The encrustation and blockage of long-term indwelling bladder catheters: a way forward in prevention and control.

OBJECTIVES: To review the literature showing that understanding how Foley catheters become encrusted and blocked by crystalline bacterial biofilms has led to strategies for the control of this complication in the care of patients undergoing long-term indwelling bladder catheterization. METHODS: A comprehensive PubMed search of the literature published between 1980 and December 2009 was made for relevant articles using the Medical Subject Heading terms 'biofilms', 'urinary catheterization', 'catheter-associated urinary tract infection' and 'urolithiasis'. Papers on catheter-associated urinary tract infections and bacterial biofilms collected during 40 years of working in the field were also reviewed. RESULTS: There is strong experimental and epidemiological evidence that infection by Proteus mirabilis is the main cause of the crystalline biofilms that encrust and block Foley catheters. The ability of P. mirabilis to generate alkaline urine and to colonize all available types of indwelling catheters allows it to take up stable residence in the catheterized tract in bladder stones and cause recurrent catheter blockage. CONCLUSION: The elimination of P. mirabilis by antibiotic therapy as soon as it appears in the catheterized urinary tract could improve the quality of life for many patients and reduce the current expenditure of resources when managing the complications of catheter encrustation and blockage. For patients who are already chronic blockers and stone formers, antibiotic treatment is unlikely to be effective owing to the resistance of cells in the crystalline biofilms. Strategies such as increasing fluid intake with citrated drinks could control the problem until bladder stone removal can be organized.

Effect of opiate analgesia and opioid blockade on urethral mucosal sensitivity threshold.

The effect of opiate analgesics (omnopon, pethidine, pentazocine) on the urethral mucosal sensitivity threshold in 37 patients, and of the potent opiate/opioid antagonist naloxone on 10 volunteers is described. Omnopon and pentazocine caused a significant decrease in sensitivity (p less than 0.02) and naloxone caused a significant increase in sensitivity (p less than 0.02). The results confirm a role for the endogenous opioids in modulating urethral sensitivity, and the implications of this are discussed.

Urethral closure in management of urinary incontinence.

Urethral closure with suprapubic catheterization has been used in 50 patients with urethral destruction due to an indwelling catheter. Thirty-seven of the patients were dry after the initial operation. Long-term complications were seen in 33 patients. Those that did occur were not life threatening. This relatively minor procedure offers a good alternative to formal diversion in this group of severely disabled patients.

Voiding disorders in young male adult.

Two hundred four male patients (aged twenty to forty-five years) with symptoms of lower urinary tract dysfunction have been investigated by urodynamic studies. Patients with symptoms of bladder overactivity (53 per cent) had a low incidence of bladder outflow obstruction but a high incidence of bladder hypersensitivity and bladder instability. Their symptomatic complaints accurately reflected their cystometric findings and, therefore, a urine flow rate estimation was the only necessary urodynamic investigation in most cases. Urine flow studies are an essential first investigation in all patients with possible bladder outflow obstruction (26 per cent), and full studies were necessary in many patients to discriminate the low flow rates produced both by outflow obstruction and by bladder underactivity which were diagnosed in a high proportion of patients. Similarly, in the neurologically abnormal patients (12 per cent), full urodynamic studies were necessary with the studies described in this article the minimum required.

Treatment of bladder carcinoma with tumor-immune pig lymph node cells. Phase I study.

A total of 77 patients with invasive TCC of the urinary bladder each received a single arterial injection of tumor-immune pig lymph node cells (LNC), into the tumor blood supply. The patients were divided into 4 groups: those receiving pig LNC as the only treatment (16 patients); those who received pig LNC on relapse (judged by EUA cystoscopy and biopsy) following radical radiotherapy, 5,500 cGy (34 patients); those who received pig LNC followed after an interval of six weeks by radiotherapy, 4,000 cGy (10 patients); as in Group 3 but with the dose of radiotherapy increased to 5,500 cGy (17 patients). Complete remission was characterized by complete disappearance of the tumor (for a varying time) following treatment. Partial remission was defined as: a reduction in the level of symptoms and a decrease in tumor size on EUA and/or cystoscopy. There were 1 complete and 3 partial remissions among the patients in Group 1, 5 complete and 7 partial in Group 2, 6 complete and 2 partial in Group 3, and 8 complete and 1 partial in Group 4. Of the 20 patients showing complete remission, 7 lived for more than five years after treatment.

