- Kidney Stones: Your Questions Answered
- Patient Education
- Kidney Stones
- How common are kidney stones?
- What is a kidney stone?
- What are the most common types of kidney stones?
- What are the symptoms of a stone?
- What should I do if I have these symptoms and think I have a stone?
- How are stones diagnosed?
- Why does the doctor need to examine the contents of the stone?
- Are there any long term consequences of having a kidney stone?
- What can I do to decrease the risk of kidney stones?
- Do children get kidney stones?
- How are kidney stones treated?
Kidney Stones: Your Questions Answered
busy_bee: I recently went to the doctor for lower abdominal pain that would not go away. They did a CT scan, and a large kidney stone was found. How often is this type of pain associated with stones? Is this type of pain indicative of a kidney stone?
Dr__Monga: It is often difficult to determine if a stone is the cause of a patient’s pain. If the stone is on the same side as the pain, then it is certainly possible that the pain is caused by the stone even if it is in the lower abdomen. It would also depend on the location of the stone within the kidney (i.e., is it causing an obstruction or not?). Sometimes, we have to remove the stone with the understanding that the pain may or may not improve.
age_first: My doctor has said that when the pain stops, the stone has moved into the bladder. That happened 5 days ago, and I still have not passed the stone. How long does this typically take?
Dr__Monga: Once it reaches the bladder, the stone typically passes within a few days, but may take longer, especially in an older gentleman with a large prostate. However, pain may subside even if the stone is still in the ureter, so it is important to follow up with imaging if you do not pass the stone within 4-6 weeks.
alexm: A kidney stone was detected during a recent echo exam, with estimated size of 7-10 mm. Then I had an X-ray of the stone, and this time the stone’s size was estimated to be only 3-4 mm. In your opinion, do I need any other diagnostic exam to clarify the discrepancy between these two conflicting results?
Dr__Monga: CT scan is the most accurate but also uses more radiation. Would only recommend CT if you are having pain. Otherwise KUB (plain X-ray) is more reliable than US (ultrasound) for stone size. This is good news for you!
MikeLR: I have passed 2 calcium oxalate stones (2.5m on left side in 2008 and 3.0m on right side in 2012). I had been told to avoid oxalate-rich foods, red wine, and to drink more water and lemonade. Do you have any other specific recommendations as far as my diet to avoid another occurrence?
Dr__Monga: General guidelines are:
- drink plenty of fluids – target is to make 2 liters of urine a day
- limit your sodium
- increase citrates (lemonade is only 15% lemon juice)
- oxalates – main issues are spinach and rhubarb. Other oxalate foods should be avoided only if your oxalates are high in the urine.
- additional dietary recommendations should be based on a 24-hour urine collection
songcanary: Forty years ago as a teenager I had one calcium oxalate stone lodged in the ureter, which required major surgery to remove. I was told to drink more water and have not had a recurrence since then. However, I am currently taking vitamin D3 1000 IU every day since I was diagnosed with osteopenia 2 years ago. Does this increase my risk for another stone?
Dr__Monga: One study from the University of Wisconsin shows no increased risk with vitamin D. The best way to answer this is for you to do a 24-hour urine collection to assess your stone risk.
clara: I have read drinking lemons in water helps kidney stones. Also, I have been told not to drink city water. What is the best water to drink?
C_Snyder_RD: One-half cup of lemon juice concentrate added to drinking water over the course of the day is a preventive therapy for calcium oxalate stone formation.
As for city water, it is safe to drink but the concern is with water softened using a sodium ion exchange. Softened water should not be used for cooking, drinking, or for ice dispensers.
DeeC: What is the best diet for oxalate stone prevention? I eat a bowl of fruit every day as well as salads and vegetables; I ate this way before and after my stones were found (3 weeks ago). I have already taken beef, pork, pops and sugary juices, nuts, chocolate, and most dairy (cow, skim, and soy milk, yogurt and huge amounts of cheese) out of my diet. Thanks.
Dr__Monga: The most important foods to limit if you have high oxalate in the urine are spinach and rhubarb. A good resource for oxalate and diet is: https://regepi.bwh.harvard.edu/health/Oxalate/files. You might consider a vitamin b6 supplement if your oxalates remain high despite dietary modification.
robtoby: Hello! I have had a few kidney stones. I’ve passed one and ‘blasted’ a couple others. I now have one left that I’m leaving alone for now. I drink a LOT of water and have cut back on my protein intake. I have also increased my vitamin D due to a high PTH level which has now come back down. Any other suggestions from a medical or nutritional aspect? Thanks!
Dr__Monga: General guidelines are:
- drink plenty of fluids – target is to make 2 liters of urine a day
- limit your sodium
- increase citrates (lemonade is only 15% lemon juice)
- oxalates – main issues are spinach and rhubarb. Other oxalate foods should be avoided only if your oxalates are high in the urine.
- additional dietary recommendations should be based on a 24-hour urine collection
lauschke: I have read of many foods that are said to contribute to stone formation. How strong are these associations really?
Dr__Monga: Most studies are based on epidemiologic studies. The level of evidence is usually fair to poor. Only a few studies have had patients follow a regimented diet and compared outcomes to those who didn’t follow those diets. From these studies, the only solid recommendation is DRINK MORE FLUIDS!
Cami: Do I have to refrain from eating so many antioxidants like strawberries, spinach, and so on, in order to avoid more stones?
C_Snyder_RD: Make sure you are not confusing oxalates with antioxidants. Foods high in antioxidants may not be high in oxalates. While you do not have to eliminate these foods from the diet, having a dairy product that is calcium-based will bind the oxalates in the gut and reduce the oxalate load for the kidneys.
joker: Does alcohol consumption have anything to do with kidney stones?
