Kidney stones are hard deposits made of minerals and salts that form inside your kidneys.
Kidney stones are a common urological condition. About 1 in 10 people experience kidney stones.
Kidney stones can cause severe discomfort. Leaving them untreated can lead to complications.
They can affect any part of the urinary tract and cause significant pain when passing through the urinary system.
Urologists at WashU Medicine
Urologists at WashU Medicine see patients at Barnes-Jewish Hospital, one of the top hospitals in the nation, as well as convenient locations across the St. Louis region.
Kidney stone symptoms
Kidney stone symptoms typically occur suddenly when a stone starts to pass. Kidney stones can cause several symptoms, including:
- Severe pain in the side and back
- Pain during urination
- Nausea
- Frequent urination
- Blood in urine (called hematuria)
Kidney stone causes
The main cause of kidney stones is dehydration.
Usually, particles in your kidneys are dissolved in urine. When you are dehydrated, these particles can form into stones.
Several factors can contribute to the formation of kidney stones. These factors can include:
- Dehydration
- Certain diets
- Obesity
- Some medical conditions
- Certain supplements and medications
Read more: Hydration and kidney function>>
Risk factors
A risk factor is anything that increases your chance of developing kidney stones. Some risk factors include:
- Family history
- Chronic dehydration
- High-sodium diets
- Obesity
Screenings and diagnosis
If you or your doctor thinks you might have kidney stones, there are tests to help diagnose the condition. These tests might include:
- Patient history
- Physical exams
- Imaging techniques like CT scans
- Urine tests to identify and evaluate kidney stones accurately
Kidney stone treatments
Many small stones will pass naturally. For stones that pass naturally, there are medications that can help keep you comfortable during the process. This process may take a few days to a week or more
For larger stones that cause severe symptoms, or for stones that will not pass with medical treatment, there are procedures to treat them.
Kidney stone procedures
Shockwave lithotripsy
Shockwave lithotripsy is a common treatment for small-to-medium-sized kidney stones. It is non-invasive and usually performed under sedation.
This procedure uses sound waves to break the kidney stones into smaller pieces that can be easily passed through the urinary tract. The small pieces of stone then wash out of the kidney with normal urine flow, usually with little or no discomfort. This procedure is highly effective for most stones in the kidney and ureter.
Advantages of shockwave lithotripsy include:
- Excellent success rate for small-to-medium sized stones
- Outpatient procedure
- Minimal discomfort
- No incisions or invasive procedures
- Fast and easy scheduling
Ureteroscopy
Ureteroscopy and laser lithotripsy is a common treatment for small-to-medium stones.
During this procedure, the urologist inserts a small scope through the urethra into the urinary tract. A laser is used to break the stone into smaller pieces. These smaller pieces are then removed or allowed to wash out of the kidney with the normal flow of urine.
This is typically a same-day procedure with the patient under general anesthesia.
Often, a small tube, called a stent, will be placed temporarily to help the kidney drain after the operation. The stent is completely internal, and is generally removed after 3-10 days. Removal is performed quickly and easily in the office without the need for anesthesia.
Although slightly more invasive than shockwave lithotripsy, ureteroscopy may be the preferred option if you have certain types of hard stones that don’t respond to shockwave lithotripsy, or a stone that is not visible on X-ray. In addition, ureteroscopy is often preferable to shockwave lithotripsy for stones that are low in the urinary tract, in the region approaching the bladder.
Advantages of ureteroscopy include:
- Excellent results for small- and medium-sized kidney stones
- Versatility and capability of treating some stones that won’t break with shockwave lithotripsy
- Can be performed without stopping blood-thinning medication
- Outpatient procedure
- No incisions
- Easy and fast scheduling
Percutaneous nephrolithotomy
For exceptionally large or complex kidney stones, or for a large number of small stones in one kidney, the recommended method of treatment is percutaneous nephrolithotomy.
