KIDNEY STONES
Summertime, and Risk Grows for Kidney Stones
Dehydration in hot, dry weather can encourage kidney stones to form
Sumanthi Reddy : WSJ : May 25, 2015
Summer is a big season for kidney stones.
Doctors say more people suffer the condition when the weather is hot and dry and people become dehydrated. That can encourage minerals in the body to crystallize in the kidneys. When the so-called stones move to other parts of the urinary tract they can cause severe pain depending on their size.
About 9% of U.S. adults will develop kidney stones, a rate that has nearly doubled over the past 15 years, according to a 2012 study in the journal European Urology. The reason for the increase isn’t entirely clear, but it is believed to be connected to rising obesity rates. Men are more likely than women to get kidney stones, though a recent study found the gap has been narrowing.
For people who have suffered a kidney stone, the chance of having another is high. Doctors say there are steps to help prevent a recurrence, mainly through changes in diet, such as drinking lots of water and avoiding sugary sodas. Other prevention tips may depend on what type of kidney stone you had. For a common type of stone, doctors might recommend avoiding spinach and consuming moderate levels of dietary calcium, for example.
Almost all first-timers end up in the emergency room, said Gregory Jack, director of the Kidney Stone Center at University of California, Los Angeles. “If they’ve never had a stone before, if it’s on the right side they always think it’s a burst appendix. If it’s on the left, they come in thinking it’s a heart attack. They’re that awful, they’re that painful,” he said.
Genetics is believed to play a role. One in four people with the condition report having relatives with kidney stones, Dr. Jack said.
Once kidney stones pass through the body—which can take between a day and as much as several weeks from when symptoms begin—the pain goes away and complications are rare.
Most stones that are 5 millimeters in size or less will pass on their own within a week or two. Doctors often give patients medication to relax the muscles in the ureters. But if the pain is too much to bear, or the stones are too big, doctors might use shock wave lithotripsy, a noninvasive treatment that breaks stones into smaller pieces with high-energy shock waves. Minor outpatient surgeries also are sometimes performed to remove or break stones apart.
Fifteen percent of people who get a kidney stone will have another episode within a year, said Matthew Gettman, a professor of urology at Mayo Clinic in Rochester, Minn. That rate rises to 35% to 40% within five years and 50% by 10 years. Kidney stones also are associated with other conditions, including cardiovascular disease, Type 2 diabetes and high blood pressure.
KIDNEY STONE FACTS
Increasing fluid intake, particularly water, is an important prevention strategy for all types of stones, doctors say. Recommendations often include drinking 10 to 12 glasses of water a day, and avoiding sugar-sweetened sodas, which can contribute to stone formation, and high sugary foods. Doctors also recommend limiting consumption of animal protein, including chicken, beef and fish, to 12 ounces a day.
Most kidney stones—as many as 80% of all cases—are deposits of calcium oxalate. For people who have had these types of stones, experts recommend a moderate intake of dietary calcium—too much or too little can increase risk for stones. A low sodium diet and eating more fruits and vegetables is also advised.
Doctors are divided on how much patients with calcium oxalate stones should limit consumption of oxalate, which is found in many vegetables. Gary Curhan, a professor of medicine at Harvard Medical School, says if a patient’s urine test shows a high oxalate level he recommends avoiding the highest oxalate-containing foods, including spinach, potatoes, rhubarb and certain types of nuts.
Christopher Courtheyn has managed his kidney-stone disease by making changes to his diet. The 34-year-old graduate student at the University of North Carolina, Chapel Hill, woke up with intense back pain three years ago. After going to the hospital he learned he had a small kidney stone that was causing the pain, and an X-ray found he had another large stone developing in his other kidney. He got surgery at Duke University Medical Center to remove the calcium oxalate stone.
Since then Mr. Courtheyn has stopped eating frozen dinners that were high in salt and cut out spinach. He also started eating dairy to get calcium and drinks a lot more water and tea. “Now three years later I haven’t had any [kidney stones] since then,” he said. “Changing my diet seems to be working.”
Two other types are calcium phosphate stones and uric acid stones, which are more common in people with diabetes. There are also some rare types of stones, such as struvite stones, which can be caused by urinary-tract infections.
Less is known about the dietary factors that contribute to calcium phosphate stones but Dr. Curhan said a low sodium and low phosphate diet could help. Colas are acidified with phosphoric acid so should be avoided, he said.
Reducing the acidity of the urine with a medicine like potassium citrate can help dissolve uric acid stones. Charles Scales, an assistant professor of urology at Duke University, said he sometimes recommends lemonade therapy for people with low levels of citrate. He advises them to drink homemade lemonade made by squeezing four ounces of natural lemon juice into two quarts of water and to avoid sweetening it with sugar.
Various medications are also available to help prevent formation of the different types of stones.
Although kidney stones affect more men than women, the gap might be narrowing. The proportion of women treated for kidney stones is increasing while the proportion of men with stones is decreasing, according to a recent study in the Journal of Urology that tracked more than 116,000 kidney-stone treatments over two decades in an Ontario health database. The reason for the changing trend wasn’t clear.
“Obesity is an important contributor,” said Dr. Curhan, of Harvard Medical School, who wasn’t involved in the Ontario study. “In both men and women, particularly women, there’s a greater increase in risk with increasing” body-mass index.
Dehydration in hot, dry weather can encourage kidney stones to form
Sumanthi Reddy : WSJ : May 25, 2015
Summer is a big season for kidney stones.
Doctors say more people suffer the condition when the weather is hot and dry and people become dehydrated. That can encourage minerals in the body to crystallize in the kidneys. When the so-called stones move to other parts of the urinary tract they can cause severe pain depending on their size.
About 9% of U.S. adults will develop kidney stones, a rate that has nearly doubled over the past 15 years, according to a 2012 study in the journal European Urology. The reason for the increase isn’t entirely clear, but it is believed to be connected to rising obesity rates. Men are more likely than women to get kidney stones, though a recent study found the gap has been narrowing.
For people who have suffered a kidney stone, the chance of having another is high. Doctors say there are steps to help prevent a recurrence, mainly through changes in diet, such as drinking lots of water and avoiding sugary sodas. Other prevention tips may depend on what type of kidney stone you had. For a common type of stone, doctors might recommend avoiding spinach and consuming moderate levels of dietary calcium, for example.