Dr__Monga: Alcohol is not a direct contributor to stone formation, but the dehydrating effects of the alcohol can be an issue. The mixes used for the alcohol such as dark carbonated beverages can lead to stone formation.
Conversely, beer (not draft beer) is protective for men, and wine is protective for women. Limit use to within recommended guidelines, and replace each ounce of alcohol consumed with an ounce of compensatory water to prevent dehydration side effects.
Other conditions (vitamin D deficiency, osteoporosis, hypercalciuria, urinary tract infections)
DianeF: I would like to discuss the relationship between hypercalciuria (high levels of calcium in the urine), osteoporosis, calcium oxalate stones, and current treatment options.
Dr__Monga: Hypercalciuria is an important cause of calcium oxalate stones. First-line therapy is sodium restriction and fish oil supplements. If you remain hypercalciuric, then a thiazide diuretic is usually the next step. It is important to check a parathyroid hormone (PTH) level to make certain this is not the cause. Dietary calcium is the best, but if you need calcium supplements due to osteoporosis, then it is best to take calcium citrate.
jumping_beans: When someone has vitamin D deficiency and low calcium, can that cause stone formation?
Dr__Monga: Bone metabolism and stone risk are closely linked. I would encourage you to have your vitamin D deficiency treated. It may help and is unlikely to hurt your stone risk. If you need calcium supplements, calcium citrate is the best.
llison: I am 72 years old and have osteoporosis and a history of kidney stones. Taking calcium for the osteoporosis seems to cause me to get a lot of kidney stones. What can I do to stop bone loss and not have to deal with recurrent kidney stones?
Dr__Monga: Hypercalciuria is an important cause of calcium oxalate stones. First line therapy is sodium restriction and fish oil supplements. If you remain hypercalciuric, then a thiazide diuretic is usually the next step. It is important to check a PTH level to make certain this is not the cause. Dietary calcium is the best, but if you need calcium supplements due to osteoporosis, then it is best to take calcium citrate.
my_oh_my: Is it common for women who get kidney stones to also have frequent UTI’s? Does one cause the other?
Dr__Monga: Kidney stones and UTIs can be linked. Certainly, stones made up of “struvite” are stones caused by infections from certain organisms. This is a relatively uncommon type of stone (less than 5%). Other more common stones are less likely to cause infection. If a stone is blocking the ureter and the patient has an infection, the situation becomes more of an emergency.
partners: I have had multiple stones for years, and the doctors can’t seem to help. My thyroid and parathyroid have tested normal. We have been playing the trial and error game. I have tried hydrochlorothiazide (HCTZ) but had to go off. Any suggestions? What can a person do to prevent them from forming; that seems like the best proposal to me!
Dr__Monga: I typically rely on a 24-hour urine test to guide what diet and medication to try: allopurinol if the uric acid is high; potassium citrate if the urine pH or citrate is low; HCTZ or other thiazides if the calcium is high; Vitamin B6 if the oxalate is high. These are all performed in conjunction with dietary modification (usually tried first before starting a medication) and follow-up urine tests to see if we are having a positive impact.
zoobee: Flomax for kidney stones? Does it work?
Dr__Monga: It works for stones in the ureter; it will increase the chance that they will pass spontaneously by about 20%, decreases the need for surgery and the time it takes for stones to pass, as well as the amount of associated pain.
let_go: What is an IVP?
Dr__Monga: Intravenous pyelogram. Contrast is given intravenously (through the veins) and then monitored as it is excreted. It is not used as commonly now – CT scans are more commonly used for stone disease.
just_so: I have had two litho procedures on the same stone in the lower pole, without success, and there is also a stone in the upper pole. I would like to know whether a single PCNL (percutaneous nephrolithotomy) procedure could retrieve the stones in both the upper and lower pole with a single incision/hole into the kidney.
Dr__Monga: A PCNL would have a 95% chance of a stone-free result through a single incision. It is often a good alternative if attempts at less invasive approaches have not been successful.
robtoby: My urologist says that once stones get to about 5mm in size, lithotripsy should be considered. I’m inclined to not go through yet another one of those (I’ve had 3 already over the past few years). What’s your take on this? My nephrologist says to ‘wait and see’ for right now.
Dr__Monga: Both options are reasonable – it depends on your preference. Once a stone gets above 5mm in size, the likelihood of passage if it moves into the ureter is less than 40%. With this in mind, if you don’t mind the 60%+ risk of needing a more invasive procedure (i.e., ureteroscopy and stent), then leaving the stones alone is the right thing to do. On the other hand, if you prefer to limit the amount of procedures you undergo, then waiting is the best option. The good news is that we can now do lithotripsy with sedation, so you don’t need to go to sleep. However, lithotripsy is only effective if the stone is in the kidney or upper portion of the ureter; once it drops to the lower ureter, ureteroscopy is required.
hilo: When is surgery necessary to remove a stone(s)?
Dr__Monga: First, surgery is needed if:
- you are having pain because of the stone and would prefer not to wait to see if it will pass
- the stone is too large to pass
- you have waited for it to pass, and it has not
Second, if the stone is not causing pain but you are worried about the risks of watching it which are:
- it may grow
- it may move and cause pain
- it may be associated with infections or (very rarely) problems with kidney function
This is obviously a very complex question that has to factor in the size and location of the stone, if it is causing blockage, how healthy you are, and what your preferences are (observation vs. intervention).
ohohoh: Can the Clinic help my son? He has had debilitating stones for a few years now. His life is on hold right now. He has seen several doctors who have not been able to help him. What is new out there that may be of use to him? He is 25. I’m not really seeking a diagnosis here; I know you can’t do that. What I’m looking for is hope for my son.
