MSQR - V21. N1. Spring 2002
Harris E. Foster, Jr., MD, Associate Professor of Surgery (Urology), Yale University School of Medicine, New Haven, CT
Progress to Date
As the ads for adult urinary pads discretely imply, bladder control problems are uncomfortable and potentially embarrassing. Unfortunately, bladder symptoms are very common in patients with multiple sclerosis (MS). Up to 80% of patients with newly diagnosed MS and up to 96% who have had MS for 10 years or more experience some difficulty with voiding during the course of their illness.
As with other MS symptoms, the kinds of bladder problems vary from person to person and can change over time. People may have trouble controlling the release of urine (incontinence), may experience frequent urges to urinate, may feel constant bladder fullness, or may have difficulty in starting to urinate or sustaining a steady stream. In fact, some people may experience urinary retention and will require some form of catheterization. These symptoms usually indicate problems in the functioning of the muscles that control urination, although urinary tract infection (UTI) must be eliminated as a cause. (The topic of UTI will be addressed in another article in the next issue.) A set of tests called a “urodynamic assessment” is needed to understand exactly what the underlying problems are, because bladder symptoms indicate only that something is wrong—they don’t provide good clues to understanding the problem.
Normal bladder function is well understood. Kidneys filter the blood, thereby producing urine, which flows into the bladder through tubes called ureters. The bladder then collects the urine by relaxing as it fills. When the bladder empties, the urine flows through a tube called the urethra to exit the body. To control the exit of urine from the bladder, a muscle called a sphincter contracts, thereby closing the bladder outlet. The nervous system monitors how full the bladder becomes by measuring the amount of stretch in the bladder wall as it distends. When the bladder gets full enough, the nervous system tells the bladder muscle, called the detrusor muscle, to contract when a socially appropriate place has been reached. If the sphincter does not open, however, urine may not flow out of the bladder. People can generally keep the sphincter closed (if there is not an involuntary bladder contraction) until they reach a toilet, at which point the sphincter relaxes in coordination with a contraction of the detrusor, and the bladder empties. When different elements of this system fail, or are incorrectly coordinated, problems with voiding arise.
Urodynamic assessment involves a cadre of tests that measure a variety of physiologic parameters in the bladder and/or urethra. Examples include tests to measure (1) urine flow rate, (2) the amount of urine expelled from or retained in the bladder, (3) the strength of the detrusor muscle contraction, (4) the amount of urine required to cause a detrusor contraction, (5) the ability of the sphincter to remain closed when abdominal pressure increases, (6) the ability of the sphincter to relax in coordination with a detrusor muscle contraction, and other variables. A complete evaluation will give a urologist a clear idea about the underlying problems that lead to bladder symptoms.
The reason for a complete urodynamic assessment is to provide appropriate treatment. Treatment for urinary dysfunction related to MS can include bladder training (i.e., urinating on a schedule as opposed to when there is urgency), oral medications, catheterization, and surgery. The exact treatment prescribed will depend on many factors, including the type and severity of the disorder and the patient’s level of disability, manual dexterity, independence, and social support (Litwiller, Frohman, & Zimmern, 1999).
Current Research and Issues
Bladder problems associated with MS. Several studies have been done to define the bladder problems that are most common in MS, and the results of these studies have been collected and reviewed (see Hinson & Boone, 1996; Litwiller et al., 1999). According to the reviews, the most common problem is called “detrusor hyperreflexia,” which is similar to having an overactive bladder. This problem is seen in 60% or more of persons with MS who have bladder symptoms. The symptoms associated with detrusor hyperreflexia include urgency, frequency, a need to awaken at night to urinate, and urgency incontinence, which is incontinence preceded by the need to urinate.
Detrusor hyperreflexia can occur alone, but it is often found in combination with other problems. The most common combination is hyperreflexia associated with the uncoordinated contraction of the voluntary sphincter, called “detrusor external sphincter dyssynergia” (DESD). In this condition, an individual may experience an urge to urinate but is unable to relax the sphincter completely, leading to a sensation of incomplete emptying or total urinary retention. Although not always related to MS, poor tone in the sphincter muscles can result in incontinence following an increase in abdominal pressure (i.e., coughing, sneezing, exercise), termed stress urinary incontinence. Sphincteric problems can affect 12% to 84% of patients with MS with bladder symptoms (Litwiller et al., 1999).
