AGING AND THE FEMALE LOWER URINARY TRACT

When considering the effects of increasing age on any organ system, a crucial distinction must be made between true age-related changes that occur in everyone and age-associated changes resulting from the accumulation of pathologic conditions that do not occur in everyone. Table 94-1 lists age-related changes and age-associated factors that can influence lower urinary tract function and symptoms in elderly women. Because determining true age-related changes in the female lower urinary tract would involve invasive procedures (e.g., catheterization for urodynamic studies, cystoscopy) in continent elderly women without urinary symptoms, this type of information is rarely sought. Despite these difficulties in obtaining data, several types of age-related changes are known to have a prominent influence on lower urinary tract function.

Table 94-1 Aging and the Female Lower Urinary Tract

Change or Effect	Potential Effects
Age-related changes
Altered cell function	Altered interstitial tissues and mucosal surfaces
Altered cell function	Increased likelihood of pelvic prolapse and urinary infection
Decreased estrogen level	Thinner and more friable mucosa and interstitial tissues
Decreased estrogen level	Increased likelihood of pelvic prolapse, urinary symptoms, and infection
Altered concentrations of central nervous system	Increased likelihood of bladder and urethral dysfunction
neurotransmitters; altered nerve conduction
Altered immune function	Increased susceptibility to infection
Altered bladder function	Increased likelihood of urinary symptoms, incontinence, and infection
Decreased capacity
Increased uninhibited contractions
Increased residual volume
Lower urethral pressure	Increased likelihood of incontinence
Age-associated factors
Cognitive and sensory impairment	Decreased ability to relate symptoms
Locomotor disturbances and immobility	More difficulty getting to a toilet; increased likelihood of fecal
Stroke	impaction and incontinence
Hip fracture
Peripheral vascular disease
Parkinson’s disease
Poor fluid intake	Increased likelihood of fecal impaction and bacteriuria
Central nervous system diseases affecting bladder function	Increased likelihood of incontinence
Stroke
Dementia
Parkinson’s disease
Other diseases affecting bladder function	Increased likelihood of bladder dysfunction
Malignancy
Atherosclerotic vascular disease
Drug usage (see Table 94-2)	Increased likelihood of bladder or urethral dysfunction

One of the most important age-related changes affecting the female lower urinary tract is the postmenopausal decline in estrogen. This remains true, even though evidence has suggested that oral estrogen supplementation is linked to worse continence outcomes.¹ The bladder, urethra, and genital tract have a common embryologic origin, and the epithelium of all of these tissues responds to hormonal changes. When the influence of estrogen declines, the epithelium and supporting tissues of the pelvic area atrophy, resulting in a friable mucosa and a tendency toward prolapse. The lower glycogen content in the vaginal epithelium results in less lactic acid metabolism by Doderlein’s bacilli and an increase in the pH of vaginal secretions that may increase susceptibility to infection. Changes occur in the concentration of certain neurotransmitters in various locations in the central nervous system with increasing age. Given the important influence of the central nervous system on human bladder function, these age-related changes in central neurotransmitters may play a role in disorders of micturition in the elderly. Alterations in immune function also occur with increasing age. Although these changes have been seen mainly in cellular immunity, age-related changes in immune function, especially local immune activity in the lower urinary tract, may play an important role in susceptibility to bacteriuria and symptomatic UTI in older women.