Dr__Monga: We would be glad to see your son. One of my partners, Dr. Mark Noble, has pioneered a new procedure (autotransplant) specifically for those few select stone patients who have debilitating disease. There may be other dietary, medical, or surgical options that we could consider.
klp876: My brother has over a thousand kidney stones. His doctors have told him that the situation was inoperable. He trusts his doctors and is following along with their advised treatment. The question I have is, with this many stones growing within the “meat” of his kidneys, is there a risk of some of the larger stones eroding through the kidney’s wall? (Some of these stones are now 13mm in diameter.) He has medullary sponge kidneys, with ptosis of right kidney (not really sure what that means.)
Dr__Monga: With medullary sponge kidney, a “thin lining” typically covers the stones and, yes, eventually the stones may erode through the lining, leading to stone passage. There are a few surgical options that may be helpful – one can unroof the stones with a laser or an autotransplant will help with easier passage of stones when they do occur. Working on diet and medications is also important to prevent stone growth.
moore3: Is there any way to completely prevent kidney stones?
Dr__Monga: No. Part of your risk is genetics. Part of it is environment (your diet, etc.) You can decrease your risk, but unfortunately cannot “guarantee” that stones will never recur. Keep trying your best!
Pirates: Does vitamin D3 or whey protein cause stones?
C_Snyder_RD: Vitamin D3 does not cause stones and is actually needed for calcium absorption. As for whey protein, the literature does point to the fact that the whey does play a role in stone formation but may not be the single cause. This is only as relates to whey supplementation.
clara: I have an osmosis type tank for drinking water that a filter is replaced every year. Is that safe for someone with kidney stone problems?
C_Snyder_RD: Osmosis-type water filtration is acceptable for use by stone patients. The issue for water treatment is using sodium ion exchange whereby the sodium molecules are still in the water that is used for cooking, drinking, and ice making.
poppies: Can you get kidney stones at any age?
Dr__Monga: You can get kidney stones at any age. For males, the risk rises at age 20 and peaks between age 40 and 60, then decreases. For females, the peak is in the late twenties and then decreases thereafter.
gotta_go: What makes one more prone to getting stones?
Dr__Monga: A combination of genetics and diet. When we studied identical twins, about 80% of the risk of stones was related to genes. However, there is much you can do with diet and, on occasion, medications to decrease your risk of stones.
half_way: How long does it usually take to pass a kidney stone? Does it depend on the size?
Dr__Monga: On average, it takes a stone less than 4mm stone 1 to 2 weeks to pass and a stone greater than 4mm stone 2 to 3 weeks to pass.
Cleveland_Clinic_Host: I’m sorry to say that our time with Dr. Manoj Monga and Carolyn Snyder is now over. Thank you again for taking the time to answer questions about Treatment Options and Prevention for Kidney Stones.
Dr__Monga: Thank you for participating in our web chat today. Great questions! Keep drinking your fluids.
C_Snyder_RD: Thank you for joining Dr. Monga and myself today for the kidney stone web chat. We appreciate your questions and interest in stone prevention.
If you would like to make an appointment with Dr. Monga or any of our other urologists in the Glickman Urological & Kidney Institute, please call 800.223.2273 or request an appointment online by visiting www.clevelandclinic.org/appointments. Thank you!
A remote second opinion may also be requested from Cleveland Clinic through the secure eCleveland Clinic MyConsult Web site. To request a remote second opinion, visit eclevelandclinic.org/myconsult.
This information is provided by Cleveland Clinic as a convenience service only and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. Please remember that this information, in the absence of a visit with a health care professional, must be considered as an educational service only and is not designed to replace a physician’s independent judgment about the appropriateness or risks of a procedure for a given patient. The views and opinions expressed by an individual in this forum are not necessarily the views of the Cleveland Clinic institution or other Cleveland Clinic physicians. ©Copyright 1995-2012 The Cleveland Clinic Foundation. All rights reserved.
Each year, there is a 5% to 10% chance that a new stone will form (50% chance over the next 5 to 7 years). The risk is higher if you have a family history of kidney stones or have certain chronic illnesses such as hypertension, obesity, or diabetes. However, there are lifestyle and dietary changes that you can make to reduce the risk of a recurrence.
Most kidney stones are made of calcium. The following is advice for preventing a recurrence of calcium stones. If you don’t know the type of stone you have, follow this advice until the cause of your stone is determined.
Things that help:
The most important thing you can do is to drink plenty of fluids each day, as described above.
Certain foods, such as wheat, rice, rye, barley and beans, contain phytate, a compound that may lower the risk of recurrence of any type of stone.
Eat more fruits and vegetables (especially those high in potassium).
Eat foods high in natural citrate like fruit and fruit juices (using low sugar).
Low calcium contributes to the formation of calcium type kidney stones. Eat a normal calcium diet and speak with your doctor if you are taking calcium supplements. It may be detrimental to reduce your calcium intake. New research shows that eating calcium-rich and oxalate-rich foods together lowers your risk of stones by binding the minerals in the stomach and intestines before they can reach the kidneys.
Limit salt intake to 2 grams (1 teaspoon) per day. Use limited amounts when cooking, and don’t add salt at the table. Processed and canned foods are usually high in salt.
Spinach, rhubarb, peanuts, cashews and almonds, grapefruit and grapefruit juice are all high oxalate foods and should be reduced, or eaten with calcium rich foods. These foods include dairy, dark leafy greens, soy products, and calcium enriched foods.
Reducing the amount of animal meat in your diet may lower your risk of uric acid stones.
Don’t have excess sugar (sucrose) and fructose (sweetener in many soft drinks) in your diet.
If you take vitamin C as a supplement, do not take more than 1,000 milligrams (mg) per day.
