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If you’ve ever passed a kidney stone, you’re not likely to forget the experience-- it can be excruciatingly painful. What’s more, kidney stones (renal lithiasis) are a fairly common disorder. In fact, there’s evidence these stones have plagued humans for millennia -- scientists have found traces of kidney stones in mummies more than 7,000 years old. Today, more than 1 million cases are reported each year in the United States, and that number is steadily increasing. Your chance of passing at least one kidney stone in your lifetime is 10 percent.

Kidney stones often occur when urine becomes too concentrated. This causes minerals and other substances in your urine to form crystals on the inner surfaces of your kidneys. Over time these crystals may combine to form a small, hard, stone-like mass. Sometimes this mass, or stone, breaks off and passes into the ureter, one of the two thin tubes that lead from your kidneys to your bladder.

About 80 percent of stones are a combination of calcium and oxalate (oxalic acid), a substance found in many fruits, vegetables and grains. Most other stones are composed of uric acid, which is a byproduct of protein metabolism. A few are made of struvite and result from urinary tract infections. About 1 percent of stones are composed of the amino acid cystine and occur in people who have an inherited disorder.

Not all kidney stones cause symptoms. In fact, it’s not unusual for stones to be discovered in the kidneys during X-rays for an unrelated problem. They also may be discovered when you seek medical care for blood in your urine, recurring urinary tract infections or a vague pain or ache in your side -- all common symptoms of kidney stones. It’s only when a stone breaks loose and begins to work its way down the ureter that the pain becomes agonizing.

Most kidney stones pass into your bladder without causing any permanent damage. Still, it’s important to determine and treat the underlying cause so that you don’t form more stones in the future.

Fortunately, you may be able to prevent kidney stones simply by making a few dietary changes and increasing the amount of water you drink.



You may not have symptoms unless a kidney stone is large or causes a blockage or infection. Then the most common symptom is an intense, colicky pain that may fluctuate in intensity over a period of 5 to 15 minutes. The pain starts in your back or your side just below the edge of your ribs. As the stone moves toward your bladder, the pain may radiate down to your groin. If the stone stops moving, the pain may stop too. Other signs and symptoms may include:

-Bloody, cloudy or foul-smelling urine

-Nausea and vomiting

-Persistent urge to urinate

-Fever and chills if an infection is present



They’re located in back of your abdomen on either side of your spine. The kidneys are part of a complex system that removes excess fluid and waste from your blood. Other structures in this system include the ureters, bladder and urethra. The ureters are two muscular tubes that carry urine from your kidneys to the bladder-- a chamber in your abdomen where urine is stored. The walls of the bladder stretch to hold urine until you eliminate it from your body through a narrow tube called the urethra.

Each kidney contains more than a million nephrons -- the functional parts of your kidneys. The nephrons manufacture urine as they filter water, salt and waste products from circulating blood.

Some of the substances filtered by your kidneys --especially calcium, oxalate (oxalic acid), uric acid and cystine --have a tendency to form crystals. Other substances, such as citrate and magnesium, help prevent crystal formation. Normally, these substances are in balance.

Sometimes, however, the balance may tip in favor of the elements that form crystals. This can happen when your urine contains too many of these elements or too little of the protective substances.

Crystals also are likely to form if your urine becomes too concentrated or is too acidic or alkaline. These changes in your urine may be caused by a number of factors, including heredity, diet, drugs, climate or lifestyle factors and certain medical conditions.

In some cases, though, the exact cause of kidney stones may never be known (idiopathic nephrolithiasis).

There are four main types of kidney stones, each of which tends to have a different cause. They include:

Calcium stones. Approximately 75 percent to 85 percent of all kidney stones are calcium stones. These stones are usually a combination of calcium and oxalate and may occur if you have too much of either of these substances in your urine. A number of factors can cause high calcium concentrations in urine, including large amounts of vitamin D -- which may cause your body to absorb too much calcium --drugs such as thyroid hormones and diuretics, certain cancers and some kidney conditions. You may also have high levels of calcium if your parathyroid glands, which regulate calcium, are overactive (hyperparathyroidism). In addition, a gene that’s present in some people with calcium stones may cause excess levels of calcium in the urine. You may have increased levels of oxalate if you eat a lot of foods high in this substance or as a result of certain genetic factors. People who have had intestinal bypass operations are also at increased risk of oxalate stones.

Uric acid stones. As the name suggests, these stones are formed of uric acid, a byproduct of protein metabolism. A diet high in meat may cause excess amounts of uric acid in your urine. You also may have high levels of uric acid in your blood and urine if you have gout or are receiving chemotherapy.

Struvite stones. Found mainly in women, struvite stones are almost always the result of urinary tract infections caused by bacteria that secrete specific enzymes. These enzymes increase the amount of ammonia in the urine, which makes up the crystals in struvite stones. These stones are often large and have a characteristic stag’s horn shape that can cause serious damage to your kidneys.

Cystine stones. These stones represent only about 1 percent of kidney stones. They form in people with a hereditary disorder that causes the kidneys to excrete excessive amounts of certain amino acids (cystinuria).



These factors may increase your risk of developing kidney stones:

Family or personal history. If someone in your family has kidney stones, you’re more likely to develop these stones too. And if you’ve already had one or more kidney stones, you’re at increased risk of developing another. The recurrence rate is about 3 percent after the first stone and 6 percent after the second.

Age, gender and race. Most people who develop kidney stones are between 20 and 40 years of age. Men are more likely to develop kidney stones than women are, although for unknown reasons the number of women with kidney stones is increasing. In addition, Caucasians are at higher risk of kidney stones than blacks in America.

Certain diseases. Rare, inherited diseases such as renal tubular acidosis and cystinuria can increase your risk of kidney stones. So can more common disorders such as gout, chronic urinary tract infections, high blood pressure (hypertension), cystic kidney disease and hyperparathyroidism.

