132 CHAPTER 4 Incontinence

Incontinence in the elderly patient

Prevalence

UI increases markedly with advancing age, affecting 10–20% of women and 7–10% of men >65 years who are living at home. These figures escalate if older people are institutionalized, as follows: residential home, 25%; nursing home, 40%; long-stay hospital ward, 50–70%.

Functional incontinence is often associated with factors outside of the urinary tract, such as permanent immobility, cognitive impairment, and environmental changes.

Transient causes of UI (“DIAPPERS”)

•Dementia/delirium

•Infection

•Atrophic vaginitis or urethritis

•Pharmaceuticals (opiates and calcium antagonists cause urinary retention and constipation; anticholinergics cause increased PVR and retention;

•Psychological problems—depression; neurosis; anxiety

•Excess fluid input or output (diuretics; CHF; nocturnal polyuria)

•Restricted mobility

•Stool impaction (constipation)

Management

Simple measures such as timed voids or laxative use may be helpful and should be attempted initially. Biofeedback and behavioral methods are appropriate only if cognition is intact.

Treat any vaginitis (0.01% estriol cream topically) in postmenopausal females.

Absorbent appliances include bed pads and body-worn pad products (pull-up adult diapers); body-worn external urine collection devices (condom catheter) or compression devices (Cunningham clamp) may be helpful for severe leakage in males.

Indwelling catheters are initially preferable when UI is due to obstruction or no alternative intervention is suitable. Suprapubic tube placement is preferable to long-term indwelling urethral catheterization, which is often associated with pressure necrosis and/or erosion of the urethra.

Infections and inflammatory conditions

Urinary tract infection: definitions, incidence, and investigations 134

Urinary tract infection: microbiology 138 Lower urinary tract infection 140 Recurrent urinary tract infection 142 Urinary tract infection: treatment 146 Acute pyelonephritis 148

Pyonephrosis and perinephric abscess 150 Other forms of pyelonephritis 152 Chronic pyelonephritis 154

Septicemia and urosepsis 156 Fournier gangrene 160 Epididymitis and orchitis 162 Periurethral abscess 164

Prostatitis: epidemiology and classification 166 Prostatitis: presentation, evaluation, and treatment 168 Other prostate infections 170

Interstitial cystitis 172 Tuberculosis 176 Parasitic infections 178

HIV in urological surgery 180

Inflammatory and other disorders of the penis 182

134 CHAPTER 5 Infections and inflammatory conditions

Urinary tract infection: definitions, incidence, and investigations

Definitions

Urinary tract infection (UTI) is currently defined as the inflammatory response of the urothelium to bacterial invasion. UTI due to other organisms is less common and addressed elsewhere.

This inflammatory response causes a constellation of clinical symptom. In bladder infection this is described as cystitis—frequent small-volume voids, urgency, suprapubic pain or discomfort, and urethral burning on voiding (dysuria).

In acute kidney infection (acute pyelonephritis) the symptoms are fever, chills, malaise, and flank pain, often with associated LUTS of frequency, urgency, and urethral pain on voiding.

Bacteriuria is the presence of bacteria in the urine and may be asymptomatic or symptomatic and varies by age and sex (Table 5.1). Bacteriuria without pyuria indicates the presence of bacterial colonization of the urine, rather than the presence of active infection, where “active” implies an inflammatory response to bacterial invasion of the urothelium.

Risk factors for bacteriuria include female sex; increasing age; low estrogen states (menopause); pregnancy; diabetes mellitus; previous UTI; institutionalized elderly; indwelling catheters; urolithiasis; genitourinary malformation; and voiding dysfunction (including obstruction).

Pyuria is the presence of white blood cells (WBCs) in the urine in dipstick or 10 WBC/HPF (400x) in resuspended sediment of centrifuged urine. Pyuria implies an inflammatory response of the urothelium to bacterial infection or, in the absence of bacteriuria, some other pathology such as carcinoma in situ, TB infection, bladder stones, or other inflammatory conditions.

An uncomplicated UTI is one occurring in a patient with a structurally and functionally normal urinary tract. The majority of such patients are women who respond quickly to a short course of antibiotics.

A complicated UTI is one occurring in the presence of an underlying anatomical or functional abnormality (e.g., functional problems causing incomplete bladder emptying, such as bladder outlet obstruction due to BPH, DSD in spinal cord injury), urolithiasis, fistula between bladder and bowel, etc. Most UTIs in men occur in association with a structural or functional abnormality and are therefore defined as complicated UTIs.

Complicated UTIs take longer to respond to antibiotic treatment than uncomplicated UTIs, and if there is an underlying anatomical or structural abnormality they are at increased risk of recurrence within days, weeks, or months.

UTI may also be classified as isolated, recurrent, or unresolved.

Isolated UTI has an interval of at least 6 months between infections.

Recurrent UTI is >2 infections in 6 months, or 3 within 12 months. Recurrent UTI may be due to reinfection (i.e., infection by a different

URINARY TRACT INFECTION 135

Table 5.1 Prevalence of bacteriuria

bacteria) or bacterial persistence (infection by the same organism originating from a focus within the urinary tract).

Bacterial persistence is caused by the presence of bacteria within calculi (e.g., struvite calculi), a chronically infected prostate (chronic bacterial prostatitis), or an obstructed or atrophic infected kidney, or it occurs as a result of a bladder fistula (with bowel or vagina) or urethral diverticulum.