Certain functional changes appear to occur in the bladder and urethra with increasing age. In one study, abnormal cystometrographic results were found for 15 of 24 continent elderly women who were free of neurologic disease.² Twelve of these 15 showed uninhibited contractions; 10 had a bladder capacity of less than 250 mL. Other studies have shown prevalence rates of 5% to 11% of abnormalities in continent older women.^3,⁴

Some work has attempted to elucidate in the underlying anatomic basis of these changes. In a series of investigations in symptomatic and asymptomatic adults older than 65 years using urodynamics and electron microscopy of bladder biopsy specimens, investigators found that patients with detrusor activity had specific anatomic abnormalities, including a dysjunction pattern with protrusion junctions and ultraclose abutments. These changes are believed to be the anatomic explanation for the propagation of involuntary detrusor contractions in older patients.⁵^–⁷

Maximal urethral pressure and functional urethral length are decreased in continent elderly women.^8,⁹ In one study, the maximal urethral pressure in continent women fell from a mean of 87 cm H₂O in the third decade to 42 cm H₂O in the seventh decade, a value that overlapped that of younger women with stress incontinence.⁸ These age-related changes in lower urinary tract function should be considered when evaluating urodynamic findings in elderly women. One postmortem study of 25 bladders from women between the ages of 74 and 102 years revealed marked trabeculation, diverticula, and cellular formation.¹⁰ Another study demonstrated continuous loss of striated muscle cells of the rhabdosphincter due to apoptosis, which eventually may reach a critical mass, leading to reduced function of the muscle with resultant urinary incontinence.¹¹ Histologic section of the bladder outlet showed a high incidence of chronic inflammation, edema, and fibrosis, presumed to be related to chronically infected residual urine. The trabeculation in these bladders was thought to be the result of loss of elastic tissue and coalescence of muscle fiber and of muscle hypertrophy resulting from bladder outlet obstruction or frequent uninhibited bladder contractions against a closed sphincter, or both. Other investigators have reported that the bladder in elderly women is more often decompensated and thin walled and that hypertrophy does not occur with uninhibited contractions.¹² Further research on the anatomic changes that occur in the aging lower urinary tract will help to clarify these issues.

Several age-associated factors (Table 94-1) can have an important influence on lower urinary tract function and symptoms in elderly women. Although most elderly individuals are generally active and healthy, the incidence of several disorders does increase with age. Impairments of cognitive and sensory function are more common in the elderly than in younger populations. These impairments may make it difficult for the elderly to interpret and relate symptoms of lower urinary tract dysfunction accurately. Poor nutritional and fluid intake can predispose the elderly to fecal impaction and urinary infection. The prevalence of asymptomatic bacteriuria increases with age (discussed later), and this situation predisposes to symptomatic urinary infection. Locomotor disturbances are common in the elderly. The incidence of stroke, arthritis, osteoporosis with resultant hip fractures, peripheral vascular disease with claudication or resultant amputations, Parkinson’s disease, and other gait disorders increase with age. These disorders can make it difficult for the elderly to reach a toilet, especially in the setting of urinary frequency and urgency. Impaired mobility may play a prominent role in the development of incontinence in elderly women (discussed later). The incidence of diseases of the central nervous system, such as stroke, dementia, and Parkinson’s disease, increases with age. Given the important role of higher centers in the control of micturition, these diseases are frequently involved in urinary dysfunction in the elderly.

An associated problem is that as a result of the high prevalence of so many diseases among the elderly, they are also likely to be taking a wide variety of drugs (often several different agents in complex dosage schedules), many of which can affect lower urinary tract function (Table 94-2). An important component of the assessment of older women with lower urinary tract symptoms is evaluation of the potential role of medications in causing or contributing to their symptoms. It is important to understand the potential effects of acetylcholinesterase inhibitors, given for dementia to stabilize cognitive decline, because these procholinergic agents can worsen or cause incontinence. Bladder relaxant agents may worsen cognition in some older adults.¹³

Table 94-2 Medications That Can Negatively Affect Continence

Type of Medication	Potential Effects on Continence
Diuretics	Polyuria, frequency, urgency
Anticholinergics	Urinary retention, overflow incontinence, impaction
Acetylcholinesterase inhibitors (for dementia)	Urgency, urge urinary incontinence
Psychotropics
Antidepressants	Anticholinergic actions, sedation, rigidity, immobility
Antipsychotics	Anticholinergic actions, sedation
Sedatives and hypnotics	Sedation, delirium, immobility, muscle relaxation
Narcotic analgesics	Urinary retention, fecal impaction, sedation, delirium
α-Adrenergic blockers	Urethral relaxation
α-Adrenergic agonists	Urinary retention
β-Adrenergic agonists	Urinary retention
Calcium channel blockers	Urinary retention
Alcohol	Polyuria, frequency, urgency, sedation, delirium, immobility

