Urinary incontinence is the involuntary loss of urine. It is not a disease in itself, but a symptom of many different disease processes.
The only two functions of the bladder are to store urine and to expel urine in a co-ordinated fashion under appropriate circumstances. The bladder needs to be of adequate capacity and compliance in order to store urine. The tone within the bladder neck and sphincter (valve) prevents urine from leaking from the bladder. During voiding the bladder muscle contracts while the sphincter relaxes in a coordinated fashion.
Incontinence can be classified according to the mechanism causing the leakage of urine or according to the type of symptoms.
The main types of urinary incontinence are:
- Stress urinary incontinence
- Urge incontinence
- Overflow incontinence
- Total incontinence
Stress urinary incontinence is the leakage of urine associated with episodes of increased intra-abdominal pressure such as coughing or sneezing. It is caused by loss of bladder neck and urethral support or inherent sphincter (valve) deficiency.
Urge incontinence is the leakage of urine associated with a great desire to urinate that cannot be suppressed. It is invariably associated with symptoms of urgency and frequency. The bladder is incapable of storing adequate amounts of urine, because it is either too small or unstable. There are many different causes of urge incontinence (see causes).
Overflow incontinence is associated with chronic retention of urine. The bladder is permanently full and distended with urine. The kidneys continue to produce urine and the excess spills out of the urethra, much like a dam that is overflowing. Overflow incontinence is associated with a poor stream and difficulty passing urine. Chronic retention is either due to bladder outlet obstruction or bladder muscle dysfunction. Bladder outlet obstruction is relatively common in elderly males and is rare in females.
Total incontinence is the continuous leakage of all the urine. It is most often due to a vesicovaginal fistula, which is an abnormal communication between the bladder and the vagina.
Urinary incontinence affects about 8% of females and 3% of males. It is more common in the elderly but should not be regarded as normal at any age. There is no single treatment for urinary incontinence. The treatment options will depend on the type and severity of the incontinence. Most patients with urinary incontinence can be cured or improved.
The causes of urinary incontinence vary depending on the type of incontinence (see description).
Stress urinary incontinence in females
- Hypermobility of the bladder neck and urethra related to the effects of childbirth
- Urethral sphincter (valve mechanism) dysfunction related to:
- childbirth injury
- previous surgery to the urethra or bladder neck
- atrophy of the genital tissues related to the menopause
Stress urinary incontinence in males
Urethral sphincter (valve mechanism) injury due to:
- transurethral resection of the prostate gland (1% risk)
- radical prostatectomy (approximately 5% risk)
- pelvic fracture
Urge incontinence (males and females)
- Detrusor (bladder muscle) instability due to:
- old age
- unknown cause (idiopathic)
- bladder stones
- bladder tumours
- Small capacity bladder due to:
- interstitial cystitis
- tuberculosis of the bladder
- schistosomiasis (Bilharzia) of the bladder
- neuropathic bladder
- Obstruction of the bladder outlet (rare in females)
- benign prostatic enlargement (hyperplasia)
- prostate cancer (carcinoma)
- urethral strictures (narrowing)
- Poor bladder contraction due to damage to its nerve supply by:
- diabetes mellitus
- pelvic surgery
- low spinal cord injury
- multiple sclerosis
Total incontinence is usually due to an abnormal communication between the urinary tract and the outside:
- vesicovaginal fistula (a communication between the bladder and the vagina)
- ureterovaginal fistula (between the ureter and the vagina)
- ectopic ureter (a ureter opening in an abnormal position e.g. vagina)
Stress urinary incontinence
In stress urinary incontinence the continence mechanism cannot deal with elevations in intra-abdominal pressure. The intra-abdominal pressure is transmitted onto the bladder, causing urine to leak from the urethra. Patients are classically dry while sitting still or lying down.
Activities like coughing, sneezing, lifting of heavy objects or getting up from a chair causes an increase in intra-abdominal pressure that is associated with leakage of urine. In very mild cases only a few drops of urine are lost with strenuous activity. In severe cases large amounts of urine can leak with moderate increases in intra-abdominal pressure.