Almost all first-timers end up in the emergency room, said Gregory Jack, director of the Kidney Stone Center at University of California, Los Angeles. “If they’ve never had a stone before, if it’s on the right side they always think it’s a burst appendix. If it’s on the left, they come in thinking it’s a heart attack. They’re that awful, they’re that painful,” he said.
Genetics is believed to play a role. One in four people with the condition report having relatives with kidney stones, Dr. Jack said.
Once kidney stones pass through the body—which can take between a day and as much as several weeks from when symptoms begin—the pain goes away and complications are rare.
Most stones that are 5 millimeters in size or less will pass on their own within a week or two. Doctors often give patients medication to relax the muscles in the ureters. But if the pain is too much to bear, or the stones are too big, doctors might use shock wave lithotripsy, a noninvasive treatment that breaks stones into smaller pieces with high-energy shock waves. Minor outpatient surgeries also are sometimes performed to remove or break stones apart.
Fifteen percent of people who get a kidney stone will have another episode within a year, said Matthew Gettman, a professor of urology at Mayo Clinic in Rochester, Minn. That rate rises to 35% to 40% within five years and 50% by 10 years. Kidney stones also are associated with other conditions, including cardiovascular disease, Type 2 diabetes and high blood pressure.
KIDNEY STONE FACTS
- About 9% of U.S. adults will develop kidney stones, a rate that has nearly doubled over the past 15 years. In men, the rate is 11% and in women it is 7%. But the gap between the genders is narrowing.
Calcium oxalate stones make up the majority of cases. Other types of kidney stones include calcium phosphate, uric acid and struvite.
A family history of kidney stones increases your risk. One in four people with a stone reports having a relative with them.
Cases of stones are more common in hot, dry environments because of dehydration. Doctors recommend drinking 10 to 12 glasses of water a day and avoiding sugar-sweetened sodas.
Diet can play a role. Studies have found that following the DASH diet, designed to reduce blood pressure, reduces the likelihood of forming stones.
Doctors recommend eating lots of fruits and vegetables and consuming a moderate amount dietary calcium (too much or too little can contribute to stone formation). Other advice: limit meat consumption to 10 to 12 ounces a day and in some cases avoid foods with high levels of oxalate, such as spinach.
Increasing fluid intake, particularly water, is an important prevention strategy for all types of stones, doctors say. Recommendations often include drinking 10 to 12 glasses of water a day, and avoiding sugar-sweetened sodas, which can contribute to stone formation, and high sugary foods. Doctors also recommend limiting consumption of animal protein, including chicken, beef and fish, to 12 ounces a day.
Most kidney stones—as many as 80% of all cases—are deposits of calcium oxalate. For people who have had these types of stones, experts recommend a moderate intake of dietary calcium—too much or too little can increase risk for stones. A low sodium diet and eating more fruits and vegetables is also advised.
Doctors are divided on how much patients with calcium oxalate stones should limit consumption of oxalate, which is found in many vegetables. Gary Curhan, a professor of medicine at Harvard Medical School, says if a patient’s urine test shows a high oxalate level he recommends avoiding the highest oxalate-containing foods, including spinach, potatoes, rhubarb and certain types of nuts.
Christopher Courtheyn has managed his kidney-stone disease by making changes to his diet. The 34-year-old graduate student at the University of North Carolina, Chapel Hill, woke up with intense back pain three years ago. After going to the hospital he learned he had a small kidney stone that was causing the pain, and an X-ray found he had another large stone developing in his other kidney. He got surgery at Duke University Medical Center to remove the calcium oxalate stone.
Since then Mr. Courtheyn has stopped eating frozen dinners that were high in salt and cut out spinach. He also started eating dairy to get calcium and drinks a lot more water and tea. “Now three years later I haven’t had any [kidney stones] since then,” he said. “Changing my diet seems to be working.”
Two other types are calcium phosphate stones and uric acid stones, which are more common in people with diabetes. There are also some rare types of stones, such as struvite stones, which can be caused by urinary-tract infections.
Less is known about the dietary factors that contribute to calcium phosphate stones but Dr. Curhan said a low sodium and low phosphate diet could help. Colas are acidified with phosphoric acid so should be avoided, he said.
Reducing the acidity of the urine with a medicine like potassium citrate can help dissolve uric acid stones. Charles Scales, an assistant professor of urology at Duke University, said he sometimes recommends lemonade therapy for people with low levels of citrate. He advises them to drink homemade lemonade made by squeezing four ounces of natural lemon juice into two quarts of water and to avoid sweetening it with sugar.
Various medications are also available to help prevent formation of the different types of stones.
Although kidney stones affect more men than women, the gap might be narrowing. The proportion of women treated for kidney stones is increasing while the proportion of men with stones is decreasing, according to a recent study in the Journal of Urology that tracked more than 116,000 kidney-stone treatments over two decades in an Ontario health database. The reason for the changing trend wasn’t clear.
“Obesity is an important contributor,” said Dr. Curhan, of Harvard Medical School, who wasn’t involved in the Ontario study. “In both men and women, particularly women, there’s a greater increase in risk with increasing” body-mass index.
Kidney Stones
Kidney Stones : An Overview
A kidney stone is a solid mass made up of tiny crystals. One or more stones can be in the kidney or ureter at the same time.
Alternative Names
Renal calculi; Nephrolithiasis; Stones - kidney
Causes »
Kidney stones can form when the urine contains too much of certain substances. These substances can create small crystals that become stones. Kidney stones may not produce symptoms until they begin to move down the ureter, causing pain. The pain is usually severe and often starts in the flank region, then moves down to the groin.
Kidney stones are common. A person who has had kidney stones often gets them again in the future. Kidney stones often occur in premature infants.
Risk factors include renal tubular acidosis and resultant nephrocalcinosis.
Some types of stones tend to run in families. Certain kinds of stones can occur with bowel disease, ileal bypass for obesity, or renal tubule defects.