A dietitian or your healthcare provider can provide you with specific details about dietary changes to prevent kidney stone recurrence.
How common are kidney stones?
Each year, more than half a million people go to emergency rooms for kidney stone problems. It is estimated that one in ten people will have a kidney stone at some time in their lives.
The prevalence of kidney stones in the United States increased from 3.8% in the late 1970s to 8.8% in the late 2000s. This increase was seen in both men and women, and both whites and blacks. The lifetime risk of kidney stones is about 19% in men and 9% in women. In men, the first episode is most likely to occur after age 30, but it can occur earlier. Other diseases such as high blood pressure, diabetes, and obesity may increase the risk for kidney stones.
What is a kidney stone?
A kidney stone is a hard object that is made from chemicals in the urine. Urine has various wastes dissolved in it. When there is too much waste in too little liquid, crystals begin to form. The crystals attract other elements and join together to form a solid that will get larger unless it is passed out of the body with the urine. Usually, these chemicals are eliminated in the urine by the body’s master chemist: the kidney. In most people, having enough liquid washes them out or other chemicals in urine stop a stone from forming. The stone-forming chemicals are calcium, oxalate, urate, cystine, xanthine, and phosphate.
After it is formed, the stone may stay in the kidney or travel down the urinary tract into the ureter. Sometimes, tiny stones move out of the body in the urine without causing too much pain. But stones that don’t move may cause a back-up of urine in the kidney, ureter, the bladder, or the urethra. This is what causes the pain.
Possible causes include drinking too little water, exercise (too much or too little), obesity, weight loss surgery, or eating food with too much salt or sugar. Infections and family history might be important in some people. Eating too much fructose correlates with increasing risk of developing a kidney stone. Fructose can be found in table sugar and high fructose corn syrup.
What are the most common types of kidney stones?
There are four main types of stones:
- Calcium oxalate: The most common type of kidney stone which is created when calcium combines with oxalate in the urine. Inadequate calcium and fluid intake, as well other conditions, may contribute to their formation.
- Uric acid: This is another common type of kidney stone. Foods such as organ meats and shellfish have high concentrations of a natural chemical compound known as purines. High purine intake leads to a higher production of monosodium urate, which, under the right conditions, may form stones in the kidneys. The formation of these types of stones tends to run in families.
- Struvite: These stones are less common and are caused by infections in the upper urinary tract.
- Cystine: These stones are rare and tend to run in families. What are Cystine Stones?
What are the symptoms of a stone?
Some kidney stones are as small as a grain of sand. Others are as large as a pebble. A few are as large as a golf ball! As a general rule, the larger the stone, the more noticeable are the symptoms.
The symptoms could be one or more of the following:
- severe pain on either side of your lower back
- more vague pain or stomach ache that doesn’t go away
- blood in the urine
- nausea or vomiting
- fever and chills
- urine that smells bad or looks cloudy
The kidney stone starts to hurt when it causes irritation or blockage. This builds rapidly to extreme pain. In most cases, kidney stones pass without causing damage-but usually not without causing a lot of pain. Pain relievers may be the only treatment needed for small stones. Other treatment may be needed, especially for those stones that cause lasting symptoms or other complications. In severe cases, however, surgery may be required.
What should I do if I have these symptoms and think I have a stone?
See a doctor as soon as possible. You may be asked to drink extra fluid in an attempt to flush out the stone out in the urine. If you strain your urine and can save a piece of the stone that has passed, bring it to your doctor. Or, the stone may need to be removed with surgery.
How are stones diagnosed?
Diagnosis of a kidney stone starts with a medical history, physical examination, and imaging tests. Your doctors will want to know the exact size and shape of the kidney stones. This can be done with a high resolution CT scan from the kidneys down to the bladder or an x-ray called a “KUB x-ray” (kidney-ureter-bladder x-ray) which will show the size of the stone and its position. The KUB x-ray is often obtained by the surgeons to determine if the stone is suitable for shock wave treatment. The KUB test may be used to monitor your stone before and after treatment, but the CT scan is usually preferred for diagnosis. In some people, doctors will also order an intravenous pyelogram or lVP, a special type of X- ray of the urinary system that is taken after injecting a dye.
Second, your doctors will decide how to treat your stone. The health of your kidneys will be evaluated by blood tests and urine tests. Your overall health, and the size and location of your stone will be considered.
Later, your doctor will want to find the cause of the stone. The stone will be analyzed after it comes out of your body, and your doctor will test your blood for calcium, phosphorus and uric acid. The doctor may also ask that you collect your urine for 24 hours to test for calcium and uric acid.
Why does the doctor need to examine the contents of the stone?
There are four types of stones. Studying the stone can help understand why you have it and how to reduce the risk of further stones. The most common type of stone contains calcium. Calcium is a normal part of a healthy diet. The kidney usually removes extra calcium that the body doesn’t need. Often people with stones keep too much calcium. This calcium combines with waste products like oxalate to form a stone. The most common combination is called calcium oxalate.
Less common types of stones are: Infection-related stones, containing magnesium and ammonia called struvite stones and stones formed from monosodium urate crystals, called uric acid stones, which might be related to obesity and dietary factors. The rarest type of stone is a cvstine stone that tends to run in families.
Are there any long term consequences of having a kidney stone?
Kidney stones increase the risk of developing chronic kidney disease. lf you have had one stone, you are at increased risk of having another stone. Those who have developed one stone are at approximately 50% risk for developing another within 5 to 7 years.
What can I do to decrease the risk of kidney stones?
Drinking enough fluid will help keep your urine less concentrated with waste products. Darker urine is more concentrated, so your urine should appear very light yellow to clear if you are well hydrated. Most of the fluid you drink should be water. Most people should drink more than 12 glasses of water a day. Water is better than soda, sports drinks or coffee/tea. lf you exercise or if it is hot outside, you should drink more. Sugar and high-fructose corn syrup should be limited to small quantities.