Urge incontinence is caused by the inability of the bladder to store adequate amounts of urine for long enough between voiding. The bladder is either too small or unstable. The classic symptom is a great desire to urinate that cannot be suppressed. The patient leaks urine before getting to a toilet.
Urge incontinence is associated with the frequent passage of urine during the day (frequency) and night (nocturia). Bladder muscle instability caused by pathology in the bladder, such as infection, stones or tumour, is often associated with burning urine (dysuria) and blood in the urine (hematuria). Bladder pain is common with infections, stones and interstitial cystitis.
In overflow incontinence the bladder is chronically distended and permanently full of urine. The kidneys continue to produce urine and the excess "spills" out of the bladder. The incontinence is usually a persistent low-level leakage, which is often worse at night. Patients are still able to pass urine, but only pass small amounts with difficulty. They often complain of a poor stream, straining while passing urine and a feeling of incomplete emptying.
A vesicovaginal fistula is an abnormal communication between the bladder and the vagina. With large fistulae there is a constant leakage of all of the urine via the vagina. A patient with a tiny fistula may pass urine in the normal way, as well as suffer from a constant leak from the vagina.
An ureterovaginal fistula is an abnormal communication between the ureter and the vagina. Urine from the kidney on the affected side will continuously leak out. If the opposite ureter and the bladder are normal the patient will pass the urine coming from the unaffected side in the normal manner.
An ectopic ureter is a congenital (born with) abnormality in which the ureter opens in an abnormal position. Depending on the position of the opening it can cause incontinence in females but not in males. If only one side is affected the patient passes urine in the normal manner, while also suffering from a continuous leak. Symptoms are present from birth.
Urinary incontinence affects about 5% of the population with 8% of females and 3% of males affected respectively. It is more common in old age and in debilitated patients. Approximately 50% of all nursing home residents, as well as 15-30% of women over age 65 in retirement communities suffer from urinary incontinence. In the USA approximately $16 billion is spent on the problem annually. Despite being more common in old age, incontinence should not be regarded as "normal" at any age.
- Female sex
- Multiple childbirth
- Old age
- Pelvic radiation
- Pelvic surgery
- Pelvic trauma
- Tuberculosis of the urinary tract
Females are more prone to incontinence than males. The female urethra is short and the continence mechanism is less well developed than in the male. The female bladder neck and urethra are also much less well supported than in the male, and are subjected to the rigours of childbirth.
Multiple childbirths stretch and weaken the support of the bladder and urethra. This can cause hypermobility of the bladder neck and the urethra, leading to stress urinary incontinence. Injury during childbirth or caesarian section can cause a vesicovaginal fistula to develop.
Detrusor (bladder muscle) instability is common in old age and can lead to urge incontinence. Menopause causes atrophy of the vagina and urethra, which impairs the occlusive function of the urethra. Elderly men are prone to benign prostatic hyperplasia (enlargement), which can lead to chronic retention and overflow incontinence.
Tuberculosis of the urinary tract can lead to a small contracted bladder incapable of storing adequate amounts of urine. Trauma, surgery or radiation to the pelvis can either damage the bladder or urethra directly, or can damage the nerves that control bladder function. Almost any neurological disease can affect the control of bladder function. Strokes, dementia and spinal cord injuries commonly lead to incontinence.
When to see a doctor
All but the most minor degrees of incontinence tend to be extremely inconvenient for the patient. Although incontinence per se is not detrimental to the physical well being of the patient, it impacts negatively on the social, sexual, recreational and working lives of people. The majority of incontinent patients can either be cured or markedly improved.
Anybody with a degree of incontinence that affects his or her lifestyle should see a health professional. Patients with blood in the urine, bladder pain or burning of urine need to have serious underlying causes of the incontinence excluded and should seek help promptly.
No specific preparation is necessary for the first visit. The health professional will want to check a urine sample, so it is best not to empty the bladder immediately prior to the visit. The health professional will take a detailed history and perform a physical examination. The examination should include a vaginal and a rectal examination. Subsequent tests or procedures are usually scheduled for a mutually convenient time.