Certain medications. Taking certain types of water pills (diuretics), some thyroid medications or calcium-based antacids (Tums, Alka-Seltzer, Rolaids) may increase your risk of forming kidney stones. On the other hand, thiazide diuretics may help lessen the chance of stone formation. A single kidney. Although most people have two kidneys, approximately 1 in every 1,500 babies is born with only one kidney. Many people live full healthy lives with a single kidney, but they do have an increased risk of kidney stones.

Diet. A diet that’s high in protein (meat, chicken, fish) and low in fiber (fruits, vegetables and whole grains) may increase your risk of some types of kidney stones.

A lack of fluids. If you don’t drink enough fluids, especially water, your urine is likely to have higher concentrations of substances that form stones. That’s also why you’re more likely to develop kidney stones if you live in a hot, dry climate, work in a hot environment such as a commercial kitchen or exercise strenuously and don’t replenish lost fluids.

Limited activity. You’re more prone to develop kidney stones if you’re bedridden or very sedentary for a period of time. That’s because limited activity can cause your bones to release more calcium.




Although stones that don’t cause symptoms (silent stones) may be discovered during a routine medical exam, the majority of kidney stones are diagnosed when a person complains of severe kidney pain, chronic urinary tract infections or blood in the urine. If your doctor suspects you have kidney stones, he or she will likely request a chemical analysis of your blood and a 24-hour collection of urine. You also may have X-rays or ultrasound-- a diagnostic technique that combines high-frequency radio waves and computer processing to view internal organs. In some cases your doctor may recommend an X-ray known as intravenous pyelography (IVP) or an excretory urogram to look for stones that don’t show up on traditional X-rays. In this test a contrast dye is injected into a vein in your arm. A series of X-rays is taken as the dye moves through your kidneys, ureters and bladder. If any abnormalities show up on the X-ray, your doctor may follow up with a computerized tomography (CT) scan ½ a test that uses a series of thin X-ray beams to produce two-dimensional images of your organs.

If you’re in extreme pain, you may have a spiral CT scan. Not only can this scan check your entire abdomen in just 3 minutes, it also can reveal the presence of very small stones and uric acid stones that don’t show up on conventional X-rays. If you’re about to pass a stone, your doctor may ask you to urinate through a strainer so that the stone can be recovered and analyzed. The right treatment and preventive measures depend on knowing what type of kidney stone you have.



If a stone stays inside one of your kidneys, it usually doesn’t cause a problem unless it becomes so large it blocks the flow of urine. This can cause pressure and pain, along with the risk of severe kidney damage, bleeding and infection. Smaller stones may block the thin tubes that connect each kidney to your bladder (ureters) or the outlet from the bladder itself. These stones may cause ongoing urinary tract infection or kidney damage.




Treatment for kidney stones varies, depending on the type of stone and the cause. You may be able to move a stone through your urinary tract simply by drinking plenty of water ½ as much as 2 to 3 quarts a day-- and by staying physically active.

Stones that can’t be treated with more conservative measures --either because they’re too large to pass on their own or because they cause bleeding, kidney damage or ongoing urinary tract infection--may have to be surgically treated. Surgical procedures include:

Extracorporeal shock wave lithotripsy (ESWL). This is the most commonly used surgical procedure for kidney stones. It uses shock waves to break the stones into small crystals that are then passed in your urine. In some cases you may be partially submerged in a tub of water during the procedure. In others, you may lie on a soft cushion. You won’t be hurt by the shock waves, and you won’t feel them. But a loud noise is produced each time a shock wave is generated, and you’ll wear earphones to protect your hearing.

Your doctor will likely use X-rays or ultrasound to help determine the position of your stone as well as to monitor the status of the stone during treatment. In many cases the stone will begin to crumble after 200 to 400 shock waves.

Complications that may occur with ESWL include blood in the urine, bruising on the back or abdomen and discomfort as the stone fragments pass through the urinary tract. In addition, if the stone doesn’t shatter completely, you may need another treatment such as a second ESWL or ureteroscopic stone removal. After treatment it may take months for all the stone fragments to pass.

Percutaneous nephrolithotomy. When ESWL isn’t effective, or the stone is very large, your surgeon may remove your kidney stone through a small incision in your back using an instrument known as a nephroscope. Sometimes the stone may first need to be broken into pieces.

Ureteroscopic stone removal. Your surgeon may use this procedure to remove a stone lodged in one of the thin tubes leading from your kidneys to your bladder (ureter). He or she does this by passing a small instrument known as a uretoscope through your bladder into the ureter. The stone is then snared and removed. It may also be shattered using ultrasound, a laser or a technique known as electrohydraulic lithotripsy. These work especially well on stones in the ureter that can’t be treated using other methods. Parathyroid surgery. Some calcium stones are caused by overactive parathyroid glands, which are located on the four corners of your thyroid gland, just below your Adam’s apple. When these glands produce too much parathyroid hormone, your body’s level of calcium can become too high. Most often, this is the result of a small benign tumor in one of the four glands, which can be surgically removed.



In many cases you can prevent kidney stones by increasing the amount of liquid you drink and making a few changes in your diet. If these measures aren’t effective and blood and urine tests reveal you’re currently forming stones or the stones you have are get- ting bigger, your doctor may prescribe certain medications.

Lifestyle changes

If you have a history of kidney stones, it’s usually recommended that you pass at least 2 1/2 quarts of urine a day. To do this, you need to drink about 3 1/2 quarts (14 cups) of fluids. You also need to increase the amount of liquid you consume if you live in a hot, dry climate. Although most liquids count, water is best. Lemonade is

also a good choice -- the citrate in lemonade helps prevent stones from forming. In addition, if you tend to form calcium stones-a combination of calcium and oxalate-- your doctor may recommend restricting foods rich in oxalates. These include meats (especially organ meats such as liver and kidneys), chicken, fish (especially herring and anchovies), asparagus, berries, chocolate, cooked spinach, Swiss chard and rhubarb.