Types of stones include:
In-Depth Causes »
Symptoms »
Exams and Tests »
Pain can be severe enough to need narcotic pain relievers. The abdomen or back might feel tender to the touch. If stones are severe, persistent, or come back again and again, there may be signs of kidney failure.
Tests for kidney stones include:
In-Depth Diagnosis »
Treatment »
The goal of treatment is to relieve symptoms and prevent further symptoms. (Kidney stones usually pass on their own.) Treatment varies depending on the type of stone and how severe the symptoms are. People with severe symptoms might need to be hospitalized.
When the stone passes, the urine should be strained and the stone saved and tested to determine the type.
Drink at least 6 - 8 glasses of water per day to produce a large amount of urine. Some people might need to get fluids through a vein (intravenous).
Pain relievers can help control the pain of passing the stones (renal colic). For severe pain, you may need to take narcotic analgesics.
Depending on the type of stone, your doctor may prescribe medicine to decrease stone formation and/or help break down and remove the material that is causing the stone. Medications can include:
You may need to change your diet to prevent some types of stones from coming back.
In-Depth Treatment »
Outlook (Prognosis)
Kidney stones are painful but usually can be removed from the body without causing permanent damage. They tend to return, especially if the cause is not found and treated.
Possible Complications
Call your health care provider if you have symptoms of a kidney stone.
Also call if symptoms return, urination becomes painful, urine output decreases, or other new symptoms develop.
Prevention »
If you have a history of stones, drink plenty of fluids (6 - 8 glasses of water per day) to produce enough urine. Depending on the type of stone, you might need to take medications or other measures to prevent the stones from returning.
The Whys and How-to-Treats of Kidney Stones
By Laurie Tarkan
NY Times Article : October 25, 2008
Dr. James E. Lingeman is director of research at the Methodist Hospital Institute for Kidney Stone Disease in Indianapolis. He was the first urologist in the United States to perform lithotripsy, a noninvasive method of pulverizing stones, in 1984.
Q: Research shows that kidney stones are increasing. How common are they?
A: About 12 percent of men and 7 percent of women will experience a stone over a lifetime. That makes it a pretty common disease, as common as diabetes. Of course it doesn’t kill people, but it hurts like hell. There have been a few reports in the last several years suggesting that stone incidence seems to be increasing in women. It is becoming, if you will, an equal-opportunity disease.
Q: Why is the incidence increasing, and why in women?
A: Nobody knows for sure. One hypothesis, which probably is a valid one, is that the risk of kidney stones is increased by obesity, and Americans are getting fatter and fatter. Some of this data comes from the Health Professionals Follow-up Study and the Nurses’ Health Study. They’ve found that weight gain and body mass index correlate directly with the increased risk of stones. For example, a 35-pound weight gain would be associated with a 40 percent increase of stone risk in men and an 80 percent risk in women. The risk is particularly increased for a type of stone called a uric acid stone.
Q: So we’re seeing more uric acid stones?
A: There are several types of stones, the most common being calcium oxalate. About 75 percent of people form calcium oxalate stones. But we see more uric acid stones in obese individuals, and we’re seeing more calcium phosphate stones as well. The reason is unclear.
Q: Aside from obesity, what else is contributing to the increase in stones?
A: It is pretty well established that for the typical stone former, a low urinary volume is one of the most common causes of stone formation, or a risk factor for stone formation. Drink lots of fluids; anything that makes you pee is good.
Q: Do dairy products rich in calcium contribute to calcium stones?
A: Interestingly enough, epidemiologic data suggests that a healthy intake of dairy products reduces risk of kidney stones. The calcium in dairy products will bind up with oxalate, which is a byproduct of certain foods, preventing it from being absorbed into the bloodstream and then the urine. So it reduces levels of oxalate in the urine and reduces the risk of kidney stones.
People with low dairy product intake have higher urinary oxalate levels. But there’s some speculation that increased consumption of calcium supplements may increase the risk of stones, and many women take these supplements to try to prevent osteoporosis.
Q: Why are calcium supplements harmful?
A: It may be that people don’t take supplements with food, so the calcium has no effect on the oxalate levels. The body clearly doesn’t like dietary supplements as well as it likes the real stuff. It’s definitely best for people to get their R.D.A. of calcium from dairy products. A big study published in The New England Journal of Medicine found no great difference in bone density and the risk of osteoporosis in supplement takers. The only difference was that people who took the supplements had a few more kidney stones.
Q: Why are high-salt diets bad for kidney stones?
A: Sodium and calcium are similar ions. Your kidneys’ job is to get rid of salt to maintain balance, but along with the sodium comes calcium too, increasing calcium in urine. They operate in parallel. You can lower your urinary calcium by lowering salt intake.
Q: Has research shown that high-protein diets raise the risk of stones?
A: Americans tend to grossly overconsume animal protein. The body doesn’t need it, so it breaks it down into uric acid and excretes it through the urine, which can increase risk of uric acid stones. Secondly, protein, especially red meat, contains sulfuric and phosphoric acids that need to be excreted. These lower your urinary pH, which also increases the risk of stones. I recommend to folks no more than 10 ounces of animal protein a day.
Q: Are there any other foods that cause kidney stones?
A: Americans consume a lot of sucrose in soda pop, and it’s used as a sweetener in a lot of foods. Studies show it increases the risk of stones independent of the weight gain it may cause.
Q: Is there anything new in the management of kidney stones?
A: There are three mainstays of our treatment of kidney stones if you can’t pass them. The first is shock-wave lithotripsy, which is a noninvasive technique in which the stones are pulverized. The second treatment is ureteroscopy, where we send a tiny scope through the urinary opening to destroy the stone. They both work very well for smaller stones. If the stone is very large, then it’s removed through surgery from the back. With those three treatment techniques, it’s rare for a person to undergo a traditional surgical procedure with large incisions.
Q: Is any one treatment better or more popular?
A: The lithotripsy machines are not as effective as they used to be 25 years ago; however, lithotripsy is still very popular because of its noninvasive nature. The original machines were cumbersome so they’ve downsized them, but the newer techniques don’t work as well as the older ones. The risks of both are very low.
