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Kidney Stones

Last updated July 9, 2019

Approved by: Maulik P. Purohit MD, MPH

Blausen.com staff. "Blausen gallery 2014

Kidney Stones are common formations formed by the collection of various salts and minerals. Some of the common stones consist of calcium compounds (calcium oxalate), ammonium compounds (ammonium phosphate), uric acid, and cystine.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Nephrolithiasis
  • Renal Calculi
  • Ureterolithiasis

What are Kidney Stones? (Definition/Background Information)

  • Kidney Stones are common formations formed by the collection of various salts and minerals. Some of the common stones consist of calcium compounds (calcium oxalate), ammonium compounds (ammonium phosphate), uric acid, and cystine
  • These stones are abnormal collection of minerals that can range in size from a few millimeters to several centimeters. They can occur in the kidney, ureter, and urinary bladder
  • The Kidney Stones are likely to form due to increased concentration of urine, which allows minerals to crystallize and stick together. Thus, the substances that are normally found in the urine, become highly concentrated and change to solid form
  • The common signs and symptoms of Kidney Stones include severe abdominal pain radiating to the groin and testes, pain while urination, nausea, and vomiting. An abdominal CT scan is the best modality to diagnose these stones
  • The presence of small Kidney Stones may not need any specific treatment; these may be passed out of the body through drinking plenty of fluids and medications. The larger stones may have to be removed using medical procedures such as shock wave lithotripsy. However, once an individual is diagnosed with a Kidney Stone, there is a risk of getting them again after treatment

Who gets Kidney Stones? (Age and Sex Distribution)

  • Kidney Stones can occur at any age, but are most commonly observed after the age of 30 years
  • Men between the ages of 20-49 years are more vulnerable to developing them. Women are less susceptible to Kidney Stones
  • However, struvite stones are more common in women with urinary tract infections
  • Uric acid stones are more frequently seen in males than females
  • All racial and ethnic groups are affected; although, non-Hispanic Caucasians seem to have a higher risk

What are the Risk Factors for Kidney Stones? (Predisposing Factors)

Following are the risk factors associated with Kidney Stones:

  • Being overweight or obese
  • Insufficient fluid intake

Individuals with the following conditions are more at risk of Kidney Stones:

  • Hypercalciuria: A condition in which urine contains excess amount of calcium
  • A family history of Kidney Stones
  • Cystic kidney diseases: Disorders which cause the formation of fluid-filled sacs in the kidneys
  • Hyperparathyroidism: A medical condition wherein the parathyroid glands release excess hormones to produce excess calcium
  • Renal tubular acidosis: A disorder in which the kidneys do not excrete acid in the urine leading to the presence of excess acid in blood
  • Cystinuria: A disorder in which urine contains excess amounts of an amino acid called cystine
  • Hyperoxaluria: A condition in which the urine contains too much of oxalates
  • Hyperuricosuria: A disorder affecting uric acid metabolism
  • Diabetes and high blood pressure can place one at a higher risk for Kidney Stones
  • Individuals having inflammatory bowel diseases are more at risk than others
  • Those who have undergone intestinal bypass surgery are more susceptible to Kidney Stone formation
  • Blockage in the urinary tract
  • Stressful exercises without adequate fluid replacement
  • Climate: Those living in hot and dry climates can easily become dehydrated, which can lead to Kidney Stone formation

Consumption of certain medications such as:

  • Diuretics, which help the kidneys remove fluid from the body
  • Calcium-based antacids
  • Indinavir - a medicine that is used to treat HIV infection
  • Anti-seizure medicine such as topiramate

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Kidney Stones? (Etiology)

The following are the possible causes for the formation of Kidney Stones:

  • When substances, such as calcium, oxalate, and phosphorous, present in the urine becomes highly-concentrated in the urine, resulting in the formation of Kidney Stones
  • When there is lack of substances in the urine to keep the crystals from sticking together
  • Decrease in urine volume could result in Kidney Stones
  • Presence of excess stone-forming substances in urine can lead to Kidney Stone
  • Dietary habits may be a causative factor
  • Infections of the urinary tract
  • Hereditary factors and family history may also play an important role

What are the Signs and Symptoms of Kidney Stones?

