Kidney Stones*The information on this website is not intended to diagnose, treat, cure or prevent any disease.
What are Kidney Stones?
Kidney stones are solid, mineralized objects which form in the urinary tract (usually in the kidney), which then travel down the urinary tract. The stones can vary in size, and very small stones may be passed without causing any symptoms, while larger stones can block different parts of the urinary tract (such as the ureter or urethra), resulting in severe pain and potentially kidney damage.
Kidney stones are extremely common, affecting up to 15% of people at least once in their lifetime (although those that have had one are at increased risk throughout their lifetime). They can be fatal, although the mortality rate is extremely low (less than 0.001%). They have become more common in developed countries over the last several decades, and men generally are at higher risk than women.
There are multiple types of kidney stones which are defined by the types of material they are composed of. The most common types of stones are made of calcium oxalate, a combination of the mineral calcium and oxalates, which are found in plants. Calcium phosphorous stones are another mineral-based stone which are relatively common. Struvite stones are composed of magnesium, ammonium, and phosphorous.
Certain metabolites that are excreted in the urine can also develop into stones. Purines are organic compounds that are found in meats. One of the break-down products of purines is uric acid, which can develop into urate stones, while one purine itself, xanthine, can also form into stones. Finally, cystine stones are made from an amino acid cysteine. Cysteine is normally not excreted into the urine, but some people have a mutation which results in loss of cysteine and formation of crystals.
Kidney stones often develop silently, and symptoms may not arise until they begin to migrate down the urinary tract. The most common symptoms are as follows:
- Severe lower back/side/groin pain which may wax and wane in intensity
- Red/brown/pink urine
- Cloudy urine
- Painful urination
- The feeling of urgency to urinate
- Polyuria (urinating more often)
- Urinating small amounts/straining to urinate
- Inability to pass urine
Evaluation of kidney stones often begins with imaging to visualize the stones, however there are often additional tests which are recommended as well. Diagnostics commonly performed are as follows:
- Imaging: Different types of imaging studies can be done to identify kidney stones. While x-rays are commonly performed, not all types of stones actually show up on x-rays. Other types of imaging which may be done include a CT scan or ultrasound. Sometimes, a contrast study may be performed where a radio-opaque dye is injected into the body and then excreted into the urine. This can help doctors see if there is an obstruction in the urinary tract.
- Urinalysis: Evaluation of the urine can reveal lots of information about kidney stones. Crystals, which are the microscopic basis of stones, can be identified in the urine, which may help diagnosis what type of stones are present. Urinalysis can also identify alterations in pH or identify urinary tract infections which may conditions more favorable to stone formation.
- Blood tests: This may be performed to determine if you have excessive calcium, phosphorous, magnesium or uric acid (a metabolite) in your blood, which can lead to stone formation.
- Genetic testing: Certain genetic mutations are associated with an increased risk of stone formation (particularly cystine stones).
Stone analysis: Stones which are recovered or passed in the urine can be analyzed to determine their composition. This can help identify underlying causes which led to stone formation in the first place.
There are multiple treatment options for kidney stones. The best treatment option for you will depend on the type of stones you have, the size, how many are present, and the urgency with which they need to be removed.
- Alpha-receptor blockers: These medications actually relax the muscles which line the ureters and the urethra, making it easier for stones to pass. As stones pass through these structures, the muscles often spasm, trapping them in place. Alpha blockers can help block this response and allow the stones to continue to transit out of the body.
- Diuretics: These medications tend to increase urine production, but also make urine more dilute. Stones tend to form better in more concentrated urine, so diluting the urine may help prevent additional stone formation.
- Sodium bicarbonate or sodium citrate: These medications alter the pH of the urine, which can make conditions less favorable for stone formation, depending on the type of stones you have. They may also help dissolve some stones slowly over time.
- Allopurinol: This medication decreases circulating levels of uric acid in the blood and can help prevent the formation of urate stones. This medication blocks one of the metabolic processes in the body which generates uric acid.
- Antibiotics: Urinary tract infections are often associated with stone formation, and stones themselves can make an environment favorable to infection setting in. For many people with stones, antibiotics are necessary to clear the infection and prevent future stone formation.
- Over-the-counter Pain medications: Over-the-counter medications are often helpful in managing the pain and discomfort associated with kidney stones. Ibuprofen (Advil), naproxen (Aleve), and acetaminophen (Tylenol) can all be helpful in relieving mild to moderate pain.
- Narcotic pain medications: For moderate to severe pain, opioid medications may be required, such as hydrocodone. These require a prescription from a doctor.
- Shock-wave Lithotripsy: Lithotripsy involves breaking down the stones into smaller pieces, and there are various strategies in which this can be done. Shock-wave lithotripsy uses sound waves to pulverize the stones into smaller fragments. It is typically performed with sedation or anesthesia because it is an uncomfortable procedure.
