Monday, July 6, 2009

KiDneY StOnE

What are kidney stones?

Kidney stones are made of salts and minerals in the urine that stick together to form small "pebbles." They can be as small as grains of sand or as large as golf balls. They may stay in your kidneys or travel out of your body through the urinary tract . The urinary tract is the system that makes urine and carries it out of your body. It is made up of the kidneys, the tubes that connect the kidneys to the bladder (the ureters), the bladder, and the tube that leads from the bladder out of the body (the urethra).
When a stone travels through a ureter, it may cause no pain. Or it may cause great pain and other symptoms.
See pictures of a kidney stone and a stone traveling through a ureter .

What causes kidney stones?

Kidney stones form when a change occurs in the normal balance of water, salts, minerals, and other things found in urine. The most common cause of kidney stones is not drinking enough water. Try to drink enough water to keep your urine clear (about 8 to 10 glasses of water a day). Some people are more likely to get kidney stones because of a medical condition or family history.
Kidney stones may also be an inherited disease. If other people in your family have had them, you may have them too.

What are the symptoms?

Kidney stones often cause no pain while they are in the kidneys, but they can cause sudden, severe pain as they travel from the kidneys to the bladder.
Call a doctor right away if you think you have kidney stones. Watch for severe pain in your side, belly, or groin or for urine that looks pink or red. You may also feel sick to your stomach (nausea) and may vomit.

How are kidney stones diagnosed?

You may first find out that you have kidney stones when you see your doctor or go to an emergency room with pain in your belly or side. Your doctor will ask you questions about your pain and lifestyle. He or she will examine you and may do imaging tests such as X-rays to look at your kidneys and urinary tract.

You may need more tests if you have more than one stone or have a family history of stones. To find out the cause of your kidney stones, your doctor may order a blood test and ask you to collect your urine for 24 hours. This can help your doctor find out if you are likely to have more stones in the future.

Kidney stones may not cause any pain. If this is the case, you may learn you have them when your doctor finds them during a test for another disease.

How are they treated?

For most stones, your doctor will suggest drinking enough water to keep your urine clear, or about 8 to 10 glasses of water a day, to help flush the stones out. You may also need to take pain medicine. You can do this at home. Your doctor may give you a medicine to help the stone pass.
If a stone is too large to pass on its own, or if it gets stuck in the urinary tract, you may need more treatment. About 1 or 2 out of every 10 kidney stones needs more than home treatment.1The most common medical treatment is extracorporeal shock wave lithotripsy (ESWL). This uses shock waves to break a kidney stone into small pieces. The bits can pass out of your body in your urine. Other times, a doctor will need to remove the stone or place a small flexible plastic tube (called a stent) in the ureter to keep it open while stones pass

Types of kidney stones

There are four main types of kidney stones.

Calcium stones
Nearly 80% of all kidney stones are made of calcium compounds, especially calcium oxalate.1 Calcium phosphate and other minerals also may be present. Conditions that cause high calcium levels in the body, such as hyperparathyroidism, increase the risk of calcium stones. High levels of oxalate also increase the risk for calcium stones.
Certain medicines may prevent calcium stones.

Uric acid stones
About 5% to 10% of kidney stones are made of uric acid, a waste product normally passed out of the body in the urine.1 You are more likely to have uric acid stones if you have:
· Low urine output.
· A diet high in animal protein, such as red meat.
· An increase in how much alcohol you drink.
· Gout.
· Inflammatory bowel disease.
Certain medicines may prevent or dissolve uric acid stones.

Struvite stones
About 10% to 15% of kidney stones are struvite stones.1 They can also be called infection stones if they occur with kidney or urinary tract infections (UTIs). These types of kidney stones sometimes are also called staghorn calculi if they grow large enough.
Struvite stones can be serious because they are often large stones and may occur with an infection. Medical treatment, including antibiotics and removal of the stone, is usually needed for struvite stones. Women are affected more than men because of their higher risk of urinary tract infections.

Cystine stones
Less than 1% of kidney stones are made of a chemical called cystine.1 Cystine stones are more likely to develop in families with a condition that results in too much cystine in the urine (cystinuria).
Cystine stones may be prevented or dissolved with medicine, but this may be difficult and not very effective. If the stones cause blockage in the urinary tract or are too large, then removal of the stone will be needed.

Kidney Stones - Treatment Overview

Your first diagnosis of kidney stones often occurs when you see your doctor or go to an emergency room because you are in great pain. Your doctor may suggest that you wait for the stone to pass and take pain medicine or have a procedure to remove the stone.
Most small stones [less than 5mm] move out of the body (pass) without the need for any treatment other than drinking extra fluids and taking pain medicine.1

· The smaller a stone is, the more likely it is to pass on its own. About 9 out of every 10 stones smaller than 5mm and about 5 out of every 10 stones 5mm to 10mm pass on their own.1 Only 1 or 2 out of every 10 kidney stones need more than home treatment.1

· The average time a stone takes to pass ranges between 1 and 3 weeks,1 and two-thirds of stones that pass on their own pass within 4 weeks of when the symptoms appeared.2
Not all kidney stones are diagnosed because of immediate symptoms. Your stone may not be causing you pain, and your doctor may find it during a routine exam or an exam for another condition or disease. In this case, you have the same treatment options as noted below.

