Genitourinary Dysfunction

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Chapter 23 Genitourinary Dysfunction

PELVIC ORGAN PROLAPSE, URINARY INCONTINENCE, AND INFECTIONS

A better understanding of the anatomic basis of pelvic relaxation defects has led to less invasive techniques and better outcomes for the treatment of female genitourinary dysfunction.

image Pelvic Organ Prolapse

Pelvic organ prolapse (POP) refers to protrusion of the pelvic organs into the vaginal canal or beyond the vaginal opening. It results from a weakness in the endopelvic fascia investing the vagina, along with its ligamentous supports. Defects in vaginal support may occur in isolation (e.g., anterior vaginal wall only) but are more commonly combined. The nomenclature of POP has evolved such that cystocele, rectocele, and enterocele have been replaced by more anatomically precise terms (Figure 23-1).

QUANTIFYING AND STAGING PELVIC ORGAN PROLAPSE

The preferred method to describe and document the severity of POP is the Pelvic Organ Prolapse Quantification (POP-Q) system. The extent of prolapse is evaluated and measured relative to the hymen, which is a fixed anatomic landmark. The anatomic position of the six defined points for measurement is denoted in centimeters above the hymen (negative number) or centimeters below the hymen (positive number). The plane at the level of the hymen is defined as zero (Figure 23-3).

image

FIGURE 23-3 Illustration showing a side view of female pelvis. Six sites (points Aa, Ba, C, D, Bp, and Ap), genital hiatus (gh), perineal body (pb), and total vaginal length (tvl) used for pelvic organ support quantitation.

(Reproduced with permission from Bump RC, et al: The standardization of terminology of female pelvic organ prolapse and pelvic floor dysfunction. Am J Obstet Gynecol 175:10, 1996.)

Stages of POP can be assigned according to the most severe portion of the prolapse after the full extent of the protrusion has been determined. An ordinal system is used for measurements of different points along the vaginal canal and allows for better communication among clinicians. This staging system enables more objective tracking of surgical outcomes (Table 23-1).

TABLE 23-1 PELVIC ORGAN PROLAPSE STAGING SYSTEM

Stage Characteristics
0 No prolapse
Aa, Ba, Ap, Bp are −3 cm and C or D ≤ −(tvl −2) cm
1 Most distal portion of the prolapse −1 cm (above the level of hymen)
2 Most distal portion of the prolapse ≥ −1 cm but ≤ +1 cm (≤1 cm above or below the hymen)
3 Most distal portion of the prolapse > +1 cm but > +(tvl − 2) cm (beyond the hymen; protrudes no farther than 2 cm less than the total vaginal length)
4 Complete eversion; most distal portion of the prolapse ≥ +(tvl − 2) cm

Aa, point A of anterior wall; Ba, point B of anterior wall; Ap, point A of posterior wall; Bp, point B of posterior wall; −, above the hymen; +, beyond the hymen; tvl, total vaginal length.

Reproduced with permission from Harvey MA, Versi E: Urogynecology and pelvic floor dysfunction. In Ryan KJ, Berkowitz RS, Barbieri RL, Dunaif A (eds): Kistner’s Gynecology and Women’s Health, 7th ed. St. Louis, Mosby, 1999. Copyright © 1999 Elsevier.

MANAGEMENT

Prophylactic measures to mitigate the symptoms of POP include identifying and treating chronic respiratory and metabolic disorders, correction of constipation and intraabdominal disorders that may cause repetitive increases in intraabdominal pressure, and administration of estrogen to menopausal women. Failure to recognize and treat significant support defects at the time of concomitant gynecologic surgery may lead to progression of existing prolapse and the development of urinary incontinence or retention and urinary tract infections (UTIs).