But there is disagreement about whether you should restrict your intake of calcium. In fact, researchers have found that women

with the highest calcium intake were less likely to develop kidney stones than women who ate the least amount of calcium. Why?

Researchers note that dietary calcium binds with oxalates in the gastrointestinal tract so that oxalates can’t be absorbed from the

intestine and excreted by the kidney to form stones.

Calcium supplements may not have the same protective effect, however, if they’re not taken with meals. When taken on an empty

stomach, the calcium can’t bind with the oxalates in food.



In general, kidney stone medications control the level of acid or alkaline in your urine. The type of medication your doctor pre- scribes will depend on the kind of kidney stone you have. These may include:

Calcium stones. To help prevent calcium stones from forming, your doctor may prescribe a thiazide diuretic or a phosphate-con- taining preparation. If you have calcium stones because of a condition known as renal tubular acidosis, your doctor may suggest taking sodium bicarbonate or potassium bicarbonate.

Uric acid stones. Your doctor may prescribe allopurinol (Zyloprim) and a medicine to keep your urine alkaline. In some cases allopurinol may also dissolve the uric acid stones.

Struvite stones. To prevent struvite stones, the first goal is to keep urine free of bacteria that cause infection. In some cases, your doctor may prescribe the drug acetohydroxamic acid (Lithostat) in addition to antibiotics.

Cystine stones. Cystine stones are the hardest stones and the most difficult to treat. Your doctor may prescribe certain medications when all other approaches have failed.


Additional Resources

National Institute of Diabetes and Digestive and Kidney Diseases

National Kidney Foundation


January 26, 2001

© 1998-2002 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these mate

rials may be reprinted for noncommercial personal use only. “Mayo,” “Mayo Clinic,” “,” “Mayo Clinic Health Information,” “Sharing our Tradition of Trusted Answers” and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.



Your kidneys are two bean-shaped organs about the size of your fist. They’re located at the back of your upper abdomen on either side of your spine. The kidneys’ main function is to eliminate excess fluid and waste material from your blood, but they also pro- duce hormones that help regulate your blood pressure, make red blood cells and form bone.

Normally, your kidneys perform all these tasks flawlessly. But sometimes the kidneys lose their ability to filter fluids and waste, causing dangerous levels of these substances to accumulate in your body. This condition is known as kidney (renal) failure.


There are three types of kidney failure: acute, chronic and end-stage renal disease. Acute kidney failure occurs suddenly, often after complicated surgery or severe injuries (trauma), as a result of some infectious diseases or when blood vessels leading to the kidneys become blocked.

Chronic renal failure usually develops slowly, with few symptoms in the early stages. In fact, many people with chronic renal failure don’t have symptoms until their kidney function has decreased to less than 25 percent of normal. High blood pressure and diabetes-- a disorder that causes high levels of sugar in the blood -- are the most common causes of chronic renal failure.

In end-stage renal disease, the kidneys function at only 5 percent to 10 percent or less of normal capacity. At this point they’re simply not able to sustain life. People with end-stage renal failure need either dialysis or a kidney transplant to stay alive. When a transplant isn’t possible-- often because of poor general health--- dialysis becomes the only option. More than 300,000 people in the United States receive long-term dialysis therapy, and about 60,000 Americans live with a functioning kidney transplant.



The signs of kidney failure vary, depending on whether the failure is acute or chronic.

Acute kidney failure

Acute kidney failure occurs when the kidneys suddenly stop filtering waste products from your blood. The signs and symptoms

may include:

-              Fluid retention

-              Bleeding in the stomach or intestines

-              Confusion

-              Seizures

-              Coma


Chronic kidney failure

Chronic kidney failure develops slowly and often imperceptibly, yet it can affect almost every system in your body. Over time,

chronic kidney failure can lead to congestive heart failure , weak bones, stomach ulcers and damage to the central nervous system.

Unfortunately, signs and symptoms often don’t appear until irreversible damage has occurred. They include:

-              Abnormal urine tests

-              High blood pressure

-              Unexplained weight loss

-              Anemia

-              Nausea or vomiting

-              Malaise or fatigue

-              Headaches that seem unrelated to any cause

-              Decreased urine output

-              Decreased mental sharpness

-              Muscle twitches and cramps

-              Bleeding in the intestinal tract

-              Yellowish-brown cast to the skin

-              Unusual itching

-              Sleep disorders


End-stage renal disease

For some people, end-stage renal disease is the final result of chronic kidney failure. At this point, kidney function is so poor that

either dialysis or kidney transplantation is needed to sustain life. A number of complications may develop with end-stage renal

disease, depending on how rapidly it occurs, including:

-              Anemia in all cases

-              High blood pressure

-              Congestive heart failure

-              Bone disease

-              Digestive tract problems

-              Loss of mental functioning (dementia)



Your kidneys are part of a complex system that removes excess fluid and waste material from your blood. Blood enters your kidneys through the renal arteries, which are branches of the aorta, the main artery leading from your heart. From there, blood moves through structures known as nephrons, which are the functional units of your kidneys. Each kidney contains more than a million nephrons. A nephron consists of a tuft of small capillary blood vessels (glomerulus) and tiny tubules that lead into larger collecting tubes. The glomerulus filters fluid from your bloodstream.

The filtered material -- which contains both waste products and substances vital for your health -- passes into the tubules. From there, waste byproducts such as urea, uric acid and creatinine are excreted in your urine while sugar, protein, calcium and salts are absorbed back into your bloodstream.

