Treatment

The first step in the management of urinary retention, regardless of etiology, is bladder decompression through the insertion of a urethral Foley catheter. Should this prove difficult, attempts should be made to insert a coudé-tipped catheter. Difficult catheterization often indicates the presence of an obstructing process such as urethral stricture or prostatic in-growth, benign or malignant. Situations such as this may require formal cystoscopy and possible urethral dilation for catheter insertion. In the event that all attempts at catheterization fail, the insertion of a suprapubic cystosto-my tube is the most appropriate alternative. This can usually be performed percutaneously at the bedside. A history of lower abdominal or pelvic surgery is a contraindication to the percutaneous insertion of an su-prapubic tube since intervening bowel may be injured. In this circumstance, suprapubic drainage should be established under radiologic guidance or in the operating room through open techniques.

Relief of longstanding bladder outlet obstruction can result in a postobstructive diuresis. This most commonly reflects the appropriate excretion of retained sodium, water and urea; however, a concentrating defect or a sodium-wasting nephropathy, both secondary to distal renal tubular damage, may also play a role. Management is similar to that arising from upper tract obstruction.

Once bladder decompression has been achieved, further management is dictated by the underlying pathologic process. Depending on the patient's health and prior voiding status, a trial of voiding is warranted in most cases. Retention secondary to neurophysiologic bladder dysfunction often resolves after a period of bladder decompression. Cases in which spontaneous voiding is slow to return require the initiation of clean intermittent catheterization every 4-6 h (Lapides et al. 1972). Intermittent catheterization has demonstrated clear superiority over chronic indwelling catheterization in terms of preserving upper tract function and minimizing urinary tract infection and stone formation. Benign prostatic hypertrophy alone or together with neurologic dysfunction warrants a trial of a-adrenergic blockade (Flomax 0.4 mg p.o. daily) and/or 5-a-reductase inhibition (Finasteride 5 mg p.o. daily) therapy.

Locally advanced prostate cancer, not uncommonly, precipitates urinary retention through compression of the prostatic urethra and bladder neck. The most appropriate initial therapy in the hormonally naive patient is androgen deprivation therapy. This may involve either surgical (bilateral orchiectomy) or chemical castration (LHRH agonist). Although castrate levels of serum testosterone are achieved much more rapidly with bilateral orchiectomy (immediate) than with LHRH agonist therapy (3-4 weeks), the reduction in prostate and tumor volume is delayed with both, as is the ability to spontaneouslyvoid. Two-thirds ofpatients thus treated will ultimately regain the ability to void; however, roughly 50 % of patients will require catheterization for a period of 21-60 days in the interim (Fleischmann and Catalona 1985). Temporary drainage can be achieved through either continuous or intermittent catheteriza-tion, depending on the ease of catheterization. Up to 22 % of patients will develop urinary retention a mean of 21 months after the initiation of hormonal therapy (Sehgal et al. 2005). Prognostic factors for urinary retention in this circumstance include a high Gleason score (> 7) and urinaryretention at the start ofhormon-al therapy. Those cases that are unresponsive to androgen deprivation or known to be resistant at baseline require TURP or intraprostatic urethral stenting. The insertion of a urethral stent is most appropriate for those patients who are poor surgical candidates and refuse an indwelling catheter. As many as 88 % -100 % of patients are able to void through a urethral stent with acceptable morbidity out to 1 year (Ok et al. 2005; Guazzoni et al. 1994). Based on concerns over the risk of infection and possible obstruction secondary to progressive tumor growth, urethral stents are only recommended in patients with a limited life expectancy.

Palliative or channel TURP is the gold standard treatment for PCa-related urinaryretention unresponsive to medical therapy. Although less successful and associated with more complications than TURP performed for BPH, palliative TURP is considered a safe and efficacious procedure. Up to 79% of patients will regain the ability to void despite the relatively high rate of failure at initial trial of voiding (42 %) (Crain et al. 2004). Morbidity is acceptable with an 8% transfusion rate and negligible perioperative mortality rate. The reoperation rate is relatively high (22 % - 29 %) and likely reflects less than complete resection (mean 12-g resection), continued local tumor growth, and the propensity of tumor to bleed (Mazur and Thompson 1991; Crain et al. 2004). Photoselective vaporization of the prostate (PVP) using high-power potassium-titanyl-phosphate (KTP) laser energy is a relatively new procedure that appears to be an acceptable alternative to standard TURP for symptomatic obstructive uropathy secondary to either PCa or BPH (Sulser et al. 2004). Although no randomized controlled trials have compared these two modalities in the setting of PCa, similar improvement in peak flow rates and urinary symptom scores have been demonstrated in patients with BPH (Shing-leton et al. 1999). Perceived advantages to PVP include less bleeding, lower transfusion rate, shorter catheteri-zation, and more rapid convalescence (Kumar 2005).

Chronic catheterization via an indwelling urethral or suprapubic catheter is an option of last resort typically reserved for terminally ill patients or those who fail medical and surgical therapies. Suprapubic cathe-terization maybe preferable to urethral catheterization based on long-term data in spinal cord-injured patients, demonstrating lower rates of symptomatic urinary tract infection and upper tract deterioration with suprapubic drainage (Ku et al. 2005; Esclarin de Ruz et al. 2000). To minimize catheter-related morbidity, scheduled catheter changes should be conducted on a monthly basis (Russo 2000). Chronic suppressive antibiotics are not recommended in catheterized patients but short-course antibiotic therapy may be used at the time of catheter exchange.

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