Causes and Symptoms Continence is a skill acquired in humans by the interaction of two processes: socialization of the infant and maturation of the central nervous system. Without society’s expectation of continence, and without broadly accepted definitions of appropriate behavior, the concept of “incontinence” would be meaningless. There are many causes for urinary incontinence. Three broad (interrelated and often overlapping) categories are physiologic voiding dysfunction, factors directly influencing voiding function, and factors affecting the individual’s capacity to manage voiding.
The causes of physiologic voiding dysfunction involve an abnormality in bladder or sphincter function, or both. The bladder and sphincter have only two functions: to store urine until the appropriate time for urination and then to empty it completely. Voiding dysfunction involves the failure of one or both of these mechanisms. Four basic types of voiding dysfunction can be distinguished: detrusor instability, genuine stress incontinence, outflow obstruction, and atonic bladder.
Detrusor instability is a condition characterized by involuntary bladder (detrusor muscle) contraction during filling. While all the causes of bladder instability are not fully understood, it can be associated with the following: neurologic disease (brain and spinal cord abnormalities), inflammation of the bladder wall, bladder outlet obstruction, stress urinary incontinence, and idiopathic (spontaneous or primary) dysfunction. Detrusor instability usually causes symptoms of frequency, urgency, and possibly nocturia or enuresis.
Genuine stress incontinence is caused by a failure to hold urine during bladder filling as a result of an incompetent urethral sphincter mechanism. If the closure mechanism of the bladder outlet fails to hold urine, incontinence will occur. This is usually manifested during physical exertion or abdominal stress (such as coughing or sneezing). It can occur in either sex, but it is more common in women because of their shorter urethra and the physical trauma of childbirth. Men can experience stress incontinence following traumatic or surgical damage to the sphincter.
Obstruction of the outflow of urine during voiding can produce various symptoms, including frequency, straining to void, poor urinary stream, preurination and posturination dribbling, and a feeling of urgency with resulting leakage (urge incontinence). In severe cases, the bladder is never completely emptied and a volume of residual urine persists. Overflow incontinence can result. Common causes of bladder outlet obstruction are prostatic enlargement, bladder neck narrowing, or urethral obstruction. Functional obstruction occurs when a neurologic lesion prevents the coordinated relaxation of the sphincter during voiding. This phenomenon is termed detrusor-sphincter dyssynergia.
An atonic bladder—one with weak muscle walls—does not produce a sufficient contraction to empty completely. Emptying can be enhanced by abdominal straining or manual expression, but a large residual volume persists. The sensation of retaining urine might or might not be present. If sensation is present, frequency of urination is common because only a small portion of the bladder volume is emptied each time. Sensation is often diminished, and the residual urine volume can be considerable (100 to 1,000 milliliters). Overflow incontinence often occurs.
An acute urinary tract infection can cause transient incontinence, even in a fit, healthy young person who normally has no voiding dysfunction. Acute frequency and urgency with disturbed sensation and pain can result in the inability to reach a toilet in time or to detect when incontinence is occurring. If an underlying voiding dysfunction is also present, an acute urinary tract infection is likely to cause incontinence.
Many drugs can also disturb the delicate balance of normal functioning. The most obvious category consists of diuretics, those drugs that increase urinary discharge; a large, swift production of urine will give most people frequency and urgency. If the bladder is unstable, it might not be able to handle a sudden influx of urine, and urge incontinence can result. Sedation can affect voiding function directly (for example, diazepam can lower urethral resistance) or can make the individual less responsive to signals from the bladder and thus unable to maintain continence. Other commonly prescribed drugs have secondary actions on voiding function. Not all patients, however, will experience urinary side effects from these drugs.
Various endocrine disorders can upset normal voiding function. Diabetes can cause polydypsia (extreme thirst), requiring the storage of a large volume of urine. Glycosuria (sugar in the urine) might encourage urinary tract infection. Thyroid imbalances can aggravate an overactive or underactive bladder. Pituitary gland disorders can result in the production of excessive urine volumes because of an antidiuretic hormone deficiency. Estrogen deficiency in postmenopausal women causes atrophic changes in the vaginal and urethral tissues and will worsen stress incontinence and an unstable bladder.
