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CHAPTER 24: BLADDER, URINARY, AND KIDNEY CONDITIONS

Overview

Symptoms

    Blood in the Urine (Hematuria)

    Loss of Bladder Control (Urinary Incontinence)

Conditions

    Urinary Tract Infection

    Bladder Cancer

    Kidney Problems Caused by Blood Vessel Disease

    Problems with the Kidneys' Filtering Apparatus

    (Glomerulonephritis)

    Sudden Kidney Failure


Overview

The kidneys are responsible for a number of activities, including monitoring and maintaining a normal balance of body salt and water. The kidneys become smaller and filter less blood as we age. These changes increase the vulnerability of the kidneys to damage caused by diseases and toxins. Nevertheless, aging kidneys usually maintain adequate function even in extreme old age.

    In general, the signs and symptoms of kidney disease in older people are similar to those in younger people. A few of the many signs of kidney disease are increasing fluid accumulation, swelling in the extremities, blood in the urine, and high levels of various compounds in the blood normally filtered and removed by the kidney.

SYMPTOMS Blood in the Urine (Hematuria)

Blood in the urine, or hematuria, has been documented in approximately 10 percent of men 50 years or older who had no other symptoms. Microscopic hematuria means that there is a small amount of blood in the urine that is not visible to the naked eye. Hematuria cannot be diagnosed if a special tube called a catheter was used to obtain the specimen by passing it up the urethra into the bladder because the catheter itself can cause enough injury to produce temporary bleeding. If an older person is catheterized when the hematuria is found, the catheter must be withdrawn and the urine reexamined several days after the catheter has been removed.

Causes of Hematuria and Their Symptoms

Conditions causing hematuria can be categorized according to (1) diseases that affect the kidney, (2) diseases in the bladder or urethra, or (3) problems that cause blood-clotting abnormalities. Some prescription and over-the-counter medications can also cause blood in the urine.

    Hematuria in association with fever, pain on urinating, or frequent urination may suggest a urinary tract or prostate infection. Many elderly people do not experience all these symptoms, so their absence does not mean that an infection is not present. A sense of burning, urgency, or dribbling, and a narrow urinary stream suggest obstruction or prostate disease. If hematuria is associated with high blood pressure, swelling of the legs and sometimes around the eyes, and signs of reduced kidney function on blood testing, it suggests disease within the kidney. The combination of hematuria, changes in blood pressure, and pain in the flank may indicate a blood clot or an embolus that has traveled to the kidney. In this setting, an embolus could be a piece of debris that has broken off from a cholesterol deposit occurring within the wall of the aorta.

Evaluation of Hematuria

To help identify the cause of hematuria, the physician examines a freshly voided urine specimen. A doctor may perform additional procedures, such as culturing the urine to look for infection and having the person collect all of their urine over a 24-hour period to determine the overall kidney function more precisely. Blood tests will make sure that the person's blood clots normally and determine additional aspects of kidney function. Special x-ray procedures are sometimes required to look for masses within the kidney. Occasionally a urologist may be consulted to look within the bladder to see if a bleeding source can be identified.

    After a thorough evaluation, the cause of blood in the urine can be identified in approximately 85 percent of cases. Various growths within the kidney account for between one-fourth and one-third of all hematuria in elderly people. Of these, prostate cancer and cancer involving the kidney are the two most common types of growths discovered. If no cause for hematuria is discovered after initial evaluation, periodic follow-up is appropriate; most people in this category, however, will not discover the reason for their hematuria even after a period of up to five years.

Loss of Bladder Control (Urinary Incontinence)

Urinary incontinence is the involuntary loss of urine that can cause a social or hygienic problem.

    Approximately one-third of community-living people over the age of 60 experience some degree of urinary incontinence; its prevalence is twice as high in women as in men. Approximately 5 percent of this age group have very severe incontinence, with urinary accidents occurring weekly or more often. In the nursing home setting, the prevalence of incontinence approaches 50 percent. Clearly, incontinence can have significant psychological, social, medical, and economic consequences. If not effectively treated, it increases social isolation, frequently resulting in a loss of independence through institutionalization, and predisposes the person to infection and skin breakdown.

    The degree of incontinence may change over time. Over the course of one year, incontinence may affect 20 percent of women and 10 percent of men, but within these groups it may disappear spontaneously in about 12 percent of the women and 30 percent of the men. The factors associated with the development and remission of incontinent symptoms are under investigation. Fewer than half of older adults affected by urinary incontinence consult a health professional about the condition. Because the majority of people with incontinence can be cured, there is room and need for considerable education about the availability of treatment options.

