Foley Catheter Related Bladder Discomfort (FCRBD): Role of Neutrophil Cells

Overview

Urinary \[Foley\] catheters \[tubes\] are commonly placed in patients undergoing surgery; approximately 25% of surgical patients will receive one. Among patients who receive urinary catheters, discomfort associated with the Foley catheter is common; between 47-90% of patients experience catheter related bladder discomfort \[CRBD\]. Presence of a foreign object in the bladder even for short periods of time may result in symptoms such as a burning sensation, pain in the lower abdomen, muscle spasms and a sense of urgency to urinate. There is some evidence that suggests that hospital-acquired urinary tract infections are directly related to catheter placement, which causes mechanical damage and local inflammation to the urethra and the bladder. Based on research conducted on a similar mechanism where an airway tube is inserted into a patients throat for delivery of general anesthesia - we hypothesize that CRBD is related to injury and inflammation caused by the catheter placement and that this occurs in a sterile environment.

Urinary catheterization has been implicated in up to 80% of hospital-acquired UTIs, and has been associated with evidence for immunological and histological damage frequently in the absence of bacteria31. In a recent human study in elderly patients with ASB and UTI analysis of neutrophil activity showed evidence of enzymatic involvement during bladder infection32, and some appeared to relate to pain and inflammation, however no analysis was conducted regarding neutrophil phenotypes and the impact of mtDNA on sterile local injury mediated exclusively by a Foley catheter. The bladder irritation that results from Foley catheterization appears to be mediated by muscarinic receptors that mediate involuntary bladder smooth-muscle contractility. Thus the main therapy relies on agents with anti-muscarinic activity such as oxybutynin, tolterodine and butylscopolamine, whereas some benefit has been shown with tramadol, ketamine, paracetamol, pregabalin and gabapentin. However no single commonly accepted therapy for FCRBD is available, and there is uncertainty about the safety and efficacy of the current treatments available. Some research has suggested a role for inflammatory mediators in the occurrence of FCRBD as evident by induction of prostaglandin synthesis and cyclooxygenase-2 (COX-2) inhibitors alleviating symptoms related to FCRBD. In summary various therapies to control FCRBD are available but none have directly addressed the acute inflammatory reaction likely mediating these symptoms1,2,3,4. Hence our interest in analyzing the activity of acute inflammatory cells in particular neutrophil activation as a mediator of bladder inflammation and trigger of FCRBD. Although the exact pathophysiology of FCRBD has not been elucidated, we recently showed expression of inflammatory mediators, neutrophil infiltration and mucosal surface injury in the absence of bacterial infection using a human model of tracheal injury. As it has been clearly shown that neutrophil infiltration and activation can be driven in response to sterile cell death8, our preliminary data suggest that the link between Foley catheter and possible bladder neutrophil accumulation is through mucosal cell injury.