Urinary Incontinence

Question 1

Primary mechanism of maintaining urinary continence at rest?

Answer 1

Continuous contraction of the internal sphincter (urethrovesical junction):
Intraurethral pressure > intravesical pressure.

Question 2

Three mechanisms of maintaining urinary continence?

Answer 2

Internal and external sphincters and estrogen-sensitive mucosal coaptation from urethral vasculature.

Question 3

Sympathetic innervation of the bladder (and location) and function?

Answer 3

Hypogastric nerve T10-L2. Constricts bladder neck and internal sphincter.

Question 4

Parasympathetic innervation of the bladder (and location) and function?

Answer 4

Pelvic nerve S2-4. Allows mictruition

Question 5

Somatic innervation of the bladder and function?

Answer 5

Pudendal nerve. Constricts external sphincter and pelvic floor.

Question 6

What initiates voluntary voiding?

Answer 6

Stretch receptors in the bladder send signal to CNS which inhibit sympathetic and somatic signals then activates the parasympathetics.

Question 7

Four types of urinary incontinence?

Answer 7

Stress incontinence, detrusor overactivity, mixed incontinence, and overflow incontinence.

Question 8

Purpose of cotton swab test?

Answer 8

Diagnose hypermobile urethra due to stress incontinence.

Question 9

Two specific urodynamic tests?

Answer 9

Cystometrogram (pressure sensors to assess detrusor reflex after bladder filling) and uroflowmetry (good at determining if outflow obstruction)

Question 10

Pathogenesis of stress incontinence?

Three most common risk factors?

Answer 10

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.

Question 11

Does a patient with stress incontinence have normal Detrusor contractions?
Cystometrogram?
Cotton Swab test?
Bladder Capacity and sensation?

Answer 11

Yes.
Yes.
No - hypermobile urethra (swab moves >30*)
Yes.

Question 12

Treatment for stress incontinence?

Answer 12

You can try Kegels and estrogens and pessaries…but you’re gonna need surgery to resuspend the hypermobile urethra.

Question 13

Pathogenesis of detrusor overactivity?
Cause?
Most common symptoms?

Answer 13

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

Question 14

Treatment of detrusor overactivity?

Answer 14

Bladder training and Kegels etc…
Anticholinergics (oxybutynin), smooth msucle relaxants (tolterodine).

NOT TREATED SURGICALLY

Question 15

Treatment of mixed incontinence? MOA?

Answer 15

Tofranil (Tricylic antidepressant) - anticholinergic and alpha adrenergic activity

Question 16

Bladder contractions are mediated by the release of what chemical?
Bladder relaxation is mediated by the release of what chemical?

Answer 16

Acetylcholine

Norepinephrine

Question 17

Two mechanisms of overflow incontinence?
Causes?
Which drug would you presribe for mixed incontinence, but would make overflow incontinence far worse?

Answer 17

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)

Question 18

How does overflow incontinence present?

Treatment (4 methods)?

Answer 18

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

Question 19

Most common cause of bypass incontinence in developing countries?
In developed countries?

Answer 19

Urinary fistula from obstetric trauma.

Urinary fistula from pelvic radiation/surgery (50% come from hysterectomies).

Question 20

Presentation of urinary fistula in the US?
Diagnostic tests?
Treatment?
Reasons to delay treatment?

Answer 20

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.

Question 21

What is functional incontinence?

Answer 21

Urinary loss due to physical/mental inability to attend to voiding cues ie. delirium/dementia/meds - treat the root cause.