URINARY TRACT INFECTION IN ELDERLY WOMEN

Asymptomatic and symptomatic UTIs are common in the elderly. The overall expenditures for the treatment of UTIs in women in the United States, excluding spending on outpatient prescriptions, were approximately $2.47 billion in 2000.¹⁴ The estimated lifetime risk for a woman to have a UTI is greater than 50%.¹⁴ The prevalence of bacteriuria increases with age; it is more common in elderly women than in men and in patients in nursing homes and hospitals than in elderly people residing at home. Compared with younger women, elderly women are at higher risk for hospitalization from a UTI¹⁴ and have twice the risk for developing bacteruria after urodynamic procedures,¹⁵ Table 94-3 summarizes several studies of the prevalence of bacteriuria in the elderly.¹⁶^–²⁶ Longitudinal studies of bacteriuria among older women have documented that the organisms change over time and that bacteriuria resolves and returns spontaneously in many women.^20,²⁴^–²⁶ Several factors have been implicated in the increased prevalence of bacteriuria in the elderly, including atrophic mucosal changes as a result of estrogen deficiency, increased residual urine volumes, immobility, the prevalence of fecal and urinary incontinence, and the relatively common use of indwelling catheters.²⁷ Risk factors for bacteruria and UTIs in postmenopausal women include sexual activity, diabetes, urinary incontinence, and past UTIs.²⁸ Symptoms common in elderly women that are usually associated with UTI, such as frequency, urgency, dysuria, and incontinence, do not reliably predict whether the urine is infected.^17–19,²¹ Midstream urine specimens from elderly women are highly unreliable in predicting true bladder infection. The white blood cell count on urinalysis correlates poorly with bladder infection,¹⁰ and there is at least a 17% incidence of false-positive cultures when midstream urine specimens are repeated or compared with suprapubic aspirates.^20,²⁹ Growth of between 10⁴ and 10⁹ colonies/mL and contaminated specimens are also more common with midstream specimens. Taking two consecutive midstream specimens increases the reliability substantially. These factors can make the accurate diagnosis of true bladder infection difficult in elderly women.

Table 94-3 Prevalence of Bacteriuria in Elderly Women

Setting of Population	Women Affected (%)
Community	11–17
Nursing home	23–27
Hospital	32–50

Asymptomatic bacteriuria is generally considered a benign condition in the elderly who are free of catheters. Studies have, however, shown a substantial incidence of potentially correctable lower urinary tract disease that can contribute to bacteriuria in asymptomatic elderly patients.²² One study found that bacteriuric elderly nursing home residents had a 30% to 50% lower survival rate (deaths from a variety of causes) when followed for 10 years compared with nonbacteriuric residents matched for age, blood pressure, smoking habits, hematocrit, and blood cholesterol levels.³⁰ A second study of community-dwelling elderly also showed an association between bacteriuria and mortality,³¹ but a cause-and-effect relationship has not been documented. Two studies of treated asymptomatic bacteriuria in older institutionalized³² and ambulatory³³ women have not documented substantial effects on mortality. In summary, therapy for asymptomatic bacteruria in older individuals has not produced improvements in survival or amelioration of genitourinary symptoms, but it has correlated with increased antimicrobial resistance and adverse drug effects. For these reasons, guideline consensus statements have recommended against the routine screening for and treatment of asymptomatic bacteriuria in older persons resident in the community elderly institutionalized residents of long-term care facilities.³⁴