Most of the time this elegant filtration system works perfectly -- in fact you can easily live a normal life span with one normal kidney. But problems can occur if the tubules or glomeruli are damaged or diseased. Many factors can damage your kidneys, including kidney disease, injury, high blood pressure, exposure to toxins and certain medications, kidney stones, tumors and even infections in other parts of your body. Many of these may cause no signs or symptoms until irreparable damage has occurred.

Acute renal failure

Factors that can cause your kidneys to suddenly shut down include:

Complicated surgery, severe burns or trauma. Forty percent to 50 percent of all cases of acute kidney failure are related to surgery or trauma that involves severe bleeding, dehydration or shock. In these cases, acute kidney failure often results from a drastic

drop in blood pressure that prevents enough blood from reaching your kidneys. In addition, when muscles are crushed in severe

injuries, they release a molecule called myoglobin that lodges in the kidney’s tubules, blocking the flow of urine.

Renal ischemia. One of the most common causes of acute kidney failure, renal ischemia occurs when an obstructed or constricted blood vessel prevents your kidneys from getting enough blood.

-              Drugs. A number of substances can be toxic to your kidneys. These include contrast dyes used in tests such as arteriography.

An arteriography is used to diagnose conditions such as coronary artery disease, stroke and aneurysms. Contrast dyes are most likely to cause acute renal failure in people with diabetic kidney disease. Certain antibiotics-- especially streptomycin or gentamicin (Garamycin) -- and common pain medications, such as aspirin and ibuprofen (Motrin, Nuprin, Advil), can also damage the kidneys. Pain medications have the potential to cause acute kidney failure even in healthy people who use them regularly. Antibiotics pose a greater risk of acute renal failure if you already have liver or kidney disease, are older or use diuretics or other drugs that affect your kidneys.

-Toxins. Exposure to toxic substances, including excessive amounts of alcohol, heavy metals -- such as lead -- and solvents -such as carbon tetrachloride -- can lead to acute kidney failure.

Heat stroke and severe exercise. Both heatstroke -- a condition that occurs when your body isn’t able to deal with heat stress -and extreme exercise may occasionally lead to acute kidney failure. Severe dehydration usually plays a major role in these cases.

-              Multiple organ failure. In some people, acute kidney failure occurs as part of multiple organ failure in which the heart, lungs, liver, brain and kidneys may totally or partially shut down. This is most often the result of major trauma or serious systemic infection (sepsis).

-              Obstructed urine flow. This may be due to a narrowing of the urinary tract, a tumor or, rarely, chronic enlargement of the prostate. A sudden release of cholesterol-containing material. This material can come from an ulcerated plaque (a buildup of fatty deposits) in the wall of an artery.

-              Hemolytic uremic syndrome (HUS). HUS is a complex condition caused by certain strains of Escherichia coli (E. coli) bacteria. It’s the leading cause of acute kidney failure in infants and young children. This condition occurs less often in older children and rarely strikes adults.

-              Kidney disease (nephritis). Diseases such as interstitial nephritis -- an inflammation of the spaces between the glomeruli and tubules -- can sometimes lead to acute kidney failure.


Chronic renal failure

Unlike acute kidney failure, chronic kidney failure slowly destroys your kidney’s nephrons over a period of years. Many factors may lead to chronic kidney failure, including:

Diabetes mellitus . Type 1 diabetes, once known as insulin-dependent diabetes mellitus, is a leading cause of chronic kidney failure, accounting for 35 percent of new cases each year in the United States. Approximately 5 percent to 10 percent of people who have had type 2 diabetes, once known as non-insulin-dependent diabetes mellitus, for at least 20 years will also develop kidney disease. Yet because so many people have type 2 diabetes, it accounts for a very large number of cases of chronic renal failure.

Analgesic nephropathy. This condition may result from the long-term use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin, Nuprin, Advil) and indomethacin (Indocin). Large amounts of acetaminophen (Tylenol, Panadol) also may harm the kidneys, especially in children.

Kidney diseases. These include clusters of cysts in the kidneys (polycystic kidney disease), kidney infection (pyelonephritis) and a condition that causes your kidneys to leak protein into your urine (glomerulonephritis).

Renal artery stenosis. This is a blockage of the renal artery before it enters your kidney. In older adults, blockages often result when fatty deposits accumulate under the lining of the artery walls (atherosclerosis). Renal artery stenosis can also affect young women who have a condition known as fibromuscular dysplasia, which causes the walls of the arteries to become thicker. Both these conditions are almost always associated with high blood pressure.

High blood pressure (hypertension). Untreated high blood pressure can cause chronic renal failure.

-Toxins. Long-term exposure to fuels and solvents, such as carbon tetrachloride, can lead to chronic kidney failure.

Lead poisoning. Ongoing exposure to lead -- in lead-based paint, lead pipes, soldering materials, jewelry and even alcohol distilled in old car radiators --can lead to chronic renal failure.

End-stage renal disease

Diabetes mellitus is the most common cause of end-stage renal disease in the United States. Other causes of end-stage renal disease include:

-              Vesicoureteral reflux. This urinary tract problem is one of several causes of end-stage renal failure in children and young adults

Kidney disease. Polycystic kidney disease , an inherited disorder, may cause only mild symptoms in some adults, but it can lead to end-stage renal failure in others. Some people may have kidney cysts-- a benign condition that’s unrelated to polycystic kidney disease and which usually causes no problems. Other kidney diseases that may lead to end-stage renal failure include glomerulonephritis and congenital nephrotic syndrome -- an inherited disorder that may cause death in the first year of life.



