Editing Functional: Pathophysiology and Classification of LUT Dysfunction (section)

== Abnormal lower urinary tract function ==

=== Classification ===
* '''<span style="color:#ff0000">Failure to empty:</span>''' because of the bladder vs. because of the outlet
* '''<span style="color:#ff0000">Failure to store:</span>''' because of the bladder vs. because of the outlet

=== Failure to store ===

* '''<span style="color:#ff0000">Results from (or a combination of) (3):</span>'''
*# '''<span style="color:#ff0000">Bladder overactivity (involuntary contraction and/or decreased compliance)</span>'''
*# '''<span style="color:#ff0000">Decreased outlet resistance</span>'''
*# '''<span style="color:#ff0000">Altered sensation</span>'''

==== Bladder Overactivity ====

* Overactivity of the bladder during filling/storage can be expressed as phasic involuntary contractions, as low compliance, or as a combination.
* If an individual has urgency urinary incontinence (UUI), it can be assumed that an involuntary contraction has occurred.
** The symptom of urgency without incontinence suggests detrusor overactivity, but this is often not demonstrable on urodynamic study. Conversely, urodynamically demonstrable detrusor overactivity may not be associated with clinically troublesome filling/storage symptoms.
* '''<span style="color:#ff0000">Involuntary contractions are most commonly seen in association with (6):</span>'''
*# '''<span style="color:#ff0000">Neurologic conditions</span>'''
*# '''<span style="color:#ff0000">Bladder outlet obstruction</span>'''
*# '''<span style="color:#ff0000">Iatrogenic</span>''' (radiation)
*#'''<span style="color:#ff0000">Aging</span>''' (probably related to neural degeneration)
*#'''<span style="color:#ff0000">Stress urinary incontinence</span>''' (perhaps because of sudden entry of urine into the proximal urethra, eliciting a reflex contraction)
*# '''<span style="color:#ff0000">Increased afferent input related to inflammation or irritation of the bladder or urethral wall or an increased sensitivity</span>'''
*# '''<span style="color:#ff0000">Idiopathic</span>'''
*
* '''<span style="color:#ff0000">Neurologic conditions</span>'''
** '''Any neurologic process interrupting the normal suprapontine inhibition of the pontine micturition center may result in neurogenic detrusor overactivity (NDO) and cause urge urinary incontinence.'''
*** '''<span style="color:#ff0000">Most common neurologic causes of urge urinary incontinence</span>'''
***#'''<span style="color:#ff0000">CVAs</span>'''
***#'''<span style="color:#ff0000">Multiple sclerosis</span>'''
***#'''<span style="color:#ff0000">Parkinson disease</span>'''
* '''<span style="color:#ff0000">Bladder outlet obstruction</span>'''
** <span style="color:#ff0000">'''In males, bladder outlet obstruction induced by prostatic enlargement (or other obstructive process) can be associated with detrusor overactivity and resultant urgency urinary incontinence.'''</span>
**In females, obstruction resulting from anti-incontinence surgery can lead to de novo urgency urinary incontinence secondary to induced detrusor overactivity.
* '''<span style="color:#ff0000">Iatrogenic</span>'''
**'''<span style="color:#ff0000">Pelvic external beam radiation can alter bladder compliance</span>''', increase detrusor leak point pressure, and contribute to UI.
*'''<span style="color:#ff0000">Diabetes, even early in diagnosis, has been associated with neurogenic detrusor overactivity and urge urinary incontinence</span>'''
** '''Whereas early in the diabetes disease process can lead to urge urinary incontinence, later in the process sensation can be altered as can detrusor contractility, resulting in impaired bladder emptying, UTIs, and urinary incontinence.'''