Surgical Treatment

The main objectives of surgery are to relieve symptoms and restore normal anatomic relationships and visceral function. Preservation or restoration of satisfactory coital function when desired and a lasting operative result are also important goals.

image Urinary Incontinence

Urinary incontinence is defined as the involuntary loss of urine that is objectively demonstrable and is a social or hygienic problem. Urinary incontinence has been reported to affect 15% to 50% of women. The problem increases in prevalence with age, reaching more than 50% in elderly persons in nursing homes. It is estimated that the direct financial cost of urinary incontinence in the United States is between $10 and $15 billion per year.

image Stress Urinary Incontinence

SUI is involuntary leakage of urine in response to physical exertion, sneezing, or coughing.

DIAGNOSTIC TESTS

Cystometrogram

Cystometry consists of distending the bladder with known volumes of water and observing pressure changes in bladder function during filling. The most important observation is the presence of a detrusor reflex and the patient’s ability to control or inhibit this reflex.

The first sensation of bladder filling should occur at volumes of 150 to 200 mL. The critical volume (400 to 500 mL) is the capacity that the bladder musculature tolerates before the patient experiences a strong desire to urinate. At this point, if the patient is asked to void, a terminal contraction may appear and is seen as a sudden rise in intravesical pressure. At the peak of the contraction, the patient is instructed to inhibit this reflex (indicated by arrows in Figure 23-6). A normal person should be able to inhibit this detrusor reflex and thereby bring down intravesical pressure (see Figure 23-6A). In a urologically or neurologically abnormal patient, the detrusor reflex may appear without the specific instruction to void, and the patient cannot inhibit it (see Figure 23-6B); this observation is referred to as an uninhibited detrusor contraction. Other terms for this disorder include overactive bladder, detrusor dyssynergia, detrusor hyperreflexia, irritable bladder, hypertonic bladder, unstable bladder, and uninhibited neurogenic bladder.

These cystometric procedures allow differentiation between patients who are incontinent as a result of uninhibited detrusor contraction and those who have SUI. Conversely, the hypotonic bladder accommodates excessive amounts of gas or water with little increase in intravesical pressure, and the terminal detrusor contraction is absent when the patient is asked to void (see Figure 23-6C).

TREATMENT

Intravaginal Devices

Larger sizes of pessaries (see Figure 23-4) have been used to elevate and support the bladder neck and urethra. They have been shown to be effective for SUI.

Surgical Therapy

Surgery is the most commonly employed treatment for SUI. The aim of all surgical procedures is to correct the pelvic relaxation defect and to stabilize and restore the normal supports of the urethra. The approach may be vaginal, abdominal, or combined abdominovaginal.

image Urge Urinary Incontinence and Overactive Bladder

The two terms are often used interchangeably to describe a problem with bladder control that is associated with a strong desire to pass urine with a decreased ability to control it. Urge urinary incontinence (UUI) is defined as the involuntary leakage of urine accompanied by or immediately preceded by urgency. UUI can be associated with small losses of urine between normal micturitions or large volume losses with complete bladder emptying. Overactive bladder (OAB), previously described as UUI associated with detrusor muscle instability, is a more descriptive symptom-based term and more accurately encompasses the common clinical presentation. OAB is defined as “urgency, with or without urge incontinence, usually with frequency and nocturia.”OAB has become the preferred term because it comprises symptoms of urgency, urge urinary incontinence, frequency, and nocturia.

The incidence of overactive bladder increases with age, approximating 30% in the geriatric patient population. In most patients, the exact etiology of bladder instability remains unknown, but a number of risk factors are associated with its development (Box 23-1).

Classically, women with OAB describe a sudden strong urge to urinate with an inability to suppress the feeling, rushing to the bathroom, and leaking before making it to the toilet. Awakening several times a night to urinate is also a prominent feature.

TREATMENT

The optimal treatment of OAB starts with behavioral modification, adding pharmacologic and physical interventions, such as electrical stimulation, as needed. Identification of any dietary triggers, like caffeine, alcohol, or carbonated beverages, is important. The use of a self-reported bladder diary can be helpful for obtaining this information.

Pharmacologic Treatment

Antimuscarinics, or anticholinergics, have become the mainstays of drug treatment for OAB.