The Urinary System: How It Works

Stretch receptors located in the bladder wall communicate to the brain how full the bladder is--they play a key role in maintaining continence. When a critical degree of bladder distention is reached, bladder contractions of increasing force occur; these contractions must be inhibited by the brain to avoid the abrupt and unwanted emptying of the bladder.

    In order to hold the urine in the bladder, the pressure within the bladder must always be less than that in the urethra. Bladder pressure is affected by three factors: abdominal pressure, the amount of urine collected in the bladder, and the bladder muscle tone.

    The pressure within the urethra is maintained through skeletal muscle (muscle that contracts voluntarily) that lines the urethra, smooth muscle (muscle that contracts involuntarily) of the urethra and bladder neck, and the thickness of the urethral lining. The thickness of the urethral lining in women is maintained by estrogens and thins significantly after the menopause due to estrogen deficiency.

Table 39. Causes of Urinary Incontinence

CLINICAL CONDITION

MECHANISM

SYMPTOMS

Detrusor overactivity

Bladder contracts when it shouldn't

Difficulty holding urine

Stress incontinence

Urethral resistance is too low

Difficulty holding urine

Overflow incontinence

Bladder does not contract or urethral resistance is too high

Difficulty emptying the bladder

Functional incontinence

Problem not in urinary system; usually musculoskeletal or psychiatric illness

Other difficulties

The Causes of Urinary Incontinence

Urinary incontinence occurs when the bladder pressure overcomes the urethral resistance. Whereas a bewildering array of terms have been proposed to classify urinary incontinence, in reality there are only five basic mechanisms that can occur singly or in combination to produce incontinence: (1) the bladder contracts when it shouldn't (this goes under the clinical name of detrusor overactivity), (2) urethral resistance is too weak to hold urine (stress incontinence), (3) the bladder doesn't contract when it should (overflow incontinence), (4) the urethral resistance is too high (overflow incontinence), or (5) the problem is not in the urinary system at all (functional incontinence). (See Table 39).

Detrusor Overactivity. Detrusor overactivity occurs when involuntary bladder contractions overcome the normal resistance of the urethra. This is also referred to as unstable bladder, spastic bladder, uninhibited bladder, or urge incontinence. This is generally the most common type of incontinence, occurring in up to 70 percent of all people with incontinence. The three basic underlying causes of this condition are: (1) defects in the brain's inhibitory mechanisms; (2) increased excitability of the bladder from such causes as infection, irritation, or a fecal impaction; and (3) a loss of the normal voiding reflexes. This loss of normal reflexes can be self-induced or can be unintentionally caused by physicians. For example, embarrassment over a single episode of incontinence may lead a person to void frequently in an attempt to keep the bladder empty to avoid another accident. Or the person may cut back on fluids in an attempt to decrease urine. Both strategies, however, eventually cause the bladder wall to contract and lose its capacity to stretch, thereby reducing bladder capacity and increasing bladder muscle tone. The ultimate result is further episodes of incontinence. Loss of bladder reflexes caused by physicians can result when toileting becomes associated with uncomfortable equipment such as cold bedpans or toilet seats, or when the increased physical or verbal attention brought on by the incontinence makes the incontinent person feel rewarded.

Stress Incontinence. Stress incontinence is very common in elderly women and occurs when the urethral resistance to flow is reduced. The probable causes are the changes in the lining in the urethra after the menopause, related to the decline of estrogens, combined with an earlier weakening of the pelvic muscles following childbirth. In addition, urinary tract infections may precipitate stress incontinence. Stress incontinence in men usually occurs only with urinary tract infections, after surgery, or as the result of severe disease of the nervous system (see Figure 42).

    The features of stress incontinence include the loss of urine following coughing, laughing, straining, sneezing, or any other condition that causes an abrupt increase in the abdominal pressure. Simply pushing on the abdomen may cause the passage of urine. People with stress incontinence usually stay dry at night. For a woman, the pelvic examination by a physician may reveal signs of decreased estrogen. For both women and men, testing may reveal signs of a urinary tract infection.

