Chapter Outline
Classification Systems of Lower Urinary Tract Dysfunction
Differential Diagnosis of Urinary Incontinence
Description and Staging of Pelvic Organ Prolapse
Classification System of Complications Related to Insertion of Vaginal Prostheses and Grafts
Classification Systems of Lower Urinary Tract Dysfunction
The purpose of any classification system is to facilitate understanding of the etiology and pathophysiology of disease, to help establish and standardize treatment and research guidelines, and to avoid confusion among those who are concerned with the problem. A number of classification systems for voiding disorders and stress urinary incontinence have been developed. These classifications have been based on various symptoms, as well as anatomic, radiographic, and urodynamic findings. The advantages, disadvantages, and applicability of the various classification systems of voiding dysfunction were described by . This chapter reviews two practical systems for the classification of voiding dysfunction in women. In addition, the differential diagnosis of urinary incontinence in women is discussed utilizing updated terminology from the International Continence Society (ICS). Last, the ICS classification system of vaginal prostheses and graft complications is presented. It is hoped that the nomenclature used in these classification systems will become more widely understood and used and that further research will be aimed at defining their clinical applicability.
International Continence Society Classification
In 1973, the ICS established a committee for the standardization of terminology of lower urinary tract function. Five of the first six reports from this committee were published. These reports were revised, extended, and collated in a monograph published in 1988 (see Appendix A ). The definitions were updated and revised by the Standardization Subcommittee of the ICS in 2002 and again in 2010 (see Appendix B ). Each report highlights the importance of basing diagnoses for pelvic floor disorders on the correlation between a woman’s symptoms, signs, and relevant diagnostic investigations. For example, stress urinary incontinence is the complaint of involuntary loss of urine with increases in intra-abdominal pressures from physical exertion, laughing, sneezing, and coughing, whereas urodynamic stress incontinence is a diagnosis by symptoms, signs, and urodynamic testing and involves the finding of involuntary leakage with increases in intra-abdominal pressure during filling cystometry in the absence of detrusor contractions. One must understand these subtle differences in the definitions of incontinence when diagnosing and classifying patients. The following is a summary of the ICS Committee’s most recent findings.
The lower urinary tract is composed of the bladder and urethra, which work together as a functional unit to promote storage and emptying of urine. Symptoms, signs, urodynamic observations, and conditions are separate categories with unique but overlapping terminologies. Although a complete urodynamic investigation is not necessary for all symptomatic patients, some clinical or urodynamic assessment of the filling and voiding phases is essential for each patient. It is useful to examine bladder and urethral activity separately in each phase. If urodynamic studies are performed, results should clearly reflect the patient’s signs and symptoms.
Filling and Storage Phase
The ICS classification of abnormalities of the storage and voiding phases is outlined in Box 8.1 and diagrammed in Figure 8.1 . Cystometry measures the pressure–volume relationship of the bladder during filling and storage and assesses bladder function in terms of bladder sensation, detrusor activity, bladder capacity, and bladder compliance.
|
Detrusor activity may be normal or overactive. Overactive detrusor function is characterized by involuntary detrusor contractions during filling. They may be spontaneous or provoked and cannot be suppressed completely. Overactive detrusor function in the absence of a known neurologic abnormality is called idiopathic detrusor overactivity ; overactivity caused by disturbance of the nervous system control mechanisms is called neurogenic detrusor overactivity. These conditions often are associated with the symptom of urinary urgency. Urgency, with or without urge incontinence, usually with frequency and nocturia in the absence of urinary tract infection or obvious pathology, is described as the overactive bladder syndrome , urge syndrome, or urgency-frequency syndrome.
Urethral function during storage can be assessed clinically (direct observation of urine loss with cough or Valsalva maneuver), urodynamically (urethral closure pressure profilometry and leak point pressure measurements), or radiographically (cystourethrography with or without video). The urethral closure mechanism may be competent or incompetent. An incompetent urethral closure mechanism is one that allows leakage of urine during activities that may raise intra-abdominal pressures in the absence of a detrusor contraction. Involuntary leakage during filling cystometry may occur during increased abdominal pressure, in the absence of a detrusor contraction ( urodynamic stress incontinence ), or as a result of urethral relaxation in the presence of raised abdominal pressure or detrusor overactivity ( urethral relaxation incontinence ). The definition and significance of the latter condition await additional data.
Urinary incontinence is the complaint of any involuntary (urethral or extraurethral) leakage of urine. Urinary incontinence is a symptom, a sign, and a condition. Urinary incontinence as a symptom means that the patient states she has involuntary urine loss. Types of incontinence symptoms include stress incontinence, urgency incontinence, mixed incontinence, nocturnal enuresis, situational incontinence, and continuous incontinence. In each specific circumstance, urinary incontinence should be described further by specifying relevant factors, such as type, frequency, severity, precipitating factors, social impact, effect on hygiene and quality of life, the measures used to contain leakage, and whether or not the individual seeks or desires help because of urinary incontinence. The sign of stress incontinence denotes the observation of urine loss from the external urethral meatus synchronously with physical exertion such as a cough or Valsalva maneuver. Because symptoms and signs of urinary incontinence can be misleading, accurate diagnosis often requires urodynamic investigation in addition to careful history and physical examination.