Eat more fruits and vegetables, which make the urine less acid. When the urine is less acid, then stones may be less able to form. Animal protein produces urine that has more acid, which can then increase your risk for kidney stones.
You can reduce excess salt in your diet. What foods are high in salt? Everyone thinks of salty potato chips and French fries. Those should be rarely eaten. There are other products that are salty: sandwich meats, canned soups, packaged meals, and even sports drinks.
You want to try to get to a normal weight if you are overweight. But, high-protein weight loss diets that include high amounts of animal-based protein, as well as crash diets can add to the risk of stone formation. You need adequate protein, but it needs to be part of a balanced diet. Seek guidance from a registered dietitian when embarking on a weight loss diet or any dietary interventions to reduce the risk of kidney stones.
Don’t be confused about having a “calcium” stone. Dairy products have calcium, but they actually help prevent stones, because calcium binds with oxalate before it gets into the kidneys. People with the lowest dietary calcium intake have an increased risk of kidney stones. A stone can form from salt, the waste products of protein, and potassium. The most common type of kidney stone is a calcium oxalate stone. Most kidney stones are formed when oxalate, a by product of certain foods, binds to calcium as urine is being made by the kidneys. Both oxalate and calcium are increased when the body doesn’t have enough fluids and also has too much salt. Based on blood and urine tests, your doctor will determine which types of dietary changes are needed in your particular case.
Some herbal substances are promoted as helping prevent stones. You should know that there is insufficient published medical evidence to support the use of any herb or supplement in preventing stones.
See your doctor and/or a registered dietitian about making diet changes if you have had a stone or think you could be at increased risk for getting a kidney stone. To guide you, they need to know your medical history and the food you eat. Here are some questions you might ask:
- What food may cause a kidney stone?
- Should l take vitamin and mineral supplements?
- What beverages are good choices for me?
Do children get kidney stones?
Kidney stones are found in children as young as 5 years. In fact, this problem is so common in children that some hospitals conduct ‘stone’ clinics for pediatric patients. The increase in the United States has been attributed to several factors, mostly related to food choices. The two most important reasons are not drinking enough fluids and eating foods that are high in salt. Kids should eat less salty potato chips and French fries. There are other salty foods: sandwich meats, canned soups, packaged meals, and even some sports drinks. Sodas and other sweetened beverages can also increase the risk of stones if they contain high fructose corn syrup.
How are kidney stones treated?
The treatment for kidney stones is similar in children and adults. You may be asked to drink a lot of water. Doctors try to let the stone pass without surgery. You may also get medication to help make your urine less acid. But if it is too large, or if it blocks the flow of urine, or if there is a sign of infection, it is removed with surgery.
Shock-wave lithotripsy is a noninvasive procedure that uses high-energy sound waves to blast the stones into fragments that are then more easily passed out in the urine. In ureteroscopy, an endoscope is inserted through the ureter to retrieve or obliterate the stone. Rarely, for very large or complicated stones, doctors will use percutaneous nephrolithotomy/nephrolithotripsy.
If you would like more information, please contact us.
Kidney stones are exceptionally common, affecting nearly one in every ten Americans. Those who have suffered from stones in the past, or who know someone else who has, understand that stones can be incredibly painful when they start to pass. Our team of stone experts at Washington University offers advanced care for the treatment and prevention of stone disease.
Below, you will find information about stone disease, links discussing treatment and prevention options available to our patients, and frequently asked questions about stone disease.
Symptoms associated with kidney stones
When a kidney stone starts to pass, symptoms typically occur suddenly and without warning. Sharp, stabbing pain usually develops in your side or back, typically right at the bottom part of the ribcage. Sometimes, the pain will travel downward into the genital area. Stones that have nearly passed into the bladder may be associated with an intense urge to urinate.
Stone pain typically comes and goes. After an initial period of severe pain, you may feel better for a few hours before developing another attack. Many patients will require medication to help with stone pain.
Nausea and vomiting are also very common and are often a reason for hospital admission during stone attacks. You might also see blood in your urine. This can be unsettling to many patients, but is generally not life-threatening.
The most concerning symptom during a stone attack is fever, which indicates that you may have an infection in addition to a kidney stone. This is a potentially life-threatening combination and requires immediate evaluation and treatment.
Treatment of kidney stones
Kidney stones can be managed in a number of ways, depending upon the size of the stone, your other medical problems, and your overall comfort level. Many small stones will pass with the help of medications, which will keep you comfortable while the stone passes naturally. This process may take a few days to a week or more.
For larger stones, stones that are associated with severe symptoms, or stones that will not pass with medical therapy, surgery is often required.
If you think you have a kidney stone
If you have been diagnosed with a kidney stone, please call (314) 362-8200 to schedule an appointment for evaluation and treatment; we will do our best to make sure you are seen promptly. You may be directed to the emergency department if you are experiencing intractable nausea, vomiting, pain or fever so that urgent treatment can be given.
We have a very limited number of same-day appointments; therefore, it is likely that you will be directed to the emergency department for rapid evaluation. There, they will obtain scans and labs that will help confirm the diagnosis of kidney stones. From that information, we can make an informed decision about your treatment.
If you have recently passed a stone, you should have close follow-up with a urologist. Our team of stone experts can accommodate you at any of our clinic locations.
Frequently Asked Questions About Stone Disease
Q. What causes kidney stones?
A. This is a complex question that is not completely understood. The most important contributing factor is dehydration, which is common among working adults. Urine is a solution, and potential stone-forming particles are typically dissolved in your urine. But, when you get dehydrated, your urine is not able to dissolve as many particles, and stone crystals can form. There are a number of other dietary factors. There can also be problems with your metabolism that may make you more likely to develop stones.
