Stress Incontinence

Stress incontinence is involuntary leakage of urine with activities that increase intra-abdominal pressure: coughing, sneezing, laughing, physical exertion or, in more severe cases, simply standing from a seated position. It reflects an incompetent urethral sphincter mechanism that cannot maintain closure against the increased pressure.

It is the commonest specific subtype of urinary incontinence in women, particularly, though not exclusively, associated with a history of vaginal childbirth.

The underlying pathophysiology is weakness of the pelvic floor musculature and supporting connective tissue responsible for normal urethral positioning and closure pressure. Its well characterised mechanism has a distinct, targeted management approach.

Pathophysiology and risk factors

• Normal continence depends on a competent urethral sphincter mechanism and adequate pelvic floor support maintaining urethral positioning and closure pressure.
• Stress incontinence results from urethral hypermobility, which is excessive downward movement of the urethra and bladder neck with increased intra-abdominal pressure, given inadequate pelvic floor and connective tissue support.
• Less commonly it results from intrinsic sphincter deficiency, a primary weakness of the urethral sphincter muscle itself. This generally produces more severe symptoms, including leakage with minimal exertion.
• Vaginal childbirth is the single most important, well established risk factor. It causes direct mechanical and neurological trauma to the pelvic floor musculature and its innervation. Risk increases with the number of vaginal deliveries.
• Further risk factors are advancing age, obesity, chronic cough (including from smoking related chronic respiratory disease), significant constipation with chronic straining, and previous pelvic surgery. Connective tissue changes of oestrogen deficiency in the menopausal transition also contribute.
• Stress incontinence in men is substantially less common than in women. It generally occurs after prostatic surgery, particularly radical prostatectomy, through direct surgical disruption of the urethral sphincter mechanism.
• It is a recognised, generally anticipated complication that needs specific counselling before such surgery.

• The defining presentation is involuntary urine leakage with activities that increase intra-abdominal pressure, including coughing, sneezing, laughing, lifting or physical exercise.
• The volume is generally small to moderate and related to the degree of exertion or pressure increase.
• Symptoms are frequently, though not universally, worse at certain times, including premenstrually or during pregnancy, reflecting hormonal and mechanical factors. They may fluctuate with bladder fullness.
• More severe disease produces leakage with progressively less provocation. In the most severe cases it occurs even with simple postural change or minimal activity.
• Pelvic organ prolapse symptoms (a sensation of vaginal pressure, bulging or a palpable lump) frequently coexist, given the shared pelvic floor weakness. Explore them specifically, as they may affect management planning, including combined surgical approaches addressing both conditions.
• The absence of a sudden, strong urge to void immediately before leakage distinguishes stress from urgency urinary incontinence.
• A substantial proportion of affected women have mixed incontinence with features of both mechanisms. Characterise which symptom pattern predominates to guide targeted management.

• The essential initial approach is a full clinical history with a structured bladder diary, characterising the pattern and triggers of leakage, following the general principles detailed under urinary incontinence.
• Pelvic examination includes assessment for pelvic organ prolapse and formal assessment of pelvic floor muscle strength, using digital palpation during voluntary pelvic floor contraction.
• A cough stress test directly observes urine leakage from the urethral meatus as the patient coughs, ideally with a comfortably full bladder. Together with examination, it gives direct clinical confirmation of stress incontinence and its approximate severity.
• Assess post-void residual bladder volume to exclude significant coexisting overflow incontinence. Perform urinalysis to exclude urinary tract infection as a contributing factor, following the same general assessment principles.
• Urodynamic studies give objective, detailed assessment, including urethral closure pressure and direct demonstration of leakage with increased abdominal pressure.
• They are generally reserved for diagnostic uncertainty, significant mixed incontinence symptoms needing clarification of the predominant mechanism, or before surgical treatment. In these circumstances they confirm the diagnosis and guide surgical planning.

• Pelvic floor muscle training (Kegel exercises) is first line, effective treatment for stress incontinence. It is performed under structured guidance from a specialist pelvic floor physiotherapist to ensure correct technique and adequate, sustained intensity and duration.
• A structured programme is typically continued for a minimum of three months before assessing response, as meaningful pelvic floor strengthening takes time.
• Supervised physiotherapy generally produces substantially better outcomes than unsupervised, self-directed exercise.
• Address modifiable contributing risk factors as a foundational part of management: weight loss where body mass index is elevated, management of chronic cough (including smoking cessation where relevant), and treatment of significant constipation.
• Vaginal pessary devices give mechanical support to the urethra and bladder neck. They are an effective, non-surgical option, particularly for women wishing to avoid or defer surgery, or where surgery is not appropriate.
• Pessary designs vary and are fitted according to individual anatomy and symptom pattern.
• Consider surgery for persistent, significant stress incontinence not adequately responding to a trial of conservative management.
• Mid-urethral sling procedures place a synthetic mesh tape beneath the mid-urethra to provide support during increased intra-abdominal pressure. They have historically been the most commonly performed procedure.
• Mesh related complications have raised important safety concerns. This has led to significant regulatory restriction and, in several jurisdictions, suspension of routine mesh sling use in recent years. Availability and recommended approach therefore vary according to current local and national guidance and regulatory status.
• Alternative surgical options are established and effective, particularly given the evolving regulatory landscape for synthetic mesh. Autologous fascial sling procedures use the patient's own tissue rather than synthetic mesh.
• Colposuspension is a traditional, open or laparoscopic procedure that supports the bladder neck by suture fixation to nearby pelvic structures.
• Individualise the surgical approach to current local guidance, patient preference and clinical factors, after informed discussion of the relative benefits and risks of the options.
• Duloxetine, a serotonin-noradrenaline reuptake inhibitor, has a licensed indication for stress incontinence. Evidence shows enhanced urethral sphincter tone through a central nervous system mediated mechanism.
• Duloxetine is generally an adjunct to, not a substitute for, pelvic floor muscle training. Its use is limited by its adverse effect profile.
• Regular follow up assesses treatment response and ongoing symptom burden, with reassessment of escalation to surgery where conservative management has proven inadequate.
• This common condition is generally substantially treatable.