Материал: Oxford American Handbook of Urology ( PDFDrive )

112 CHAPTER 4 Incontinence

Causes and pathophysiology

Risk factors

Predisposing factors

•Gender (female > males)

•Race (Caucasian > African American/Asian)

•Genetic predisposition

•Neurological disorders (spinal cord injury, stroke, MS, Parkinson disease)

•Anatomical disorders (vesicovaginal fistula, ectopic ureter, urethral diverticulum)

•Childbirth

•Anomalies in collagen subtype

•Prostate or pelvic surgery (radical prostatectomy; radical hysterectomy; TURP) leading to pelvic muscle and nerve injury

•Pelvic radiotherapy

Promoting factors

•Smoking (associated with chronic cough and raised intra-abdominal pressure)

•Obesity

•UTI

•Increased fluid intake

•Medications

•Poor nutrition

•Aging

•Cognitive deficits

•Poor mobility

Pathophysiology

Bladder abnormalities

Detrusor overactivity is a urodynamic observation characterized by involuntary bladder muscle (detrusor) contractions during the filling phase of the bladder, which may be spontaneous or provoked, and can consequently cause urinary incontinence. The underlying cause may be neurogenic, where there is a relevant neurological condition, or idiopathic, where there is no defined cause.

Low bladder compliance is characterized by a decreased volume-to-pres- sure relationship during a cystometrogram and is often associated with upper tract damage. High bladder pressures occur during filling because of alterations in the viscoelastic properties of the bladder wall, or changes in bladder muscle tone (secondary to myelodysplasia, spinal cord injury, radical hysterectomy, interstitial or radiation cystitis).

Sphincter abnormalities

Urethral hypermobility is due to a weakness of pelvic floor support causing a rotational descent of the bladder neck and proximal urethra during increases in intra-abdominal pressure. If the urethra opens concomitantly, there will be urinary leaking.

CAUSES AND PATHOPHYSIOLOGY 113

Intrinsic sphincter deficiency (ISD) describes an intrinsic malfunction of the sphincter, regardless of its anatomical position, which is responsible for type III SUI. Causes include inadequate urethral compression (previous urethral surgery; aging; menopause; radical pelvic surgery) or deficient urethral support (pelvic floor weakness; childbirth; pelvic surgery; menopause).

114 CHAPTER 4 Incontinence

Evaluation

History

Inquire about LUTS (storage or voiding symptoms), triggers for incontinence (cough, sneezing, exercise, position, urgency), and frequency and severity of symptoms. Establish risk factors (abdominal/pelvic surgery; neurological diseases; obstetric and gynecological history; medications).

A validated patient-completed questionnaire may be helpful (e.g., IPSS; see Fig. 1.1, p. 11).

Physical examination

Women

Perform a pelvic examination in the supine and standing position with a speculum while the patient has a full bladder. Ask the patient to cough or strain, and inspect for vaginal wall prolapse (cystocele, rectocele, enterocele), uterine or perineal descent, and urinary leakage (stress test). Eighty percent of SUI patients will leak with a brief squirt during cough in the supine position, while another 20% will leak only in an inclined or standing position.

Urethral hypermobility is assessed with the Q-tip test. A lubricated cot- ton-tipped applicator is introduced through the urethra to bladder neck level. Hypermobility is defined as a resting or straining angle of >30* from horizontal.

The Bonney test is used to assess continence with manual repositioning of the urethra and vesicle neck. Using one or two fingers to elevate the anterior vaginal wall laterally without compressing the urethra, relief of incontinence during cough suggests that surgical correction will be successful.

Both sexes

Examine the abdomen for a palpable bladder (indicating urinary retention). A neurological examination should include assessment of anal tone and reflex, perineal sensation, and lower limb function.

Inspect the underwear for the status of urinary collection pads; for men, a standing or squatting “cough test” gives a good indicator of the presence and severity of stress incontinence.

Investigation

Bladder diaries

Record the frequency and volume of urine voided, incontinent episodes, pad usage, fluid intake, and degree of urgency. Alternatively, pads can be weighed to estimate urine loss (pad testing).

Urinalysis can exclude UTIs.

Blood tests, X-ray imaging, cystoscopy

These are indicated for persistent or severe symptoms, bladder pain, and voiding difficulties. Cystoscopy is useful for evaluating men who have had prostatectomy—it will show the presence of clips, stones, and strictures that may develop after surgery that might need to be addressed concomitantly with anti-incontinence surgery.

EVALUATION 115

Screening tests

Uroflow testing measures the ability of the bladder to empty; a minimum bladder volume of 150 cc is desired. A low flow rate indicates bladder outflow obstruction or reduced bladder contractility. The volume of urine remaining in the bladder after voiding (post-void residual) is also important (<50 mL is normal; >200 mL is abnormal; 50–200 mL requires clinical correlation).

Urodynamic investigations

Valsalva leak point pressure (VLPP) measures the abdominal pressure at which a half-full bladder leaks during straining—normal individuals should not leak. VLPP readings <60 cm H2O suggest ISD; VLPP readings >100 cm H2O suggest hypermobility, while readings of 60–100 cm are indeterminant.

Detrusor leak point pressure (DLPP) measures the bladder pressure at which leakage occurs without valsalva—DLPP >40 cm H2O puts the upper tract at risk.

Videourodynamics can visualize movement of the proximal urethra and bladder neck, and establish the precise anatomical etiology of UI.

Sphincter electromyography (EMG)

EMG measures electrical activity from striated muscles of the urethra or perineal floor and provides information on synchronization between bladder muscle (detrusor) and external sphincter.