The diagnosis of urinary incontinence is made based on a medical history, a physical examination and some confirmatory special tests. The health professional has to identify the type and severity of the incontinence, as well as the possible underlying cause(s).
History and examination
A careful history will often indicate the type of incontinence (see symptoms). The amount of protection (e.g. pads) needed will give some indication of the severity of the problem. The voiding pattern is noted, and direct questions are asked regarding other urinary tract symptoms such as frequency or dysuria. Any concurrent or previous medical, surgical or obstetric history is noted.
The bladder is examined to see if it is full (overflow incontinence) or empty, and whether it is tender or not. A basic neurological examination is performed to rule out neurological causes for the incontinence. The underwear and pads are examined for evidence of wetness. The genital skin is inspected for evidence of urine-induced dermatitis. The urethra and vagina are examined next, usually with a speculum in place. The health professional specifically looks for atrophy of the tissues and for evidence of leaking with coughing (stress incontinence). An assessment is made of the integrity of the bladder and urethral support. A urine sample is tested for evidence of infection and blood.
Which special tests are performed will depend on the findings of the history and the physical examination, and the suspected cause of the incontinence.
List and explanation of tests
- Ultrasound scan - This uses very high frequency sound waves to obtain images of the kidneys and bladder for evidence of obstruction and incomplete emptying.
- Intravenous pyelogram (IVP) - Contrast medium is injected into a vein and excreted by the kidneys. Serial X- rays are taken while the contrast passes through the urinary tract, demonstrating both the function and the anatomy of the system.
- Micturating cystourethrogram (MCUG) - Contrast medium is inserted into the bladder and through a catheter X- rays are taken when the bladder is full and while the patient passes urine. The position and integrity of the bladder and the urethra are demonstrated.
- Urodynamic study - This is a functional test of bladder muscle and bladder outlet function. Pressure probes are inserted into the bladder and the rectum. During the initial filling phase the bladder compliance, capacity and response to filling are measured. After capacity is reached the patient is asked to pass urine and the pressure generated in the bladder as well as the bladder outlet resistance are measured.
- Cystoscopy - This is the visual inspection of the inside of the urethra and bladder with a special instrument.
Specific tests in specific situations
- Suspected stress incontinence (leaking with coughing, sneezing etc.) - In a classic case of stress urinary incontinence, without any evidence of urinary urgency or frequency, special tests are not necessarily indicated. Most specialists would confirm their clinical findings by urodynamic study prior to embarking on surgery for these patients. Urodynamic testing should confirm a stable bladder and a low bladder outlet resistance. A micturating cystourethrogram is sometimes performed to demonstrate bladder neck descent on straining.
- Suspected urge incontinence (frequency, urgency etc.) - A urine sample is inspected for evidence of infection or underlying bladder pathology (stone, tumour etc.). If there is an underlying cause of bladder instability this should be diagnosed and treated first. In the absence of an underlying cause the diagnosis is confirmed by urodynamic testing. The suspected findings are that of a small capacity bladder or an unstable bladder that contracts involuntarily at low volumes.
- Suspected overflow incontinence (obstruction or poor bladder contraction) - An ultrasound scan will confirm a large bladder volume after the patient has tried to pass urine. In a man the most likely cause is obstruction due to an enlarged prostate or a urethral stricture. A digital rectal examination and a cystoscopy will confirm the diagnosis. If the overflow incontinence is due to poor bladder contraction this can be confirmed with urodynamic testing.
- Suspected total incontinence due to vesicovaginal fistula - A micturating cystourethrogram will show contrast leaking from the bladder into the vagina. A cystoscopy is also performed in order to define the exact position and size of the fistula.
- Suspected congenital abnormality (e.g. ectopic ureter) - An intravenous pyelogram and cystoscopy will demonstrate the abnormal anatomy.
The treatment of incontinence will vary according to the cause, type and severity of the problem.
- Weight loss
- Cessation of smoking
- Pelvic floor exercises
- Vaginal weights
- Electrical stimulation
Non-medical treatment can be very effective in motivated patients with minor degrees of stress incontinence. The short-term results are often very good, but this is not always maintained in the long term. Published studies quote cure/improvement rates of 50-80% for pelvic floor exercises.