Percutaneous nephrolithotomy is an inpatient procedure, which typically requires an overnight hospital stay.
Percutaneous nephrolithotomy is performed by a urologist, typically with the assistance of an interventional radiologist. The urologist and radiologist work together to create a channel directly into the drainage system of the kidney through a small incision in the back, typically no larger than a dime.
The urologist is then able to use a set of specialized equipment to shatter the stones, which are then either vacuumed or plucked out of the kidney.
A drainage tube or stent is then left in place temporarily to help the kidney drain.
For exceptionally large or complicated stones, a second “clean-up” procedure may be necessary.
Most patients can be discharged within 24 hours of their procedure.
WashU Medicine is a major referral center for percutaneous nephrolithotomy, with urologists performing hundreds of procedures per year.
Our team includes urologists with considerable training and experience with this complex procedure, offering excellent outcomes for even the most difficult stones.
Despite its more invasive nature, this procedure remains a safe and effective form of treatment, with studies finding a high level of patient satisfaction compared to other forms of stone treatment.
Advantages of percutaneous nephrolithotomy include:
- Gold-standard for treatment of very large or complex stones, and for patients with several smaller stones in one kidney.
- Capable of clearing most stones completely with one procedure
- Safe and effective
- Highly trained WashU Medicine urologists who specialize in percutaneous nephrolithotomy
Potential Complications
While kidney stone procedures are generally safe, potential complications can include infection, bleeding, and rare damage to the urinary tract.
What to expect on the day of the procedure
Patients undergoing procedures can expect thorough pre-operative care, including instructions on fasting and medication.
On the day of the procedure, your medical team will ensure you are comfortable and inform you about the steps involved.
The exact details of what to expect depend on the procedure. After some procedures, you may be able to go home right away. For more invasive procedures, you may need to stay in the hospital for a few hours or overnight. Your urologist will answer any questions and help you understand what to expect.
Recovery
After a procedure, patients will receive detailed instructions, including dietary adjustments, hydration tips, and prescribed medications to manage pain and prevent infection.
Regular follow-ups may be scheduled to monitor recovery and prevent recurrence of kidney stones.
Medical maintenance and rehabilitation
Preventive care can help reduce the chance of more kidney stones coming back. This may include lifestyle and dietary changes to reduce the risk of new stones forming.
Learn more about kidney health problems>>
Frequently asked questions about kidney stones
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.
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.
No. Gallstones are mostly made of cholesterol, which is not found in kidney stones.
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.
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.
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.
Kidney stones can damage the kidneys, but they do not always cause damage.
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. If 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.
Many kidney stones can pass without the need for surgery. For kidney stones that don’t require surgery, medications can help with pain and speed up the passage of the stone.
Many people decide to have a procedure for their kidney stones to help get rid of them.
Large kidney stones and stones that cause other problems often require surgical treatment.
With medical expulsive therapy, most small stones (less than 5 or 6 mm) will typically pass within a few days to a few weeks. If you are in good health, you can try for up to 6 weeks to pass a stone, although most patients elect for earlier intervention.
With a surgical or minimally invasive procedure, kidney stones can pass much more quickly, or even be removed immediately.
Yes, it is still good to see a urologist.
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.
Yes. There are several situations in which immediate evaluation is recommended for kidney stones, 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
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.
Diets high in sodium can contribute to kidney stone disease. You should avoid adding table salt to food. Keep in mind that fast foods, restaurant foods, canned foods, deli meats, and 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. Before making any sudden changes to your diet, be sure to consult with your health care provider.
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.
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 have a kidney stone problem, it might be better to avoid cranberry juice.
There are other things that can increase your risk of forming a kidney stone, including:
- Grapefruit juice: One glass of grapefruit juice can also nearly double your risk of forming a kidney stone.
- Megadoses of vitamin C: Vitamin C supplements (like those sold as cold prevention remedies) can lead to a rapid formation of a kidney stone