Overflow Incontinence. Overflow incontinence occurs when the bladder cannot empty properly. This is generally the result of either very poor bladder contractions or an elevated resistance to urine flow. The bladder that cannot contract is sometimes called an atonic bladder or neurogenic bladder, and usually occurs in connection with severe diabetes mellitus, or disease of the spinal cord. Resistance to urine flow is usually due to an obstruction of the bladder outlet caused by an enlarged prostate, a stone, or cancer. A third mechanism is an impaired ability to sense that the bladder is full and requires voiding. Generally, people with overflow incontinence have the feeling that their bladder has not emptied completely, experience difficulty starting to void, and note that their urinary stream is weak and dribbly. Examination by a physician may reveal an enlarged bladder; if the bladder is drained with a catheter, large amounts of urine are obtained, confirming that the bladder was, in fact, not successfully emptied.

Functional Incontinence. Functional incontinence occurs in people who have a normal urinary system but who cannot or will not reach the toilet in time. Generally, this is due to problems in the musculoskeletal system and/or environmental limitations that can be identified. People with dementia may not be able to recognize the need to void or to locate and use toileting facilities. Sometimes incontinence is part of a psychiatric condition. This "spiteful" incontinence is intermittent and usually does not occur at night. There is often an element of depression, hostility, or anger. Drugs and other factors may aggravate or unmask any of these problems. The use of diuretics or physical restraints may make it difficult for an older person to stay continent. In addition, strong sedatives can create a loss of attention to bladder cues. Medications can also directly affect the bladder contractions and the urinary outlet.

Evaluation of Urinary Incontinence

An evaluation of urinary incontinence has three objectives: (1) to identify and manage the factors that may be contributing to the incontinence, (2) to determine if further diagnostic evaluation is indicated, and (3) to develop a management plan, which may include further evaluation or a trial of therapy. The overall goal of this evaluation is to determine how bladder pressure is overcoming the urethral resistance. Useful information includes the onset, duration, and pattern of the incontinence; the amount of urine lost; all medications used; and any associated symptoms such as straining or burning while trying to void. It is helpful to know the amount of fluid a person is taking in. It is also important to know about any existing medical or surgical conditions such as diabetes mellitus, recent surgery, or the presence of any neurologic illness.

    Detrusor overactivity often has associated symptoms of urgency where there is an intense need to void. Overflow incontinence is sometimes associated with symptoms of incomplete bladder emptying. Stress incontinence is associated with urine leakage uniquely associated with situations that increase abdominal pressure, such as coughing, jogging, laughing, sneezing, and bending over. Identification of the various types of incontinence can be simplified if the following points are kept in mind: (1) an enlarged bladder signifies overflow incontinence, (2) the absence of any signs of any overflow or stress incontinence suggests detrusor overactivity, and (3) if stress incontinence is present, particularly in older women, it may be the only condition or it may be mixed with other forms of incontinence.

    Generally, the physician's physical examination is oriented toward identifying changes in the nervous system or in the genital, pelvic, and rectal areas. A urinalysis helps to check for infections and other local problems in the bladder. Sometimes the bladder is catheterized to determine the amount of urine left in the bladder after the person has tried to void. Other diagnostic procedures may be helpful in certain cases. The use of a particular diagnostic procedure depends upon whether the result will change the way the person is managed and whether not using a procedure could cause a physician to miss a particular condition. For example, since there is evidence that behavioral treatments are effective for both stress incontinence and detrusor overactivity, expensive testing to document stress incontinence or detrusor overactivity may be unnecessary if the person is going to be treated with behavioral therapies. On the other hand, looking within the bladder may be critically important if a bladder cancer is suspected. Additional studies may be needed if surgery is being considered.

Treatment of Urinary Incontinence

The first considerations in treating urinary incontinence are that most people can be substantially improved or cured and that family members and other caregivers should provide supportive measures when possible. A number of simple interventions have produced favorable results. For elderly women living in the community who have either detrusor overactivity or stress incontinence, bladder training--where the voiding interval is progressively lengthened--has proven to be highly effective. Pelvic muscle exercises are also very helpful for women with stress incontinence. Special techniques using biofeedback to help a person become aware of muscle contractions can be used--in some cases to train a person in the use of pelvic muscle exercises and other behavioral interventions. All of these behavioral interventions require a highly motivated person and multiple sessions with a skilled and enthusiastic trainer; however, they may not be appropriate or possible for everyone. There have not been any good comparisons made between behavioral treatments and drug treatments. People with incontinence are usually offered a choice of one or a combination of both approaches. Prompted voiding (asking the person if he or she needs to urinate) and similar techniques work well for people in nursing homes who have urinary incontinence.

