Normal VoidingWhile the bladder fills with urine, pressure remains stable due to intrinsic properties of the bladder. The ability of the bladder to maintain a stable pressure is based on natural viscoelastic properties of the bladder wall and receptors within the bladder that help it relax and accommodate as it fills. Stable pressures contribute to continence; in addition, normal anatomic pelvic support, an intact urinary sphincter and neural control of the storage and voiding process are essential.
When the bladder is full, a complex neurological process consisting of conscious and unconscious activity - allows normal voiding. Once volitionally committed to voiding, the striated sphincter relaxes followed by increasing detrusor activity leading to increased bladder pressures. Once the proximal urethra and bladder neck open, voiding begins.
In men, the bladder neck is intimately associated with the prostate and provides an additional component of continence. In women, there is no bladder neck mechanism and continence relies solely on the urethral sphincter which is composed of a layer of longitudinal intrinsic urethral smooth muscle and a larger extrinsic striated muscle that extends throughout the proximal 2/3rds of urethra. Continence therefore relies on watertight apposition of the urethral lumen and external compression of the lumen by the external muscle. Finally, adequate structural support by the pelvic floor musculature is required to keep the urethra from moving during increases in abdominal pressure.
Classification of Urinary IncontinenceIncontinence is classified into a number of categories that are not mutually exclusive:
- stress urinary incontinence
- urgency urge incontinence
- mixed (stress/urge) incontinence
- mixed symptoms
- overflow incontinence
- extraurethral incontinence
- occult/latent stress incontinence
- situational incontinence
- nocturnal enuresis
|Wein AJ, Rackley RR. Overactive bladder: a better understanding of pathophysiology, |
diagnosis and management. J Urol 2006;175:S5–10.
Stress Urinary Incontinence (SUI)
- Vaginal delivery (direct injury to pelvic soft tissues and partial denervation of pelvic floor)
- Forceps delivery
- Third-degree perineal tear
- Increased duration of labor
- High birth weight (>4000 g=8lb 13oz)
- Chronic abdominal straining
- Neurologic injury (specifically pudendal nerve injury)
- Previous urethral or periurethral surgery
- Neurologic insult
- Surgical: hysterectomy or other pelvic surgeries
- Medical: multiple sclerosis, diabetic neuropathy
- Pelvic radiation: can affect neurologic function or damage local tissues leading to poor co-aptation of the urethra
Urgency Urge Incontinence (UUI)
Mixed Urinary Incontinence (MUI)
Other Types of Incontinence
 Nitti. The Prevalence of Urinary Incontinence. Rev Urol. 2001; 3(Suppl 1): S2–S6.
 Abrams P, Artibani W, Cardozo L,et al: Reviewing the ICS 2002 terminology report: the ongoing debate. Neurourol Urodyn 2009; 28: 287
 Chapple CR, Artibani W, Cardozo LD, et al. The role of urinary urgency and its measurement in the overactive bladder symptom syndrome: current concepts and future prospects. BJU Int 2005;95:335–40
Other resources for understanding incontinence include:
Chapple and Milsom. Chapter 63: Urinary Incontinence and Pelvic Prolapse in Campbell-Walsh Urology , Tenth Edition. Eds, Wein, Kavoussi, Novick, Partin, Peters. 2012.
Abrams P: ICS standardization documents. 2002