- Laser Lithotripsy: This procedure involves passing a flexible scope equipped with a laser up the urethra, bladder, or ureters. The laser is capable of breaking down the stone into smaller pieces.
- Urethroscopy: In some cases, a stone may be able to be pulled out of the bladder or urethra. A flexible scope is advanced up the urethra and a small snare is used to retrieve stones.
- Ureteral stent: In cases where a ureter becomes completely obstructed, a stent may need to be placed in order to prevent a kidney from becoming permanently damaged. When a ureter becomes blocked, the kidney may begin to swell due to the backup of urine, which may eventually cause it to fail or need to be surgically removed.
- Nephrolithotomy: This is a surgical procedure performed when less invasive options are not available or unlikely to be successful. This involves cutting over the stone and removing it from the kidney, ureter, or bladder.
There are many non-pharmaceutical therapies for kidney stones which may be beneficial in some people.
- Increase water intake: Concentrated urine tends to favor stone formation. Staying hydrated by drinking plenty of water is a key part of preventing further stone formation and keeping them from getting bigger.
- Kidney Flushes: Drink lots of water and eat specific foods and supplements to help flush and cleanse your kidneys and keep them healthy. Foods like grapes, cranberries, and seaweed are protective to the kidneys. Certain teas like stinging nettle and hydrangea are also thought to protect the kidneys and improve urine flow. Period kidney flushes can be an important part of management for those who are predisposed to developing kidney stones.
- Dietary Modifications: These are often important components of managing kidney stones in people who tend to develop them. Depending on the type of stones you may form, there may be different dietary recommendations for you. For most people, reduction of refined sugars, decreased caffeine and alcohol consumption are important. High levels of vitamin C and vitamin D also seem to be linked to an increased risk of kidney stones.
- Calcium oxalate stones: Reduce the intake of nuts and certain leafy vegetables including spinach and rhubarb. All of these are high in oxalates. Also, sodium restriction is very important, as excess dietary sodium favors stone formation. Reduced animal protein intake is also important, which needs to be offset with high-protein plant sources such as peas, beans, and lentils. Increasing dietary calcium can also help by blocking the absorption of oxalates in the GI tract.
- Calcium phosphate stones: Reducing sodium intake and animal proteins is helpful, similar to that described for calcium oxalate stones. Likewise, getting enough calcium is important to reduce the risk of stone formation.
- Uric Acid Stones: Animal-based proteins increase the formation of uric acid in the body, increasing the risk of stone formation. Weight management is also very important for reducing stone formation.
- Cystine stones: Adequate water intake is essential for reducing the formation of cystine stones.
- Probiotics: The intestinal bacteria Oxalobacter formigenes has been shown to help reduce the excretion of oxalate into the urine, and an absence of this bacteria may be associated with increased risk of calcium oxalate stones.
- Chanca Piedra: This herb is used in the treatment for a variety of conditions. It may help the body rid small kidney stones, particularly following shockwave therapy designed to crush the stones in to smaller pieces.
- Lemon juice: Lemons naturally contain citrate, which can help prevent the formation of certain stones. Lemons may also help acidify urine, helping dissolve stones slowly.
- Apple Cider Vinegar: Apple cider vinegar can help acidify the urine, leading to a slow breakdown of kidney stones
- Pomegranate juice: Similar to lemon juice and apple cider vinegar, pomegranate juice may help prevent stone formation may altering the pH of the urine.
- Tribulus terrestris: The fruit of this plant may serve as a diuretic while also decreasing the excretion of phosphorous in the urine
- Vitamin B6: Vitamin B6 deficiency may lead to increased excretion of oxalates in the urine, which may combine with calcium to form stones.
- Vitamin E: Vitamin E deficiency appears to be associated with an increased risk of stone formation.
- Vitamin K: This vitamin reduces calcium oxalate stone formation.
- Magnesium citrate supplementation: Increasing magnesium intake leads to higher levels of urinary citrate and pH levels, which may help reduce the chance of formation of some types of stones.
- Cholestyramine: Cholestyramine helps bind oxalates in the intestines, preventing their absorption.
- Calcium supplementation: Somewhat counter-intuitively, calcium supplementation may help reduce the risk of calcium oxalate stones. The body is generally very good at regulating blood calcium levels, and will not absorb excessive calcium from the intestines. Calcium in the intestine, however, can bind oxalate before it is absorbed, allowing to be passed through the body.
- Crampbark: May help relax the smooth muscles which line the urinary tract, allowing easier passage of stones.
- Bearberry: A natural diuretic and promotes general urinary tract health.
- Khella: Another herb which may have relaxing properties on the smooth muscles of the urinary tract system.
- Stone root: A diuretic which can help maintain dilute urine, important for preventing stone formation.
- Black cumin seed: Has been shown to reduce calcium oxalate stone formation in animal studies.
- Evening primrose oil: Increases citrate excretion into the urine while reducing calcium oxalate formation.