    For detrusor overactivity the goal of treatment is to decrease the bladder contractions and to improve bladder capacity. As mentioned, treatments that do not require drugs include bladder training programs, pelvic floor exercises, and biofeedback. In general, medications used to treat detrusor overactivity work by decreasing bladder contractions. Sometimes medications are given to improve the resistance of the urethral sphincter. The doses of all medications used must be carefully monitored, as they sometimes result in incomplete voiding or even the inability to void. Side effects such as confusion, agitation, a drop in blood pressure upon standing, dry mouth, and various irregularities of the heart rhythm can occur.

    The goal of treatment for stress incontinence is to increase the urethral resistance. For mild to moderate stress incontinence in women, using medication to reinforce urethral resistance is about as effective as doing exercises that strengthen the pelvic floor muscles. Estrogens offer beneficial effects on the tissues around the urethra and are often part of the regimen; but the extent of their helpfulness is not clear. In addition to strengthening the pelvic floor muscles through specific exercises, increased walking is helpful. Walking improves a person's ability to sense that the bladder is filling. In cases that do not respond to any of these treatments, surgical procedures may be necessary--for instance, to support a sagging or prolapsed bladder. Surgical techniques are improving. Injection of substances into the tissues surrounding the urethra is an option in some cases when the older woman does not want or cannot tolerate a full surgical procedure.

    The goal of treatment for overflow incontinence is to drain the bladder. Generally, a nondrug strategy works best in this condition. Surgery is preferred in those cases where there is obstruction to outflow caused by a large prostate, cancer, or a stone. When the overflow is the result of a bladder that contracts poorly, it can then be decompressed for a period of about two weeks with an indwelling catheter. If bladder function is not restored, placing a tube (catheter) into the bladder may be required for adequate drainage. Sometimes the obstruction can be overcome by the use of drugs that relax the urethral sphincter; these drugs may be helpful to delay or avoid surgery.

    Functional incontinence is best managed by a simple approach. Physical and environmental impediments to effective toileting should be recognized and corrected. To avoid inadvertent conditioning toward incontinent behavior, the person should not be asked to go to the toilet or to use other unpleasant stimuli, such as bedpans or cold toilet seats immediately after an episode of incontinence. A toileting program can be established based on an evaluation of the person's voiding pattern. To accomplish this, the person is checked every two hours over a two-day period and a record is kept of whether the person is wet or dry. The optimal toileting schedule can then be established to allow toilet use at a time when the bladder is most likely to be full. Successful toileting should be positively reinforced.

    A variety of products that are not excessively bulky under the clothing are available to keep incontinent people dry and to control odor. These items include rubber or plastic pants with absorbent pads, intermittent catheterization, and external catheters or collecting devices. Generally, these are used only as last resorts and only after careful evaluation and treatment have failed to resolve the incontinence. Because the vast majority of people with urinary incontinence can be successfully managed or cured, these items should be used very sparingly if at all.

CONDITIONS Urinary Tract Infection

Urinary tract infections occur in up to 10 percent of elderly people each year. A large proportion of these infections are in elderly women. However, urinary infections become increasingly common in older men because of prostate enlargement.

Causes of Urinary Tract Infection

Compared with younger people, older people with urinary tract infection may have a much more diverse set of bacterial organisms causing the infection. People with catheters in for a long time always have bacteria in their urine, which often contains many different types of organisms. In addition, these organisms are often highly resistant to antibiotics. People at high risk for this infection include those who have had catheters or other objects in the genitourinary tract; those who have abnormalities of function such as kidney stones, urinary incontinence, or decreased bladder emptying; or those with indwelling urinary catheters.

Symptoms of Urinary Tract Infection

Urinary tract infection should be suspected in any older person with pain, frequency or urgency of urination, or in the presence of any recent unexplained change in general function. Nonspecific complaints of urinary tract infection include fever, chills, poor appetite, or weakness. Urinary incontinence or change in mental function can also be early clues. Many older people may have a large number of bacteria in their urine, although they have no symptoms at all and appear to be well.

