Kidney Stones

What Causes Kidney Stones?

Kidney stones occur when high levels of minerals, such as calcium, oxalate and phosphorus, build up in your urine. When your kidneys do not filter these minerals out, they can build up and form hard stones.

The cause of kidney stones typically depends on the type you have:

• Calcium stones: These are most common type of kidney stone and develop when calcium binds with oxalate, phosphate and other substances to form stones. You may develop calcium stones if you eat foods high in oxalates (nuts, leafy greens and wheat bran, for example), sodium and animal protein.
• Cystine stones: These rare kidney stones are caused by cystinuria, which tends to run in families and causes an amino acid called cystine to build up in your urine.
• Struvite stones: These stones can develop after an upper urinary tract infection (UTI).
• Uric acid stones: These can occur if you eat a high-protein diet or have had chemotherapy. People with gout can develop uric acid stones.

Risk Factors for Kidney Stones

• Kidney stones can affect anyone, but they are more common in men and people ages 20 to 70.
• Around 10% of people in the United States have a kidney stone during their lifetime. You may be more likely to develop them if you have the following risk factors:
• A diet high in protein, sodium and sugar
• A history of bowel inflammation, diabetes, gout, polycystic kidney disease, UTIs or conditions affecting the digestive system
• A personal or family history of kidney stones
• Being overweight or obese
• Having had gastric bypass or another GI tract surgery
• Not drinking enough fluids
• Use of medications, including calcium-based antacids, diuretics and certain anti-seizure medications
• Working outside in extreme heat
• Have a genetic condition, such as cystinuria, that makes kidney stones more likely to form

Kidney Stone Symptoms

Kidney stones cause severe pain in the lower back, abdomen or groin. The severity of your pain and other symptoms depends on the size of the stone. Kidney stones can range from the size of a few grains of sand to as large as a golf ball. Larger stones are more likely to cause symptoms.

Kidney stones often cause pain as the stone moves through your urinary tract. The pain usually starts in your abdomen or lower back and travels to your genitals. Other symptoms you may experience with a kidney stone include:

• Cloudy or smelly urine
• Feeling unable to urinate or only urinating a small amount
• Fever and chills
• Nausea and vomiting
• Needing to urinate more often than usual
• Painful urination
• Persistent stomachache
• Urine that appears pink, red or brown, a sign that you have blood in your urine

Diagnosing Kidney Stones

Your doctor will ask about your symptoms, diet and medical history. They might perform a physical exam or order the following tests:

• Abdominal X-rays can show the position of a kidney stone in your urinary tract.
• Blood tests check for high levels of minerals in your blood.
• CT scans can show how large a stone is, where it is located and what condition may have caused it to form.
• Urine tests can check if you have blood or excess minerals in your urine or signs of a UTI.

Kidney Stone Treatment

Stones usually do not have a serious health impact. However, without treatment, they can lead to severe pain, UTIs, kidney infections and even loss of kidney function. They can also increase your chance of developing kidney disease.

You might pass small stones naturally and not need any treatment. Your doctor can prescribe medication to reduce the pain and will advise you to drink plenty of water. Medicine for kidney stones can also help them pass through your system.

However, if the stone is large and causing an obstruction, your urologist might recommend a procedure to break it up or remove it. The best option will depend on the size and location and whether it is causing pain. 

Ureteroscopy

During a ureteroscopy, your urologist inserts a small, lighted tube called a ureteroscope through the urethra and bladder into the ureters, which connect your bladder to your kidneys. Tiny instruments are sent through the ureteroscope to grab a kidney stone or break it up using a laser.

You will usually be able to go home the same day.

Surgical Options

In rare cases, you may need percutaneous nephrolithotomy and nephrolithotripsy, minimally invasive surgeries to treat kidney stones. Less common than the procedures above, your urologist may recommend surgery if stones remain after lithotripsy or ureteroscopy, you are not a suitable candidate for those procedures, or your kidney stones are large or irregularly shaped.

During percutaneous nephrolithotomy and nephrolithotripsy, a small cut is made in your back, and a tiny camera called a nephroscope is inserted into your kidneys. In nephrolithotomy, your surgeon removes the stone through a tube. With nephrolithotripsy, your surgeon breaks up the stone before removal.

Both procedures require a short hospital stay and will be performed under general anesthesia. Recovery time can be between five and seven days.

In some cases, your provider may recommend a partial nephrectomy or radical nephrectomy, robotic surgeries to either remove part of a kidney or the whole kidney.

Shock Wave Lithotripsy

Shock wave lithotripsy is an outpatient, nonsurgical procedure in which your doctor uses high-energy sound, or shock waves, to blast a kidney stone into small pieces that can pass in your urine.

You should be able to go home shortly after the procedure and can resume normal activities within a day or two.

Preventing Future Kidney Stones

If you have had a kidney stone, you have around a 50% chance of developing another one in five to seven years. Your urologist will work with you to identify why you develop kidney stones to help prevent a recurrence.

To start, your urologist may have your stone analyzed after it is passed or removed to determine what it’s made of. The results of this analysis will help you and your urologist develop a plan to prevent future stones from forming.

Next, your urologist will discuss your diet and lifestyle. To help you avoid stones in the future, they may recommend drinking more water, reducing salt and sugar in your diet and maintaining a healthy weight.

Your urologist may also prescribe kidney stone medicine to prevent you from getting another one.