- Combination of the above
Medical treatment does not have a great role in stress incontinence. Postmenopausal atrophy affects the closure of the urethra. Oestrogens, which can be taken orally or applied locally, restores the bulk of urethral tissue leading to more effective closure. Alpha-agonists increase the tone in the bladder neck, thereby increasing outflow resistance. Some studies indicate a beneficial effect using a combination of estrogen and an alpha-agonist in older post-menopausal women.
- Periurethral injections of bulking agents
- Suspension operations
- Sling operations
- Artificial urinary sphincters
Periurethral injections involve the injection of bulking agents into the urethra to improve effective urethral closure. Commonly used agents include fat, collagen, Teflon paste and silicon particles. Injection therapy is suitable for women with intrinsic sphincter deficiency rather than hypermobility, as well as for men with post-prostatectomy incontinence. The major advantage of injection therapy is that it is a minor procedure. Short-term results are good, but often not maintained long-term.
The various suspension operations restore the normal anatomy in patients with hypermobility and improve the support of the urethra and the bladder neck. Open suspension operations like the Burch coposuspension provide the best long-term results. The various needle suspensions have fallen into disuse due to high failure rates.
Urethral slings can be used in patients with intrinsic sphincter deficiency as well as those with hypermobility. It involves the placement of a strip of tissue or artificial substance that supports the urethra and bladder neck like a hammock. It increases outflow resistance and improves urethral closure by supporting the mid urethra. The vast majority of patients can be rendered dry in this way, but the operation does carry the risk of difficulty with passing urine afterwards. Other complications include infection or erosion of the synthetic sling material which then has to be removed.
An artificial urinary sphincter (AUS) made of silicone can be used in someone with total incontinence resulting from irreparable damage to the sphincter. The AUS consists of a small cuff that is placed around the urethra (bladder tube), with a reservoir (balloon) that is placed in the lower belly next to the bladder. Both of these are connected with a small tube to a valve placed in the scrotum, which the person then uses to inflate or deflate the cuff. An AUS is very effective, but it is quite expensive, and there is a risk of infection or erosion of the synthetic material.
- Bladder training
- Pelvic floor exercises
Voiding by the clock and progressively increasing the time between voids can improve the symptoms of patients with urge incontinence and otherwise normal bladders. This can be combined with biofeedback and pelvic floor exercises.
Drug therapy forms the mainstay of treatment for patients with urge incontinence due to bladder instability. These anticholinergic agents relax the bladder muscle and increase bladder capacity. Side effects include a dry mouth, constipation and blurred vision.
Injection of botulinum A toxin (Botox) into the bladder muscle (detrusor) can be used if the urge incontinence is due to a neurological disease causing overactive bladder contractions.
Tiny bladders due to radiation or tuberculosis can be enlarged surgically. A segment of intestine is patched onto the opened bladder, thereby increasing the capacity. Patients with intractable bladder instability who have failed medical treatment can also be treated in this way.
Overflow incontinence due to bladder outflow obstruction is treated by surgically alleviating the obstruction. The most common example would be a man with prostatic enlargement treated by resection of the prostate gland. If the incontinence is due to failure of the bladder to contract then intermittent clean self-catheterisation is the most appropriate treatment. Permanent indwelling catheters should be avoided if at all possible.
Total incontinence due to a vesicovaginal fistula or a ureterovaginal fistula is treated by surgical repair of the defect.
It is not possible to avoid all the potential causes of urinary incontinence. Obesity and smoking definitely make stress incontinence worse and reduce the success rate of surgery. Multiple vaginal deliveries weaken the pelvic floor and contribute to stress incontinence.
It is, however, highly debatable whether the modern practice of elective caesarian section should be encouraged, as this carries its own set of risks for the mother and the child. Regular pelvic floor exercises reduce the incidence of post-partum incontinence. Bladder training can be very effective in patients with urgency and frequency, hopefully arresting symptoms before urge incontinence develops.
(Reviewed by Prof C.F. Heyns, Department of Urology, University of Stellenbosch and Tygerberg Hospital, September 2009)