Treatment of Urinary Tract Infection

In older people, the treatment regimens for urinary tract infection vary depending upon the severity of the infection. If a person is highly functional with an uncomplicated urinary infection, then simple oral antibiotics may be used. These people are generally healthy, functionally independent, have no bladder catheter, have not been recently taking antibiotics, and have no history of recurrent urinary tract infections. Cultures ten days to two weeks later help guide the physician in knowing whether or not to change the antibiotic regimen. For people with more complicated infections, such as those who have kidney stones, have been recently taking antibiotics, or have been in the hospital, the treatment usually begins with stronger antibiotics. Again, culture results help guide the prescribing physician in deciding on the need for any changes in medications. Older people with urinary tract infections who require hospitalization usually need to be treated with medications that can only be given intravenously.

    For many older people, bacteria in the urine that do not cause discomfort or other symptoms do not need to be treated with antibiotics. Sometimes these individuals are treated, however, if there is a history of recurrent symptomatic infections or of chronic obstruction of the urinary tract (as with prostate enlargement). People with indwelling catheters will have persistent bacteria in their urine and should be treated when symptoms develop or when there is a decline in function that cannot be explained by other factors.

Bladder Cancer

The incidence of bladder cancer increases with age. It is also more common in male cigarette smokers and people exposed to chemical dyes used in manufacturing. Worldwide, bladder cancer occurs more commonly in areas infected with the schistosome parasite. Most people with bladder cancer have bloody urine without pain or other symptoms.

Treatment of Bladder Cancer

Bladder cancer that does not extend beyond the bladder lining can be controlled for a long time with local treatments, which include simple surgical removal of the tumor and instilling chemical agents or biological agents by placing a tube into the bladder. A special preparation called BCG is the most effective form of instillation therapy for the bladder. For more advanced bladder cancer, the standard treatment is removal of the bladder and surrounding tissues. With newer chemotherapeutic agents such as cisplatin, it may not be necessary to remove the bladder for individuals with advanced bladder cancer. The combination of chemotherapy and radiotherapy is comparable, in terms of survival, to complete bladder removal. However, some people who have initially been treated with medical therapies may eventually require surgery because of recurrent disease. Even people treated surgically have a 40 to 80 percent chance of having the bladder cancer recur. In two-thirds of people with cancer that has spread throughout the body, the condition can be treated but not cured by a drug regimen containing cisplatin. Even patients who are older than 80 have tolerated these aggressive treatment regimens well.

Kidney Problems Caused by Blood Vessel Disease

In about half of those people over age 60 with no symptoms for kidney disease, X rays have revealed narrowing of at least one of the large arteries supplying blood to the kidneys. (See Chapter 19 on heart and circulation problems for more information on blood vessel disease.) While this condition may be asymptomatic, it can cause high blood pressure, sudden shortness of breath, long-term kidney problems, and even serious kidney failure.

Symptoms of Kidney Problems Caused by Blood Vessel Disease

The clues that would lead one to suspect underlying vascular disease involving the kidneys in an older person include the onset of high blood pressure, worsening of preexisting high blood pressure (especially if medications do not seem to control it), or unexplained loss of kidney function, especially in people who have blood vessel disease elsewhere.

Evaluation of Kidney Problems Caused by Blood Vessel Disease

Several procedures will determine if the large artery supplying a kidney with blood (the renal artery) has narrowed. The most informative is an arteriogram, but it is also the most invasive and the most risky. This highly specialized test involves passing a catheter into the large artery in the leg (the femoral artery). It is threaded upstream toward the heart until it reaches the section through which blood flows to the kidney. The physician then injects a small amount of dye to outline the blood vessels supplying the kidney. An x-ray is then taken of the arteries, which reveals their thickness or narrowness. This test is usually needed prior to any surgical treatment.

Treatment of Kidney Problems Caused by Blood Vessel Disease

Vascular disease of the kidney, if not treated, will continue to reduce blood flow to the kidney, leading to progressive elevations of blood pressure and further compromises of kidney function. Procedures to open the blood vessels have been developed. One method requires passing a small balloon attached to a catheter into the narrowed artery and then inflating the balloon to open up the narrow area. This is called angioplasty (from the Greek, meaning "to form a vessel"). An alternative approach involves surgery. While both angioplasty and surgery relieve the high blood pressure, surgery may also preserve kidney function. Treatment of high blood pressure with medications is helpful, but it does not prevent the progressive kidney damage caused by loss of circulation.