Both treatments were developed at around the same time, but lithotripsy shot up rapidly because of its noninvasive nature. Over the last 20 years we saw an explosion of shock-wave lithotripsy treatments. While exact numbers are hard to come by, composite numbers suggest that there are probably around 350,000 shock-wave lithotripsy treatments done in the United States each year.
However, as ureteroscopes have gotten smaller and the lasers have gotten more sophisticated, we’ve seen a steady increase in the number of ureteroscopies to almost the same level as shock-wave lithotripsy. Ureteroscopes are much less expensive than shock-wave lithotripsy machines and every hospital has them, whereas not all hospitals have lithotripsy machines.
Q: Didn’t a study show that lithotripsy increased the risk of diabetes and hypertension?
A: A study noted an association of diabetes and hypertension in long-term follow-up of patients treated at the Mayo Clinic. There was some criticism of that study. We know that shock waves produce some bruising as they pass through the body. The concern or speculation is that there could be some long-term consequence.
The American Urological Association will be releasing a white paper on this towards the end of this year that will focus on how to use them most safely. The main point is that even if lithotripsy has a slight effect on blood pressure, it doesn’t change the fact that it’s the least invasive, most attractive treatment option.
Q: Do you always need surgery if you have a stone?
A: If you have symptoms, like pain or blood in the urine, you want to get it removed. The question is what if you don’t have symptoms? That becomes negotiable. If you had a stone that was too large to be passable, logic dictates that sooner or later that is going to have to be treated. But if they’re small and have a high likelihood of coming through on their own, we’d usually recommend just watching and waiting. They grow little stalactites in the kidney; as long as they’re attached and don’t move around, they often don’t cause trouble.
Q: Can medications be used to treat a stone?
A: A new thing in treatment is using medication to try to help the stones pass. Alpha blockers have become a popular treatment in the last three to four years. What they do is relax or help dilate the ureter tube, a foot-long duct that connects the kidney and the bladder. The drug helps stones pass through the duct. A fair amount of data from Europe suggest they’re beneficial, and a big trial is going on in the U.S. to study the issue. The current thinking is that these drugs are quite safe, and many urologists and E.R. doctors use them.
What to Ask About Kidney Stones
By Laurie Tarkan
NY Times Article : October 25, 2008
Confronting a new diagnosis can be frightening, and because research changes so often, confusing. Here are some questions you may not think to ask your doctor, along with notes on why they’re important.
Do I have any other stones remaining in my kidney?
Patients aren’t always told they have other stones after they pass one. The reason this is a problem is that if they change their diets and then pass another stone, they wouldn’t know if that stone was there from the start or if it developed despite the dietary changes. This can cause people to give up on preventive lifestyle changes.
Are there any abnormalities in my blood test?
Certain disorders, like parathyroid disease and diabetes, can contribute to kidney stones. It may be more important to treat these conditions than to make dietary changes to prevent further stones.
If I have another stone, do I need to remove it?
Not all stones need to be removed. However, stones should be removed if there are signs of infection, if they are causing symptoms or if they are so large that they’re likely to cause problems down the road.
What dietary changes should I make?
Depending on the urine analysis, you may need to decrease or increase certain foods in your diet. Dietary changes can reduce your risk of a recurrence by at least 40 percent, and possibly by up to 80 percent. Doctors recommend trying to lose weight if you’re overweight, drinking more fluids, increasing citrus fruits and drinks, increasing all fruits and vegetables, and reducing salt, sugar and animal protein, particularly red meat, in your diet.
Do I need to take medications?
Depending on the results of a urine analysis, you may not be able to prevent stones by diet alone. A doctor may prescribe medications to help prevent calcium and uric acid stones. These medicines control the pH balance in the urine, which affects crystal formation. Thiazide diuretics are often prescribed if urine calcium levels are high, and potassium citrate is prescribed to balance the pH in the urine.
How many patients have you treated for stone prevention?
Urologists tend to be surgeons, and many don’t necessarily focus on prevention. They may not have the time to sit and discuss all the important dietary modifications that can prevent stones. If your doctor is not that experienced in prevention, ask to see a nephrologist or kidney specialist.
What follow-up tests do I need?
If you are given dietary changes, you should have a 24-hour urine test about a month later to see if the recommendations have had any impact. If everything looks good, you could wait a year before having another urine test to make sure the diet is still helping.
5 Things to Know:
Lifestyle Changes Can Reduce the Risk of Stones
Dr. Gary Curhan is a nephrologist at Brigham and Women’s Hospital and an associate professor of medicine and epidemiology at Harvard Medical School and Harvard School of Public Health in Boston. He has conducted some of the most extensive research into the causes of and risk factors for kidney stones, with the goal of improving prevention strategies.
“Lifestyle changes can dramatically reduce the risk of stones,” Dr. Curhan said. Here are five things he believes everyone should know about kidney stones.
If you pass a stone, try to retrieve it.
That way it can be analyzed to find out what type of stone it is. The most common type is a calcium oxalate stone, followed by calcium phosphate stones and uric acid stones. “Not knowing the composition of a stone handicaps us,” Dr. Curhan said.
Drink more fluids.
Stones can be prevented if you’re willing to make changes to your diet and lifestyle. Randomized trials have found that making changes in diet can reduce your risk of a recurrence by 40 percent, and observational studies have shown an 80 percent reduction in risk. The most important thing you can do is to drink more fluids.
Consider dietary changes and medications.
Your treatment depends on what type of stone you have and may consist of dietary changes as well as medications to change the profile of your urine. Evidence suggests that the most important changes are drinking more fluids, increasing all fruits and vegetables, and reducing salt, sugar and animal protein in your diet. If urine calcium levels are high, thiazide diuretics can be used. If you have low urine citrate, potassium citrate may be prescribed to help correct the pH in the urine.
Make sure you get a blood test and full evaluation when you have a kidney stone.
Stones can be symptoms of other systemic disorders like diabetes, high blood pressure, hyperparathyroid disease and osteoporosis.
Get follow-up care.
Your doctor should regularly retest your urine with a 24-hour urine test to see if the dietary changes are working.
Kidney Stones Affecting More People, Earlier
By Laurie Tarkan
NY Times Article : October 25, 2008
In Brief:
Urologists also say that adults are showing up with their first stones at much younger ages — in their 20s and 30s, rather than their 40s and 50s, as was common in the past. And while about 12 percent of men and 7 percent of women get a kidney stone at some point, studies have found that rates are rising faster in women.
