Suzanne Pawley is aged 35 years, she presents complaining of worsening problems with her bladder. She needs to go to the toilet to pass urine a lot and when she has to go, she has to rush. Lately she has experienced urine leakage on a few occasions, which she has found very embarrassing, especially if she is out and she cannot find a toilet fast enough.
Key features of history in relation to urge incontinence - urgency associated with a compelling desire to void (if Suzanne is out she describes not being able to find a toilet fast enough) and typically patient can lose urine on the way to the toilet (Suzanne has experienced urine leakage on a few occasions), associated with a low level of urine loss. Symptoms of urinary tract infection or other bladder pathology (haematuria) should be enquired about. Need to exclude conditions that may contribute such as polydipsia or poorly controlled DM with polyuria. Medications such as diuretics may also contribute.
| Type of incontinence | Pathophysiology | Symptoms |
|---|---|---|
| Common | ||
| Stress incontinence | Lack of bladder neck support and/or poor urethral closure | Involuntary leakage on effort or exertion, coughing and or sneezing |
| Urge incontinence: detrusor overactivity/overactive bladder syndrome (previously called detrusor instability/unstable bladder) | Failure of cortical inhibition of sacral reflex arc Idiopathic - anxiety, coffee intake and cold weather are said to influence symptoms Neurogenic (upper motor neuron lesion, ie multiple sclerosis, spinal trauma and cerebral vascular accidents) ?urethral obstruction after surgery |
Urgency: compelling desire to void, accompanied by fear of leakage and/or discomfort Day time frequency Urge incontinence: involuntary loss or urine associated with a strong desire to void Nocturia: awoken at night one or more times to void Nocturnal enuresis: bedwetting |
| Less common | ||
| Retention with overflow | Over-distension of bladder following surgery or delivery Urethral obstruction from a pelvic mass or faecal impaction Drugs or neurological disease |
Dribble incontinence, symptoms of the overactive bladder and of voiding difficulty |
| Fistula | Less developed countries: prolonged obstructed labour and pressure necrosis of bladder base and vagina. More developed countries: pelvic surgical complications, radiation, advanced pelvic surgery |
Uncontrollable continuous leakage |
Urge incontinence associated with detrusor overactivity/over active bladder syndrome.
It can be:
Physical examination as in case one but particularly:
The main role of the bladder is to store urine and to act as an efficient low pressure, continent, reservoir. Urine from the kidneys enters the bladder via the ureters at a rate of 0.5-5 ml/min. Normally sensation of bladder filling is noted at between 15-250ml and there is a strong desire to void at approximately 400-600 mls.
To maintain continence urethral pressure must exceed bladder pressure at all times except during micturition. The intravesical pressure must remain low and the urethral lumen should seal completely. With voiding - cortical inhibition is released and there is a relaxation of the pelvic floor together with relaxation of the striated muscles surrounding the urethra. Parasympathetic impulses via pelvic nerve also cause the detrusor to contract. Extrinsic striated muscle of the pelvic floor contracts to stop the flow of urine. The smooth muscle of the detrusor is slower to relax.
An abnormally high detrusor pressure may occur in detrusor overactivity when there is an inability to inhibit these detrusor contractions.
A bladder diary provides an objective measure of patient's symptoms, and allows a comparison over time, and with treatment, as well as making the patient aware of her voiding habits. Time of voiding, volume voided, and whether incontinent or not is recorded. The amount of urinary loss with incontinence is not measured but the patient can make a subjective estimate, such as 'slight leakage' or 'soaked'. It is usually completed over three non-consecutive 24 hour periods.
Normal population values are difficult to establish and vary with age
| Frequency/output | Definition | Values used in clinical practice |
|---|---|---|
| Number of day time voids | Including last void before bed and first void on waking | Aim for 3-5 hourly |
| Number of night time voids | Each void is preceded by and followed by sleep | Aim for 0-1 |
| Total urine output/24 hrs | Aim for 1500-2000ml or less | |
| Nocturnal urine volume | Total volume voided after patient goes to sleep Excludes last void before bed Includes first void on waking |
Age dependent |
| Nocturnal polyuria | Increased proportion of urine output produced at night | Young adults>20% urine output at night >65 years >33% of urine produced at night |
| Max voided volume | Largest single volume voided | Aim for 300-600ml |
| Mean voided volume | Aim for 250-300ml |
Small frequent voids with leakage associated with urgency during day and at night. Minimal fluid intake with caffeinated beverages.
The aim of bladder retraining is to increase the capacity of the bladder until it can hold the normal amount of urine (400-500mls) enabling the patient to void every three to four hours. This requires learning to suppress bladder contractions using a number of techniques including:
Anti-cholinergic medications such as oxybutynin (Ditropan), tolteradine (Detrusitrol) and solifenacin (Vesicare) are muscarinic antagonists that decrease parasympathetic stimulus which is responsible for detrusor contraction.
Specific contraindications include a history for acute narrow-angle closure glaucoma, risk of gastro-intestinal obstruction, urinary tract obstruction or voiding dysfunction, myasthenia gravis.
The side-effects include dry mucous membranes (eyes, nose, mouth), constipation, heartburn, dry skin, drowsiness (particular an issue in the elderly).
Mirabegron (Betmiga) is a new drug which is a beta 3 agonist antispasmodic agent. The side effects include nausea, dizziness, constipation, diarrhoea and headache.