Symptomatic UTIs in elderly women should be treated with an antimicrobial that achieves a high concentration in the urine. Consensus guidelines recommend that trimethoprim/sulfamethoxazole (TMP/SMX) DS twice daily be first line therapy for UTIs, based on cost and efficacy considerations. Floxacins (i.e., ciprofloxacin and others) should be reserved for situations in which there are high rates of resistance (10% to 20%) to TMP/SMX.³⁴ In younger women, a 3-day regimen is associated with a 93% eradication rate. Longer courses are associated with higher eradication rates, which must be weighed against higher rates of adverse drug events.³⁵ Because of the acknowledged higher rates of failure in 3-day treatment for older women, the consensus statement recommends a 7-day treatment course for uncomplicated symptomatic infections. Drug selection should be modified based on such factors as allergy, renal function, cost, and bacterial sensitivities (especially when infections are recurrent). Although age-related changes do occur in the kidney’s ability to eliminate these drugs, dosage adjustments usually are unnecessary unless the serum creatinine level is above 2.0 mg/dL.

Compliance with drug regimens may be a problem for many elderly patients and should be kept in mind as a potential cause of treatment failure. Recurrent infections in elderly women usually are caused by reinfection with a different organism. Relapse with the same organism should prompt a search for a structural abnormality in the lower urinary tract. When relapse occurs in the absence of a structural abnormality, a 3- to 6-week course of drug therapy should be given. Infrequent symptomatic reinfections should be treated as separate episodes; frequent symptomatic infections can be managed by long-term prophylaxis. Nitrofurantoin (100 mg/day) and TMP/SMX (½ of a single strength (40 mg/200 mg) tablet/day) have been shown to prevent recurrent symptomatic infections ³⁶ and appear to be costeffective, especially in women who have three or more symptomatic infections per year.³⁷

URINARY INCONTINENCE IN ELDERLY WOMEN

Scope of the Problem

Incontinence is a common, disruptive, and potentially disabling condition in the elderly. The prevalence of urinary incontinence is illustrated in Table 94-4. Incontinence is a heterogeneous condition among older women, ranging in severity from occasional episodes of dribbling small amounts of urine to continuous urinary incontinence with concomitant fecal incontinence. The prevalence of urinary incontinence among women increases with increasing age. The likelihood of having severe urinary incontinence also increases with increasing age; compared with 8% of women between 30 and 39 years old reporting severe urinary incontinence, 33% of women between 80 and 90 years old reported severe urinary incontinence.³⁸ Although these general trends are clear, there are more subtle trends. The overall prevalence of urinary incontinence increases with rising age, but the prevalence of stress incontinence may peak at age 50 and then decrease slightly.³⁹ Parity, which is a significant risk factor for stress incontinence in younger women, is a much less important risk factor for stress incontinence in older women.^40,⁴¹

Table 94-4 Prevalence of Urinary Incontinence Among Older Women

Setting of Population	Women Affected (%)
Community	Approximately 33%: any incontinence^*
	4-6%: severe incontinence^†
Acute care hospital	Approximately 40%
Nursing home	50-70%

* Positive response to questioning about any uncontrolled urine loss in the past year.

† Incontinence that occurs more than once per week or requires the use of pads.

Not all incontinent elderly women are severely demented, bedridden, and in nursing homes. Many in institutions and in the community are ambulatory and have good mental function. Physical health, psychological well-being, social status, and the costs of health care can be adversely affected by incontinence. Physical consequences can include skin breakdown, UTIs, and fractures, which may result if patients fall when they are forced to get up in the middle of the night to urinate. The psychosocial effects can be even more devastating; many elderly patients may suffer intense embarrassment, loss of self-esteem, and feelings of helplessness, depression, and anxiety, resulting in a withdrawal from vital social contacts or at least a reluctance to go places or engage in activities that are not close to toilet facilities.⁴² The financial impact of incontinence is also significant. It has been estimated that the cost of managing incontinence in elderly nursing home residents alone is close to $3 billion per year.⁴³ Estimates put the U.S. Medicare cost of inpatient and outpatient treatment of urinary incontinence in women at $234.4 million (1998). Urinary incontinence as the main reason for physician care for a Medicare visit rose from 845 per 100,000 in 1992 to 1845 per 100,000 persons in 2000.³⁹

