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Kidney and Urinary Tract Function

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(see Table 27-1). 19 They include the use of drugs that increase sphincter tone in stress incontinence, decrease hyperexcitability of the detrusor muscle in overactive bladder/urge incontinence, or relieve outflow obstruc- tion in overflow incontinence. Surgical intervention may be considered when other treatment methods have proved ineffective. The principal objective of surgical treatment of stress incontinence is to increase outlet resistance through restoration of the proper suspension and support of the vesicourethral segment of the urethra. 23 A mini- mally invasive procedure for the treatment of stress incontinence due to internal sphincter weakness is the periurethral injection of a bulking agent. 8,19 Surgically implanted artificial sphincters are available for use in treatment of incontinence due to severe sphincter damage. 8 Other procedures remove outflow obstruc- tion to reduce overflow incontinence and detrusor muscle instability. Special Needs of Elderly Persons Urinary incontinence is a common problem in elderly persons, both male and female. 30–33 Incontinence increases social isolation, frequently leads to institu- tionalization, and predisposes to infections and skin breakdown. Many factors contribute to incontinence in elderly persons, including a reduction in bladder capacity and urethral closing pressure. Detrusor mus- cle function also tends to change with aging. There is often a reduction in the strength of bladder contrac- tion and impairment in emptying that leads to larger PVR volumes. Detrusor overactivity is also common. It is characterized by symptoms of immediate urinary urgency and frequency and, in the case of involuntary urinary loss, urge incontinence. In men, benign prostatic hyperplasia may lead to outlet obstruction and overflow incontinence. 34 Men may also develop stress inconti- nence following radical prostatectomy for treatment of prostate cancer or transurethral resection for treatment of benign prostatic hyperplasia. In each of these cases, bladder pressure exceeds the closure pressure at the ure- thral outlet, leading to urine leakage. Furthermore, advancing age often results in restricted mobility, comorbid illness, infection, and constipation or stool impaction, all of which can precipitate urinary incontinence. Many elderly persons have difficulty get- ting to the toilet in time. This can be caused by arthri- tis that makes walking or removing clothing difficult or by failing vision that makes trips to the bathroom pre- carious, especially in new and unfamiliar surroundings. Impaired thirst or limited access to fluids can lead to constipation, in which the impacted stool produces ure- thral obstruction, causing overflow incontinence. Medications prescribed for other health problems may also contribute to incontinence. Potent, fast-act- ing diuretics are known for their ability to cause urge incontinence. Diuretics, particularly in elderly persons, increase the flow of urine and may contribute to incon- tinence, particularly in persons with diminished bladder

capacity and in those who have difficulty reaching the toilet in time. Drugs such as hypnotics, tranquilizers, and sedatives can interfere with the conscious inhibition of voiding, leading to urge incontinence. Many nonurologic conditions predispose the elderly to urinary incontinence. The transient and often treat- able causes of urinary incontinence may best be remem- bered with the acronym DIAPPERS, in which the D stands for dementia/dementias, I for infection (urinary or vaginal), A for atrophic vaginitis, P for pharmaceuti- cal agents, P for psychological causes, E for endocrine conditions (diabetes), R for restricted mobility, and S for stool impaction. 32 These eight transient causes of incon- tinence should be identified and treated before other treatment options are considered. As with urinary incontinence in younger persons, incontinence in elderly persons requires a thorough his- tory and physical examination to determine the cause of the problem. A voiding history is important. A void- ing diary provides a means for the person to provide objective information about the number of bathroom visits, the number of protective pads used, and even the volume of urine voided. A medication history is also important because, as just noted, medications can affect bladder function. Treatment of incontinence in the elderly usually starts with conservation measures before considering the use of medications or surgery. Conservative treatment may involve changes in the physical environment so that the person can reach the bathroom more easily or remove clothing more quickly. Habit training with regularly scheduled toileting—usually every 2 to 4 hours—often is effective. The treatment plan may require dietary changes to prevent constipation or a plan to promote adequate fluid intake to ensure adequate bladder fill- ing and prevent urinary stasis and symptomatic urinary tract infections. ■■ Disorders of bladder structure and function include urinary obstruction with retention or stasis of urine, and urinary incontinence with involuntary loss of urine. Both types of disorders can have their origin in the structures of the lower urinary tract or in the neural mechanisms that control their function. ■■ In lower urinary tract obstructive disorders, urine is produced normally by the kidneys but is retained in the bladder, a condition that predisposes to kidney damage. Obstructions can be classified according to their location (bladder neck, urethra, or external urethral meatus), cause (congenital or acquired), degree (partial or complete), and duration (acute or chronic). SUMMARY CONCEPTS