Urinary stress incontinence is the involuntary passage of small amounts of urine due to transient episodes of raised intraabdominal pressure. This can occur when patients cough, sneeze or lift heavy objects. There are numerous predisposing factors.
Urinary stress incontinence (USI) is the passage of urine done without conscious control especially in the case of increased abdominal pressure. Typically, the urine passed is minimal. The cause behind this condition is poorly understood, although there are a number of factors that put individuals at a greater risk of developing USI. Women are more affected by this condition than men, and some of the risk factors specific to the former include pregnancy, vaginal delivery, and menopause [1] [2] [3]. Risk factors that apply to both men and women include obesity, chronically raised intraabdominal pressure as found in chronic obstructive pulmonary disease (COPD), urethral injury, pelvic surgery and smoking [4] [5] [6].
USI occurs when there is an abrupt increase in intraabdominal pressure, usually when coughing, laughing, sneezing, lifting heavy objects, or during physical exertion such as sports. Irritative voiding symptoms such as frequency and urgency, are not part of the clinical picture, and if present, may be indicative of an overactive bladder. The additional presence of hematuria may be a sign of bladder cancer.
USI may arise from a defect in the urethral sphincter, or from the urethra itself. If the urethral sphincter is responsible, symptoms are typically more pronounced, exemplified by urine passage during the action of standing up, or continuous dribbling. The features may be similar to those of a fistula, which if suspected, may be investigated.
Physical examination, of the genitals, pelvis, and rectum, and a urinary stress test are routinely done in the investigation of USI. A history of stress symptoms alone is not adequate for diagnosis, nor is it an indication for surgery [7].
There are many studies available for the investigation of urinary incontinence. A combination of a history of stress incontinence, a postvoid residual volume of less than 50 milliliters, a positive cough test and bladder capacity of more than 400 milliliters, has been suggested in the literature, for greater efficiency in the diagnosis of USI. This may be followed by more extensive urinary studies.
Initial investigations involve voiding diaries, pad test, urinalysis, and ultrasound. Further modalities include urodynamic and contrasted radiological studies of the urogenital tract.
Urodynamic studies need not be carried out on every patient, however, they are important if surgical intervention is planned [8]. This is because the former is able to objectively demonstrate the presence of urinary stress incompetence. It is also recommended that the above studies be carried out in patients with prior failed therapy, and if neuropathy is suspected.
Among the urodynamic studies that can be done are post-void urine volume, filling cystometry, and uroflow. More extensive exams include video-urodynamic studies. These tests are important in planning treatment, predicting its outcome and delineating possible reasons for treatment failure.