Several bladder pathologies can also cause incontinence by disrupting normal functioning. A patient with a neoplasm (abnormal tissue growth), whether benign or malignant, or a stone in the bladder occasionally experiences incontinence as a symptom. These are infrequent causes of incontinence.
Often it takes something else in addition to the underlying problem to tip the balance and produce incontinence. This is especially true for elderly and disabled persons who are delicately balanced between continence and incontinence. For example, immobility—anything that impedes access—is likely to induce incontinence. Immobility can be the result of the gradual worsening of a chronic condition, such as arthritis, multiple sclerosis, or Parkinson’s disease, until eventually the individual simply cannot reach a toilet in time. The condition may be acute—an accident or illness that suddenly renders a person immobile might be the start of failure to control the bladder.
In the case of children, most daytime wetting persists until the child reaches school age. It is less common than bedwetting (enuresis), and the two often go together. One in ten five-year-old children, however, still wets the bed regularly. With no treatment, this figure gradually falls to 5 percent of ten-year-olds and to 2 percent of adults. It is twice as common in boys as in girls, has strong familial tendencies, and is associated with stressful events in the third or fourth year of life. A urinary tract infection is sometimes the cause.
Fecal, as opposed to urinary, incontinence is generally caused by underlying disorders of the colon, rectum, or anus; neurogenic disorders; or fecal impaction. Severe diarrhea increases the likelihood of having fecal incontinence. Some of the more common disorders that can cause diarrhea are ulcerative colitis, carcinoma, infection, radiation therapy, and the effect of drugs (for example, broad-spectrum antibiotics, laxatives, or iron supplements). Fecal incontinence tends to be a common, if seldom reported, accompaniment.
The pelvic floor muscles support the anal sphincter, and any weakness will cause a tendency to fecal stress incontinence. The vital flap valve formed by the anorectal angle can be lost if these muscles are weak. An increase in abdominal pressure would therefore tend to force the rectal contents down and out of the anal canal. This might be the result of congenital abnormalities or of later trauma (for example, childbirth, anal surgery, or direct trauma). A lifelong habit of straining at stool might also cause muscle weakness.
The medulla and higher cortical centers of the brain have a role in coordinating and controlling the defecation reflex. Therefore, any neurologic disorder that impairs the ability to detect or inhibit impending defecation will probably result in incontinence, similar in causation to the uninhibited or unstable bladder. For example, the paraplegic can lose all direct sensation of and voluntary control over bowel activity. Neurologic disorders such as multiple sclerosis, cerebrovascular accident, and diffuse dementia can affect sensation or inhibition, or a combination of both. Incontinence occurs with some people suffering from dementia because of a physical inability to inhibit defecation. With others, it occurs because the awareness that such behavior is inappropriate has been lost.
Severe constipation with impaction of feces is probably the most common cause of fecal incontinence, and it predominates as a cause among the elderly and those living in extended care facilities. Chronic constipation leads to impaction when the fluid content of the feces is progressively absorbed by the colon, leaving hard, rounded rocks in the bowel. This hard matter promotes mucus production and bacterial activity, which causes a foul-smelling brown fluid to accumulate. If the rectum is overdistended for any length of time, the internal and external sphincters become relaxed, allowing passage of this mucus as spurious diarrhea. The patient’s symptoms usually include fairly continuous leakage of fluid stool without any awareness of control.
Most children are continent of feces by the age of four years, but 1 percent still have problems at seven years of age. Fecal incontinence or conscious soiling in childhood (sometimes referred to as encopresis) has, like nocturnal enuresis (nighttime urinary incontinence), long been regarded as evidence of a psychiatric or psychologic disorder in the child. The evidence, however, does not support the claim that incontinent children are disturbed.
Such children usually have fastidious, overanxious parents who are intent on toilet training. The child is punished for soiling, so defecation tends to be inhibited, both in the underwear and in the toilet. When toilet training is attempted, the child may be repeatedly seated on the toilet in the absence of a full rectum and be unable to perform. The situation becomes fraught with anxiety, and bowel movements become associated with unpleasantness in the child’s mind. The child therefore retains feces and becomes constipated. Defecation then becomes difficult and painful as well.
