Section 1: Epidemiology and aetiology
Urinary incontinence (UI) is a symptom-based condition described as the 'complaint of involuntary loss of urine' as set out by the International Continence Society and the International Urogynecological Association. This article focuses on UI in women.
The number of patients experiencing UI is likely to be under-reported and varies with sex, age group, parity and medication (see box).
UI is more common in women, with a prevalence of 17-40% in the UK.1,2 UI is more common in the elderly population and can have a significant impact on the psychological and social wellbeing of the person.3 Its aetiology is usually multifactorial (see box).
- Stress UI: involuntary loss of urine occurs on effort or physical exertion, related to an increase in intra-abdominal pressure. It can be associated with bladder-neck weakness, obesity, poor pelvic floor muscle strength or nerve damage.
- Urgency UI or overactive bladder (OAB): involuntary loss of urine occurs in association with urgency. This is typically caused by overactivity of the detrusor muscle and may be secondary to lesions affecting the motor or sensory pathways to the muscle. Causes include MS, neurological injury, diabetes, stroke, Alzheimer's disease, Parkinson's disease and idiopathic causes.
- Mixed UI: a combination of stress UI and urgency UI.
- Overflow incontinence: this can occur with bladder detrusor atony or bladder outlet obstruction secondary to a prolapsed uterus, previous surgery or incontinence procedure.
- Functional incontinence: this occurs when the patient has difficulty reaching the toilet in time, such as with restricted mobility or altered mental capacity.
- Nocturnal enuresis: involuntary loss of urine occurs during sleep and is more common in children. It can be due to a delay in development of bladder control, but can also be due to inadequate toilet training, urinary infections or emotional distress. There is a strong genetic association.
- Continuous UI: an involuntary continuous loss of urine. This can be due to a fistula or distorted anatomy.
Several newer classifications have also been devised:
- Postural UI: an involuntary loss of urine that occurs in association with a change in body position.
- Insensible UI: the patient is unaware of the occurrence and origin of the loss of urine.
- Coital incontinence: an involuntary loss of urine with coitus that can occur during penetration or with orgasm.
Section 2: Making the diagnosis
On average, a woman will have experienced UI for six to nine years before seeking medical help.5 Diagnosis of UI is based on history, basic investigations and examination. Guidelines issued by NICE highlight the importance of being guided by the patient's symptoms and the effect on their quality of life.6 The emphasis is on treating the predominant symptom and the vast majority of patients will fall into three categories; stress incontinence, urgency incontinence or mixed incontinence.
X-ray showing urine (white) leaking from bladder during stress test (Photograph: Zephyr/SPL)
The points to elicit are the main urinary symptoms affecting the patient. This will include UI associated with an increase in abdominal pressure (coughing, sneezing, physical activity), or incontinence with urgency, frequency and nocturia. The duration of symptoms and the impact on the patient's quality of life and wellbeing should also be recorded. Enquiries should also be made regarding intake of caffeinated drinks, red wine and acidic or spicy food.
If an acute onset of UI has occurred, a review of any new medications and a full neurological examination should be performed. Restricted mobility, cognitive impairment and depression should also be excluded as causes for UI.
If symptoms of pain, poor urinary stream or hesitancy are present, a referral for specialist urogynaecology review should be considered.
According to the NICE guideline,6 in women with UI or OAB, a urine dipstick assessment should be performed to exclude a UTI and a specimen sent for microscopy and culture (MSSU) if abnormal. The guidance suggests, in patients symptomatic of a UTI with a positive dipstick for leucocytes and/or nitrites, antibiotics may be commenced while waiting for the MSSU result. If the dipstick is negative, consideration may be given for antibiotics while awaiting the MSSU results. In those asymptomatic of a UTI with a positive dipstick, the MSSU result should be awaited before starting antibiotics.6
If possible, it is optimal to examine the patient with a comfortably full bladder. This may aid confirmation of leakage of urine with a cough test during examination. It is important to exclude any large pelvic or abdominal masses on abdominal examination. Speculum and bimanual examination will primarily be used to assess for atrophic vaginitis and prolapse. Should a pelvic mass be found, a two-week referral should be organised. Ultrasound will be needed but should not delay the referral.
A bladder diary should be completed for duration of at least three days, including a normal working day and a normal resting day. This will allow a good assessment of functional bladder capacity.
When to refer
Urgent referral should be considered (possibly via a fast-track pathway) in the following situations:
- Microscopic haematuria in the absence of a UTI
- Macroscopic haematuria
- Pelvic pain
- Pelvic or vaginal mass
- Complex neurological symptoms
- Women >40 years old with haematuria and recurrent UTIs
Routine referral should be considered in the following cases:
- History of previous pelvic surgery
- Severe prolapse (grade 3 utero-vaginal prolapse)
- Patients refractory to conservative treatment
- Sensory symptoms consistent with a change in normal sensation or function during bladder filling
- Voiding and post-micturition symptoms such as hesitancy, slow stream, intermittency, straining to void, spraying of urinary stream, feeling of incomplete bladder emptying, double voiding, post-micturition leakage, urinary retention and position-dependent micturition
Section 3: Managing the condition
Management should involve the GP, community continence adviser, specialist physiotherapist and/or specialist nurse.
Sacral nerve stimulation can improve symptoms (Photograph: Zephyr/SPL)
Fluid intake should be approximately 1.5-2 litres per day.6 Weight reduction is advisable for overweight or obese patients. Educational leaflets on pelvic floor muscle training (PFMT) should be provided and programmes should comprise at least eight contractions performed three times per day. Supervised PFMT should be undertaken for at least three months.
Caffeinated beverages should be restricted or stopped as caffeine is an irritant to the detrusor muscle, as well as a diuretic. Bladder retraining for a minimum of six weeks and avoidance of drink four hours before sleep will help towards managing OAB symptoms.6 Management of other exacerbating conditions such as constipation and smoking cessation (aiming to reduce cough) will also help.
In certain cases and in those with cognitive impairment, timed voiding can be employed to reduce the number of episodes of UI.6
In cases with predominantly stress incontinence symptoms, where standard PFMT has not given a satisfactory result, options to maximise pelvic floor contractility are:
- Biofeedback PFMT: a device is used to convert the pelvic floor contraction into an auditory or visual response, thereby allowing objective observation of improvement
- Electrical stimulation
- Weighted vaginal cones
These therapies are generally undertaken with the supervision of the community continence adviser, specialist nurse or physiotherapist.
When conservative measures for OAB are unsuccessful, the next step is pharmacological treatment. Antimuscarinics are commonly used, with similar side-effects reported and variable tolerability between patients. Two different antimuscarinics should be tried before referral to secondary care. Oxybutynin is the first-line drug, based on cost analysis, followed by several others based on local formulary agreements. See box below for a summary of common antimuscarinics used.
With mixed UI, management should aim to treat the predominant symptoms.
Urodynamic studies are undertaken to confirm stress incontinence and exclude severe voiding dysfunction in the majority of cases before surgery. In cases where the patient is unwilling or unfit to undergo surgery, the non-surgical alternative is duloxetine, although it is rarely used, due to side-effects.
The majority of procedures currently performed are mid-urethral slings (MUS), due to the lower complication rates in comparison to colposuspension (NICE suggests colposuspension or MUS may be offered).
For patients who are medically unfit for surgery or those with a rigid urethra, transurethral bulking agents can be used, but the effectiveness is greatly reduced compared with MUS.
For OAB, when the response to two antimuscarinics has not been satisfactory, the patient should be referred for consideration of intravesical injection of botulinum toxin A. This treatment does not have regulatory approval for idiopathic OAB and the patient should be advised regarding this. The effect is reversible and repeated injections will be required.
An alternative for patients unresponsive to medical treatment is the use of neuromodulation, via electrical stimulation of either the sacral, pudendal or posterior tibial nerve. Success rates are 55-65% symptom improvement and improvements in bladder capacity. Availability of this treatment is limited as there are few centres in the UK that offer it.
Uncommon procedures for severe OAB refractory to medication and neuromodulation are augmentation cystoplasty or ureteric diversion and defunctioning of the bladder.
Section 4: Prognosis
Prognosis depends on cause, patient expectations and desired outcome. Multiple outcomes are used to classify success – subjective, such as patient perception of improvement; or objective, such as urodynamic confirmation of resolution.
PFMT alone can improve symptoms of stress incontinence by 56-75%, but appears to be less effective in the long term and is dependent on compliance.7
Transurethral bulking agents can provide short-term improvement of 70-81%.8 They can be inserted under local anaesthetic, have few complications and are a suitable alternative for patients medically unfit for more complex surgery.
Burch colposuspension is known to have 85-90% continence rate during the first year and 70% in the long-term,9 and is still considered first line for surgical treatment of stress incontinence. However, MUS has a comparable improvement in symptoms of 85-96% and has overtaken colposuspension due to lower morbidity and shorter hospital stays.10
Single-incision mini-slings have come into use, but short term efficacy is reduced compared to standard MUS.11
The effect of surgical treatment for stress incontinence on OAB symptoms is conflicting. Studies have shown a decrease in prevalence of OAB symptoms postoperatively, but also a persistence of symptoms in more than one third of patients. Development of de novo OAB symptoms appears to be low.12,13
PFMT can improve OAB symptoms by up to 55%.14 Antimuscarinics have long-term symptom improvement of 60-70%,15 but side-effects are common and can affect compliance. Intravesical botulinum toxin A has 66-96% symptom improvement,16 but injections need to be repeated as the effect is reversible. Urinary retention secondary to detrusor hypotonia can also occur, necessitating intermittent self-catheterisation until the effect wears off.
Neuromodulation techniques, such as sacral nerve stimulation and percutaneous peripheral tibial nerve stimulation, have shown short to medium term symptom improvement of 65-70%.17-19 OAB is generally a lifelong condition, but symptoms can be controlled with a combination of lifestyle changes, medication and/or neuromodulation.
Section 5: Case study
A 45-year-old woman presented with a five-year history of stress incontinence. Her symptoms had worsened recently, especially with coughing, sneezing and lifting. She experienced up to two episodes of incontinence per day and required the use of sanitary pads. The patient reported occasional coital incontinence that restricted the frequency of coitus.
Symptoms of urgency and frequency up to eight times per day were also reported.
The patient had a history of two vaginal deliveries (forceps) and no other significant medical problems or current medications. She had a BMI of 35 and smoked 10 cigarettes per day.
Examination by her GP revealed a negative urine dipstick test and first-degree uterine descent with a moderate anterior vaginal wall prolapse. Cough test was negative.
After initial management involving lifestyle advice and referral to the continence adviser for PFMT and bladder retraining, the patient reported improvement of her stress incontinence symptoms and reduction in incontinent episodes to twice per week. She still required the daily use of pads and had become more aware of urgency, despite completely abstaining from caffeinated beverages. An initial trial of oxybutynin immediate release (2.5mg twice a day) was abandoned after two months due to intolerable side-effects of dry mouth and constipation.
A second-generation antimuscarinic was prescribed in combination with a laxative, giving a satisfactory reduction in frequency with tolerable side-effects. The patient continued to have small volume episodes of incontinence twice per week but felt this was manageable. She had managed to reduce her BMI to 33 but continued to smoke.
Twelve months after initial referral, the patient reported the urgency to be well controlled, but the stress incontinence had worsened.
The patient was reviewed and referred for urodynamic assessment of the bladder. This confirmed both stress incontinence and detrusor overactivity. A day-case retropubic MUS procedure was accepted by the patient for further management of her stress incontinence.
At the six-week postoperative review by the GP, the patient was very happy with the results. She continued on her antimuscarinic for treatment of her OAB symptoms.
Section 6: Evidence base
- Ogah J, Cody JD, Rogerson L. Minimally invasive synthetic suburethral sling operations for stress urinary incontinence in women. Cochrane Database Syst Rev 2009 Oct 7; (4): CD006375. This supported the suggestion that MUSs were as effective as traditional methods in the short term, with fewer complications.
- Novara G, Artibani W, Barber MD et al. Updated systematic review and meta-analysis of the comparative data on colposuspensions, pubovaginal slings and midurethral tapes in the surgical treatment of female stress urinary incontinence. Eur Urol 2010; 58(2): 218-38.
- Anger JT, Weinburg A, Suttorp MJ et al. Outcomes of intravesical botulinum toxin for idiopathic overactive bladder symptoms: a systematic review of the literature. J Urol 2010; 183(6): 2258-64. This showed an improvement in idiopathic OAB refractory to medication, but a significant increase in post-void residuals and urinary retention.
The NICE guideline, which is being updated, highlights the importance of lifestyle changes in the initial treatment of UI before more invasive treatment. It also identifies the need to continue lifestyle changes to control symptoms if treatments fail.
- NICE. Clinical guidelines in development. Urinary Incontinence (update). Publication date July 2013.
- NHS Choices. Urinary incontinence
- Womenshealth.gov. Urinary incontinence fact sheet
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