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Evaluation of Stress Urinary Incontinence

1/1/2016 - William D. Po, MD

Mentor: Christopher M. Zahn, MD

There are several different types of urinary incontinence: stress, urge, chronic urinary retention (overflow), mixed and others. An appropriate evaluation is essential to determine appropriate treatment options. In general, this should include history, urinalysis, physical exam, demonstration of stress incontinence, assessment of urethral mobility, and the measurement of a post-void residual (PVR) volume.

Differentiating complicated from uncomplicated SUI is important. Uncomplicated SUI has leakage on effort or physical exertion without symptoms associated with urgency or retention, and is classically associated with absence of infection and voiding symptoms. In addition to stress incontinence, complicated SUI may include urgency, retention, and voiding symptoms, and patients may have comorbid conditions that impact continence. Many patients will also have undergone prior anti-incontinence surgery.

A careful history includes the type of incontinence, precipitating events, frequency, severity, pad use, and effects on the activities of daily living. Other questions regarding the presence and frequency of nocturia, urgency, hesitancy, slow stream, feeling of incomplete empting, and dysuria may be asked as well. There are many validated questionnaires available to assist in completing the history; voiding diaries may also be used.  Medication history (assessing medications and agents that may affect bladder function), medical history (assessing the presence of conditions such as diabetes and neurologic disorders), and gynecologic, past surgical, and obstetrical histories should be obtained.

The physical exam should assess for factors that may contribute to the patient’s symptoms such as a urethral diverticulum or a fistula. Any pelvic organ prolapse will need to be evaluated and sometimes reduced to determine if SUI is being masked. Pelvic organ prolapse that extends past the hymen may necessitate multichannel urodynamic testing.

Depending on history and exam, a urinalysis to identify urinary tract infection may be the only necessary laboratory evaluation.

Before surgery is performed, stress urinary incontinence should be objectively demonstrated. Visualizing leakage with a cough is diagnostic (with a full bladder or at least 300 ml of fluid and the patient standing if needed). However, a delay in leakage may be due to cough-induced detrusor over-activity. If there is a delay or if leakage is not demonstrated, multichannel testing is recommended.

Surgical outcomes are more successful in patients with urethral mobility. The cotton swab test is positive when there is a 30 degree or greater displacement from the horizon when the patient is in the supine lithotomy position and straining.

A post void residual volume of less than 150 ml can help exclude a bladder-emptying abnormality or chronic urinary retention (overflow incontinence). An abnormal volume may necessitate multichannel testing. Simple office cystometry with a catheter and syringe can aid in determining post void residual, basic bladder capacity, and ensuring at least 300 ml for valsalva leakage. Multichannel urodynamic testing is not needed with uncomplicated SUI prior to surgery.

In cases of complicated SUI, multichannel urodynamic testing is typically indicated. The goal of multichannel evaluation is to objectively monitor bladder function and dysfunction so the appropriate treatment can be precisely determined. Multichannel evaluation can measure changes to intra-abdominal and intra-vesical pressures, and measure detrusor activity. Uroflowmetry can be performed to assess the voiding rate, pattern and capacity. Filling cystometry (cystometrogram [CMG]) measures pressure/volumes in the bladder during filling, storage in the context of sensation, and compliance.  The competency of the urethra is assessed by the valsalva leak point pressure (VLPP) and the urethral pressure profile (UPP). Electromyography may be performed to confirm proper coordination between the bladder and pelvic floor muscles.

 Further Reading:

Evaluation of uncomplicated stress urinary incontinence in women before surgical treatment. Committee Opinion No. 603. The American College of Obstetricians and Gynecologists. Obstet Gynecol 2014; 123:1403–7.

Initial approval 11/3/15;  Reaffirmed 5/2017.

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