Diabetes is the single greatest risk factor for kidney disease in the United States. Other medical conditions that increase your risk for kidney failure include untreated high blood pressure (hypertension), sickle cell disease, lupus erythematosus, atherosclerosis, chronic glomerulonephritis, congenital nephrotic syndrome and polycystic kidney disease.

In addition, drug overdose, excessive use of alcohol, long-term use of pain medications such as aspirin, acetaminophen (Tylenol, Panadol) and ibuprofen (Motrin, Nuprin, Advil) and treatment with the antibiotics streptomycin or gentamicin (Garamycin) can make you more vulnerable to kidney failure. So can ongoing exposure to toxic substances such as gasoline, solvents or heavy metals.

Experiencing severe injuries or burns to your body or undergoing complicated surgery increases your risk of acute kidney failure. African Americans are at high risk for high blood pressure




If you have a chronic medical condition (diabetes, hypertension, glomerulonephritis) that puts you at increased risk for chronic kidney failure, your doctor will carefully monitor your blood pressure and kidney function with urine and blood tests during regu- larly scheduled office visits. Call your doctor right away if you experience any of the signs and symptoms of chronic kidney failure between visits. These may include decreased urination, unexplained weight loss, nausea or vomiting, fatigue, headaches or a yellowish-brown cast to your skin.

Even if you have no risk factors for kidney failure, see your doctor immediately if you notice that you’re urinating more or less than usual or see any blood in your urine.



If you have diabetes, your doctor will likely schedule an annual test to measure small amounts of protein in your urine (microalbuminuria). This test can screen for early kidney damage related to diabetes (diabetic nephropathy).

If your doctor suspects acute or chronic kidney failure, he or she will order urine and blood tests to check for chemical abnormalities such as increased levels of urea and creatinine. You also may have an X-ray to check for fluid in your lungs (pulmonary edema) as well as tests to rule out other possible causes for your signs and symptoms, such as a urinary tract infection.To con- firm a diagnosis of kidney failure, you may have an ultrasound examination -- a test that uses high-frequency sound waves and computer technology to generate images of your kidneys. Ultrasound scans are painless and usually take less than 30 minutes. You also might have a computerized tomography (CT) or magnetic resonance imaging (MRI) scan. CT scans use computers to create more detailed images than conventional X-rays. CT scans are painless and take about 10 minutes. MRI scans use magnetic fields and radio waves to generate cross-sectional pictures of your body.

In some cases, your doctor may recommend a renal biopsy. In this test, a small sample of kidney tissue is removed through a needle that’s inserted in your back under local anesthesia. The sample is then sent to a laboratory to be analyzed.

End-stage renal disease is diagnosed when blood tests consistently show very high levels of urea and creatinine -- a sign that kid- ney function has been severely and permanently damaged.



Chronic kidney failure can affect almost every part of your body. Potential complications may include:

-              Fluid retention. This may lead to swollen tissues, congestive heart failure or fluid in your lungs (pulmonary edema).

-              A sudden rise in potassium levels. This could impair your heart’s function and may be life-threatening.

-              Weak bones that fracture easily

-              Anemia

-              Stomach ulcers

-              Changes in skin color

-              Damage to the central nervous system

-              Insomnia


Complications in children

One of the most serious complications affecting children with chronic kidney failure is the failure to grow. In addition to regulating fluids and ridding the body of waste, the kidneys help produce red blood cells and metabolize human growth hormone. They also regulate the interactions of calcium and vitamin D, both of which are essential for bone growth.


Complications during pregnancy

Women with chronic kidney failure who become pregnant face a number of potential complications. That’s because the kidneys must work especially hard to deal with the extra fluids of pregnancy. This may lead to worsening high blood pressure and an increase in the amount of waste products circulating in the blood. These changes affect both mother and baby. Chronic high blood pressure means the baby receives less blood through the placenta, which can seriously affect growth. And waste products in the mother’s bloodstream may harm the baby’s health. In addition, pregnant women with chronic kidney failure are at high risk for preeclampsia, a serious condition of late pregnancy.

Preeclampsia causes a dangerous rise in blood pressure. If not treated, it can lead to hemorrhages in the brain, liver or kidneys and ultimately may be fatal for both mother and baby.



Treatment for kidney failure varies, depending on whether the problem is acute, chronic or end-stage.


Acute kidney failure

Not all people with acute kidney failure regain normal kidney function. At greatest risk are those who have existing medical problems such as lung or heart disease, have recently had a stroke or develop acute kidney failure following surgery or a severe accident. Yet in many cases, acute kidney failure can be reversed.

The first goal is to treat the illness or injury that originally damaged your kidneys. Once that’s under control, the focus will be on preventing excess fluids and wastes from accumulating in your blood while your kidneys heal. This is best accomplished by limiting the amount of fluids you drink and following a high-carbohydrate, low-protein, low-potassium diet.

Your doctor will also likely prescribe medications such as calcium, glucose or sodium polystyrene sulfonate (Kayexalate) to prevent high levels of potassium from accumulating in your blood. Sometimes you may also have dialysis to help remove toxins and excess fluids from your body while your kidneys are healing.


Chronic kidney failure

Chronic kidney failure has no cure, but treatment can help control symptoms, reduce complications and slow the progress of the disease. The first priority is controlling the condition causing the kidney failure and its complications. If you have diabetes or high blood pressure (hypertension), for instance, that means carefully following your doctor’s recommendations for diet and exercise and taking any medications as directed. In addition, following a proper diet is extremely important for treatment of kidney failure itself. Restricting the amount of protein you eat may help slow the progress of the disease. It can also help ease symptoms such as nausea, vomiting and lack of appetite. You’ll likely need to limit the amount of salt you eat to help control high blood pressure and carefully regulate your water intake. Over time, you may also need to restrict the amount of potassium and phosphorous you consume. In addition, your doctor may prescribe blood pressure medications known as angiotensin-converting enzyme (ACE) inhibitors to slow the rate of kidney decline. Your doctor also may prescribe certain medications to help deal with complications. Severe anemia may require erythropoietin, a hormone drug normally produced by your kidneys that stimulates the bone marrow to produce red blood cells. You also may take a form of vitamin D to help prevent bone disease.