    Cholesterol embolization is another blood vessel problem of the kidney that frequently goes unrecognized in older people. In this condition, small fragments of cholesterol plaque break off from the wall of the aorta, travel downstream, and lodge in the kidney. Older people are predisposed to this because they frequently have advanced stages of blood vessel disease. People in this situation may have blood pressures that fluctuate. They may also show changes in their mental function, an abrupt decline in kidney function, and signs of embolization to other parts of the body. Treatment for this condition is basic supportive care. There is no specific treatment for the disorder.

Problems with the Kidneys' Filtering Apparatus (Glomerulonephritis)

The part of the kidney that filters the blood is called the glomerulus (see Figure 43). Diseases involving this structure occur in all age groups. Although these diseases are similar in young and older people, there is a tendency for physicians to overlook them in people over age 50. The two major ways that glomerular diseases show up are described below.

Symptoms of Glomerular Disease

Typically, the person with sudden inflammation of the glomerular units (acute glomerulonephritis) has the rapid onset of an elevated blood pressure, edema (fluid retention), decreasing kidney function, and blood in the urine. The condition is usually confirmed by a biopsy of the kidney. In this procedure a small needle is inserted through the skin of the flank to obtain a sample of kidney tissue. The most common form of acute glomerulonephritis in people over the age of 65 is characterized by lack of deposits of immune material (antibodies) within biopsied section of the glomerulus. Although the cause of this condition is not known, it may represent a form of blood vessel inflammation called vasculitis. Generally, the outlook for this disease is not good. However, some people have experienced improvement or even resolution of the condition after high-dose corticosteroid treatment. Other more aggressive therapies may be useful in some cases.

    The other way glomerular disease shows up is when there is too much protein in the urine, a condition called the nephrotic syndrome. It is estimated that about 25 percent of adults with nephrotic syndrome are over age 60. Usually a person with this condition has edema, a very high amount of protein in the urine, and a very low amount of albumin in the blood. Sometimes the blood pressure is high and the kidney function is impaired. Occasionally only the abnormalities in the urine are present without any symptoms at all. The treatment for nephrotic syndrome often involves corticosteroids to help relieve the condition causing the glomerular problem. The decision to use corticosteroids is difficult because of their side effects. Additional treatment includes controlling blood pressure and restricting the amount of protein in the diet.

Types of Glomerular Disease

A kidney biopsy is sometimes performed to determine the type of problem causing the glomerulonephritis. The five types most common in people over age 60 based on biopsy findings include membranous glomerulonephritis, minimal change glomerulonephritis, focalsegmental glomerulonephritis, amyloidosis, and multiple myeloma.

    Since membranous glomerulonephritis occurs with cancer in up to 70 percent of instances, people whose kidney biopsies indicate this condition are often evaluated for the presence of malignancy. About half the time this condition progresses to kidney failure. This progression can sometimes be prevented with medications.

    Minimal change glomerulonephritis usually does not progress to kidney failure and is usually treated with corticosteroids. This condition is sometimes seen with Hodgkin's disease.

    Most people with focal-segmental glomerulosclerosis have a slow progression to complete kidney failure. There is no consistent therapy for this condition.

    Amyloidosis, a condition where a silklike substance is deposited around blood vessels, is found in up to 20 percent of people over the age of 65 with nephrotic syndrome. Amyloidosis can involve just the kidneys or involve other organs as well. In people with involvement of other organs, a drop in blood pressure with standing or sitting is common. Amyloidosis is usually progressive, and the long-term outlook is not good.

    Multiple myeloma is another cause of increased protein in the urine in elderly people. Typically a large amount of a single protein is found in the person's blood or in the urine. Other clues to this condition include anemia or low back pain. Myeloma can cause kidney failure in several ways, including toxicity of the myeloma protein to the kidney, severe dehydration, kidney stones, and damage to other portions of the kidney.

Sudden Kidney Failure

Because of the normal changes that occur in the kidney with aging, older people are especially predisposed to sudden kidney failure.

Causes of Sudden Kidney Failure

Sudden kidney failure can be caused by disease within the kidney, severe dehydration, problems in regulating the kidney blood flow, and urinary tract obstruction. These circumstances can cause either sudden or gradually progressive kidney failure.

Kidney Failure Caused by Problems Within the Kidney. Many diseases and medications can injure the kidney and cause kidney failure. An allergic reaction involving the kidney is occasionally caused by a medication. A person with this situation often feels fever and malaise. High levels of a type of white blood cell called eosinophils (because they take up a chemical dye call eosin) are seen when the blood and urine are examined under a microscope. These cells are sometimes increased in allergic conditions. Usually the treatment involves very conservative care and discontinuing the offending medication.

