What is a kidney stone?

A kidney stone is a solid mass formed from substances in the urine. These substances are normally found in the urine, but become highly concentrated when there are not enough liquids to flush them out of the body in the urine. These stone-forming substances are:

  • Calcium
  • Oxalate
  • Urate
  • Cysteine
  • Xanthine
  • Phosphate

These and other chemicals are the “waste products” that must exit the body.

Kidney stones usually range in size from as small as a grain of sand to a pearl. Although rare, some stones can be as large as golf balls. Smaller stones can pass through the urinary tract on their own without any pain or notice. Larger stones can get trapped in the kidney or lodged in the ureters. When this happens, the stones keep urine from exiting the body. Blocking the flow of urine causes severe pain or bleeding. Stones that can’t pass on their own are treated with medications or surgery. The decision is based on stone size/shape, location, type, and number of stones.

What are the risk factors for developing kidney stones?

Risks for developing kidney stones include:

  • Not drinking enough liquids.
  • Repeat urinary tract infections.
  • Blockage in the urinary tract.
  • Family history of kidney stones.
  • Health conditions that affect the levels of the substances in the urine that can cause stones to form:
    • Hypercalciuria, which is high calcium levels in the urine.
    • High blood pressure.
    • Diabetes.
    • Obesity.
    • Osteoporosis.
    • Gout.
    • Kidney cysts.
    • Cystic fibrosis
    • Parathyroid disease.
    • Inflammatory bowel disease.
    • Chronic diarrhea.
    • Some surgical procedures, including weight loss surgery or other stomach/intestine surgeries.
  • Medications:
    • Diuretics (“water pills”).
    • Calcium-based antacids.
    • Crixivan® (used to treat HIV infections).
    • Topamax® and Dilantin® (used to treat seizures).
    • Cipro® (ciprofloxacin).
    • Ceftriaxone (antibiotics).
  • Certain foods and flavor enhancers including:
    • Animal proteins (meat and poultry).
    • Diets high in salt (sodium).
    • Sugars (fructose, sucrose, and corn syrup).
    • Foods specific to the type of kidney stone formed.

What are the signs and symptoms of kidney stones?

Signs and symptoms include:

  • Pain in the lower back or side of body. Pain can start as a dull ache that may come and go. Pain can become severe and result in a trip to the emergency room.
  • Nausea and/or vomiting with the pain.
  • Blood in the urine.
  • Pain when urinating.
  • Unable to urinate.
  • Feeling the need to urinate more often.
  • Fever/chills.
  • Urine that smells bad or looks cloudy.

Smaller kidney stones may not cause pain or other symptoms and are able to pass on their own.