Treatment for your first stone

If your doctor thinks the stone can pass on its own, and you feel you can deal with the pain, he or she may suggest home treatment, including:

· Drinking more fluids. You need to drink enough water to keep your urine clear, about 8 to 10 glasses a day. Try to drink 2 glasses of water every 2 hours while you are awake. If you have kidney, heart, or liver disease and are on fluid restrictions, talk with your doctor before increasing your fluid intake.

· Not drinking grapefruit juice. Drinking grapefruit juice may increase your risk for developing kidney stones.

· Using pain medicine. Nonprescription medicine, such as nonsteroidal anti-inflammatories (NSAIDs), may relieve your pain. Your doctor can prescribe stronger pain medicine if needed.
Your doctor may prescribe medicine to help your body pass the stone. Calcium channel blockers and alpha-blockers have been shown to help kidney stones pass more quickly with very few side effects.11 Ask your doctor if one of these medicines can help you.
If your pain is too severe, if the stones are blocking the urinary tract , or if you also have an infection, your doctor will probably suggest medical or surgical treatment. Your options are:

· Extracorporeal shock wave lithotripsy (ESWL). ESWL uses shock waves that pass easily through the body but are strong enough to break up a kidney stone. This is the most commonly used medical treatment for kidney stones. See a picture of ESWL .

· Percutaneous nephrolithotomy or nephrolithotripsy. The surgeon puts a narrow telescope into the kidney through a cut in your back. He or she then removes the stone (lithotomy) or breaks it up and removes it (lithotripsy). This procedure may be used if ESWL does not work or if you have a very large stone. See a picture of nephrolithotomy .

· Ureteroscopy. The surgeon passes a very thin telescope tube (ureteroscope) up the urinary tract to the stone's location, where he or she uses instruments to remove the stone or break it up for easier removal. Occasionally, you may need a small hollow tube (ureteral stent) placed in the ureter for a short time to keep it open and drain urine and any stone pieces. Ureteroscopy is often used for stones that have moved from the kidney to the ureter. See a picture of ureteroscopy .

· Open surgery. The surgeon makes a cut in the side or the belly to reach the kidneys and remove the stone. This treatment is rarely used.

Kidney Stones - Symptoms

Kidney stones form in the kidney and if they stay in the kidney, they do not typically cause pain. When they travel out of the body through the tubes of the urinary tract (including the ureters, which connect the kidney to the bladder, or the urethra, which leads outside the body), their movement may cause:
· No symptoms, if the stone is small enough.
· Sudden, severe pain that gets worse in waves. Stones may cause intense pain in the back, side, abdomen, groin, or genitals. People who have had a kidney stone often describe the pain as "the worst pain I've ever had."
· Feeling sick to the stomach (nausea) and vomiting.
· Blood in the urine (hematuria), which can occur either with stones that stay in the kidney or with those that travel through the ureters.
· Frequent and painful urination, which may occur when the stone is in the ureter or after the stone has left the bladder and is in the urethra. Painful urination may occur when a urinary tract infection is also present.


Kidney Stones in Adults

Kidney stones, one of the most painful of the urologic disorders, have beset humans for centuries. Scientists have found evidence of kidney stones in a 7,000-year-old Egyptian mummy. Unfortunately, kidney stones are one of the most common disorders of the urinary tract. Each year, people make almost 3 million visits to health care providers and more than half a million people go to emergency rooms for kidney stone problems.
Most kidney stones pass out of the body without any intervention by a physician. Stones that cause lasting symptoms or other complications may be treated by various techniques, most of which do not involve major surgery. Also, research advances have led to a better understanding of the many factors that promote stone formation and thus better treatments for preventing stones.

What is a kidney stone?

A kidney stone is a hard mass developed from crystals that separate from the urine within the urinary tract. Normally, urine contains chemicals that prevent or inhibit the crystals from forming. These inhibitors do not seem to work for everyone, however, so some people form stones. If the crystals remain tiny enough, they will travel through the urinary tract and pass out of the body in the urine without being noticed.

Kidney stones may contain various combinations of chemicals. The most common type of stone contains calcium in combination with either oxalate or phosphate. These chemicals are part of a person’s normal diet and make up important parts of the body, such as bones and muscles.
A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. Another type of stone, uric acid stones, are a bit less common, and cystine stones are rare.

Urolithiasis is the medical term used to describe stones occurring in the urinary tract. Other frequently used terms are urinary tract stone disease and nephrolithiasis. Doctors also use terms that describe the location of the stone in the urinary tract. For example, a ureteral stone—or ureterolithiasis—is a kidney stone found in the ureter. To keep things simple, the general term kidney stones is used throughout this fact sheet.

Gallstones and kidney stones are not related. They form in different areas of the body. Someone with a gallstone is not necessarily more likely to develop kidney stones

Who gets kidney stones?