Q. What are kidney stones made of?
A. The most common stones are made of calcium. Other compounds include struvite, which is associated with infections, and uric acid, which is the same material that produces gout attacks.
Q. Are kidney stones and gallstones related?
A. No. Gallstones are mostly made of cholesterol, which is not found in kidney stones.
Q. Why are stones so painful?
A. Contrary to popular belief, the pain is not from the stone itself, but from blockage of urinary flow. This typically occurs when the stone passes from the kidney into the ureter, which is the tube that drains urine from the kidney to the bladder. When the urinary flow is blocked, the urine backs up and stretches the kidney and ureter, which are covered in pain-sensing nerves that respond to stretching forces. This produces the severe pain and nausea often experienced with stones attacks.
Q. Do all stones cause pain?
A. No. Stones that are in the kidney and are not blocking urine flow are not painful. Unfortunately, some of these stones can grow quite large and damage the kidney without causing symptoms.
Q. Is severe back pain always due to a stone?
A. No. Other common causes include muscle pain, nerve pain, severe urinary tract infections, and even severe constipation. Therefore, the diagnosis of kidney stones often requires tests, including labs and X-rays.
Q. Do stones damage the kidney?
A. Potentially, but not always. Kidneys can temporarily lose some of their function when they are blocked by a stone, but in most cases, your kidney will completely recover after the stone is gone. Provided that you are in good health and have normal kidneys, your kidney can tolerate a little over a month of blockage without suffering any permanent damage.
However, large stones, especially those that fill the kidney, or stones that remain untreated after a long time, can cause permanent damage to the kidney, and may lead to kidney loss. This damage often occurs without any symptoms, which is why it is important to see a urologist if you have a stone.
Q. Do all stones require surgery?
A. While many patients will elect for surgical treatment, many small stones can pass without the need for surgery. In these situations, medications that can help your pain and speed up the passage of your stone are usually given. Large stones, or stones that cause other problems, often require surgical treatment.
Q. How long can it take for a stone to pass?
A. With medical expulsive therapy, most small stones (less than 5 or 6 mm) will typically pass within a few days to a few weeks. Provided you are in good health, you can try for up to 6 weeks to pass a stone, although most patients elect for earlier intervention.
Q. I was passing a kidney stone, but now I feel better. I didn’t catch the stone in my urine. Do I still need to see a urologist?
A. Yes. While you may have passed the stone and simply not noticed it in your urine, it is important to know that there are times that your pain might completely resolve, even though the stone is still blocking your kidney. It is critical that you follow up with a urologist to prevent these silent stones from permanently injuring your kidney.
Q. Are there any special circumstances that require immediate evaluation for kidney stones?
A. Yes. There are several situations in which immediate evaluation is recommended, even if your pain is mild. These include:
- You develop fever or chills.
- You have only one kidney (born with one kidney or had one removed, for example).
- You stop making urine.
- You develop confusion or severe fatigue.
- You develop severe nausea and vomiting.
Q. If I have formed a stone in the past, am I at risk of forming more stones?
A. Yes. Unfortunately, once you form one stone, your risk of future stones is increased. You have approximately a 50% chance of forming another stone within 5 years. There are some strategies to reduce the risk of forming stones, but at present, there is no way to completely eliminate your risk.
Q. Is there anything I can do to prevent kidney stones?
A. Diets high in sodium can contribute to kidney stone disease. You should avoid adding table salt. Keep in mind that fast foods, restaurant foods, canned foods, deli meats, even condiments such as soy sauce and ketchup contain high amounts of sodium and should be avoided or consumed in moderation. You should limit sodium intake to 2 to 3 grams or less per day. High amounts of animal protein including red meat, fish, poultry and pork can cause certain types of kidney stones, and consumption should be limited to 1-2 servings, 6-8 ounces per day. You should avoid sugary drinks such as those containing sucrose or fructose. Water is the best fluid to drink and you should aim for 2.5 to 3 liters per day, provided you are not on fluid restriction.
Q. Does calcium intake or supplementation affect my risk of stones?
A. Typically no. Although it’s true that most stones are made from calcium, for most people, normal dietary intake of calcium and even normal calcium supplementation will not increase your risk of forming kidney stones. In fact, for many stone formers, normal levels of dietary calcium may help to prevent kidney stones.
Q. I have heard that cranberry juice is good for the urinary tract. Is this true?
A. This is a common misconception shared by many people. There is actually little evidence to suggest that cranberry offers protection from urinary tract infections. But, more importantly, cranberry juices and extracts are associated with a significant increase in the risk for kidney stones! So, if you are a stone former, you should avoid cranberry juice!
Q. Anything else I should avoid?
A. Grapefruit juice. One glass of grapefruit juice can nearly double your risk of forming a stone. Also, megadoses of vitamin C (like those sold as cold prevention remedies) can lead to a rapid formation of a kidney stone and should be avoided, as well.
Q. Where do you see patients with kidney stones?
A. We offer clinic consultations and treatment for stone disease at our Barnes-Jewish Hospital, Barnes-Jewish West County Hospital and Christian Hospital locations.
She later sought care from a second urologist who also told her that the stone could not possibly be causing her pain in the absence of obstruction. This time however she was accused of having an agenda and seeking care specifically to get pain medication. Similar visits to a variety of emergency rooms elicited more CT scans as well as accusations of seeking pain medications. Each CT result was the same though, all demonstrating a 7 mm non obstructing left lower pole stone.
