The pathophysiology of stress incontinence

Genuine stress incontinence occurs when the intravesical pressure, as a result of an increase in intra-abdominal pressure, exceeds the resistance produced by the urethral closure mechanisms, in the absence of bladder activity. Other forms of incontinence may be confused with genuine stress incontinence because of the similarity in symptoms, and the ability to elicit the clinical sign of urinary loss with stress maneuvers (such as coughing and straining). Disorders associated with detrusor contraction (detrusor instability), elevated intravesical pressure (poor compliance), or increased residual urine (overflow incontinence), may have associated stress-induced symptoms. Urethral instability results from the reflex relaxation of the urethra without a detrusor contraction. These disorders should not be confused with genuine stress incontinence, which is the focus of this paper.