The mainstays of drug therapy include oxybutynin chloride (Ditropan) and tolterodine (Detrol). Oxybutynin chloride has been shown to improve symptoms of urinary urgency in about 70% of patients. Tolterodine also has anticholinergic activity. Because of its bladder specificity, tolterodine has a more favorable side-effect profile than oxybutynin. It is also dosed less frequently, which improves patient compliance. Both are available in immediate release and long-acting formulations. Oxybutynin is also available for delivery in a transdermal patch.

Trospium chloride, solifenacin, and darifenacin are newer agents used in the treatment of OAB. All significantly improve OAB symptoms compared with placebo. Evidence suggests that side-effect profiles will be similar or lower than the less specific antimuscarinics.

Imipramine hydrochloride is a tricyclic antidepressant that acts through its anticholinergic properties to increase bladder storage. The drug improves bladder compliance rather than counteracting uninhibited detrusor contractions. It is given in doses greatly reduced from those recommended for use as an antidepressant. It also blocks postsynaptic noradrenaline uptake and thereby increases bladder outlet resistance. With its dual action, imipramine may be effective in patients with both stress incontinence and OAB (mixed incontinence). It should be dosed in the evening because it may be sedating, and should be used with caution in elderly patients owing to potential orthostatic hypotension.

image Urinary Fistula

Fistulas are an uncommon cause of urinary incontinence in the United States. Obstetric fistulas, however, are a tremendous source of social and physical distress in developing countries. Obstetric injuries, once the leading cause of urinary fistulas, have almost disappeared in developed countries. They usually result from operative deliveries (e.g., forceps) rather than from neglected labor and pressure necrosis.

Pelvic surgery, irradiation, or both now account for 95% of the vesicovaginal fistulas in the United States. More than 50% occur after simple abdominal or vaginal hysterectomy. About 1% to 2% of radical hysterectomies are followed in 10 to 21 days by a urinary fistula, usually ureterovaginal. These fistulas are usually due to devascularization of the ureter rather than direct injury.

Urethrovaginal fistulas generally occur as complications of surgery for urethral diverticula, anterior vaginal wall prolapse, or SUI.

FISTULA REPAIR

Most obstetric fistulas can be repaired immediately on detection. For postsurgical fistulas, it is usual to wait some weeks to allow the inflammation to settle. During this waiting period, UTI should be treated and estrogen therapy instituted in postmenopausal women. Steroids have been advocated to hasten resolution of inflammatory changes and allow early surgical intervention. Their use in this circumstance is controversial.

image Urinary Tract Infection

UTI is one of the most frequently diagnosed infectious diseases in medical practice. Every year in the United States, about 10% of women are diagnosed with cystitis, and this is associated with direct costs of more than $1.6 billion.

About 20% to 30% of women have at least one UTI during their lifetime, and 20% develop recurrent infections. Ninety-five percent of UTIs are symptomatic, and three fourths of these symptomatic episodes show positive urine cultures. Almost all asymptomatic patients have negative cultures.

TERMINOLOGY

The terminology surrounding UTIs is rather complex and requires some definition.

MANAGEMENT

Unless physical examination and urinalysis (bacteriuria) clearly indicate urinary infection, it is advisable to withhold definite antimicrobial therapy until culture and sensitivity reports are available. As a general rule, bacteriuria should be treated, and not pyuria. General measures in the management of UTIs involve the following:

Basic Principles of Antimicrobial Therapy

The drug selected should be readily available, of low cost, rapidly absorbed from the upper gastrointestinal tract with minimal irritation, and selectively excreted in the urinary tract. A high serum level of antibiotics is undesirable in the treatment of acute cystitis because it tends to alter normal bacterial flora. Nitrofurantoin (Macrodantin) produces low serum levels with a half-life of only 19 minutes, thereby minimizing the chances of alteration of intestinal and vaginal bacterial flora. Treatment with nitrofurantoin is effective against all uropathogens except Proteus species.

