Female urinary incontinence
1- Definitions, pathophysiology, etiology
(Dr. Dark Drint)
Factors Involved in Maintaining Urethral Closure and Continence
Intrinsic Urethral Mechanism
The urethra consists largely of a rich vascular "sponge", lined by a moist mucosal layer and surrounded by a coat of smooth muscle, fibro-elastic tissue and striated muscle. The mucosa provides coaptation. The vascular submucosa creates the "washer effect" for the continence mechanism. Functionally, the surrounding smooth muscle coat contains this mechanism by directing submucosal expansile pressures inward towards the mucosa. Muscle tone is mediated by alpha-adreno receptors in the sympathetic nervous system. All three layers are under estrogen control.
Levator Ani muscles (pelvic diaphragm) support all of the pelvic organs and the pubourethralis portion form the "external sphincter".
Incidence of Subtypes of Urinary Incontinence in Women
Genuine Stress Incontinence
|Trauma and stretching of vaginal delivery|
|Hormonal changes ( Menopause)|
As the bladder neck support is weakened, the increase in intra-abdominal pressure is no longer transmitted equally to the bladder outlet, and therefore instantaneous leakage occurs.
B). Intrinsic Sphincter Dysfunction (10 - 20% of patients)
This results from damage to the sphincter due to:
|Multiple prior operations|
|Neurogenic disorders including Diabetes Mellitus|
|Atrophic changes: lack of estrogen.|