Urinary incontinence

Urinary incontinence is the involuntary leakage of urine. There are multiple types:

Stress urinary incontinence
Urge urinary incontinence
Overflow incontinence – the bladder fills, causing urine to overflow out
Functional incontinence – due to mental or physical problems
Mixed incontinence – features of more than one of the above

Stress and urge, as well as a mix of the two, account for 97% of cases of urinary incontinence.

Urinary incontinence is frequent in elderly women. 15 – 55% of women are affected. Urge incontinence is more common in males.

Risk factors

Old age
White ethnicity
Obesity
Menopause
Multiparity
Smoking and COPD
Pelvic surgery (hysterectomy, prostate surgery)
Pelvic organ prolapse

Stress incontinence

Stress incontinence is the involuntary loss of urine in association with increased intraabdominal pressure, like laughing, coughing, lifting.

Urge incontinence

Urge incontinence is the involuntary loss of urine after feeling a sudden, urgent need to void. It’s sometimes called overactive bladder because it occurs due to a detrusor muscle which is constantly contracting. This reduces the capacity of the bladder, decreasing the amount of urine in the bladder necessary to give the urge to urinate. Patients usually have to go to the bathroom every 30 minutes, even during the night.

It is known simply as “urge” if there is a strong urge to urinate but no incontinence.

Possible causes are:

UTI
Pelvic organ prolapse
Urinary tract tumour
Urolithiasis
Neurological disease (stroke, MS, spinal cord injury)
Chronic lower urinary tract obstruction, usually due to BPH

Diagnosis and evaluation

History is important, especially how many times the patient urinates every day. > 8 is usually abnormal.

Targeted questions and questionnaires can be used to evaluate and distinguish the type of urinary incontinence.

Voiding diaries are helpful. For 3 days, the patient fills in what and when they drink, the volume of urinary leakage, and provoking factors of incontinence. The volume of leakage can be estimated by using and weighing diapers before and after the leakage.

The patient should be examined for urinary retention, which is a sign of incomplete emptying. After urination, the residual urine volume should be assessed by ultrasound or catheterisation.

Physical examination includes checking for urine loss with Valsalva or coughing, as well as a neurological examination. It’s important to check the bulbocavernosus and anocutaneous reflexes, which evaluate the function of S2 – S4.

Other important examinations are:

Evaluation for pelvic organ prolapse
Q-tip test
Bimanual rectovaginal examination
Urine analysis and culture
Urodynamic studies

Urinary tract tumour should be excluded in cases of urge incontinence.

Treatment

The first line treatment is nonsurgical:

Pelvic floor exercise (Kegel exercises)
Peripheral electrical stimulation – if bladder innervation is poor
Avoid caffeine
Schedule voiding
Local oestrogen replacement therapy

Stress incontinence

In case of stress incontinence, the second line can be surgical. A type of operation called a midurethral sling is the gold standard. This involves placement of a synthetic mesh to support the pelvic floor. There are two types of midurethral sling operations, retropubic tension-free vaginal tape (TVT) and tension-free vaginal tape obturator (TVT-O or TOT).

Urge incontinence

In case of urge incontinence, the second line can be medical:

Muscarinic antagonists – block muscarinic acetylcholine receptors to decrease detrusor contraction
- Solifenacine (Vesicare®)
- Oxybutin
- Tolterodine
- Fesoterodine
Beta-3 agonist
- Mirabegron (Betmiga®)
Intravesicular botulinum toxin injection

Urodynamic studies

Urodynamic studies are tests which assess the function of the urinary tract. There are many different types, including uroflowmetry, pressure flow study, and leak point pressure. They're used to evaluate symptoms of lower urinary tract symptoms and urinary incontinence.

Uroflowmetry

Only non-invasive urodynamic study
Measures the volume of urine voided over time
Should be done with ~150 mL in the bladder to prevent false positives
Normal
- Continuous, peaked, bell-shaped curve
- Normal peak urine flow – > 30 mL/s
- Duration < 30 seconds
Abnormal
- Flat/plateau curve (urine flow is constant but very low) -> urethral stricture
- Saw-tooth curve -> detrusor sphincter dyssynergia
- Flattened bell-shaped curve -> BPH

Pressure flow study

Invasive urodynamic study
Measures the detrusor pressure while voiding
Gives information on bladder stability, contractility, and sensibility

Valsalva leak point pressure

Measures the intraabdominal pressure at which urine loss occurs