Alarmingly, kidney stones, once rare in children, are becoming more common in this age group, too, though there is no hard data on the number of cases.
Experts agree that the obesity epidemic is partly to blame. Women appear to be particularly sensitive to the effects of weight gain. One study found that a 35-pound weight gain since early adulthood increased the risk of stone formation by 40 percent in men but by 80 percent in women.
Weight gain is not the only factor associated with an increased risk of kidney stones, which form when certain substances in the urine become too concentrated and crystallize. Dietary factors, which contribute to the makeup of the urine, contribute to stone formation as well.
About 75 percent of stones are formed when calcium binds with oxalate, a byproduct of certain foods. Other common types are calcium phosphate stones and uric acid stones. All types are on the rise.
Two factors that increase the risk of stones are not drinking enough water and having a high-sodium diet, a not uncommon combination. Other risk factors include a diet high in animal protein and a diet rich in the common sweeteners fructose and sucrose (table sugar).
Contrary to what many people believe, calcium-rich dairy products appear to lower risk, and reduced consumption of dairy products may also be contributing to the rise in stones. The dietary calcium binds to oxalate in the gut, which prevents it from being absorbed into the urine.
“Some people believe that if you have a calcium stone, you should go on a low-calcium diet, and that’s absolutely the wrong thing to do,” said Dr. Gary Curhan, associate professor of medicine at Harvard Medical School.
On the other hand, calcium supplements have been shown to increase the risk of kidney stones. One explanation is that people tend to take supplements alone, not with a meal, so they’re not getting the benefit of the calcium’s binding with oxalate from food. They increase calcium levels without lowering oxalate levels.
Similarly, while some citrus fruits and drinks like lemonade and possibly orange juice can help prevent kidney stones, taking vitamin C supplements has been found to raise the risk.
Randomized trials have shown that people who made changes in their diet reduced their risk of stone recurrence by 40 percent. Observational studies have found an 80 percent reduction in risk. Certain medications can also help balance urine content and prevent stones, depending on their makeup.
Stones should be retrieved and analyzed to determine the type stone and what components in the urine are too low or too high, Dr. Curhan said. Patients should also be evaluated for other illnesses that are associated with kidney stones, including osteoporosis, high blood pressure and diabetes.
This reporter had kidney stones for two years without being adequately evaluated by her urologist. Only a routine physical later detected high calcium in the blood, which led to a diagnosis of hyperparathyroid disease, a correctable disorder that causes 5 percent of kidney stones.
The good news is that regardless of cause, treatment has gotten better. Typically a patient goes to the emergency room when a stone is passing, meaning that it has dislodged from the kidney and is traveling in the urine to the bladder through the narrow, foot-long tube called the ureter.
In the past few years, doctors have begun prescribing alpha blockers, like Flomax, which help relax and dilate the ureter, making it easier and less painful for the stone to pass through.
When stones are too large to pass — they can grow as large as golf balls — surgery is an option. But there are two procedures that don’t require surgical incisions.
Shock-wave lithotripsy uses high-energy sound waves to blast the stones into fragments, which then are passed more easily. The other method, ureteroscopy, wends a scope up the ureter and grabs the stone to remove it or destroys it with a laser. Lithotripsy is often preferred, when appropriate, because it is noninvasive, but it has a lower success rate, and the stone fragments still need to be passed.
One study from the Mayo Clinic found that lithotripsy may increase the risk of diabetes and hypertension. The concern is that the sound waves may be damaging normal kidney tissue, though some experts criticized the study.
“If there were serious and common complications, they would have been more obvious by now,” said Dr. Orson Moe, a nephrologist and professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas. “But I think until we have a multicenter or nationwide follow-up study, we won’t know.”
Fewer surgeries would be needed if prevention were taken more seriously.
“I’ve had patients who have had 20 or 30 stones,” Dr. Curhan said. “But if you are willing to make lifelong changes, stones can be prevented.”
A kidney stone is a solid mass made up of tiny crystals. One or more stones can be in the kidney or ureter at the same time.
Alternative Names
Renal calculi; Nephrolithiasis; Stones - kidney
Causes »
Kidney stones can form when the urine contains too much of certain substances. These substances can create small crystals that become stones. Kidney stones may not produce symptoms until they begin to move down the ureter, causing pain. The pain is usually severe and often starts in the flank region, then moves down to the groin.
Kidney stones are common. A person who has had kidney stones often gets them again in the future. Kidney stones often occur in premature infants.
Risk factors include renal tubular acidosis and resultant nephrocalcinosis.
Some types of stones tend to run in families. Certain kinds of stones can occur with bowel disease, ileal bypass for obesity, or renal tubule defects.
Types of stones include:
- Calcium stones are most common. They occur more often in men than in women, and usually appear between ages 20 - 30. They are likely to come back. Calcium can combine with other substances, such as oxalate (the most common substance), phosphate, or carbonate to form the stone. Oxalate is present in certain foods. Diseases of the small intestine increase the risk of forming calcium oxalate stones.
- Cystine stones can form in people who have cystinuria. This disorder runs in families and affects both men and women.
- Struvite stones are mainly found in women who have a urinary tract infection. These stones can grow very large and can block the kidney, ureter, or bladder.
- Uric acid stones are more common in men than in women. They can occur with gout or chemotherapy.
In-Depth Causes »
Symptoms »
- Abdominal pain
- Abnormal urine color
- Blood in the urine
- Chills
- Excess urination at night
- Fever
- Flank pain or back pain
- Colicky (spasm-like)
- May move lower in flank, pelvis, groin, genitals
- On one or both sides
- Progressive
- Severe
- Groin pain
- Nausea, vomiting
- Painful urination
- Testicle pain
- Urinary frequency/urgency
- Urinary hesitancy
Exams and Tests »
Pain can be severe enough to need narcotic pain relievers. The abdomen or back might feel tender to the touch. If stones are severe, persistent, or come back again and again, there may be signs of kidney failure.
