Urinary tract stones are solid build-ups of crystals made from minerals and proteins found in urine.
Urinary tract stones begin to form in a kidney and may enlarge in a ureter or the bladder. Depending on where a stone is located, it may be called a kidney stone, ureteral stone, or bladder stone.
Factors that increase your risk of developing urinary tract stones include:
Family or personal history. If someone in your family has kidney stones, you're more likely to develop stones, too. And if you've already had one or more kidney stones, you're at increased risk of developing another.
Dehydration. Not drinking enough water each day can increase your risk of kidney stones. People who live in warm climates and those who sweat a lot may be at higher risk than others.
Certain diets. Eating a diet that's high in protein, sodium (salt) and sugar may increase your risk of some types of kidney stones. This is especially true with a high-sodium diet. Too much salt in your diet increases the amount of calcium your kidneys must filter and significantly increases your risk of kidney stones.
Being obese. High body mass index (BMI), large waist size and weight gain have been linked to an increased risk of kidney stones.
Digestive diseases and surgery. Gastric bypass surgery, inflammatory bowel disease or chronic diarrhea can cause changes in the digestive process that affect your absorption of calcium and water, increasing the levels of stone-forming substances in your urine.
Other medical conditions. Diseases and conditions that may increase your risk of kidney stones include renal tubular acidosis, cystinuria, hyperparathyroidism, certain medications and some urinary tract infections.
A kidney stone may not cause symptoms until it moves around within your kidney or passes into your ureter — the tube connecting the kidney and bladder. At that point, you may experience these signs and symptoms:
Pain caused by a kidney stone may change — for instance, shifting to a different location or increasing in intensity — as the stone moves through your urinary tract.
If your doctor suspects you have a kidney stone, you may have diagnostic tests and procedures, such as:
Blood testing. Blood tests may reveal too much calcium or uric acid in your blood. Blood test results help monitor the health of your kidneys and may lead your doctor to check for other medical conditions.
Urine testing. The 24-hour urine collection test may show that you're excreting too many stone-forming minerals or too few stone-preventing substances.
Imaging. Imaging tests may show kidney stones in your urinary tract. Options range from simple abdominal X-rays, ultrasounds or computerized tomography (CT scans).
Analysis of passed stones. You may be asked to urinate through a strainer to catch stones that you pass. Lab analysis will reveal the makeup of your kidney stones. Your doctor uses this information to determine what's causing your kidney stones and to form a plan to prevent more kidney stones.
Treatment for kidney stones varies, depending on the type of stone and the cause.
Small stones with minimal symptoms
Many small kidney stones won't require treatment. You may be able to pass a small stone by:
Urinary tract stones that can't be treated with conservative measures — either because they're too large
to pass on their own or because they cause bleeding, blockage of the kidney or ongoing urinary tract
infections — will require more active treatment.
Procedures may include:
Dr Robert Tan is a practicing consultant urologist with over 35 years of experience. He graduated from the medical school at the University of New South Wales, Australia, and has cared for thousands of patients over the decades.View Profile
Dr Lincoln Tan is a consultant urologist and accredited robotic surgeon. Dr Tan is trained in all aspects of open and endoscopic urology and specialises in the minimally invasive treatment of urologic cancers.View Profile