urine in theory predisposes to development of UTI.…”