Mohammad Urinary Incontinence

What is urinary incontinence (UI)?

Urinary incontinence is defined as involuntary leakage of urine (also known as enuresis). It is often accompanied by increased daytime frequency, urgency, and/or nocturia.

Urinary incontinence results from overfunctioning or underfunctioning of the urethra, bladder, or both.

Example:

Overfunctioning bladder = leaking because the bladder is squeezing too much

Underfunctioning bladder = leaking because the bladder is holding too much.

What is urinary frequency (number)?

Urinary urgency?

Nocturia (number)?

Micturition more than 8 times per day.

A sudden, compelling desire to urinate that is difficult to delay.

More than 1 void per night.

What happens when the detrusor smooth muscle is activated?

What type of stimulation induces this?

Activation of the detrusor smooth muscle causes the bladder to contract. Detrusor contraction increases bladder pressure and, together with urethral sphincter relaxation, produces bladder emptying.

Muscarinic (M1, M2, M3) stimulation from the parasympathetic nervous system induces detrusor contractions.

What are β3-adrenergic receptors and what happens when they are stimulated?

β3-adrenergic receptors are found in the detrusor. Stimulation causes detrusor smooth muscle relaxation.

How is urethral contraction induced?

Urethral contraction is induced by adrenergic stimulation from the sympathetic nervous system.

Stimulation of α receptors in the urethra causes its closure.

What is stress urinary incontinence?

Risk factors?

Signs/Symptoms?

Stress incontinence results from urethral sphincter underactivity/weakness and decreased urethral closure. It causes involuntary transient loss of small amounts of urine when intra-abdominal pressure increases, usually during physical activity.

Pregnancy, childbirth, menopause, and age.

Urine loss with sneezing, coughing, laughing, lifting, running, or similar activities. There is no incontinence during sleeping or physical inactivity.

What is urge urinary incontinence/overactive bladder?

Risk factors?

Signs/Symptoms?

Urge incontinence results from bladder overactivity and involuntary loss of small or large urine volumes due to uninhibited detrusor contractions.

Age and neurologic disease.

Urgency, frequency, and nocturia.

What is overflow urinary incontinence?

Risk factors?

Signs/Symptoms?

Overflow incontinence results from urethral overactivity and/or bladder underactivity. The bladder becomes overfilled and is unable to empty; urine may leak involuntarily throughout the day.

Bladder outlet obstruction such as benign prostatic hyperplasia (BPH), spinal cord injuries, and pelvic surgery.

Lower abdominal fullness/pain, hesitancy, straining, incomplete bladder emptying, frequency, and urgency.

What is mixed urinary incontinence?

Any combination of UIs mentioned, but the most common is urge and stress incontinence.

What is functional urinary incontinence?

Risk factors?

Signs/Symptoms?

Functional incontinence is the inability of a normally continent person to reach the toilet in time to avoid an accident. It is linked to underlying disease or cognitive/mobility deficits.

Cognitive impairment and musculoskeletal limitations; underlying conditions may include dementia or other cognitive or mobility deficits.

Accidents on the way to the toilet and early morning incontinence.

Which types of urinary incontinence are the most common?

Urge incontinence and mixed incontinence are the most common types.

What should be assessed when evaluating urinary incontinence?

Assess urinary concerns such as symptoms and precipitating factors;

use a bladder diary;

consider the patient's degree of discomfort;

perform a physical examination;

use laboratory/diagnostic testing when indicated.

What information should be included in a bladder diary?

Time of urinary incontinence, beverages consumed, whether urination occurred in the toilet, and amount of urine loss.

What should a rectal examination assess in a patient with urinary incontinence?

What should a pelvic examination assess?

Rule out fecal impaction, enlarged prostate/BPH, and pelvic floor muscle issues.

Evaluate the urethral meatus during coughing or straining.

What laboratory tests are used in urinary incontinence assessment?

Urinalysis and urine culture are used to rule out infection that may cause similar symptoms.

Glucose is used to screen for diabetes.

What lifestyle modifications are recommended for stress, urge, or mixed incontinence?

Smoking cessation, avoiding caffeine and alcohol, weight loss, and constipation prevention.

What is bladder training/toilet scheduling?

Timed voiding regimens in which the patient gradually increases the time between bathroom breaks. (Only urinate at specific written times).

What are Kegel exercises and for which types of incontinence are they useful?

Kegel exercises are a first-line treatment. They are pelvic floor muscle exercises that strengthen the muscles to help maintain continence. Patients are instructed to squeeze as if trying to stop urine flow. They benefit stress, urge, and mixed incontinence and are one of the most effective treatments.

What supportive interventions can be used for urinary incontinence?

Pessary/bladder neck support prostheses (a removable medical device placed inside the vagina), penile clamps, bed or clothing alarms, bedside commodes or urinals, incontinence pads, and physical therapy for gait and strength training.