Treatment and Therapy The two primary methods of treating urinary incontinence involve medical and surgical intervention (drug therapy and surgery) and bladder training.
Many drugs can be prescribed to help those with urinary incontinence. Often the results are disappointing, although some drugs can be useful for carefully selected and accurately diagnosed patients. Drugs are often used to control detrusor instability and urge incontinence by relaxing the detrusor muscle and inhibiting reflex contractions. This therapy is helpful in some patients. Sometimes when the drug is given in large enough doses to be effective; however, the side effects are often so troublesome that the therapy must be abandoned. Drugs that reduce bladder contractions must be used cautiously in patients who have voiding difficulty, since urinary retention can be precipitated. Careful assessment must be made of residual urine. Drug therapy is also used with caution in patients with a residual volume greater than 100 milliliters. Some drugs are used in an attempt to prevent stress incontinence by increasing urethral tone. Phenylpropanolamine and ephedrine, those most often used, are thought to act on the alpha receptors in the urethra.
Drug therapy can also be used to relieve outflow obstruction. Phenoxybenzamine is commonly used, but this drug can have dangerous side effects, such as tachycardia (an abnormally fast heartbeat) or postural hypotension. If the bladder does not contract sufficiently to ensure complete emptying, drug therapy can be attempted to increase the force of the voiding contractions. Carbachol, bethanechol, and distigmine bromide have all been used with some success. Other drugs might be useful in treating factors affecting incontinence—for example, antibiotics to treat a urinary tract infection or laxatives to treat or prevent constipation.
Many drugs can exacerbate a tendency to incontinence. For those who are prone to incontinence, medications and dosage schedules are chosen that will have a minimal effect on bladder control. For example, a slow-acting diuretic, in a divided dose, can help someone with urgency and weak sphincter tone to avoid incontinence. An analgesic might be preferable to night sedation for those who need pain relief but who wet the bed at night if they are sedated.
Turning to surgical intervention, none of the several surgical approaches that have been used in an attempt to treat an unstable bladder has gained widespread use. Cystodistention (stretching the bladder under general anesthesia) and bladder transection, for example, are presumed to act by disturbing the neurologic pathways that control uninhibited contractions. Many vaginal and suprapubic procedures are available to help correct genuine stress incontinence in women. Surgery can also be used to relieve outflow obstruction—for example, to remove an enlarged prostate gland, divide a stricture, or widen a narrow urethra.
In cases of severe intractable incontinence, major surgery is an option. For those with a damaged urethra, a neourethra can be constructed. For those with a nonfunctioning sphincter, an artificial sphincter can be implanted. In some patients, a urinary diversion with a stoma (outlet) is the only or best alternative for continence. Although a drastic solution, a urostomy might be easier to cope with than an incontinent urethra, because an effective appliance will contain the urine.
Urinary incontinence is occasionally the result of surgery, usually urologic or gynecologic but sometimes a major pelvic or spinal procedure. Such iatrogenic incontinence can be caused by neurologic or sphincter damage, leading to various dysfunctional voiding patterns.
Several different types of bladder training or retraining are distinguishable and can be used in different circumstances. The most important element for success is that the correct regimen be selected for each patient and situation. A thorough assessment identifies those patients who will benefit from bladder training and determines the most appropriate method. Other factors that contribute to the incontinence should also be treated (for example, a urinary tract infection or constipation), because ignoring them will impair the success of a program.
Bladder training is most suitable for people with the symptoms of frequency, urgency, and urge incontinence (with or without an underlying unstable bladder) and for those with nonspecific incontinence. The elderly often have these symptoms. Patients with voiding dysfunction, other than an unstable bladder, are unlikely to benefit from bladder training.
The aim of bladder training is to restore the patient with frequency, urgency, and urge incontinence to a more normal and convenient voiding pattern. Ultimately, voiding should occur at intervals of three to four hours (or even longer) without any urgency or incontinence. Drug therapy is sometimes combined with bladder training for those with detrusor instability.