Another problem that can affect the detrusor muscle is hypocontractility, in which the muscle cannot contract strongly. Some persons, despite bladder fullness may not be able to initiate any detrusor contraction. This is the opposite of hyperreflexia, and is known as “areflexia.” Both of these conditions can result in urine being retained in the bladder.
Certain bladder and sphincter abnormalities may cause problems with kidney function. Injury to the kidneys can occur when the pressure in the bladder is elevated, such as DESD and urinary retention, or when there is reflux or backup of urine from the bladder through the ureters and into the kidneys. Although these bladder problems are known to be dangerous in persons with spinal cord injury, in those with MS, however, current research suggests that it is relatively rare for these problems to lead to kidney disease (see Hinson & Boone, 1996; Giannantoni et al., 1998).
Contribution of MS lesions to bladder problems. Research indicates that the reason so many people with MS experience bladder symptoms is that MS often affects the nerves responsible for urinary control. The affected regions are usually located in the part of the spinal cord that runs through the neck, where MS lesions are often found (Hinson & Boone, 1996; Litwiller et al., 1999). Lesions in other parts of the nervous system, including the lower spinal cord and the brain, may also be involved in bladder symptoms (Litwiller et al., 1999).
There is also evidence that the nerve pathways that control urination are especially vulnerable in MS. For example, even persons with MS who do not have bladder symptoms may demonstrate abnormalities in urodynamic assessment. In one study, of 40 patients without bladder symptoms, 88% had underlying abnormalities. These patients had not had MS for very long (a mean of 5 years). Therefore, the nerve pathways that are involved in urinating may often be affected very early in MS (see Hinson & Boone, 1996). In support of this idea, some individuals experience bladder problems as their first MS symptoms. One study found that persons who had bladder symptoms from the start of their MS had more severe bladder dysfunction disorders than did other patients (Giannantoni et al., 1999).
MS nervous system lesions tend to resolve and then recur in somewhat different patterns, resulting in unpredictable alterations in symptoms. Likewise, bladder symptoms in persons with MS can change over time. For example, one study of 22 patients found that 12 (55%) showed changes in their urinary function over the duration of the study, about 31¼2 years (Ciancio, Mutchnik, Rivera, & Boone, 2001). These results and others from similar studies emphasize the importance of re-evaluation in individuals with MS at regular intervals so that treatment can be altered, if necessary. Although some bladder problems may improve over time, Ciancio et al. (2001) found that DESD did not improve during their study (also see Litwiller et al., 1999). This result suggests that some disorders of urinary function may be irreversible in people with MS.
Treatment. Current research into treatment for urinary disorders has identified several medications that can be helpful in controlling detrusor hyperreflexia. Most of these medications work by blocking detrusor muscle contraction. Typical side effects include dry mouth, blurry vision, and constipation. Newer medications may have fewer side effects. It is also possible to combine these medications with self-catheterization to eradicate incontinence and permit the controlled emptying of the bladder (Litwiller et al., 1999).
To avoid the side effects of oral medications, medicine can also be given in other ways. Some medications can be infused directly into the bladder through the urethra. One of these, oxybutinin, a detrusor muscle contraction blocker, was effective in treating detrusor hyperreflexia in 86% of patients in certain studies when administered by this method. It is, however, an inconvenient way to administer medication for most patients, and many are not enthusiastic about it (Litwiller et al., 1999). Another promising treatment for incontinence at night is the use of a drug called desmopressin (DDAVP), which reduces urine production although it doesn’t have any effect on MS-induced detrusor hyperreflexia, which can also cause bedwetting (Litwiller et al., 1999).
For persons who have trouble emptying their bladder, the most common treatment is catheterization. Some individuals choose indwelling catheters, but many can perform self-catheterization on a regular schedule or have caregivers who can help. An effort is being made to find medications to treat urine retention, with a focus on stimulating detrusor muscle contraction. So far, although some studies have been promising, no reliably effective medication has been identified (see Litwiller et al., 1999).
Finally, many of these bladder problems can be treated with surgery. Surgery can be used to reroute the urinary tract to bypass the bladder, for example, with the urine being collected outside the body. Other kinds of surgery can improve the ability of the bladder to store urine by enlarging its capacity. For those who find it difficult to catheterize the urethra, primarily females, an opening can be created in the abdomen to allow the catheter to be inserted into the bladder. There are a variety of surgical procedures to correct stress urinary incontinence, which is caused by weak sphincter muscles. Some of these can be performed on an outpatient basis.