For unknown reasons, the number of people in the United States with kidney stones has been increasing over the past 30 years. In the late 1970s, less than 4 percent of the population had stone-forming disease. By the early 1990s, the portion of the population with the disease had increased to more than 5 percent. Caucasians are more prone to develop kidney stones than African Americans. Stones occur more frequently in men. The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s. For women, the prevalence of kidney stones peaks in their 50s. Once a person gets more than one stone, other stones are likely to develop.

What causes kidney stones?

Doctors do not always know what causes a stone to form. While certain foods may promote stone formation in people who are susceptible, scientists do not believe that eating any specific food causes stones to form in people who are not susceptible.

A person with a family history of kidney stones may be more likely to develop stones. Urinary tract infections, kidney disorders such as cystic kidney diseases, and certain metabolic disorders such as hyperparathyroidism are also linked to stone formation.
In addition, more than 70 percent of people with a rare hereditary disease called renal tubular acidosis develop kidney stones.

Cystinuria and hyperoxaluria are two other rare, inherited metabolic disorders that often cause kidney stones. In cystinuria, too much of the amino acid cystine, which does not dissolve in urine, is voided, leading to the formation of stones made of cystine. In patients with hyperoxaluria, the body produces too much oxalate, a salt. When the urine contains more oxalate than can be dissolved, the crystals settle out and form stones.

Hypercalciuria is inherited, and it may be the cause of stones in more than half of patients. Calcium is absorbed from food in excess and is lost into the urine. This high level of calcium in the urine causes crystals of calcium oxalate or calcium phosphate to form in the kidneys or elsewhere in the urinary tract.

Other causes of kidney stones are hyperuricosuria, which is a disorder of uric acid metabolism; gout; excess intake of vitamin D; urinary tract infections; and blockage of the urinary tract. Certain diuretics, commonly called water pills, and calcium-based antacids may increase the risk of forming kidney stones by increasing the amount of calcium in the urine.

Calcium oxalate stones may also form in people who have chronic inflammation of the bowel or who have had an intestinal bypass operation, or ostomy surgery. As mentioned earlier, struvite stones can form in people who have had a urinary tract infection. People who take the protease inhibitor indinavir, a medicine used to treat HIV infection, may also be at increased risk of developing kidney stones.

Foods and Drinks Containing Oxalate
People prone to forming calcium oxalate stones may be asked by their doctor to limit or avoid certain foods if their urine contains an excess of oxalate.

High-oxalate foods—higher to lower
swiss chard
wheat germ
soybean crackers
black Indian tea
sweet potatoes
Foods that have medium amounts of oxalate may be eaten in limited amounts.

Medium-oxalate foods—higher to lower
green pepper
red raspberries
fruit cake

Source: The Oxalosis and Hyperoxaluria Foundation.

What are the symptoms of kidney stones?

Kidney stones often do not cause any symptoms. Usually, the first symptom of a kidney stone is extreme pain, which begins suddenly when a stone moves in the urinary tract and blocks the flow of urine. Typically, a person feels a sharp, cramping pain in the back and side in the area of the kidney or in the lower abdomen. Sometimes nausea and vomiting occur. Later, pain may spread to the groin.

If the stone is too large to pass easily, pain continues as the muscles in the wall of the narrow ureter try to squeeze the stone into the bladder. As the stone moves and the body tries to push it out, blood may appear in the urine, making the urine pink. As the stone moves down the ureter, closer to the bladder, a person may feel the need to urinate more often or feel a burning sensation during urination.

If fever and chills accompany any of these symptoms, an infection may be present. In this case, a person should contact a doctor immediately.

How are kidney stones diagnosed?

Sometimes “silent” stones—those that do not cause symptoms—are found on x rays taken during a general health exam. If the stones are small, they will often pass out of the body unnoticed. Often, kidney stones are found on an x ray or ultrasound taken of someone who complains of blood in the urine or sudden pain.

These diagnostic images give the doctor valuable information about the stone’s size and location. Blood and urine tests help detect any abnormal substance that might promote stone formation.The doctor may decide to scan the urinary system using a special test called a computerized tomography (CT) scan or an intravenous pyelogram (IVP). The results of all these tests help determine the proper treatment

Preventing Kidney Stones

A person who has had more than one kidney stone may be likely to form another; so, if possible, prevention is important. To help determine their cause, the doctor will order laboratory tests, including urine and blood tests. The doctor will also ask about the patient’s medical history, occupation, and eating habits. If a stone has been removed, or if the patient has passed a stone and saved it, a stone analysis by the laboratory may help the doctor in planning treatment.

The doctor may ask the patient to collect urine for 24 hours after a stone has passed or been removed. For a 24-hour urine collection, the patient is given a large container, which is to be refrigerated between trips to the bathroom. The collection is used to measure urine volume and levels of acidity, calcium, sodium, uric acid, oxalate, citrate, and creatinine—a product of muscle metabolism. The doctor will use this information to determine the cause of the stone. A second 24-hour urine collection may be needed to determine whether the prescribed treatment is working.