Transfer of adoptive immunity by intra-arterial injection of tumor-immune pig lymph node cells: treatment of recurrent urinary bladder carcinoma after radical radiotherapy.

Twenty-four patients with invasive transitional cell carcinoma of the urinary bladder, recurrent after radiotherapy, were treated by intra-arterial infusion of tumor-immune pig lymph node cells. In 11 patients there was a remission of the disease process, and 3 patients remain alive and free of disease in excess of one year after treatment.

Funding clinical research: the need for information and longer term strategies.

The Chief Medical Officer's Working Group on Specialist Medical Training recommended that training in research methodology should be a recognised component of all postgraduate training programmes and that further consideration be given by those responsible for postgraduate education, training and research to establishing how this might be achieved. Funding of the trainee in research is a crucial aspect of this directive, yet both trainers and trainees have described this as haphazard, invariably reliant on 'soft' money. The subject has raised wide discussion and debate. A questionnaire was sent to 205 consultant urologists in the UK, 154 (75%) replied and 130 (84%) had experience of research during their training. The first report examined their opinion about the contribution of research to their training; this report covers the questions directed towards funding, the source of their funding, whether sufficient funds, advice and information were available and where they might expect to obtain such details. The replies indicated a variety of sources of funding; knowledge about the financial support available for research was sparse and the majority considered there was insufficient advice and information available for trainees on the subject. Substantial funds are available for high quality scientific research programmes providing unprecedented opportunities for multidisciplinary collaboration that is essential for advancing clinical practice alongside technological developments. The process of obtaining support can be a time-consuming exercise, raising the need for an administrative infrastructure to select, prioritise and co-ordinate an appropriate research strategy for the future.

A departmental audit of patients with bladder cancer.

In keeping with the recent demands of the Department of Health for medical audit in clinical practice, an audit was undertaken of the management of bladder cancer patients in a large department of urology having three consultants with varied approaches of management. This study revealed interesting controversial areas for further scrutiny. For example, the poor prognosis of grade 3 T1 tumours with and without associated carcinoma-in-situ (CIS) and the speed of progression to invasive disease have indicated that a change to a more aggressive approach to the management of these tumours is necessary. High recurrence rates at the site of the original tumour (60%) and the presence of CIS also indicate the need for expert and thorough initial tumour assessment. The delays in diagnosis and treatment lend further support to the need for a 'haematuria clinic' to minimise such delays, which may influence prognosis. To reduce the occurrence of systematic errors in the recording, follow-up and surveillance of patients with bladder cancer, a protocol is suggested for a structured approach to optimise results, particularly in the poor prognostic categories.

Mobile versus fixed site lithotripsy.

The efficacy of a mobile Dornier HM4 lithotriptor, was compared with that of a fixed site Siemens Lithostar. A total of 115 calculi in 98 patients were treated, 55 on the mobile Dornier and 60 on the Lithostar. The groups were similar except for stone size, the mean of the Lithostar group being 11 mm compared with 7.7 mm in the Dornier group. Fragmentation rates were not significantly different, 88% and 75% on the mobile and fixed site machines, respectively and, at 3 months follow-up 66% and 46% were stone free or with fragments of less than 2 mm. There were no serious complications, and the incidence of mild complications was similar in the two groups. We conclude that the mobile Dornier HM4 is an effective lithotriptor and can offer several advantages over fixed site machines.

A modified semi-automated technique for in vitro assessment of encrustation of materials.