On one instance a treating practitioner even admonished her, saying that nonobstructing stones don’t cause pain and he should know since he too had been diagnosed with such stones incidentally on a CT scan.
Ultimately she made her way to the clinic for consultation at which point she was offered a ureteroscopy and stone removal. The procedure went well and she was discharged with a stent for one week. She was last seen back 5 weeks after the procedure and reported complete resolution of her pain. She was no longer taking any pain medication whatsoever and there was no evidence of any stone or hydronephrosis on follow-up imaging.
What is Known to Date
Such patients are frequently encountered. Despite a lack of physiologic explanation as to why these non-obstructing stones may cause pain, there is emerging evidence that they do and therefore that removal can cure it.
In 2006 Taub et al. described outcomes of twenty such patients who had chronic flank pain as well as radiographically evident calcifications within their papillae without obvious collecting system stones. Ureteroscopy with laser papillotomy to unroof and remove all evident stone was performed on twenty seven kidneys. Pain improvement was seen in 85% of cases with a durable improvement for greater than one year in nearly 60% of cases.
This study was then repeated on a multi-institutional level with 65 patients undergoing similar procedures over a ten year period. Overall there were 176 procedures performed in this cohort with patients reporting less pain after the procedure 85% of the time. The mean duration of response was 26 months with 60% of patients having sustainable improvements in their pain levels for over one year.
Finally, this clinical scenario is seen commonly enough that it garnered its own nickname at Massachusetts General Hospital where it has been described as “small stone syndrome”. In a retrospective review of patients treated there with ureteroscopic removal of small nonobstructing stones (<4mm) for reasons related to chronic pain, 11/13 patients reported being pain free after the procedure with the other two noting a partial response.
What I think
We still do not completely understand the physiologic explanation for pain in these patients. However, much like Hippocrates over two thousand years ago, clinical observation often precedes scientific understanding. In this regard it is unfair to dismiss the notion that small non obstructing stones can elicit legitimate renal colic.
Physiologic breakthroughs in the understanding of pain signaling and inflammation are currently happening at a rapid rate and it is likely that in time we may be able to better decipher which non-obstructing stones are truly responsible for symptoms. However, until then, such scenarios will continue to be a commonly encountered clinical complexity for urologists.
For the time being I would still advocate consideration of alternative causes of pain in such situations including urinary infection, obstruction and malignancy. A careful history is critical to rule out non-urologic sources such as pathology within the musculoskeletal, pulmonary, gynecologic and gastrointestinal systems. Another important element of the history is whether the patient has previously passed a stone and if the current symptoms are similar to that experience.
Once other explanations have been ruled out, offering stone removal is entirely reasonable. This not only has the potential to improve pain but may also decrease the risk of future stone growth or spontaneous passage at a later date. In such instances, I prefer flexible ureteroscopy with stone removal to shock wave lithotripsy. First, ureteroscopy maximizes the likelihood that all stones can be identified and removed which is especially important in the event that pain persists after the procedure. Second, with ureteroscopy one can inspect the inside of the kidney in high definition which has the potential to offer information not readily available on x-rays and CT scans such as embedded stones, tissue calcifications, and other pathology (Figure 4).
Figure 4 – High definition images obtained during renal endoscopy demonstrating tubular plugging (stones embedded in the kidney) (Courtesy: AE Evan, IMCD and BD plugs: Do they have a role in stone formation).
Finally, it is critical to establish realistic expectations before surgery in regards to pain control. Our understanding of this concept is in evolution and the published literature suggesting a treatment response is limited to relatively few patients. However, as science and history have shown us, just because we don’t fully understand the connection doesn’t mean it doesn’t exist.
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The prevalence of stones has been rising over the past 30 years and is of concern in an aging population. Several factors may contribute to this rise including improved diagnostic abilities, longer life spans, changes in health related behaviours (eg. consumption of soft drinks and animal proteins), environmental changes, or diuretic utilisation).3–6 By 70 years of age, 11% of men and 5.6% of women will have a symptomatic kidney stone.6 Calculi are typically diagnosed based on the presenting symptoms along with an imaging modality, however, classification of the calculus is based on its composition which requires analysis of the calculus after passage or removal. Conservative treatment options/recommendations are frequently determined and implemented at this point.
The underlying mechanism for calculus formation is that of supersaturation in the urine. Saturation is often described as the concentration ratios of calcium oxalate or calcium phosphate to its solubility. The majority of kidney stones contain calcium (approximately 90% in men and 70% in women) while the remainder consist of cystine (<1%), pure uric acid (10–15%) and struvite (10–15%).7 Calcium based stones are most commonly composed of calcium oxalate, calcium phosphate or both. Several factors can affect stone formation and each need to be addressed once they have been identified.