Tests for kidney stones include:
- Analysis of the stone to show what type of stone it is
- Straining the urine to catch urinary tract stones
- Uric acid level
- Urinalysis to see crystals and red blood cells in urine
- Abdominal CT scan
- Abdominal/kidney MRI
- Abdominal x-rays
- Intravenous pyelogram (IVP)
- Kidney ultrasound
- Retrograde pyelogram
In-Depth Diagnosis »
Treatment »
The goal of treatment is to relieve symptoms and prevent further symptoms. (Kidney stones usually pass on their own.) Treatment varies depending on the type of stone and how severe the symptoms are. People with severe symptoms might need to be hospitalized.
When the stone passes, the urine should be strained and the stone saved and tested to determine the type.
Drink at least 6 - 8 glasses of water per day to produce a large amount of urine. Some people might need to get fluids through a vein (intravenous).
Pain relievers can help control the pain of passing the stones (renal colic). For severe pain, you may need to take narcotic analgesics.
Depending on the type of stone, your doctor may prescribe medicine to decrease stone formation and/or help break down and remove the material that is causing the stone. Medications can include:
- Allopurinol (for uric acid stones)
- Antibiotics (for struvite stones)
- Diuretics
- Phosphate solutions
- Sodium bicarbonate or sodium citrate (which make the urine more alkaline)
You may need to change your diet to prevent some types of stones from coming back.
In-Depth Treatment »
Outlook (Prognosis)
Kidney stones are painful but usually can be removed from the body without causing permanent damage. They tend to return, especially if the cause is not found and treated.
Possible Complications
- Decrease or loss of function in the affected kidney
- Kidney damage, scarring
- Obstruction of the ureter (acute unilateral obstructive uropathy)
- Recurrence of stones
- Urinary tract infection
Call your health care provider if you have symptoms of a kidney stone.
Also call if symptoms return, urination becomes painful, urine output decreases, or other new symptoms develop.
Prevention »
If you have a history of stones, drink plenty of fluids (6 - 8 glasses of water per day) to produce enough urine. Depending on the type of stone, you might need to take medications or other measures to prevent the stones from returning.
The Whys and How-to-Treats of Kidney Stones
By Laurie Tarkan
NY Times Article : October 25, 2008
Dr. James E. Lingeman is director of research at the Methodist Hospital Institute for Kidney Stone Disease in Indianapolis. He was the first urologist in the United States to perform lithotripsy, a noninvasive method of pulverizing stones, in 1984.
Q: Research shows that kidney stones are increasing. How common are they?
A: About 12 percent of men and 7 percent of women will experience a stone over a lifetime. That makes it a pretty common disease, as common as diabetes. Of course it doesn’t kill people, but it hurts like hell. There have been a few reports in the last several years suggesting that stone incidence seems to be increasing in women. It is becoming, if you will, an equal-opportunity disease.
Q: Why is the incidence increasing, and why in women?
A: Nobody knows for sure. One hypothesis, which probably is a valid one, is that the risk of kidney stones is increased by obesity, and Americans are getting fatter and fatter. Some of this data comes from the Health Professionals Follow-up Study and the Nurses’ Health Study. They’ve found that weight gain and body mass index correlate directly with the increased risk of stones. For example, a 35-pound weight gain would be associated with a 40 percent increase of stone risk in men and an 80 percent risk in women. The risk is particularly increased for a type of stone called a uric acid stone.
Q: So we’re seeing more uric acid stones?
A: There are several types of stones, the most common being calcium oxalate. About 75 percent of people form calcium oxalate stones. But we see more uric acid stones in obese individuals, and we’re seeing more calcium phosphate stones as well. The reason is unclear.
Q: Aside from obesity, what else is contributing to the increase in stones?
A: It is pretty well established that for the typical stone former, a low urinary volume is one of the most common causes of stone formation, or a risk factor for stone formation. Drink lots of fluids; anything that makes you pee is good.
Q: Do dairy products rich in calcium contribute to calcium stones?
A: Interestingly enough, epidemiologic data suggests that a healthy intake of dairy products reduces risk of kidney stones. The calcium in dairy products will bind up with oxalate, which is a byproduct of certain foods, preventing it from being absorbed into the bloodstream and then the urine. So it reduces levels of oxalate in the urine and reduces the risk of kidney stones.
People with low dairy product intake have higher urinary oxalate levels. But there’s some speculation that increased consumption of calcium supplements may increase the risk of stones, and many women take these supplements to try to prevent osteoporosis.
Q: Why are calcium supplements harmful?
A: It may be that people don’t take supplements with food, so the calcium has no effect on the oxalate levels. The body clearly doesn’t like dietary supplements as well as it likes the real stuff. It’s definitely best for people to get their R.D.A. of calcium from dairy products. A big study published in The New England Journal of Medicine found no great difference in bone density and the risk of osteoporosis in supplement takers. The only difference was that people who took the supplements had a few more kidney stones.
Q: Why are high-salt diets bad for kidney stones?
A: Sodium and calcium are similar ions. Your kidneys’ job is to get rid of salt to maintain balance, but along with the sodium comes calcium too, increasing calcium in urine. They operate in parallel. You can lower your urinary calcium by lowering salt intake.
Q: Has research shown that high-protein diets raise the risk of stones?
A: Americans tend to grossly overconsume animal protein. The body doesn’t need it, so it breaks it down into uric acid and excretes it through the urine, which can increase risk of uric acid stones. Secondly, protein, especially red meat, contains sulfuric and phosphoric acids that need to be excreted. These lower your urinary pH, which also increases the risk of stones. I recommend to folks no more than 10 ounces of animal protein a day.
Q: Are there any other foods that cause kidney stones?
A: Americans consume a lot of sucrose in soda pop, and it’s used as a sweetener in a lot of foods. Studies show it increases the risk of stones independent of the weight gain it may cause.
Q: Is there anything new in the management of kidney stones?
A: There are three mainstays of our treatment of kidney stones if you can’t pass them. The first is shock-wave lithotripsy, which is a noninvasive technique in which the stones are pulverized. The second treatment is ureteroscopy, where we send a tiny scope through the urinary opening to destroy the stone. They both work very well for smaller stones. If the stone is very large, then it’s removed through surgery from the back. With those three treatment techniques, it’s rare for a person to undergo a traditional surgical procedure with large incisions.