    Sometimes changes in kidney function are due to problems within the kidney tubules. The tubules help adjust the concentration of acids and salts in the urine. Tubular dysfunction can be caused by poor blood flow or by specific kidney poisons.

    In some cases, the older kidney is more sensitive to contrast material (dye) used for various diagnostic X ray procedures to identify problems in the circulation. Sometimes the people who have these X ray procedures are dehydrated at the time of testing. They may also have diabetes mellitus or other conditions that can compromise the kidney. This combination predisposes the individual to kidney failure. If kidney failure occurs, the management consists of careful monitoring and watching for complications such as heart failure or infection, although dialysis (a technique using the abdominal cavity or a machine to filter the blood) is sometimes needed for purifying the blood. The loss of kidney function is usually temporary unless the person has had significant kidney disease before the X ray study. The most important form of management is to anticipate and prevent this condition. Commonsense ways to do this include carefully evaluating the need for an X ray test and making sure the person is well hydrated if such testing becomes necessary.

    Medications can also produce sudden loss of kidney function. Certain antibiotics can be especially toxic to the kidney. In addition, drugs used to treat arthritis, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can cause kidney problems with certain diseases such as congestive heart failure, liver failure, and dehydration. NSAIDs seem to reduce the ability of the kidney to regulate its own blood flow. This can result in creating areas of the kidney that do not receive enough blood. Sometimes kidney failure can occur within days. Kidney function is usually checked when these medications are first started in very old people. If no change in kidney function is noted in three weeks, it is unlikely to occur at a later time unless other factors interfere.

    Usually the sudden kidney failure reverses once the medications are stopped. Not all NSAIDs affect the kidney to the same degree, but if a person has had kidney failure caused by these medications, it seems wise to avoid them. In addition to kidney failure, these drugs can cause increased amounts of protein in the urine, an increased potassium in the blood, retention of salt and water, and other forms of kidney damage. They may also reduce the effectiveness of some high blood pressure medications.

Kidney Failure Caused by Dehydration. Many diseases reduce blood flow to the kidney, which in turn decreases the kidney's ability to produce urine (dehydration is one of the most common causes). Elderly people are predisposed to developing salt and water depletion because of age-related changes in the kidney. In addition they are often taking diuretic medications. In the hospital they are not allowed to eat or drink by mouth before having many medical and surgical procedures. Low blood pressure, congestive heart failure, and blood vessel disease involving the kidney and other conditions can worsen the situation.

    For the person who is dehydrated, the treatment involves replacing the lost fluid. If, however, the problem is one of poor circulation, such as congestive heart failure, treatment is directed toward the underlying disease.

Kidney Failure Caused by Severe Muscle Damage. Extreme damage to muscles can cause kidney failure in elderly people. This may develop in a person who is immobilized because of illness or who has fallen and been unable to get up for an extended period of time. During this time, components of the dying muscles are released into the bloodstream and excessive amounts of them can poison the kidney. The treatment involves correcting any dehydration that is present and increasing the urine flow by forcing fluids to help wash the material from the kidney.

Kidney Failure Caused by Obstructed Urinary Flow. In people who are 65 and older, obstruction of urine flow is a frequent cause of kidney failure and therefore must be considered in any elderly person with new or worsening kidney disease. The flow of urine can be blocked either because changes in body structures obstruct the flow or because certain valves within the urinary system do not open properly. In men, an enlarged prostate is by far the most common cause of obstruction. In women, a change in the position of the uterus or uterine or ovarian cancer is a likely cause. Neurological disorders affecting the bladder's ability to contract can cause urinary obstruction in people with diabetes mellitus. Sometimes bladder cancer, enlarged lymph glands, kidney stones, and other conditions obstruct the urinary flow. In addition, medications can cause an obstruction by disrupting delicate neurologic reflexes. A procedure called kidney ultrasound is one way to look for obstruction. This test sends sound waves from a microphone placed on the abdominal wall and uses the echoes to produce pictures of the underlying tissues. This test is especially helpful in kidney disease because it avoids the use of potentially toxic intravenous contrast agents. The treatment of urinary obstruction is often surgery to remove the blockage. Other treatments depend upon the cause of the obstruction.




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