What are kidney stones?

Kidney stones are hard, pebble-like masses that form when concentrations of certain minerals and salts rise in the urine. A stone may remain in the kidney without causing symptoms, or move into the ureter and cause severe pain if it obstructs urine flow.

Pain alone does not determine the seriousness of the problem; a small stone in a narrow location may cause clear symptoms, while a larger stone may be found incidentally. The decision therefore depends on symptoms, location, size, and whether there is obstruction, infection, or impaired kidney function.

What symptoms may appear?

Severe pain in the flank or back, which may spread to the lower abdomen or genital area, is one of the best-known symptoms. It may be accompanied by blood in the urine, burning or frequent urination, nausea, or vomiting.

When should you seek urgent medical help? If the pain is severe, or is accompanied by fever or chills, inability to urinate, persistent vomiting, or visible blood in the urine. A combination of obstruction and infection may require rapid intervention.

How does a doctor reach a diagnosis?

Assessment starts with the symptom history and examination, followed by a urine test to look for blood or infection; kidney-function tests may also be requested. Imaging shows the stone's location and size and whether there is obstruction. Depending on the situation, the doctor may choose ultrasound or a CT scan.

If stones recur, analysis of the stone's composition or urine and blood tests may be needed to identify recurrence factors and build more tailored prevention advice.

How is the treatment approach chosen?

Some small stones can pass on their own with pain control and follow-up, and a doctor may prescribe medication in selected cases. This does not mean that increasing fluids or taking painkillers on your own is suitable in every situation, particularly with vomiting, obstruction, or kidney disease.

Intervention options

  • Shock-wave lithotripsy: Breaks the stone from outside the body in situations where the size and location are suitable.
  • Ureteroscopy and laser: Passes through the urinary tract to reach the stone and remove or fragment it.
  • Percutaneous nephrolithotomy: Used for some large or complex stones through a small opening in the back.

The benefits, side effects, and recovery time vary between options; the plan is therefore discussed after reviewing the imaging, overall health, and the patient's preferences.

How can you reduce the chance of recurrence?

Drinking enough fluids - with water as the main choice - helps keep urine less concentrated. The appropriate amount may differ if you have heart or kidney disease, so follow your doctor's guidance.

  • