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Stress urinary incontinence in women: a common problem

Mike Kirby
MBBS LRCP MRCS FRCPI
Visiting Professor
Faculty of Health and Human Sciences
Centre for Research in Primary and Community Care (CRIPACC)
University of Hertfordshire

Stress urinary incontinence occurs when sneezing, coughing or laughing causes accidental leaks. It is surprisingly common, affecting one in three women at some point in their lives. This article examines the causes and recommended treatment options; it also reminds you that it can happen in men too!

It has been estimated that around 42% of women in the UK suffer from some form of urinary incontinence (UI).1 In 2002, the International Continence Society standardised the terminology of lower urinary tract function.2 It defined urinary incontinence as "any involuntary leakage of urine" and classified the three types as:

  • Stress urinary incontinence (SUI) - involuntary leakage of urine on effort, exertion, sneezing or coughing.
  • Urge urinary incontinence (UUI) - involuntary leakage of urine immediately preceded by or accompanied by urgency.
  • Mixed urinary incontinence (MUI) - involuntary leakage of urine associated with urgency and also with exertion, effort, coughing or sneezing.

SUI is the most common form of incontinence in women and SUI and MUI are more prevalent in women than men. The Bowel and Bladder Foundation suggests that around one-third of women in the UK have SUI. 

Risk factors for SUI
Also known as bladder weakness, SUI usually occurs when muscles of the pelvic floor or sphincter have been weakened or damaged. Women are more likely to experience damage to these structures than men, due to pregnancy, childbirth, hormonal changes during the menopause and following hysterectomy. However, men can develop it after bladder neck surgery and radical prostatectomy.

During pregnancy the muscles of the pelvic floor may be weakened by hormonal changes and the extra weight placed upon them. Childbirth is a common cause of damage, particularly if the baby is large and the delivery is prolonged. Further problems may be caused by muscle tearing, episiotomy and forceps or ventouse-assisted deliveries. 

SUI may develop after the menopause, when the reduction in female hormones causes weakening of the pelvic floor. Chronic constipation may increase the risk of SUI.

Increasing age and obesity are associated risk factors for SUI, and psychological factors, caffeine and smoking may aggravate the condition.

The consequences of SUI
Urinary incontinence may cause a great deal of distress and severely impact on quality of life. Fear of leakage and the associated embarrassment often prevents sufferers leading normal lives. Activities such as travelling, shopping, playing with the children or grandchildren, exercising or sexual intercourse can evoke an episode of involuntary leakage and may be avoided for this reason.

Despite these problems, many women who suffer from urinary incontinence seem reluctant to seek medical help. A recently published American study investigating the prevalence of undiagnosed urinary incontinence in 136,457 women aged 25-80 found the prevalence of undiagnosed stress, urge and mixed incontinence to be 19%, 7% and 12% respectively.3

Diagnosing SUI in women
Women may be reticent about seeking help for urinary incontinence, so opportunistic questioning is important. A question such as "Are you bothered by urinary symptoms?" can easily be incorporated into routine checks in primary care such as smear tests, postnatal checks, and in menopause and diabetes clinics.

Asking the right questions is the key to differentiating between the different types of incontinence. The following questions can be used to differentiate stress from urge incontinence:

  • Do you have strong, sudden urges to pass urine?
  • Do you find it hard to complete what you are doing when you feel the urge to pass urine?
  • Do you get up twice or more during the night to pass urine?
  • Do you pass urine more than eight times in a 24-hour period?
  • Do you use pads to protect your clothes from wetting?
  • Do you leak urine when exercising, coughing or sneezing?

If urinary incontinence is suspected, the first step is a comprehensive patient history, including assessment of fluid intake and voiding behaviours.

Physical examination is essential and should include abdominal, pelvic, genital and neurological examination. To help identify SUI, women can be asked to cough or strain during urethral examination. A digital rectal examination (DRE) should be performed in men to assess the size and consistency of the prostate.

Urinalysis will exclude other causes of urinary frequency and/or urgency such as infection or diabetes. Blood tests are used to check for blood glucose, prostate specific antigen and renal and electrolyte abnormalities.

Indications for referral include a palpable bladder after voiding and a symptomatic prolapse visible at, or below, the vaginal introitus. Further tests and a referral to secondary care may indicated in the case of:4

  • Symptoms suggestive of voiding difficulty.
  • Evidence of unexplained neurologic or metabolic disease.
  • Persisting bladder or urethral pain.  
  • Clinically benign pelvic masses.
  • Associated faecal incontinence.
  • Suspected urogenital fistulae.
  • Prior continence surgery.
  • Prior pelvic cancer surgery.
  • Prior pelvic radiation therapy.
  • Symptoms that don't respond to treatment within two to three months.

Tests performed in secondary care may include: inspection of the inside of the bladder by cystoscopy; pelvic or abdominal ultrasound; pad test to determine the degree of urine loss; post-void residual (PVR) to measure the amount of urine left in the bladder after urination; urodynamic studies to measure pressure and urine flow; X-rays with contrast dye of the kidneys and bladder; and, rarely, an electromyogram (EMG) to study muscle activity in the pelvic floor or urethra.

Treatment of SUI in women
Treatment depends upon the severity of the symptoms and how much they impact on the patient's everyday life. Symptom improvement is a realistic goal for the majority of patients with SUI and this should constitute a primary outcome measure. In general, treatments for SUI fall into two categories: non-invasive conservative management and invasive surgical procedures.

Conservative management is the initial treatment of choice. This should include lifestyle advice on fluid intake, weight loss, appropriate exercise, avoiding constipation and smoking cessation. This is usually followed by non-invasive measures, such as pelvic floor re-education. Pelvic floor physiotherapy is the mainstay of conservative management and combines instruction on exercising the relevant muscles with the use intravaginal devices (for example, electrical stimulation probes, biofeedback or weighted cones). It is effective in the majority of cases; but for the best results, exercises need to be performed correctly and continued long term.

Concomitant treatment with oral medication may facilitate concordance with exercise programmes because the patient is likely to see results faster. Duloxetine is licensed for the treatment of SUI. Designed primarily to treat depression, duloxetine was found to help SUI by improving the function of the urethral sphincter muscle. The main side-effect is nausea, which may reduce over time. The use of oestrogen for SUI remains controversial and should be avoided in women with a history of breast or uterine cancer. A three-day bladder diary is useful for assessing symptoms before and after a trial of treatment.

For the people who do not improve with conservative management, surgery is likely to be the next step. Colposuspension is considered the "gold standard" operation for SUI. It is performed under general anaesthetic and involves raising the bladder neck to improve pressure transmission and compression. Colposuspension can be performed through a large cut in the abdomen or by laparoscopy. The former is associated with a longer recovery time but seems to provide better results long term. Other surgical interventions include vaginal sling procedures, urethral tape procedures and collagen injections around the urethra.

Guidance on urinary incontinence
The National Institute for Health and Clinical Excellence (NICE) produced guidelines on the management of urinary incontinence in women in October 2006.4 These guidelines are due for review this year. They recommend that UI in women is classified as stress UI, urge UI or mixed UI, with treatment directed towards the predominant symptom. NICE advises that all women presenting with UI should have a urine dipstick test and women with UI and a BMI >30 should be advised to lose weight.

For women with SUI, firstline treatment should be a trial of supervised pelvic floor muscle training of at least three months duration. Routine digital assessment of pelvic floor contraction should be undertaken before the use of supervised pelvic floor muscle training.

Pelvic floor muscle training programmes should include a minimum of eight contractions performed three times per day. Electrical stimulation and/or biofeedback should be considered in women who cannot actively contract the pelvic floor muscles. Pelvic floor muscle training should be offered to women during their first pregnancy as a preventative strategy for UI.

NICE recommends that duloxetine is not used firstline, or routinely as secondline treatment for women with SUI, although it may be offered as a secondline therapy if women prefer pharmacological to surgical treatment. 

Regarding surgical procedures for SUI, NICE recommends that if conservative treatments have failed, retropubic mid-urethral tape procedures, open colposuspension and autologous rectus fascial sling can be considered. The routine use of laparoscopic colposuspension is not recommended for SUI.

Conclusion
Although we are witnessing the gradual disappearance of the common belief among medical and nursing professionals that incontinence is more of a nuisance than a real problem, many women are continuing to live with bothersome symptoms that can often be effectively treated without surgical procedures. Encouraging patients and healthcare professionals to initiate conversations about UI symptoms should help reduce the unnecessary burden of this disease.

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References
1. Hunskaar S, Lose G, Sykes D, Voss S. The prevalence of urinary incontinence in women in four European countries. BJU Int 2004;93(3):324-30.
2. Abrams P, Cardozo L, Fall M et al. The standardisation of terminology of lower urinary tract function: report from the standardisation sub-committee of the International Continence Society. Neurol Urodyn 2002;21:167-78.
3. Wallner LP, Porten S, Meenan RT et al. Prevalence and severity of undiagnosed urinary incontinence in women. Am J Med 2009;122(11):1037-42.
4. National Institute for Health and Clinical Excellence (NICE). Clinical guideline 40. The management of urinary incontinence in women. London: NICE; 2006. Available from: http://guidance.nice.org.uk/CG40/Guidance/pdf/English

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