A recent advancement in surgery for incontinence similar to many cases seen in patients with MS is sacral nerve stimulation. One study evaluated the results of this surgical treatment to treat incontinence in nine patients, five of whom had MS (Chartier-Kastler et al., 2000). In this study, patients who had detrusor hyperreflexia and urge incontinence had an electrical device similar to a heart pacemaker surgically implanted to stimulate the sacral nerves (usually at the level of the third sacral vertebra, or S3). The persons in this study did not respond to oral medications and were candidates for surgery. All of the patients benefited from the treatment: by 6 months of stimulation, six of the patients were no longer incontinent, and three used fewer pads. The patients’ symptoms returned to pre-treatment levels when the stimulator was turned off. Two patients, both with MS, continued to use the stimulator for 72 months, and three, two of whom had MS, used it for 60 months. The authors of this study believe this method has considerable potential as a therapeutic strategy with relatively low cost ($10,000 to $15,000) and few side effects.
Most surgical procedures should be considered irreversible and the decision to undergo this type of treatment should take into account many factors including patient mobility, support system, life expectancy, and response to alternative treatments (Litwiller et al., 1999).
A better understanding of the dynamic nature of bladder disorders in persons with MS is needed. For example, it is unknown which disorders are likely to be temporary and which permanent, although poor coordination between the sphincter and the detrusor muscle may be permanent (Ciancio et al., 2001; Litwiller et al., 1999). This knowledge could help identify individuals who are appropriate candidates for surgery and perhaps limit the number of diagnostic tests such as urodynamics.
Research is needed to develop new medications for bladder disorders that can be effective without serious side effects. Surgical advances may also offer promising treatments, including the placement of nerve stimulators, as described above.
Implications for Patient Care
The very frequent occurrence of bladder symptoms in people with MS and the finding that, even among persons without symptoms, the vast majority demonstrate bladder dysfunction on urodynamic assessment, indicates that all persons with MS should discuss with their physician whether or not baseline and follow-up urodynamic testing is warranted in their case. The fact that urodynamic patterns often change over time for a large percentage of individuals suggests that urological assessment and testing should play an integral role in the care of most persons with MS.
There is currently some controversy about the likelihood that bladder
dysfunction will lead to kidney disease in individuals with MS. Although
there is a consensus that a baseline check of the upper urinary tract should
be performed, some physicians are discontinuing annual checkups because
kidney disease seems to be relatively rare in MS (Hinson & Boone, 1996).
In contrast, Giannantoni and colleagues (1998) recommend performing annual
baseline upper urinary tract imaging and laboratory tests, because of correlations
between some bladder problems and upper urinary tract involvement.
Finally, it is a good idea to remember that, like many other MS symptoms, bladder symptoms and their underlying dysfunctions can change over time (Ciancio et al., 2001). This tendency to change should be considered carefully when deliberating the use of irreversible treatments, like many surgeries.
References (*denotes suggested readings)
Chartier-Kastler, E. J., Bosch, J. L. H. R., Perrigot, M., Chancellor, M. B., Richard, F., et al. (2000). Long-term results of sacral nerve stimulation (S3) for the treatment of neurogenic refractory urge incontinence related to detrusor hyperreflexia. Journal of Urology, 164, 1476-1480.
Ciancio, S. J., Mutchnik, S. E., Rivera, V. M., & Boone, T. (2001). Urodynamic pattern changes in multiple sclerosis. Urology, 57(2), 239-245.
Giannantoni, A., Scivoletto, G., Stasi, S. M., Grasso, M. G., Vespasiani, G., et al. (1998). Urological dysfunctions and upper urinary tract involvement in multiple sclerosis patients. Neurourology and Urodynamics, 17, 89-98.
Giannantoni, A., Scivoletto, G., Stasi, S. M., Grasso, M. G., Agrò, E. F., et al. (1999). Lower urinary tract dysfunction and disability status in patients with multiple sclerosis. Archives of Physical Medicine and Rehabilitation, 80, 437-441.
*Hinson, J. L., & Boone, T. B. (1996). Urodynamics II. Urodynamics and multiple sclerosis. Urologic Clinics of North America, 23, 475-482.
*Litwiller, S. E., Frohman, E. M., & Zimmern, P. E. (1999). Multiple sclerosis and the urologist. Journal of Urology, 161, 743-757.
*Urinary dysfunction and MS, by the MS Council for Clinical Practice
Guidelines, and Controlling bladder problems in multiple sclerosis, by
the National Multiple Sclerosis Society. Both are available by calling
toll-free (800) FIGHTMS (press 1 to get your local chapter).
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