Unresolved infection is failure of the initial treatment course to eradicate bacteria from the urine. It is usually due to pre-existing or acquired antimicrobial resistance, patient noncompliance with therapy, insufficient antibiotic dosing, or disorders that decrease drug bioavailability (i.e., azotemia, urinary calculus)

UTI incidence

•Newborns <1 year: Male children have a slightly higher risk of UTI than females, which is thought to be caused by foreskin contamination and congenital structural abnormalities.

•Children 1–5 years: Females have approximately a 5% incidence of UTI compared to 0.5% in males, and anatomic anomalies account for the majority of UTIs in both sexes.

•Children 6–15 years: Functional voiding abnormalities account for the increased incidence of UTIs (about 5% in females) with a low rate (<0.5–1%) in males.

•Adolescents and adults 16–35 years: Females have a much higher risk of UTI related to sexual activity and the use of intravaginal contraceptives.

•Adults >35 years: The incidence of UTI gradually increases in both sexes until the incidence is similar above age 65 (40% incidence in females vs. 35% in males)

UTI investigations

Urine dipstick

Urine dipstick, obtained from a mid-stream sample, is used as a first-line screening. Urine dipstick has the following performance characteristics: leukocyte esterase, 50% positive predictive value and 92% negative predictive value; nitrate, sensitivity 35%–85%. Best performance for dipstick is when urine culture colony counts are >100,000 CFU/HPF.

However, if the dipstick is negative for blood, protein, leukocyte esterase, and nitrite, <2% of urine samples will be positive for cultured bacteria.

136 CHAPTER 5 Infections and inflammatory conditions

Leukocyte esterase

Leukocyte esterase activity detects the presence of white blood cells in the urine. Leukocyte esterase is produced by neutrophils and causes a color change in a chromogen salt on the dipstick.

•False positive (pyuria present but negative dipstick test): concentrated urine, glycosuria, presence of urobilinogen, consumption of large amounts of ascorbic acid

•False positive (pyuria absent, but positive dipstick test): contamination (vaginal, etc).

There are many causes for pyuria and a positive leukocyte esterase test occurring in the absence of bacteria on urine microscopy. This is so-called sterile pyuria and it occurs with TB infection, renal calculi, bladder calculi, glomerulonephritis, interstitial cystitis, and carcinoma in situ. Thus, the leukocyte esterase dipstick test may be truly positive and suggest a significant disease process, in the absence of infection.

Nitrites

Nitrates are not normally found in urine and are produced by the dietary breakdown of nitrates in the urine by various gram-negative bacteria. Nitrite testing is therefore indirect testing for bacteriuria but may miss gram-positive infections.

Many species of gram-negative bacteria can convert nitrates to nitrites, and these are detected in urine by a reaction with the reagents on the dipstick that form a red azo dye.

The specificity of the nitrite dipstick for detecting bacteriuria is >90% with sensitivity of 35–85% (i.e., false negatives are common—a negative dipstick in the presence of active infection) and is less accurate in urine containing fewer than 105 organisms/mL. So, if the nitrite dipstick test is positive, the patient probably has a UTI, but a negative test can occur in the presence of infection.

•False positive: with contamination (i.e., vaginal)

•False negative: common in setting of low dietary nitrate, diuretics, and with certain species of bacteria (e.g., Enterococcus, Staphylococcus, Pseudomonas)

Urine microscopy

Microscopic examination of the urine sediment is also helpful. After centrifugation of the sample, the observation of bacteria and >3 WBC/HPF is diagnostic of a urinary tract infection. Occasionally, a Gram stain of an uncentrifuged urine may demonstrate gram-positive or gram-negative bacteria.

If the urine specimen contains large numbers of squamous epithelial cells (cells derived from the foreskin, vaginal, or distal urethral epithelium), this suggests contamination of the specimen, and the presence of bacteria in this situation may indicate a false-positive result.

Urine culture and collection

Urine culture is the gold standard for the diagnosis of a bacterial UTI. Urine samples must be properly collected, the method of collection documented, and samples cultured immediately or, if this is not possible, stored in a refrigerator (not frozen) for up to 24 hours.

URINARY TRACT INFECTION 137

The diagnosis of UTI is based on symptomatology, urinalysis, and urine culture findings. The traditional strict definition of >105 bacteria/mL of urine is no longer required to make a diagnosis of UTI. Treatment is usually indicated if t102 CFU/mL in a patient with symptoms of UTI, particularly with associated pyuria.

The method of collection and sex of the patient can influence the results of the urine culture; see Table 5.2.

Further investigation

Based on the initial clinical evaluation, further diagnostic testing may be necessary to evaluate the cause of the urinary tract infection. While most cases of simple UTI do not require further investigation, complicated or recurrent UTI may require imaging (plain abdominal film, CT, ultrasound) or functional studies (uroflow, post void residual urine determination, urodynamics studies) Further workup is needed if the following occur:

•Symptoms and signs of upper tract infection (flank pain, malaise, fever) that suggest acute pyelonephritis, a pyonephrosis, or perinephric abscess

•Recurrent UTIs develop (see p. 142).

•The patient is pregnant.

•Unusual infecting organism (e.g., Proteus), suggesting the possibility of an infection stone

Table 5.2 Probability of UTI based on urine culture and collection method

CFU, colony-forming unit.

Reproduced with permission from Chapter 13. Bacterial infections of the genitourinary tract. In Smith’s General Urology, 17th Edition, 2008. Emil A. Tanagho and Jack W. McAninch, Eds. New York: McGraw Hill.