1. Aetiology and epidemiology
Bladder dysfunction is a common problem, which affects the physical, psychological, social and economic well-being of individual patients and their families.
The literature reports varying rates of prevalence of bladder dysfunction. However, community-based studies indicate that about 17 per cent of the population, particularly women and older men, will have urinary incontinence of sufficient severity to interfere with their quality of life. Most patients put up with these symptoms and do not seek medical advice. They may wait years before finally seeking assistance.
In the UK, continence problems cost the NHS an estimated £70 million a year in pads and aids alone. Diagnosis and care add an additional burden to this expense, and this ignores the cost to individuals in terms of impaired quality of life.
The continence cycle
Patients with normal bladder function should have a urinary frequency of less than eight voids a day and should not have to get up more than once during the night to pass urine. Patients will receive a warning that their bladder is near capacity, but they should be able to hold on until they reach a toilet.
Types of urinary incontinence
The aetiology of lower urinary tract dysfunction is multifactorial, so urinary incontinence should be considered a symptom, not a diagnosis.
Urinary incontinence can be broadly classified in five groups.
Stress urinary incontinence (SUI) is the most common group. This condition is predominantly the result of injury to the pelvic floor at the time of childbirth. Patients have normal urinary frequency, do not experience nocturia and usually have a normal voiding function. Sudden movement, including physical exertion, such as coughing or sneezing, usually precipitates short spurts of incontinence. By the time patients present, they are often already using pads. These patients lose small amounts of urine at any one time.
Overactive bladder (OAB) patients present with urinary frequency and nocturia which can have either motor or sensory causes. They need to urinate more than eight times during the day and need to get up at least twice during the night.
These patients also suffer from urgency and if they cannot reach a toilet in time, they have urge incontinence. The urinary loss involves large quantities of urine and may often require a change of clothes. Patients plan their activities around the availability of public toilets and often become housebound.
Mixed incontinence occurs when there is a combination of the conditions of SUI and OAB. It is important to establish which symptoms are dominant because management of SUI can worsen OAB symptoms. It can be difficult to manage.
True incontinence can be either congenital or acquired. Congenital conditions usually present in childhood and are often a result of anatomical abnormalities. Acquired causes, such as birth-induced fistulae, are rare in the UK.
Neurogenic incontinence occurs in association with systemic disorders, such as diabetes, MS and Parkinson’s disease. These forms of incontinence are rare. Neurogenic incontinence and true incontinence are usually diagnosed following referral to a specialist unit, or failed conservative management.
- Stress urinary incontinence.
- Overactive bladder.
- Mixed urinary incontinence.
- True incontinence.
- Neurogenic incontinence.
The clinical assessment of a patient with urinary incontinence should include an accurate history and a thorough physical examination to make a presumptive diagnosis. In uncomplicated cases, a short trial of conservative treatment can be carried out in primary care.
A careful urinary history is essential. GPs should ask about storage and voiding phase problems, as well as urinary frequency, nocturia, urgency and urinary flow. The nature of urine loss must be established to distinguish between the short burst of urine that is characteristic of SUI and the larger leak associated with urgency in OAB.
A pelvic examination is essential to exclude local pathology. Urinalysis is also important to exclude low-grade infection. If haematuria is identified without infection, the patient should be sent for urological assessment. If a dipstick test is positive, an MSU should be sent for culture and sensitivity.
The patient should be asked to complete a frequency volume chart over a 24-hour period. This will provide accurate information about the patient’s bladder habits.
Patients with SUI should be referred to a physiotherapist with an interest in pelvic floor disorders. At least 12 weeks of physiotherapy will be needed to see an improvement.
The recently published NICE guidelines on management of urinary incontinence recommend that drug treatments should not normally be offered to treat SUI. Duloxetine, an SNRI and noradrenaline reuptake inhibitor, should not be used as a first-line treatment for SUI or routinely used as a second-line treatment. It may be offered as an alternative to surgery, but women should be properly counselled about its side-effects.
Treatment for OAB
Patients diagnosed with OAB should be offered lifestyle advice, including information on weight loss, diet and bladder retraining. Ideally, these patients should be referred to a continence adviser for help.
Patients should be offered a course of an anticholinergic drug, such as tolterodine sustained release (4mg once daily) or oxybutynin sustained release (10–30mg daily).
Alternatively, the quaternary amine anticholinergic trospium chloride (20mg twice a day) may be used.
Trospium chloride has significantly fewer CNS side-effects, so may be useful in elderly patients with cognitive impairment.
Anticholinergics improve the symptoms of OAB, but have side-effects, such as dry mouth, dyspepsia and constipation.
Newer-generation anticholinergics have a substantially reduced side-effect profile.
Oxybutynin in the form of a transdermal patch is now available. The 36mg patch releases oxybutynin at approximately 3.9mg daily and should be changed twice weekly. It has significantly better tolerability than oral administration of the drug because it avoids gastrointestinal metabolism.
Solifenacin is a newer selective anti-muscarinic agent. Solifenacin (5–10mg daily) significantly improves all major symptoms of OAB. At 10mg daily, it also decreases frequency of nocturia.
Where the cause of urinary incontinence is unclear, patients can be referred for urodynamics. The two basic aims are to reproduce patients’ complaints and give a pathophysiological explanation for their symptoms.
In SUI, the two main operations offered are tension-free vaginal tape (TVT) and Burch colposuspension. Both have a success rate of 80–90 per cent, but TVT has the advantage that it can be carried out under local anaesthetic, is less invasive and can result in earlier discharge and a shorter convalescence.
Intramural bulking agents, such as silicone, hyaluronic acid/dextran co-polymers, glutaraldehyde cross-linked collagen and carbon-coated zirconium beads, should be considered if conservative treatments fail. However, the effect of bulking agents diminishes over time and repeat injections might be needed. The procedure is less effective than retropubic suspension or sling.
In OAB, larger doses of anticholinergics can be tried and early work suggests that botulinum toxin injected into the detrusor muscle may be of value. Sacral nerve stimulation can help, but it is expensive. Surgical management of OAB, such as bladder augmentation or substitution, should only be considered after careful evaluation.
The NICE guidelines advise that surgical procedures should only be performed by surgeons who are trained in the management of urinary incontinence, or working in a multidisciplinary team with such training that regularly performs this type of surgery.
- Drug treatment should not normally be used to treat SUI.
- Duloxetine should be offered as an alternative to surgery.
- Patients with OAB should be offered lifestyle advice.