Bladder training aims to restore an individual’s confidence in the bladder’s ability to hold urine and to reestablish a more normal pattern. Initially, a patient keeps a baseline chart for three to seven days, recording how often urine is passed and when incontinence occurs. This chart is reviewed with the program supervisor, and an individual regimen is developed. The purpose is to extend the time between voiding gradually, encouraging the patient to practice delaying the need to void, rather than giving in to the feeling of urgency. Initially, the times chosen can be at set intervals throughout the day (for example, every one or two hours) or can be variable, according to the individual’s pattern as indicated by the baseline chart. When the baseline chart reveals a definite pattern to the incontinence, it might be possible to set voiding times in accordance with and in anticipation of this pattern.
A pattern of voiding is set for patients throughout the day (timed voiding). Usually no pattern is set at night, even if nocturia or nocturnal enuresis is a problem. Patients are instructed to pass urine as necessary during the night. Sometimes the provision of a suitable pad or appliance helps to increase confidence and means that, if incontinence does occur, the results will not be disastrous. If urgency is experienced, patients are taught to sit or stand still and try to suppress the sensation rather than to rush immediately to the toilet. A normal fluid intake is encouraged because the goal is to have the patient continent and able to drink fluids adequately.
As patients achieve the target intervals without having to urinate prematurely or leaking, the intervals can gradually be lengthened. The speed of progress depends on the individual and on other variables, such as the initial severity of symptoms, motivation, and the amount of professional support. Patients usually remain at one time interval for one to two weeks before it is increased by fifteen to thirty minutes for another two weeks. Once the target of three- to four-hour voiding without urgency has been achieved, it is useful to maintain the chart and set times for at least another month to prevent relapse.
Some people find that practicing pelvic muscle exercises helps to suppress urgency. Any weakness in the pelvic floor muscles will cause a tendency not only to urinary incontinence but also to fecal stress incontinence. Mild weakness can respond to pelvic muscle exercises similar to those used in alleviating the symptoms of stress incontinence, but with a concentration on the posterior rather than the anterior portion of the pelvic muscles. Rectal tone is assessed by digital examination, during which the patient is instructed to squeeze. Regular contractions on the posterior portion of the pelvic muscles are then practiced often for at least two months (usually in sets of twenty-five, three times a day).
In cases of fecal impaction, a course of disposable phosphate enemas—one or two daily for seven to ten days, or until no further return is obtained—is the treatment of choice. A single enema is seldom efficient, even if an apparently good result is obtained, because impaction is often extensive: The first enema merely clears the lowest portion of the bowel. If fecal incontinence persists once the bowel has been totally cleared (a plain abdominal X ray can be helpful in confirming this), the condition is assumed to be neurogenic in origin rather than caused by the impaction.
Perspective and Prospects Historically, most health professionals have been profoundly ignorant of the causes and management of incontinence. Incontinence was often regarded as a condition over which there was no control, rather than as a symptom of an underlying physiologic disorder or as a symptom of a patient with a unique combination of problems, needs, and potentials. The unfortunate result of such limited understanding was passive acceptance of the symptom of incontinence. Incontinence, often viewed as repulsive, is often a condition that is merely tolerated. As public recognition of the implications of incontinence has increased, however, the stigma associated with it has slowly decreased. It has become common knowledge that millions of Americans suffer from incontinence, and most pharmacies and supermarkets have a section for incontinence products.
At one time, incontinence was primarily regarded as a “nursing” problem, with nurses providing custodial care—keeping the patient as clean and comfortable as possible and preventing pressure ulcers from developing. Gradually, nurses were not alone in acknowledging that incontinence was a symptom requiring investigation and intervention; those in other health professions also began to realize this need. In the 1980s, research funds began to be allocated for the study of incontinence. In 1988, US surgeon general C. Everett Koop estimated that $8 billion was being spent by the federal government on incontinence in nursing homes in the United States annually.
As incontinence began to be recognized by the public as a health problem rather than as an inevitable part of aging, more people admitted having the symptoms of incontinence and sought medical attention. It has been estimated that, of all cases of incontinence, more than one-third can be cured, another one-third can be dramatically improved, and most of the remainder can be significantly improved.
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