End-stage renal disease

By the time end-stage renal disease develops, the conservative measures used to treat chronic kidney failure --diet, medications and controlling the underlying cause and complications -- are no longer enough. The kidneys aren’t able to support life on their own, and dialysis or a kidney transplant becomes the only option. The exact point at which these are needed varies from person to person. In most cases doctors will try to manage chronic kidney failure as long as possible because both dialysis and transplantation present serious risks and can be life-threatening. Eventually, however, a time may come when the benefits outweigh the risks. Dialysis is an artificial way of removing waste products and extra fluid from the blood when your kidneys aren’t able to do so on their own. It’s not a miracle cure, and it presents significant risks, including infection and malnutrition. Still, it can help prolong life for people with end-stage renal disease.

There are several different types of dialysis. They include:

Hemodialysis. The most common form of dialysis is known as hemodialysis. It removes extra fluids, chemicals and wastes from your blood by filtering it though an artificial kidney (dialyzer). Blood is pumped from your body to the artificial kidney through an access point that’s created surgically, usually in your arm or leg. Inside the artificial kidney, your blood moves across membranes that filter out wastes. Less than 1 cup of blood is outside your body at any one time. Most people on dialysis require approximately 12 hours of dialysis each week. This is often divided into three sessions.

Peritoneal dialysis. Instead of filtering your blood through a machine, this type of dialysis uses the vast network of tiny blood vessels in your own abdomen (peritoneal cavity) to filter your blood. First, a small, flexible tube (catheter) is implanted into your abdomen. Then, dialysis solution is infused into and drained out of your abdomen for as long as necessary to remove waste and excess fluid.

Continuous ambulatory peritoneal dialysis (CAPD). You perform this type of dialysis yourself at home, exchanging the dialysis solution in your abdomen four times a day, 7 days a week. The exchanges are spaced throughout the day. Continuous cycling peritoneal dialysis (CCPD). In this type of dialysis, a machine (cycler machine) automatically infuses dialysis solution into and out of your peritoneal cavity over a period of 10 to 12 hours while you sleep. If you’re age 80 or younger (some European countries perform kidney transplants on people up to age 85) and have no other serious medical conditions, a kidney transplant is usually a better option than dialysis because it provides a healthier and better quality of life. But you may need dialysis until a suitable kidney donor can be found.

The actual kidney operation isn’t an especially complicated procedure. What is often much more difficult is finding the right donor. The more compatible the donor is with your blood type, cell surface proteins and antibodies, the less likely your body is to reject the new kidney. A sibling is likely to be the best donor. But you may not have siblings, or they may not qualify for various reasons. In that case, another blood relative, such as a parent, aunt, uncle or cousin, may be considered. When a living donor isn’t available, tissue-typing centers throughout the country may search for a kidney from an accident victim or other person who has offered to donate organs after his or her death.



In many cases it may be impossible to prevent kidney failure. But you may reduce your risk by following these suggestions:

-              Don’t abuse alcohol or other drugs, including over-the-counter pain medications such as aspirin, acetaminophen (Tylenol, Panadol) and ibuprofen (Motrin, Nuprin, Advil).

-              Avoid long-term exposure to heavy metals, such as lead, as well as solvents, fuels and other toxic substances.

If you have a chronic medical condition, such as diabetes or hypertension, that increases your risk of kidney failure, carefully follow all your doctor’s recommendations for managing your condition.

If you have chronic kidney failure and are thinking of becoming pregnant, consider a pre-pregnancy consultation with a knowledgeable obstetrician or nephrologist to discuss your risks.

-              If you’re already pregnant, be sure to get comprehensive medical care -- including prenatal visits every 2 weeks for at least the first 32 weeks.



If you have kidney failure, your doctor may ask you to limit the amount of fluids you consume every day. In most cases, limiting fluids means more than reducing the amount of water you drink. It may include cutting back on your consumption of such things as ice cubes and ice chips, coffee and tea, sodas, fruit and vegetable juices, soups, milk, cream, ice cream, sherbets, sorbets, popsicles and even gelatin.

When you limit liquids, you may have a hard time controlling your thirst. The following suggestions may help you feel less thirsty:

-              Suck on a lemon wedge or a few ice chips.

-              Rinse your mouth with water but don’t swallow it.

Eat sour candy or chew gum to increase the moisture level in your mouth. Be sure to choose sugar-free types if you have diabetes.


Additional Resources

National Institute of Diabetes and Digestive and Kidney


National Kidney Foundation



January 26, 2001

© 1998-2002 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these mate- rials may be reprinted for noncommercial personal use only. “Mayo,” “Mayo Clinic,” “,” “Mayo Clinic Health Information,” “Sharing our Tradition of Trusted Answers” and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.




The term urinary tract infection (UTI) is used to describe an infection that begins in the urinary system. UTIs can be painful and annoying. They can also become a serious health problem if the infection spreads to the kidneys.

Women are most at risk of developing a UTI. In fact, 1 in 5 women will develop one during her lifetime, and many will have more than one. Young girls -- as well as men-- also are at risk of developing UTIs.

The urinary system is composed of the kidneys, ureters, bladder and urethra. All play a different role in removing waste from the body.

The kidneys, a pair of bean-shaped organs in your upper abdomen, filter waste from the blood. Tubes called ureters carry urine (fluid excreted by the kidneys) to the bladder, where it is stored until it exits the body through the urethra. All of these components can become infected, but most infections involve the lower tract (the urethra and the bladder).