Which medications/classes can worsen all types of urinary incontinence?

Diuretics and sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors). They increase urination.

Which medications can worsen functional incontinence and why?

Opioids, benzodiazepines, alcohol, antipsychotics, and anticholinergics can impair functioning and/or cognition, making it harder to reach the toilet.

Which medications can worsen stress incontinence and why?

Alpha-1 receptor antagonists such as doxazosin and terazosin reduce urethral tone through smooth muscle relaxation.

ACE inhibitors can worsen stress incontinence through ACE inhibitor-induced cough.

Which medications can worsen overflow incontinence by increasing urethral tone and relaxing the detrusor?

Adrenergic agonists such as pseudoephedrine, alpha receptor agonists such as clonidine, beta blockers through unopposed alpha stimulation, calcium channel blockers, anticholinergics, tricyclic antidepressants, antipsychotics with anticholinergic effects, and skeletal muscle relaxants.

Which medications can worsen urge/overactive bladder incontinence?

Cholinesterase inhibitors such as donepezil and bethanechol. They increase cholinergic stimulation of the bladder.

What is a pharmacologic treatment for functional urinary incontinence?

No pharmacologic agents exist specifically for functional urinary incontinence. Treatment focuses on removing underlying causes, discontinuing precipitating medications, and using non-pharmacologic efforts.

What is the mainstay pharmacologic therapy for stress urinary incontinence + mechanism?

Regimen?

Adverse effects?

Local estrogens.

They increase vascularity and thickness of urethral tissue, increase urethral tone, and increase the number and/or sensitivity of urogenital alpha-adrenergic receptors.

Conjugated estrogen vaginal cream or an estradiol vaginal ring.

Vaginal spotting, breast tenderness, and nausea. Use for the shortest time possible to prevent long-term adverse effects.

How do α-adrenergic receptor agonists treat stress urinary incontinence?

Regimen?

Adverse effects?

Contraindications?

They cause α1-mediated smooth muscle contraction of the bladder neck and urethra, improving tone.

Pseudoephedrine or phenylephrine.

Dizziness, increased blood pressure, insomnia, and headache.

Hypertension, arrhythmias, and coronary artery disease.

Can you use combination therapy with topical estrogen and an α-adrenergic agonist?

Yes. Combination therapy with topical estrogen and an α-adrenergic agonist may be more effective than monotherapy.

What is bethanechol's role in overflow urinary incontinence?

Bethanechol provides cholinergic stimulation of the detrusor muscle, but it is FDA approved for urinary retention rather than overflow incontinence and is not very effective for overflow incontinence.

When is catheterization used in overflow incontinence?

Catheterization is used when nerve function to the bladder is poor. A catheter physically provides an exit route for the urine. It is more invasive and costly.

How do anticholinergic/antimuscarinic drugs treat urge urinary incontinence?

Adverse effects?

They antagonize muscarinic cholinergic receptors, reducing uninhibited detrusor contractions.

Dry mouth, dry eyes, constipation, urinary retention, cognitive impairment, sedation, dizziness, vision changes, headache, and thirst.

Avoid anticholinergics in older adults with delirium, dementia, cognitive impairment, or chronic constipation.

Where are M1 receptors found and what happens when they are blocked?

M3?

M1 receptors are found in neural tissue. Blockade can cause impaired memory/cognition.

M3 receptors are found in detrusor muscle and salivary glands. Blockade can cause bladder relaxation and dry mouth.

(M2 is also found in detrusor muscle but M3 is the functionally predominant receptor for detrusor contraction).

What antimuscarinics treat urge urinary incontinence? Which are better tolerated?

Oxybutynin, solifenacin, darifenacin, trospium

Better tolerated: solifenacin, darifenacin, trospium, tolterodine, fesoterodine → M3-selective → less dry mouth.

Why is oxybutynin difficult to tolerate?

Oxybutynin is highly potent at reducing detrusor contractions but also blocks M3 receptors in salivary glands. It is also lipophilic so it easily crosses the BBB.

It is described as the most difficult agent to tolerate, producing systemic anticholinergic adverse effects.

How should oral oxybutynin be dosed (generally)?

Start with a low dose and titrate slowly.

Which β3-adrenergic receptor agonists are used for urge urinary incontinence?

Mechanism?

Adverse effects?

Mirabegron and vibegron.

They activate β3-adrenergic receptors, relaxing the detrusor muscle during the storage phase and increasing bladder capacity.

Hypertension, headache, diarrhea, nausea, and

urinary tract infection (more urine remaining → urinary stasis → easier bacterial growth).

When should therapy be changed if there is inadequate response?

If symptoms do not improve after an adequate 8-12 week trial at the maximally tolerated dose, consider switching to a different agent.