Single-dose therapy is an effective alternative to a 3- to 7-day course, especially in patients with acute uncomplicated cystitis. Single-dose therapy fails, however, in more than 50% of patients with an upper tract infection. Table 23-2 lists some common antibiotic regimens for uncomplicated cystitis along with their relative costs.

TABLE 23-2 COMMON TREATMENT REGIMENS FOR UNCOMPLICATED BACTERIAL CYSTITIS

Antimicrobial Agent Dose Relative Cost
SINGLE-DOSE TREATMENTS    
Ampicillin 2 g 1
Amoxicillin 3 g 1
Nitrofurantoin 200 mg 1
Fosfomycin tromethamine 3 g (powder) 3
THREE-DAY COURSE    
Ampicillin 250 mg 4 times daily 1
Amoxicillin 500 mg 3 times daily 1
Trimethoprim 100 mg twice daily 2
Ciprofloxacin 250 mg twice daily 3
SEVENTO 10-DAY COURSE    
Nitrofurantoin 100 mg at bedtime 3
Nitrofurantoin macrocrystals 50-100 mg 4 times daily 4

Relative cost: 1-4, less to more expensive.

Resistance among more common uropathogens is increasing.

For pyelonephritis, an antibiotic should be selected that will attain a significant serum level because the badly infected renal tissue is poorly perfused. The cephalosporins are more effective and cause fewer side effects and relapses. Cephalosporins (e.g., Keflex, Duricef) are slowly and effectively excreted in urine, thereby reducing the frequency of daily drug administration (500 to 1000 mg twice daily).

Antibiotics such as ampicillin, tetracycline, and trimethoprim-sulfamethoxazole (e.g., Septra, Bactrim) alter the intestinal flora, destroy the normal vaginal and periurethral flora, and may result in a relapse of the UTI. Quinolones, both first- and second-generation (e.g., ciprofloxacin, norfloxacin) have been found to be very effective against uropathogens.

The high pH of urine associated with Proteus species infection results from the splitting of urea and the subsequent liberation of ammonia. The urine has a characteristic “fishy” smell. If the urine is very alkaline (pH > 8.0), trimethoprim-sulfamethoxazole should be prescribed.

For patients with renal insufficiency, ampicillin, trimethoprim-sulfamethoxazole, and doxycycline have been shown to reach adequate levels in the urine without toxic levels in serum. Nitrofurantoin should be avoided because high serum levels may lead to peripheral neuropathy. Similarly, tetracycline may lead to severe hepatic damage. Dosages of aminoglycosides should be adjusted in accordance with creatinine clearance, and the serum levels should be monitored.

RECURRENT URINARY TRACT INFECTIONS

Patients with recurrent infections demonstrate abnormal vaginal biologic factors. Colonization of vaginal and urethral epithelium usually precedes bacteriuria. Bacterial adherence to squamous cells and lack of vaginal antibody to E. coli probably lead to vaginal colonization. Women resistant to E. coli carry specific antibodies to their own E. coli.

The benefit of long-term administration (6 to 18 months) of antimicrobials in women with recurrent UTIs has been demonstrated. Trimethoprim-sulfamethoxazole has been found to be effective and is the only antibacterial agent known to be excreted in vaginal fluid. Sulfonamides, tetracycline, and ampicillin are not effective prophylactically because of the rapid emergence of resistant fecal strains. Recurrent infections tend to occur in clusters. Prolonged remissions often occur between these clusters, and the timing of the clusters cannot be predicted. Prophylactic therapy should be initiated when the patient has had two infections within 6 months because she faces a 65% chance of another infection within the next 6 months.

For women who are able to relate the frequently recurring infections to sexual activity, a single dose of an antimicrobial drug immediately after coitus has been shown to prevent bacteriuria and symptomatic infection.

Prevention of hospital-acquired UTIs in patients is important.

Sixty percent of hospital-acquired infections in gynecologic patients involve the urinary tract and occur particularly in association with catheterization. The principles shown in Box 23-3 should be employed when drainage of the urinary bladder is performed.