Different types of UTIs are given different names, depending on which part of the urinary tract is affected. They include:

-              Pyelonephritis. This is an infection of the kidneys. It often occurs when infection spreads to the kidneys and the ureters from the


-              Cystitis . This is an infection of the bladder.

-              Urethritis. This is an infection of the urethra.



Not everyone with a UTI will develop symptoms, but most people have some. They can include:

-              A strong persistent urge to urinate

-              A burning sensation when urinating

-              Passing frequent, small amounts of urine

-              Blood in the urine (hematuria) or cloudy, strong-smelling urine

There are more specific signs and symptoms for each type of UTI. In addition to the symptoms listed above you may experience the following:

-              Acute pyelonephritis may cause flank pain, high fever, shaking chills and nausea or vomiting.

-              Cystitis may result in pressure in the lower abdomen and strong-smelling urine.

-              Urethritis may lead to pus in the urine. In men, urethritis may cause penile discharge.



Urinary tract infections typically occur when bacteria enter the urinary tract from the outside, usually through the urethra, and begin to multiply. The urinary system is uniquely designed to keep out such microscopic invaders. Urine also has antibacterial properties that inhibit the growth of bacteria. However, certain factors increase the chances that bacteria will take hold and multi- ply into a full-blown infection.

Cystitis commonly occurs in women as a result of sexual intercourse. But even sexually inactive girls and women are susceptible to lower urinary tract infections because the anus, a constant source of bacteria, is so close to the female urethra. More than 90 percent of cystitis cases are caused by Escherichia coli (E. coli) , a species of bacteria commonly found in the rectal area.

In urethritis the same organisms that infect the kidney and bladder can infect the urethra. In addition, because of the female urethra’s proximity to the vagina, sexually transmitted infections such as the herpes simplex virus and chlamydia are also possible.

In men urethritis often is the result of bacteria acquired through sexual contact. The vast majority of such infections are caused by gonorrhea and chlamydia .



Some people appear to be more likely than others to develop UTIs. Women are one such group. Up to 20 percent will develop a bladder infection over a lifetime. A key reason is their anatomy. Women have a shorter urethra than men have, which cuts down on the distance bacteria must travel to reach the bladder.

Women who are sexually active tend to have more UTIs because sexual intercourse can result in bacteria being pushed into the urethra. Studies have also shown that women who use diaphragms for birth control may be at higher risk. After menopause UTIs may become more common because tissues of the vagina, urethra and the base of the bladder become thinner and more fragile due to loss of estrogen.

Other risk factors include anything that impedes the flow of urine, such as an enlarged prostate or a kidney stone. Changes in the immune system, which can occur with conditions like diabetes, also can increase the risk of UTIs. So can the prolonged use of bladder catheters, which may be needed by the chronically ill or older adults.

New research funded by the National Institutes of Health suggests that a woman’s blood type may play a role in her risk of recur- rent UTIs. Bacteria may be able to attach to cells in the urinary tract more easily in those with certain blood factors. But more research is needed to determine whether an association exists and whether it could be useful in identifying people at risk of recur- rent UTIs.


If you have any symptoms of a urinary infection, contact your physician as soon as possible. If a UTI is suspected, your physician will most likely ask for a urine sample to determine if bacteria are present in your urine. A urinalysis, sometimes followed by a urine culture, can reveal whether you have an infection. Although no simple test can differentiate between an upper and lower urinary tract infection, the presence of fever and flank pain may indicate that the infection involves the kidneys.



When treated promptly and properly, UTIs rarely lead to complications. But if they are left untreated, a lower urinary tract infection can become something more serious than a set of uncomfortable symptoms.

Untreated UTIs can lead to potentially life-threatening complications, such as acute or chronic pyelonephritis, which could permanently damage your kidneys. Young children and older adults are at the greatest risk of kidney damage due to UTIs because their symptoms are often overlooked or mistaken for other conditions.

Women who have UTIs while pregnant may also have an increased risk of delivering low birth weight or premature infants .



Antibiotics are the first line of treatment for most UTIs. Which drugs are used and for how long depends on your health condition and the bacteria found in your urine tests. Drugs most commonly recommended for simple UTIs include amoxicillin (Amoxil, Trimox, Wymox), nitrofurantoin (Macrodantin), sulfamethoxazole (Bactrim, Septra) and trimethoprim (Trimpex). Make sure your doctor is aware of any other drugs you are taking or any allergies you might have. This will help him or her select the best treat- ment.

Usually, UTI symptoms clear up within a few days of treatment. But you’ll likely need to stay on antibiotics for a week or more. Indeed, it’s important to take the entire course of antibiotics recommended by your doctor to ensure that the infection is completely eradicated. For an uncomplicated UTI that occurs when you’re otherwise healthy, your doctor may recommend a shorter treatment with a double-strength version of a prescription drug. But this will depend on your particular symptoms and history. If you have recurrent UTIs, your doctor may recommend longer antibiotic treatment or refer you to a urologist or nephrologist for an evaluation to see if urologic abnormalities may be causing the infections. If abnormalities of the urinary tract are not to blame, taking a single dose of antibiotic each time after sexual intercourse may be helpful.

For severe UTIs hospitalization and treatment with intravenous antibiotics may be required. When recurrences are frequent or a kidney infection becomes chronic, it’s important to have a urologic evaluation because an underlying physical problem may require treatment.



You can take steps to reduce the risk of bladder infections. Women, in particular, may benefit from the following:

-              Drink plenty of liquids, especially water. Cranberry juice may have infection-fighting properties.

-              Urinate frequently, and avoid retaining your urine for a long time after you feel the urge to void.

-              Wipe from front to back after a bowel movement to prevent bacteria in the anal region from spreading to the vagina and urethra.