In vitro study of encrustation is an important part of assessment of materials as potential alloplasts or devices in the urinary tract. This modified semi-automated technique comprises a circular reaction chamber with an encrustation mixture, the level of which is controlled by a float switch which operates the exit peristaltic pump. The composition of the reactants used simulates infected urine with alkaline pH. Results of a preliminary study of the deposits by scanning electron micrography (SEM) and energy dispersive X-ray (EDX) microanalysis are consistent with struvite and hydroxyapatite, similar to the main minerals deposited on urinary catheters. It is a relatively simple, effective and inexpensive set-up for study of encrustation on materials.

Developing alternative devices to the long-term urinary catheter for draining urine from the bladder.

The self-retaining urinary catheter is used for long-term drainage of urine from the bladder only as a last resort because of serious associated complications, yet it remains a routine method for managing older and disabled patients with loss of bladder control. Blockage of the catheter from calcified deposits within its lumen is a common occurrence, obstructing the passage of urine and causing an urgent, unpredictable problem for patients, carers and the nursing staff. The need for further research on the subject has been recognized for many years. The SuPort Project aimed to develop an alternative suprapubic urine collection system. This report outlines the approach adopted towards the design and selection of the novel device, the production problems that ensued and the small clinical trial of a modified prototype.

Extraurinary manifestations of chronic pyonephrosis.

Twenty-five patients who underwent nephrectomy for chronic pyonephrosis were studied retrospectively. Such patients may present with a wide range of symptoms. Marked haematological and biochemical abnormalities are found, the most striking being a gross elevation of plasma viscosity (or ESR) and a raised alkaline phosphatase. The resulting picture often suggests extrarenal disease, and diagnostic confusion occurred in a number of patients.

Factors modulating the pH at which calcium and magnesium phosphates precipitate from human urine.

The factors controlling the rate at which crystalline bacterial biofilms develop on indwelling bladder catheters are poorly understood. It is known that normally the pH of voided urine (pHv) is lower than the pH at which calcium and magnesium phosphates come out of urine solution (pHn). In patients who develop infections with urease producing bacteria, however, the pHv rises above the pHn and precipitation of the phosphates occurs in the urine and the biofilm. The aim of this study was to examine ways of manipulating the pHn of urine so that more of its calcium and magnesium remain in solution under alkaline conditions. The experimental data show that pHn can be elevated by decreasing the calcium, magnesium and phosphate concentrations. Increasing the fluid intake of a human subject so that the urinary calcium fell from 120 mg/l to 25 mg/l, for example, resulted in the pHn increasing from 6.48 to 8.22. The addition of citrate to urine also produced a rise in the pHn. The daily consumption of 500 ml of fresh orange juice increased urinary citrate concentrations from 0.35 to around 1.21 mg/ml and the pHn rose from 7.24 to 8.2. The pHn of urine is thus a highly variable parameter. It can be manipulated by controlling the urinary concentrations of magnesium, calcium, phosphate and citrate ions. We suggest that increasing fluid intake with citrate containing drinks would reduce the extent of encrustation on catheters in patients infected with urease producing bacteria.

The management of female incontinence by suprapubic catheterisation, with or without urethral closure.

Thirty-two female patients with continued urinary incontinence, following a period of urethral catheterisation, have been treated by suprapubic catheterisation. A technique is described for closure of the female urethra and this has been effective in 20 out of 24 patients. The procedure has been undertaken in some patients with advanced neurological disease and in the presence of pressure sores.

The actions of prostaglandins on the smooth muscle of the human urinary tract in vitro.

14 experiments, 10 on bladder muscle strips and 4 on samples of ureteric muscle, were performed to examine the actions of 4 prostaglandins (PGE, PGE2, PGF1alpha and PGF2alpha) on these tissues. Each of the prostaglandins caused bladder muscle to contract and prostaglandin F2alpha was the most potent in this respect. The F series prostaglandins also caused increased ureteric muscle contraction whilst those of the E series inhibited contractions. It is unlikely that contraction is produced by the direct action of prostaglandins on urinary smooth muscle. The suggestion is made that prostaglandins may have a function in the maintenance of vesical tone.