Voiding Phase
During the voiding phase, the detrusor muscle may be normal, underactive, or acontractile. Normal voiding usually is achieved by an initial voluntary reduction in intraurethral pressure (urethral relaxation) followed by a continuous detrusor contraction that leads to complete bladder emptying within a normal time span and in the absence of obstruction. Detrusor underactivity during micturition implies that the detrusor contraction is of inadequate strength or duration to effect bladder emptying within a normal time span. An acontractile detrusor is one that cannot be demonstrated to contract during urodynamic studies, resulting in incomplete bladder emptying.
During voiding, urethral function may be normal or abnormal. Abnormal urethral function may be due to either uncoordinated or involuntary urethral contractions, urethral stricture, or obstruction from an anatomic abnormality, such as severe pelvic organ prolapse or changes after a stress incontinence procedure.
Simultaneous measurement of intravesical or detrusor pressure and urine flow is necessary to determine whether the patient’s voiding is obstructed. In general, high detrusor pressures with low flow rates suggest an obstructive problem, whereas low detrusor pressures with low flow rates imply that the problem is one of detrusor underactivity or acontractility. Simultaneous external urethral sphincter electromyography is necessary to determine whether an obstructive voiding pattern is secondary to urethral overactivity or mechanical obstruction.
Functional Classification
classified voiding dysfunction on a functional basis, describing the dysfunction simply in terms of whether the deficit is primarily one of the bladder (detrusor) or bladder outlet (sphincter) during the filling and storage phase or the voiding and emptying phase. The expanded functional classification, with relevant symptoms and pathophysiology as suggested by , is shown in Box 8.2 . This classification system takes into account pelvic floor activity in addition to bladder and sphincter function. Classification of neurologic voiding dysfunction also has been adapted into a functional classification system by and is useful for the diagnosis and management of patients with primary neurologic disorders.
| OUTLET DYSFUNCTION |
| UNDERACTIVE OUTLET (REDUCED URETHRAL RESISTANCE) |
| Stress urinary incontinence ∗ |
| Anatomic support defects |
| Intrinsic sphincter deficiency (ISD) |
| Combination of anatomic support defects and ISD |
| Pelvic floor underactivity (failure to inhibit the detrusor) |
| OVERACTIVE OUTLET (INCREASED URETHRAL RESISTANCE) |
| Frequency-urgency, urinary retention, and overflow incontinence ∗ |
| Anatomic obstruction |
| Surgical |
| Congenital |
| Inflammatory |
| Neoplastic |
| Traumatic |
| Functional obstruction |
| Failure of urethra to relax |
| Neurogenic—detrusor-sphincter dyssynergia |
| Behavioral |
| Combination of anatomic and functional obstruction |
| Pelvic floor overactivity |
| BLADDER DYSFUNCTION |
| DETRUSOR OVERACTIVITY |
| Urge-frequency, urgency urinary incontinence ∗ |
| Involuntary detrusor contractions |
| Idiopathic |
| Neurogenic—detrusor-sphincter dyssynergia |
| Decreased bladder compliance |
| Fibrosis |
| Inflammatory |
| Immune response |
| Neurogenic |
| Combination of involuntary detrusor contractions and decreased bladder compliance |
| UNDERACTIVE DETRUSOR |
| Urinary retention ∗ |
| Peripheral neuropathy |
| Congenital |
| Trauma |
| Neoplastic |
| Diabetes |
| Metabolic |
| Detrusor myopathy |
| Fibrosis |
| Inflammatory |
| Obstruction |
| Pharmacologic |
| Antimuscarinics |
| Muscle relaxants |
| Pelvic floor overactivity |
∗ Presenting symptoms
A reasonably accurate urodynamic description is required for proper use of a functional system for a given voiding problem, but an exact diagnosis is not required for treatment. Several deficits can be present in the same patient, and all of them must be recognized to properly use this classification system.
Differential Diagnosis of Urinary Incontinence
Among women complaining of urinary incontinence, the differential diagnosis includes genitourinary and nongenitourinary conditions ( Box 8.3 ). As mentioned, genitourinary disorders include problems of bladder filling and storage, as well as extraurethral disorders such as fistula and congenital abnormalities. Nongenitourinary conditions that cause urinary incontinence generally are functional conditions that occur simultaneously with normal or abnormal urethral and bladder function. These conditions are most common in elderly women.