-              Take showers rather than tub baths.

-              Wash the skin around the vagina and anus daily.

-              Empty your bladder as soon as possible after intercourse, and drink a full glass of water to help flush bacteria.

-              Avoid using deodorant sprays or feminine products such as douches in the genital area that could irritate the urethra.




UTIs can be painful, but you can take steps to ease your discomfort until antibiotics clear the infection. Sometimes a heating pad placed over the abdomen can help minimize feelings of stomach pressure or pain. It’s also a good idea to avoid coffee, alcohol, soft drinks with caffeine, citrus juices and spicy foods until you have finished a course of antibiotics. These items can irritate the bladder and aggravate the frequent or urgent need to urinate.

If recurrent bladder infections are a problem, make sure your physician is aware of this. Together, you can develop a strategy to reduce recurrences and the discomfort they can bring into your life.


Additional Resources

National Institute of Diabetes and Digestive and Kidney Diseases

American College of Obstetricians and Gynecologists

National Women’s Health Resource Center


January 26, 2001

© 1998-2002 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these mate- rials may be reprinted for noncommercial personal use only. “Mayo,” “Mayo Clinic,” “,” “Mayo Clinic Health Information,” “Sharing our Tradition of Trusted Answers” and the triple-shield Mayo logo are trademarks of Mayo Foundation for


Medical Education and Research.






*ED is the same thing as impotence and means that a man is not able to get or keep an erection firm enough for successful sexual intercourse

*If you have ED, it does not mean that you are unable to have an orgasm or have a decreased sex drive, or have premature ejaculation

*When erectile dysfunction proves to be a pattern or a persistent problem, it can interfere with a man’s self-image as well as his and his partner’s sexual life. Erectile dysfunction may also be a sign of a physical or emotional problem that requires treatment.

*Erectile dysfunction was once a taboo subject, but more men are seeking help. Doctors are gaining a better understanding of what causes erectile dysfunction and are finding new and better treatments.



*Overall, between 10 and 30 per cent of men of all ages will suffer from ED on an ongoing or recurring basis

*Most men will experience the problem at some stage in their lives. The incidence of ED increases with age


Physical causes



Physical causes account for many cases of erectile dysfunction and may include:

*Nerve damage from longstanding diabetes (diabetic neuropathy)

*Cardiovascular disorders affecting the blood supply to the pelvis

*Certain prescription medications

*Operations for cancer of the prostate

*Fractures that injure the spinal cord

*Multiple sclerosis

*Hormonal disorders

*Alcoholism and other forms of drug abuse

In fact, erectile dysfunction may be one of the first signs of an underlying medical problem.


Nonphysical causes

Nonphysical causes may account for impotence. They may include:

*Psychological problems. The most common nonphysical causes are stress, anxiety and fatigue. Impotence is also an occasional side effect of psychological problems such as depression.

*Negative feelings. Feelings that you express toward your sexual partner or that are expressed by your sexual partner such as resentment, hostility or lack of interest also can be a factor in erectile dysfunction.

*Men who suffer from ED due to a physical problem, often have a psychological reaction to it such as depression or loss of selfesteem. This is a normal reaction and should not be confused with psychological ED

Is ED a normal part of aging?

*ED is more common in older men, however, difficulty in maintaining an erection is NOT a normal part of aging



In some cases, yes. Reducing stress, or sharing concerns with your partner or doctor can help psychological ED. Physical ED can be avoided by following a sensible diet and lifestyle that includes cutting back on alcohol and smoking. Diabetics must control their blood sugar levels within normal ranges

Although most men experience episodes of erectile dysfunction from time to time, you can take these steps to decrease the likelihood of occurrences:

*Limit or avoid the use of alcohol and other similar drugs.

*Stop smoking.

*Exercise regularly.

*Reduce stress.

*Get enough sleep.

*Deal with anxiety or depression.

*See your doctor for regular checkups and medical screening tests.



*An occasional loss of erection is nothing to worry about. But if it happens consistently, you should see your family doctor who may recommend treatment or refer you to a specialist

*If you are experiencing signs of ED, take a few minutes to answer the questions at the end of this brochure and make an appointment with your family doctor. Tear off the perforated question sheet and take it to your appointment




Because there are a variety of causes for ED, there are several different tests your doctor may use to diagnose the condition and determine its cause. Only after the cause of ED is determined can it be effectively treated.


Before ordering any tests, your doctor will review your medical history and perform a thorough physical examination. The doctor will also “interview” you about your personal and sexual history. Some of these questions will be very personal and may feel intrusive. However, it is important that you answer these questions honestly. The questions asked may include:

*What medications or drugs are you currently using? This includes prescription drugs, over-the-counter drugs, herbal supplements, dietary supplements and illegal drugs.

*Have you had any psychological problems such as stress, anxiety and depression?

*When did you first notice symptoms of ED?

*What are the frequency, quality, and duration of any erections you have had?

*What are the specifics of the circumstances under which ED first occurred?

*Do/did you experience erections at night or during the morning?

*What sexual techniques do you use?

*Are there problems in your current relationship?

The doctor may also wish to interview your sexual partner since your partner may be able to offer in sight about the underlying


After your physical examination and interview, your doctor may then order any one of the following tests:

*Complete blood count (CBC): This is a set of blood tests that, among other things, can detect the presence of anemia. Anemia is caused by a low red blood cell count and can cause fatigue, which in turn can cause ED.

*Liver and kidney function tests: These blood tests may indicate whether ED may be due to your kidneys or liver functioning improperly.

*Lipid proļ¬le: This blood test measures the level of lipids (fats), like cholesterol. High levels may indicate atherosclerosis (hardening

of the arteries), which can affect blood circulation in the penis.

*Thyroid function test: On

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