Kidney Stones are small-to-big, hard mineral deposits in the kidneys. They may be rough or smooth and are usually yellow or brown in color. They are of variable chemical composition such as:

  • Calcium- containing compounds
  • Struvite (magnesium, ammonium, phosphate compounds)
  • Uric acid
  • Cystine stones
  • Other compounds

The following are the common signs and symptoms exhibited by individuals with Kidney Stones:

  • Pain while urination, frequent urge to urinate
  • Presence of blood in the urine
  • Sharp pain in the back or lower abdomen that radiates to the groin and testicles
  • Nausea, vomiting
  • Fever and chills
  • Penile pain

How are Kidney Stones Diagnosed?

The diagnosis of Kidney Stones may involve:

  • A thorough physical examination checking for the symptoms of the condition
  • A careful evaluation of medical history to look for:
    • Family history of Kidney Stones
    • Examine one’s diet
    • Health conditions related to the digestive tract
  • Diagnostic tests may include the following:
    • Urinalysis to check for the presence of substances that can form Kidney Stones
    • Blood tests to check for calcium, phosphorus, and uric acid
    • Abdominal x-ray: This will reveal the exact location of Kidney Stones
    • CT scan of the abdomen: 3-dimensional images taken through CT scans can help show the exact location of the stones
    • Ultrasound scan of the kidneys
    • Intravenous pyelogram

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Kidney Stones?

Under normal circumstances, most Kidney Stones do not give rise to any severe complications. However, some complications may include:

  • Unbearably severe pain in the back or lower part of the abdomen
  • Blockage of the urinary tract may lead to kidney damage
  • Increased incidence of urinary tract infections
  • Hydronephrosis of kidneys (swollen kidneys)

How are Kidney Stones Treated?

The treatment and management of Kidney Stones depends upon the following parameters:

  • The size of the stone
  • The composition of the stone
  • The presence of symptoms such as pain
  • Blockage of urinary tract

Small Kidney Stones may normally pass in the urine without any treatment, but the individual may need to take:

  • Pain medication to control pain
  • Drink lot of fluids

Individuals who are diagnosed with large-sized Kidney Stones may be treated using:

  • Shock wave lithotripsy: Kidney Stones are broken and smashed, with the help of a machine called the lithotripter, which uses shock waves that passes through the body and breaks the stones
  • Ureteroscopy: A long tube-like instrument, called the ureteroscope, is inserted into the urethra and further into the bladder and ureter. Laser energy is used to crush the Kidney Stones, which is then allowed to pass from the body through urine
  • Percutaneous nephrolithotomy: An instrument called the nephroscope, which is a thin wire-like instrument, is used to locate and remove the stones. A nephrostomy tube is inserted into the kidney through the skin which drains urine and any other stone into a urine collection bag

How can Kidney Stones be Prevented?

Following measures can be adopted to prevent the formation of Kidney Stones:

  • Drinking plenty of water and keep oneself well hydrated
  • Bringing about suitable dietary changes in the amounts of sodium, animal protein, calcium, and oxalate consumed can also help in preventing stone formation

Preventive methods for certain specific types of Kidney Stones (for high-risk individuals) include:

  • Calcium oxalate stone:
    • Sodium consumption should be reduced
    • Consumption of animal protein, such as meat, egg, and fish, must be reduced
    • Increasing calcium level by taking calcium supplements
    • Avoiding foods such as spinach, nuts, and wheat bran, which are rich in oxalate
  • Calcium phosphate stones:
    • Sodium consumption should be reduced
    • Consumption of animal protein, such as meat, egg, and fish, must be reduced
    • Increasing calcium level by taking calcium supplements
  • Uric acid stones: Consumption of animal protein such as meat, egg, and fish, must be reduced

Certain medications may be recommended to prevent the formation of Kidney Stones and these may include:

  • Hyperuricosuria: Allopurinol to decrease uric acid in blood and urine
  • Hyperoxaluria: Potassium citrate to raise the citrate and pH of urine
  • Uric acid stones: Allopurinol and potassium citrate
  • Cystine stones: Mercaptopropionyl glycerine to decrease cystine levels in urine
  • Struvite stones: Antibiotics
  • Calcium stones: Surgery to remove the parathyroid glands

What is the Prognosis of Kidney Stones?

  • Small-sized Kidney Stones often pass out without the need for any treatment
  • Larger-sized Kidney Stones can be removed with proper treatment and surgical procedures
  • Once an individual has had a Kidney Stone, the risk of getting it again always remains

Additional and Relevant Useful Information for Kidney Stones:

The following DoveMed website link is a useful resource for additional information:


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

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Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 29, 2015
Last updated: July 9, 2019