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What Causes Kidney Stones?

Asian Institute of Nephrology and Urology | April 05, 2023


Types of kidney stones:

There are several types of kidney stones, and each type is formed by a different combination of minerals or substances in the urine. The most common types of kidney stones are:

Calcium stones: These are the most common type of kidney stones, accounting for about 80% of cases. They are typically composed of calcium oxalate, although they can also be made of calcium phosphate.

Uric acid stones: These stones are formed when the urine is too acidic, causing uric acid to crystallize and form stones. They can be caused by a diet high in animal protein and certain medical conditions such as gout.

Struvite stones: These stones are less common and are usually the result of a urinary tract infection. They are composed of magnesium, ammonium, and phosphate.

Cystine stones: These stones are rare and are caused by a genetic disorder that causes the kidneys to excrete too much of certain amino acids, including cysteine.

Less common types of kidney stones include those composed of xanthine, indinavir, and other substances.

Identifying the type of kidney stone is important for determining the underlying cause and the most appropriate treatment approach. It can also help in developing strategies to reduce the risk of future kidney stones.

Here are some examples of how identifying the type of kidney stone can inform treatment and prevention:

Calcium stones: If a person has calcium stones, they may be advised to reduce their intake of foods high in oxalate, such as spinach, nuts, and chocolate. They may also be advised to increase their intake of fluids, especially water, to help prevent the concentration of minerals in the urine.

Uric acid stones: If a person has uric acid stones, they may be advised to reduce their intake of foods high in purines, such as red meat and shellfish, and to increase their intake of fluids to help dilute the urine.

Struvite stones: If a person has struvite stones, they may need antibiotics to clear up any urinary tract infections and prevent further stone formation.

Cystine stones: If a person has cystine stones, they may need to take medication to reduce the amount of cystine in their urine, and may be advised to increase their fluid intake to help prevent stone formation.

In addition to these specific treatments, all individuals who have had kidney stones are advised to increase their fluid intake and make dietary modifications as needed to reduce their risk of future stone formation. Regular follow-up with a healthcare provider may also be recommended to monitor kidney function and identify any changes in stone formation.

Who gets kidney stones? What are the risk factors?

Kidney stones can develop in anyone, but some people are at higher risk than others. Here are some factors that can increase a person's risk of developing kidney stones:

Family history: If a person has a family history of kidney stones, they may be more likely to develop them themselves.

Age and gender: Men are more likely than women to develop kidney stones, and the risk increases with age.

Diet: A diet high in sodium, sugar, and animal protein can increase the risk of kidney stones, as can a diet low in calcium and water.

Medical conditions: Certain medical conditions, such as hyperparathyroidism, gout, and inflammatory bowel disease, can increase the risk of kidney stone formation.

Medications: Some medications, such as diuretics and antacids, can increase the risk of kidney stones.

Dehydration: Not drinking enough fluids can cause the urine to become concentrated, which can increase the risk of kidney stones.

Obesity: Being overweight or obese can increase the risk of kidney stone formation.

Previous kidney stones: People who have had kidney stones in the past are at higher risk of developing them again.

Geography: People who live in areas with hot and dry climates may be at higher risk of kidney stones due to dehydration.

It's important to note that while these factors may increase the risk of kidney stones, they do not guarantee that someone will develop them. Conversely, someone without any of these risk factors may still develop kidney stones.

What are the symptoms of kidney stones?

The symptoms of kidney stones can vary depending on the size and location of the stone. Some people with kidney stones may not experience any symptoms, while others may experience severe pain. Here are some common symptoms of kidney stones:

Pain: The most common symptom of kidney stones is pain, which can be severe and sudden. The pain may come and go, and can be felt in the back, side, lower abdomen, or groin.

Nausea and vomiting: Some people with kidney stones may experience nausea and vomiting, especially if the pain is severe.

Changes in urine: The presence of kidney stones can cause changes in the urine, such as blood in the urine, cloudy urine, or a foul odor.

Urinary urgency: Some people with kidney stones may feel a strong urge to urinate frequently, or may have difficulty urinating.

Fever and chills: In some cases, kidney stones can cause a fever and chills, which may be a sign of an infection.

If you are experiencing any of these symptoms, especially severe pain, it's important to seek medical attention right away. Your healthcare provider can diagnose kidney stones with imaging tests, such as X-rays or ultrasound, and can provide treatment to help manage the pain and prevent further complications

How are kidney stones diagnosed?

Kidney stones are typically diagnosed through a combination of medical history, physical examination, and imaging tests. Here are some common methods used to diagnose kidney stones:

Medical history: Your healthcare provider will ask you questions about your symptoms, including the location and severity of any pain, changes in urine, and any other related symptoms.

