Urinary Incontinence Flashcards
Primary mechanism of maintaining urinary continence at rest?
Continuous contraction of the internal sphincter (urethrovesical junction):
Intraurethral pressure > intravesical pressure.
Three mechanisms of maintaining urinary continence?
Internal and external sphincters and estrogen-sensitive mucosal coaptation from urethral vasculature.
Sympathetic innervation of the bladder (and location) and function?
Hypogastric nerve T10-L2. Constricts bladder neck and internal sphincter.
Parasympathetic innervation of the bladder (and location) and function?
Pelvic nerve S2-4. Allows mictruition
Somatic innervation of the bladder and function?
Pudendal nerve. Constricts external sphincter and pelvic floor.
What initiates voluntary voiding?
Stretch receptors in the bladder send signal to CNS which inhibit sympathetic and somatic signals then activates the parasympathetics.
Four types of urinary incontinence?
Stress incontinence, detrusor overactivity, mixed incontinence, and overflow incontinence.
Purpose of cotton swab test?
Diagnose hypermobile urethra due to stress incontinence.
Two specific urodynamic tests?
Cystometrogram (pressure sensors to assess detrusor reflex after bladder filling) and uroflowmetry (good at determining if outflow obstruction)
Pathogenesis of stress incontinence?
Three most common risk factors?
Increasing abdominal pressure, in combination with a hypermobile urethra from pelvic relaxation, results in intravesical pressure > intraurethral pressure.
Pelvic relaxation, chronic increased intra-abdominal pressures, and menopause.
Does a patient with stress incontinence have normal Detrusor contractions?
Cystometrogram?
Cotton Swab test?
Bladder Capacity and sensation?
Yes.
Yes.
No - hypermobile urethra (swab moves >30*)
Yes.
Treatment for stress incontinence?
You can try Kegels and estrogens and pessaries…but you’re gonna need surgery to resuspend the hypermobile urethra.
Pathogenesis of detrusor overactivity?
Cause?
Most common symptoms?
Urge incontinence is caused by involuntary and uninhibited detrusor contractions during the filling phase.
Idiopathic - UTI, cancer, device, foreign body, stroke, alzheimer’s, etc.
Urgency, Frequency, nocturia
Treatment of detrusor overactivity?
Bladder training and Kegels etc…
Anticholinergics (oxybutynin), smooth msucle relaxants (tolterodine).
NOT TREATED SURGICALLY
Treatment of mixed incontinence? MOA?
Tofranil (Tricylic antidepressant) - anticholinergic and alpha adrenergic activity
Bladder contractions are mediated by the release of what chemical?
Bladder relaxation is mediated by the release of what chemical?
Acetylcholine
Norepinephrine
Two mechanisms of overflow incontinence?
Causes?
Which drug would you presribe for mixed incontinence, but would make overflow incontinence far worse?
Detrusor insufficiency (bladder hypotonia) and detrusor areflexia (bladder acontractility) - results in weak contractions and an overdistended bladder.
Post-operative urinary retention, diabetes, spinal cord injuries, lower motor neuron disease.
Tofranil (alpha adrenergic agonist and anticholinergic)
How does overflow incontinence present?
Treatment (4 methods)?
Constant urinary dribbling.
Reduce urethral closing pressure (resistance) - prazosin (alpha blocker)
Reduce bladder outlet resistance - Diazepam (muscle relaxant)
Increase contractility - Bethanechol (cholinergic)
Release bladder volume - catheterization
Most common cause of bypass incontinence in developing countries?
In developed countries?
Urinary fistula from obstetric trauma.
Urinary fistula from pelvic radiation/surgery (50% come from hysterectomies).
Presentation of urinary fistula in the US?
Diagnostic tests?
Treatment?
Reasons to delay treatment?
Woman 5-14 days after surgery presents with painless continuous loss of urine after a hysterectomy or pelvic radiation.
Methylene blue dye and IV indigo carmine to determinel location of the fistula - or voiding cystourethrogram.
Immediate surgical closure.
Delay surgery 3-6 months if post-surgical fistula to allow inflammation to decrease.
What is functional incontinence?
Urinary loss due to physical/mental inability to attend to voiding cues ie. delirium/dementia/meds - treat the root cause.