Q: Is any one treatment better or more popular?
A: The lithotripsy machines are not as effective as they used to be 25 years ago; however, lithotripsy is still very popular because of its noninvasive nature. The original machines were cumbersome so they’ve downsized them, but the newer techniques don’t work as well as the older ones. The risks of both are very low.
Both treatments were developed at around the same time, but lithotripsy shot up rapidly because of its noninvasive nature. Over the last 20 years we saw an explosion of shock-wave lithotripsy treatments. While exact numbers are hard to come by, composite numbers suggest that there are probably around 350,000 shock-wave lithotripsy treatments done in the United States each year.
However, as ureteroscopes have gotten smaller and the lasers have gotten more sophisticated, we’ve seen a steady increase in the number of ureteroscopies to almost the same level as shock-wave lithotripsy. Ureteroscopes are much less expensive than shock-wave lithotripsy machines and every hospital has them, whereas not all hospitals have lithotripsy machines.
Q: Didn’t a study show that lithotripsy increased the risk of diabetes and hypertension?
A: A study noted an association of diabetes and hypertension in long-term follow-up of patients treated at the Mayo Clinic. There was some criticism of that study. We know that shock waves produce some bruising as they pass through the body. The concern or speculation is that there could be some long-term consequence.
The American Urological Association will be releasing a white paper on this towards the end of this year that will focus on how to use them most safely. The main point is that even if lithotripsy has a slight effect on blood pressure, it doesn’t change the fact that it’s the least invasive, most attractive treatment option.
Q: Do you always need surgery if you have a stone?
A: If you have symptoms, like pain or blood in the urine, you want to get it removed. The question is what if you don’t have symptoms? That becomes negotiable. If you had a stone that was too large to be passable, logic dictates that sooner or later that is going to have to be treated. But if they’re small and have a high likelihood of coming through on their own, we’d usually recommend just watching and waiting. They grow little stalactites in the kidney; as long as they’re attached and don’t move around, they often don’t cause trouble.
Q: Can medications be used to treat a stone?
A: A new thing in treatment is using medication to try to help the stones pass. Alpha blockers have become a popular treatment in the last three to four years. What they do is relax or help dilate the ureter tube, a foot-long duct that connects the kidney and the bladder. The drug helps stones pass through the duct. A fair amount of data from Europe suggest they’re beneficial, and a big trial is going on in the U.S. to study the issue. The current thinking is that these drugs are quite safe, and many urologists and E.R. doctors use them.
What to Ask About Kidney Stones
By Laurie Tarkan
NY Times Article : October 25, 2008
Confronting a new diagnosis can be frightening, and because research changes so often, confusing. Here are some questions you may not think to ask your doctor, along with notes on why they’re important.
Do I have any other stones remaining in my kidney?
Patients aren’t always told they have other stones after they pass one. The reason this is a problem is that if they change their diets and then pass another stone, they wouldn’t know if that stone was there from the start or if it developed despite the dietary changes. This can cause people to give up on preventive lifestyle changes.
Are there any abnormalities in my blood test?
Certain disorders, like parathyroid disease and diabetes, can contribute to kidney stones. It may be more important to treat these conditions than to make dietary changes to prevent further stones.
If I have another stone, do I need to remove it?
Not all stones need to be removed. However, stones should be removed if there are signs of infection, if they are causing symptoms or if they are so large that they’re likely to cause problems down the road.
What dietary changes should I make?
Depending on the urine analysis, you may need to decrease or increase certain foods in your diet. Dietary changes can reduce your risk of a recurrence by at least 40 percent, and possibly by up to 80 percent. Doctors recommend trying to lose weight if you’re overweight, drinking more fluids, increasing citrus fruits and drinks, increasing all fruits and vegetables, and reducing salt, sugar and animal protein, particularly red meat, in your diet.
Do I need to take medications?
Depending on the results of a urine analysis, you may not be able to prevent stones by diet alone. A doctor may prescribe medications to help prevent calcium and uric acid stones. These medicines control the pH balance in the urine, which affects crystal formation. Thiazide diuretics are often prescribed if urine calcium levels are high, and potassium citrate is prescribed to balance the pH in the urine.
How many patients have you treated for stone prevention?
Urologists tend to be surgeons, and many don’t necessarily focus on prevention. They may not have the time to sit and discuss all the important dietary modifications that can prevent stones. If your doctor is not that experienced in prevention, ask to see a nephrologist or kidney specialist.
What follow-up tests do I need?
If you are given dietary changes, you should have a 24-hour urine test about a month later to see if the recommendations have had any impact. If everything looks good, you could wait a year before having another urine test to make sure the diet is still helping.
5 Things to Know:
Lifestyle Changes Can Reduce the Risk of Stones
Dr. Gary Curhan is a nephrologist at Brigham and Women’s Hospital and an associate professor of medicine and epidemiology at Harvard Medical School and Harvard School of Public Health in Boston. He has conducted some of the most extensive research into the causes of and risk factors for kidney stones, with the goal of improving prevention strategies.
“Lifestyle changes can dramatically reduce the risk of stones,” Dr. Curhan said. Here are five things he believes everyone should know about kidney stones.
If you pass a stone, try to retrieve it.
That way it can be analyzed to find out what type of stone it is. The most common type is a calcium oxalate stone, followed by calcium phosphate stones and uric acid stones. “Not knowing the composition of a stone handicaps us,” Dr. Curhan said.
Drink more fluids.
Stones can be prevented if you’re willing to make changes to your diet and lifestyle. Randomized trials have found that making changes in diet can reduce your risk of a recurrence by 40 percent, and observational studies have shown an 80 percent reduction in risk. The most important thing you can do is to drink more fluids.
Consider dietary changes and medications.
Your treatment depends on what type of stone you have and may consist of dietary changes as well as medications to change the profile of your urine. Evidence suggests that the most important changes are drinking more fluids, increasing all fruits and vegetables, and reducing salt, sugar and animal protein in your diet. If urine calcium levels are high, thiazide diuretics can be used. If you have low urine citrate, potassium citrate may be prescribed to help correct the pH in the urine.