Physical examination: Your healthcare provider may perform a physical examination to check for signs of pain, tenderness, or swelling in the abdomen, back, or side.

Imaging tests: Imaging tests can help identify the presence of kidney stones and determine their size and location. Common imaging tests include:

X-rays: X-rays can help detect most types of kidney stones, but they may not be able to detect smaller stones or stones that are made of certain materials, such as uric acid.

CT scan: A CT scan is a more detailed imaging test that can detect even small kidney stones and determine their location and size.

Ultrasound: An ultrasound uses sound waves to create images of the kidneys and can help detect kidney stones, especially in people who are pregnant or have allergies to contrast dye used in other imaging tests.

Urine tests: Your healthcare provider may also collect a urine sample to check for signs of infection or other conditions that may be contributing to the formation of kidney stones.

If you are experiencing symptoms of kidney stones, it's important to seek medical attention. Your healthcare provider can diagnose the condition and recommend appropriate treatment to manage your symptoms and prevent further complications

What are the treatment options for kidney stones?

The treatment for kidney stones depends on the size, location, and type of the stone, as well as the severity of the symptoms. In many cases, small kidney stones may pass on their own with plenty of fluids and pain management, while larger stones or stones that cause severe symptoms may require medical intervention. Here are some common treatment options for kidney stones:

Drinking plenty of fluids: Drinking water and other fluids can help flush out kidney stones and prevent them from forming in the first place. Your healthcare provider may recommend drinking at least 2-3 liters of fluids per day.

Pain management: Over-the-counter pain medications such as ibuprofen or acetaminophen can help manage pain associated with kidney stones.

Medical therapy: Some medications can help dissolve certain types of kidney stones or prevent them from forming in the first place. For example, alpha-blockers can help relax the muscles in the ureter and make it easier for small stones to pass.

Other medications include oral alkalinization used to increase urine pH for uric stones and hypercalciuria for calcium stones.

Extracorporeal shock wave lithotripsy (ESWL): ESWL uses shock waves to break up kidney stones into smaller pieces, which can then be passed more easily. This procedure is non-invasive and does not require surgery.

Ureteroscopy: Ureteroscopy involves using a small, flexible scope to visualize and remove kidney stones that are located in the ureter or bladder.

Percutaneous nephrolithotomy (PCNL): PCNL is a surgical procedure that involves making a small incision in the back and using a scope to remove larger kidney stones.

If you have kidney stones, it's important to talk to your healthcare provider about the best treatment options for your specific case. In addition to medical treatment, lifestyle changes such as a healthy diet and regular exercise can also help reduce the risk of kidney stone formation.

At AINU's Stone Treatment Center – providing services at our BANJARA HILLS, DILSUKH NAGAR, HI-TEC CITY, and VIKRAMPURI (SECUNDERABAD) – we offer state-of-the-art and minimally invasive care for kidney stones.

As kidney stones have a rate of recurrence of up to 50% at 5 years, surveillance with imaging modalities is necessary to ensure treatment success or to guide further changes to the treatment plan.

AINU's Stone Treatment Center has state-of-the-art operating rooms that are equipped with the latest technology including ultra-thin flexible and rigid ureteroscopes, high-end digital imaging, and a variety of lasers including HOLMIUM LASER, THULIUM FIBRE LASER. AINU’s urologists are fellowship trained and perform high-volume weekly caseloads.

As a result, AINU has a reputation for the successful management of difficult stones, and many of our patients are able to go home within a day or two after surgery.

Kidney Stone Prevention

Are there prevention programs for kidney stones?

AINU's Stone Treatment Center concentrates not only on the treatment of kidney stones but also on prevention once the initial stone is removed.

At AINU we have a commitment to 24-hour urines and metabolic work-up to prevent future recurrences.

We also provide dietary counseling for appropriate diet and nutrition planning to prevent a recurrence of kidney stones.

One of the best preventative measures against kidney stones is proper fluid intake.

It is recommended that you drink at least 8 glasses or 3 liters of water each day in order to pass about 2.6 quarts (2.5 liters) of urine daily. Other general diet and prevention recommendations include:

  • Moderate calcium (1000-1200 mg/day)
  • Low sodium (less than 2300 mg of salt/day)
  • Low refined sugar (less than 100 g/day)
  • Decrease oxalate (40-50 mg/day of foods such as beets, spinach, sweet potatoes)
  • Decrease intake of animal protein
  • Increase citrate (lemons and limes)
  • Increase intake of fruits and veggies
  • Increase dietary insoluble fiber (around 20 g/day of foods such as whole grains and nuts)
  • Magnesium supplement (for calcium stones)
  • Potassium supplement (for uric acid and cystine stones)