==== Decreased Outlet Resistance ====
* '''<span style="color:#ff0000">May result from any process that damages the (2):</span>'''
*#'''<span style="color:#ff0000">Innervation of structural elements of the smooth or striated sphincter, or both</span>'''
*#'''<span style="color:#ff0000">Support of the bladder outlet in women</span>'''
* A major factor required for the prevention of urinary leakage during increases in intra-abdominal pressure is the presence of at least equal pressure transmission to the proximal urethra (the mid-urethra as well in women) during such activity. Failure of this mechanism is an invariable correlate of effort-related urinary incontinence in women and men.
* Sphincteric incontinence in men is not associated with hypermobility of the bladder neck and proximal urethra but is similar to what is termed intrinsic sphincter dysfunction in women.
* '''<span style="color:#ff0000">Causes of intrinsic sphincteric deficiency (ISD)</span>'''
*# '''<span style="color:#ff0000">Iatrogenic (most common)</span>'''
*#* '''<span style="color:#ff0000">Radical prostatectomy</span>'''
*#** '''Most common surgical cause of incontinence in men'''
*#** Generally causes leakage via a direct impairment of sphincter function.
*#* '''In females, urethral surgery or anti-incontinence surgery can lead to urethral scarring, periurethral fibrosis, and ISD.'''
*# '''<span style="color:#ff0000">Neurologic disease</span>'''
*# '''<span style="color:#ff0000">Traumatic or vascular injury to the lumbosacral cord</span>'''
*# '''<span style="color:#ff0000">Any medication with either α-antagonistic properties or skeletal muscle relaxant properties</span>'''
*#* Can cause UI by inhibiting outlet resistance.
*# '''<span style="color:#ff0000">Prolonged labor, third-degree lacerations, large birth weight, multiparity, and forceps deliveries</span>''' are all aspects of labor and delivery that have been associated with sphincteric dysfunction.

==== Altered Sensation ====
* '''May occur due to increased afferent input''' from inflammation, irritation, other causes of hypersensitivity, and pain.

==== Management ====

* '''<span style="color:#ff0000">Directed towards:</span>'''
*# '''<span style="color:#ff0000">Inhibiting bladder contractility</span>'''
*# '''<span style="color:#ff0000">Decreasing sensory output</span>'''
*# '''<span style="color:#ff0000">Mechanically increasing bladder capacity</span>'''
*# '''<span style="color:#ff0000">Mechanically increasing outlet resistance, either continuously or just during increases in intra-abdominal pressure</span>'''
*# '''<span style="color:#ff0000">Combination of the above</span>'''

=== Failure to Empty ===

* '''<span style="color:#ff0000">Results from (or a combination of) (2):</span>'''
*# '''<span style="color:#ff0000">Bladder underactivity (a decrease in magnitude, coordination, or duration)</span>'''
*# '''<span style="color:#ff0000">Increased outlet resistance</span>'''
*'''Poor emptying from detrusor underactivity or detrusor areflexia (causing overflow incontinence) might also cause urinary incontinence.''' 
**'''This type of detrusor dysfunction is common with neurologic diseases affecting the lumbosacral cord or conus medullaris.'''
*'''Systemic diseases, which can result in peripheral neuropathies such as diabetes, tabes dorsalis, and alcoholism, can similarly cause overflow incontinence.'''
*'''Radical pelvic surgeries (i.e., radical hysterectomy, abdominoperineal resection) can also result in significant, sometime permanent, neurogenic detrusor dysfunction leading to urinary retention and overflow incontinence.'''
* '''Other processes such as traumatic cervical or upper thoracic spinal cord injury can cause detrusor sphincter dyssynergia, creating impaired bladder emptying and UI, particularly when coupled with neurogenic detrusor overactivity'''.

==== Bladder Underactivity ====

* May result from temporary or permanent failure or impairment in one of the neuromuscular mechanisms necessary for initiating and maintaining a normal detrusor contraction.
* '''<span style="color:#ff0000">Causes:</span>'''
** '''<span style="color:#ff0000">Neurologic diseases affecting the lumbosacral cord or conus medullaris.</span>'''
** '''<span style="color:#ff0000">Systemic diseases, which can result in peripheral neuropathies such as diabetes, tabes dorsalis, and alcoholism</span>'''
*** Whereas early in the disease process diabetes can lead to UUI, later in the process sensation can be altered as can detrusor contractility, resulting in impaired bladder emptying, UTIs, and UI.
** '''<span style="color:#ff0000">Radical pelvic surgeries''' (i.e., radical hysterectomy, abdominoperineal resection)</span>

==== Increased Outlet Resistance ====

* Much more common in men than in women
* Most often secondary to anatomic obstruction; may be secondary to a failure of relaxation or active contraction of the striated or smooth sphincter during bladder contraction

==== Management ====

* '''<span style="color:#ff0000">Directed towards:</span>'''
*# '''<span style="color:#ff0000">Increasing intravesical/detrusor pressure</span>'''
*# '''<span style="color:#ff0000">Facilitating the micturition reflex</span>'''
*# '''<span style="color:#ff0000">Decreasing outlet resistance</span>'''
*# '''<span style="color:#ff0000">Combination of the above</span>'''
*# '''<span style="color:#ff0000">If other means fail or are impractical, intermittent (or continuous) catheterization is an effective way to circumvent emptying failure.</span>'''