Make sure you get a blood test and full evaluation when you have a kidney stone.
Stones can be symptoms of other systemic disorders like diabetes, high blood pressure, hyperparathyroid disease and osteoporosis.
Get follow-up care.
Your doctor should regularly retest your urine with a 24-hour urine test to see if the dietary changes are working.
Kidney Stones Affecting More People, Earlier
By Laurie Tarkan
NY Times Article : October 25, 2008
In Brief:
- Pediatric experts are noting a rise in kidney stones in young adults and children.
- Obesity, high-salt diets and even calcium supplements have been linked to the increase in kidney stones, but dietary measures can prevent stone formation.
- Stones can now be removed through minimally or noninvasive techniques, and new drugs are helping people pass stones without surgery.
Urologists also say that adults are showing up with their first stones at much younger ages — in their 20s and 30s, rather than their 40s and 50s, as was common in the past. And while about 12 percent of men and 7 percent of women get a kidney stone at some point, studies have found that rates are rising faster in women.
Alarmingly, kidney stones, once rare in children, are becoming more common in this age group, too, though there is no hard data on the number of cases.
Experts agree that the obesity epidemic is partly to blame. Women appear to be particularly sensitive to the effects of weight gain. One study found that a 35-pound weight gain since early adulthood increased the risk of stone formation by 40 percent in men but by 80 percent in women.
Weight gain is not the only factor associated with an increased risk of kidney stones, which form when certain substances in the urine become too concentrated and crystallize. Dietary factors, which contribute to the makeup of the urine, contribute to stone formation as well.
About 75 percent of stones are formed when calcium binds with oxalate, a byproduct of certain foods. Other common types are calcium phosphate stones and uric acid stones. All types are on the rise.
Two factors that increase the risk of stones are not drinking enough water and having a high-sodium diet, a not uncommon combination. Other risk factors include a diet high in animal protein and a diet rich in the common sweeteners fructose and sucrose (table sugar).
Contrary to what many people believe, calcium-rich dairy products appear to lower risk, and reduced consumption of dairy products may also be contributing to the rise in stones. The dietary calcium binds to oxalate in the gut, which prevents it from being absorbed into the urine.
“Some people believe that if you have a calcium stone, you should go on a low-calcium diet, and that’s absolutely the wrong thing to do,” said Dr. Gary Curhan, associate professor of medicine at Harvard Medical School.
On the other hand, calcium supplements have been shown to increase the risk of kidney stones. One explanation is that people tend to take supplements alone, not with a meal, so they’re not getting the benefit of the calcium’s binding with oxalate from food. They increase calcium levels without lowering oxalate levels.
Similarly, while some citrus fruits and drinks like lemonade and possibly orange juice can help prevent kidney stones, taking vitamin C supplements has been found to raise the risk.
Randomized trials have shown that people who made changes in their diet reduced their risk of stone recurrence by 40 percent. Observational studies have found an 80 percent reduction in risk. Certain medications can also help balance urine content and prevent stones, depending on their makeup.
Stones should be retrieved and analyzed to determine the type stone and what components in the urine are too low or too high, Dr. Curhan said. Patients should also be evaluated for other illnesses that are associated with kidney stones, including osteoporosis, high blood pressure and diabetes.
This reporter had kidney stones for two years without being adequately evaluated by her urologist. Only a routine physical later detected high calcium in the blood, which led to a diagnosis of hyperparathyroid disease, a correctable disorder that causes 5 percent of kidney stones.
The good news is that regardless of cause, treatment has gotten better. Typically a patient goes to the emergency room when a stone is passing, meaning that it has dislodged from the kidney and is traveling in the urine to the bladder through the narrow, foot-long tube called the ureter.
In the past few years, doctors have begun prescribing alpha blockers, like Flomax, which help relax and dilate the ureter, making it easier and less painful for the stone to pass through.
When stones are too large to pass — they can grow as large as golf balls — surgery is an option. But there are two procedures that don’t require surgical incisions.
Shock-wave lithotripsy uses high-energy sound waves to blast the stones into fragments, which then are passed more easily. The other method, ureteroscopy, wends a scope up the ureter and grabs the stone to remove it or destroys it with a laser. Lithotripsy is often preferred, when appropriate, because it is noninvasive, but it has a lower success rate, and the stone fragments still need to be passed.
One study from the Mayo Clinic found that lithotripsy may increase the risk of diabetes and hypertension. The concern is that the sound waves may be damaging normal kidney tissue, though some experts criticized the study.
“If there were serious and common complications, they would have been more obvious by now,” said Dr. Orson Moe, a nephrologist and professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas. “But I think until we have a multicenter or nationwide follow-up study, we won’t know.”
Fewer surgeries would be needed if prevention were taken more seriously.
“I’ve had patients who have had 20 or 30 stones,” Dr. Curhan said. “But if you are willing to make lifelong changes, stones can be prevented.”
THE CLAIM:
Fruit Juice Can Prevent Kidney Stones
By Anahad O'Connor : NY Times : March 2, 2010
THE FACTS:
Kidney stones strike more than a million Americans every year, sometimes causing enough pain to bring them literally to their knees.
Along with medication to discourage the formation of kidney stones, sufferers are often encouraged to make dietary changes, among them drinking more citrus juices. Citrate in the fruit reduces the formation of calcium
But not all juices have the same effect. Lemonade or diluted lemon juice is the usual recommendation for people with calcium stones. But a study financed by the National Institutes of Health in 2006 compared lemonade with orange juice in patients with calcium stones and found that three cups of orange juice a day — along with other standard dietary changes for kidney stone patients — did a better job of raising citrate levels and decreasing urine acidity than lemonade or distilled water.
Then there are cranberry and apple juices, which, according to studies. are good for some stones and bad for others. They raise the recurrence risk of calcium stones, but help prevent a far less common subset of kidney stones called brushite. Grapefruit juice, in contrast, raises the risk across the board. One large study in The Annals of Internal Medicine found that a daily cup of grapefruit juice raised the risk of stone formation as much as 44 percent.
THE BOTTOM LINE:
Some fruit juices protect against kidney stones; others raise the risk of recurrence.
Passing A Kidney Stone Can Be VERY Painful