- Fenugreek: Has been shown to reduce kidney mineralization in animals.
- Rose hips: Combined with magnesium, this herb increases urinary citrate excretion, which interferes with stone formation.
Varuna bark: An Ayurvedic herb which may help reduce kidney stone formation.
Prevention is key for the management of kidney stones. Fortunately, prevention is often achievable for most people, but it does tend to require lifestyle modifications. Some of these are very easy, such as drinking plenty of water to ensure dilute urine. Other modifications can be a little bit more difficult, such as cutting out caffeine and alcohol, losing weight, or sticking to a diet which is lower in animal proteins or moderately sodium restricted. For those who are at risk of stone formation, these are important strategies (any anyone who has gone through the pain of a kidney stone would certainly prefer to not to have to endure another).
If you have ever had a kidney stone, it is extremely important to adopt the lifestyle changes recommended for your specific type of stone. Those who have had a kidney stone in the past are at a much-increased risk of developing another within 10 years of the original event.
For most people, increasing intake of calcium will help decrease the absorption of oxalates from the intestinal tract. It is better to obtain calcium from food rather than supplements. Likewise, reduction ins sodium is also generally helpful for most people who are trying to manage kidney stones. Restriction to less than 1,500 mg of sodium per day may help reduce the risk of stone formation.
Animal proteins are also an important component of reducing the risk of stone formation. Animal proteins cause increased uric acid production, but also reduce the urinary excretion of citrate. These two processes are why most people who have a tendency to develop kidney stones will benefit from reducing animal protein intake.
Reducing the intake of dietary oxalates is also important. Foods high in oxalates include spinach, rhubarb, nuts, tea, chocolate, beets, and dark sodas. Try and avoid these foods if you have a history of stones. Vitamin C can also be converted into oxalates, so avoid high doses which are often included in multivitamins or other supplements.
Finally, staying hydrated and practicing routine kidney flushes can help protect the health of your kidneys and minimize the chances of stone formation. Concentrated urine, which happens with dehydration, favors stone formation. Keeping urine dilute through oral intake of water is one of the most important preventative measures.
There are many possible causes of kidney stones. Often, there is no clear cause other than dietary issues such as low water intake, high salt intake, and a diet high in oxalates and low in calcium. Correcting these issues may resolve stones for many people. Other people are certainly at increased risk of kidney stones due to other conditions.
Obesity is closely linked with kidney stone formation, with overweight people having nearly double the risk of kidney stone development. Weight loss through dietary modification and increased exercise are the best strategies for managing these stones. Studies have shown that weight-loss surgeries (such as gastric bypass or belly banding procedures) may increase the risk of stone formation as well, so it is better to naturally lose weight through non-surgical means.
Endocrine disorders can also cause dysregulation in calcium and phosphorous handling, or result in increased uric acid production. Hyperparathyroidism results in high levels of calcium through hormonal signaling. These leads to increased amounts of calcium lost in the urine, which then favor stone formation. Type II diabetes, on the other hand, can alter the pH of the urine in a way which favors stone formation as well.
People who suffer from gout are also at higher risk of urate stone formation. Gout is excessive uric acid production, which leads to deposition into joints, nailbeds, and also as stones in the urine. People with this condition likely need to make major dietary modifications as well as consider medications such as allopurinol.
People with conditions which tend to make them dehydrated are also at risk of developing stones. Intestinal diseases like Crohn’s disease and ulcerative colitis tend to cause loss of water through the GI tract. The body compensates for this water loss by highly concentrating the urine in order to minimize loss of water through the kidneys. This favors stone formation by creating high concentrations of calcium, phosphorous, and uric acid.
There are also certain medications which can favor stone formation. Some antibiotics such as ciprofloxacin and sulfa- based antibiotics like trimethoprim sulfa (TMS) increase the risk of stone formation, particularly if treated for a long time. Some anti-retroviral drugs used in the treatment of HIV also can predispose to stones.
Infections and inflammatory conditions can also lead to stone formation. Certain urinary tract infections can lead to alterations in urine pH, which favors stone formation. E. coli and Pseudomonas bacteria are often cultured from kidney stones. These bacteria can lead to a favorable stone-formation environment, but they can also themselves become trapped in the stones. Often, treatment of urinary tract infections with simultaneous kidney stones can be frustrating, as the bacteria can find shelter inside the stones and survive the antibiotics, only to re-emerge once the antibiotic has been discontinued. These conditions require simultaneous treatment with antibiotics as well as elimination of the stones themselves.
Lyme disease can cause inflammation of the kidneys (called nephritis) which may alter their function and lead to abnormal handling of calcium. Many Lyme disease sufferers also report dealing with kidney stones after their diagnosis. If you live in a Lyme-endemic area (such as the Northeastern United States), this may be a consideration as well.
Clinics for Management of Kidney Stones