Various factors can increase an individual’s risk of calculus development. Individuals with renal conditions such as polycystic kidney disease or renal tubular acidosis or metabolic syndromes are at increased risk.8,9 Additionally, lifestyle and dietary factors such as low urine volume, diets predominantly consisting of animal protein, oxalate or sodium, and abnormal body weight, sedentary activity and stressful life events may increase an individuals risk for calculus development.10
Urolithiasis is often easily identified due to its classic presentation as is demonstrated in this case. However in certain situations, it is possible that there is a mechanical pain experienced in conjunction with the visceral pain which can often confuse the treating clinician. Table 1 describes some common mechanical and visceral conditions which can present as abdominal, back, flank or groin pain. Deciphering the source of pain is essential to appropriate management as mechanical pain may be relieved temporarily with manual therapy, however the underlying visceral pain is usually persistent unless identified and further managed.11
Common mechanical and visceral origins of abdominal, low back, flank, groin pain
|Sprain/Strain||Pelvic disease (prostatitis, endometriosis, inflammatory diseases, etc)|
|Discogenic||Renal disease (pyelonephritis, urolithiasis nephrolithiasis, perinephric abscess, etc)|
|Traumatic fracture||Aortic aneurysm|
|Compression/Insufficiency fracture||Gastrointestinal disease (cholecystitis, appendicitis, ulcers, etc)|
|Alignment disorders (scoliosis, kyphosis, spondylolisthesis, etc)|
Diagnosis is usually suspected from a history and examination. Patients often complain of severe back, flank or groin pain that is colicy in nature. Physical examination often reveals a restless patient with tenderness at the costovertebral angle which is reproduced with gentle tapping. Although a clinician’s level of suspicion may be heightened following the history and physical examination, confirmation with diagnostic imaging is often required. Conventional radiographs have been utilised to identify the location and size of the calculus. Figure 3 demonstrates a conventional abdominal radiograph of the patient described in this case revealing a 6–7 mm radio-dense concretion in the right ureter (Arrow A). Incidental note is made of a probable pelvic phlebolith (Arrow B) that may be misinterpreted as a distal ureteric or bladder calculi. When circular concretions are located lower in the pelvis, they are more likely to be phleboliths than calculi.
More recently, computerized tomography(CT) has been recognized as the method of choice.12,13 Non-enhanced CT affords the ability to rapidly identify the presence of calculi in the urinary system, however, it is not possible to determine the composition of the calculi. Advances in technology have led to the utilisation of dual energy CT which does have added ability to differentiate the stone material by better characterizing the stone material.14 Although not widely used, the added benefit of dual energy CT can significantly affect the therapeutic options as a trial of urinary alkalinisation is warranted if the calculus is composed of uric acid.
Management options follow two distinct routes. In the acute stage, unless there is obstruction, signs of infection, significant bleeding, or persistent pain, removal or fragmentation is not required.15 In the event that there is significant pain, opioids and nonsteroidal anti-inflammatories are often effective options.15 This was the initial choice of management for the patient described in this case. Alternatively, a randomized study by Mora et al., demonstrated that Trans Electrical Nerve Stimulation (TENS) was beneficial for decreasing pain, anxiety, nausea and heart rate while increasing satisfaction in acute renal colic episodes that were being transported to the hospital by paramedics.16 This form of intervention, although transient, may prove beneficial for chiropractors in situations where patients with acute renal pain present and require transportation to the emergency department.
In general, renal calculi that are >10mm in diameter will not pass on their own as compared to those that are <5mm. Calculi between 5–10 mm have variable outcomes and will either pass on their own or require further interventional management. Ureteral calculi are often managed with interventions such as shockwave lithotripsy or laser lithotripsy.17–20. In the context of infection, initial treatment with ureteric stenting and antibiotics is required. For calculi that are present in the kidneys, the intervention is often dependent on the composition of the calculus. Percutaneous nephrolithotomy may be utilised for calculi that are >20mm, staghorn calculi, or calculi that are not able to be removed cytoscopically.21 Alkalination is often selected to dissolve calculi composed of uric acid.14
Once the calculus has passed, management should focus on prevention. Healthcare practitioners should focus on educating patients about their future prognosis and risk for future calculus formation. Twenty-six percent of individuals with calculi have been shown to recur symptomatically, while 28% have been found in asymptomatic individuals.22 Hence, approximately 50% of individuals (symptomatic and asymptomatic) with a history of calculus formation may develop subsequent calculi over a 10 year period. Self care and lifestyle modifications are thought to help reduce the risk of recurrence.
Prevention of calculi development requires decreasing supersaturation by increasing the individuals’ urine volume and lowering the solubility of calcium oxalate or phosphate. With respect to calculi composed of calcium oxalate, the goal is to raise urine volume while decreasing calcium and oxalate excretion. Increasing daily fluid intake to more than 2 liters has been shown to significantly reduce recurrent calculi formation.23 Other strategies include dietary modifications such as adapting a low sodium, normal calcium, and restricting foods high in oxalate (spinach, rhubarb, wheat bran, chocolate, beets, miso, tahini and most nuts).24
In situations of metabolic abnormalities such as citraturia, individuals are often instructed to follow a prophylactic therapeutic regimen of potassium citrate while others have suggested utilising alkalinizing substitutes while hydrating such as lemonade.25 A recent trial by Tosukhowong et al has suggested that this may be beneficial as individuals utilising a lime powder mixed into their drinks had an increase in alkalinizing and citraturic actions as well as provided an antioxidant effect to attenuate renal tubular damage.26 This may prove to be a viable alternative and a simple addition into the management of individuals susceptible to repeated calculus formation.
Much debate exists about the utilisation of probiotics in preventing oxalate supersaturation. The current belief is that microorganisms such as Oxalobacter formigenes are important for metabolising oxalate.27 However, Lieske et al reported that dietary restriction of oxalate resulted in decreased urinary oxalate levels; but, there were no effects of probiotic utilisation.24 The current research in this area is lacking a standardised sample population to conduct trials. Several authors have suggested that probiotic utilisation is beneficial in moderate to high oxalate diets, whereas Lieske’s study was performed on individuals with low-oxalate diets. To the authors’ knowledge, there is insufficient evidence to support or refute the utilisation of probiotics in prevention of stone development.
Complications of renal and ureteric calculi include: hydronephosis, renal damage, infection of the urinary tract and urosepsis. Hydronephrosis is a condition in which the urinary system is obstructed causing dilation and swelling of the kidney. Unilaterally, it occurs in 1 in 100 people and is often treated by removing the obstruction as well as undergoing a regimen of antibiotics for infections.14 If mismanaged or untreated, hydronephrosis can result in permanent kidney damage and potentially renal failure, particularly devastating in an individual with a solitary kidney.28