Urinary incontinence is curable in many elderly patients, especially those who have adequate mobility and mental function. There is growing literature suggesting that for some individuals, urinary incontinence can be prevented or delayed by exercises and behavioral strategies.⁴⁴ Even when urinary incontinence is not curable, incontinence can always be managed in a manner that keeps patients comfortable, makes life easier for caregivers, and minimizes the cost of caring for the condition and its complications.

Acute, Reversible Incontinence versus Persistent Incontinence

The distinction between acute, reversible forms of incontinence and persistent incontinence is clinically important in older women because incontinence is often contributed to or caused by factors outside the lower urinary tract in this population. Acute incontinence refers to situations in which the incontinence is of sudden onset, usually related to an acute illness or an iatrogenic problem, and subsides after the illness or medication problem has been resolved. Persistent incontinence refers to incontinence that is unrelated to an acute illness and persists over time. The causes of acute and reversible forms of urinary incontinence can be remembered by the acronym DRIP (Table 94-5). Many of the reversible factors listed in this table can also play a role in patients with persistent forms of incontinence. A search for these factors should be undertaken in all incontinent geriatric patients.

Table 94-5 Reversible Factors That May Contribute to Urinary Incontinence

DRIP Acronym	Definition	Description
D	Delirium	New-onset urinary incontinence (UI) may be associated with delirium because of acute underlying conditions requiring diagnosis and treatment.
R	Restricted mobility	Acute conditions causing immobility may precipitate UI; environmental manipulation and scheduled toileting are appropriate until the condition resolves.
R	Retention	Urinary retention may be precipitated by many drugs (see Table 94-2) or may occur acutely because of anatomic obstruction; immobility and large fecal impactions may also contribute.
I	Infection	Acute cystitis may precipitate urge UI.
	Inflammation	Otherwise asymptomatic bacteriuria may contribute to urinary frequency and should be eradicated before any urodynamic evaluations are carried out.
	Impaction	Atrophic vaginitis and urethritis can cause irritative voiding symptoms, including UI.
		Fecal impaction and fecal incontinence may be associated with UI.
P	Polyuria	Poorly controlled diabetes with glucosuria can contribute to urinary frequency and UI.
P	Pharmaceuticals	Edema due to congestive heart failure or venous insufficiency can cause nocturia and exacerbate nocturnal UI (see Table 94-2)

Persistent forms of incontinence can be classified clinically into four basic types in the geriatric population: stress, urge, overflow, and functional. These types can overlap each other, and an individual patient may have more than one type simultaneously. Although this classification does not include all of the neurophysiologic abnormalities associated with incontinence (e.g., reflex or “unconscious” incontinence), it is helpful in approaching the clinical assessment and treatment of incontinence in the elderly.⁴⁵

Stress incontinence is the most common type among women younger than 75 years, especially in ambulatory clinic settings.⁴⁶^–⁴⁸ It may be infrequent and involve very small amounts of urine, and it may need no specific treatment in women who are not bothered by it. However, it may be so severe or bothersome that it requires surgical correction. It is most often associated with weakened supporting tissues and consequent hypermobility of the bladder outlet and urethra caused by lack of estrogen or by previous vaginal deliveries or surgery. Older adults with stress incontinence, compared with their continent older counterparts, are more likely to be white, have arthritis, be using oral estrogen therapy, have chronic obstructive pulmonary disease, and be obese.⁴⁹ Parity appears to be a somewhat weaker risk factor among women 60 years old or older than among women younger than 60 years.³⁰

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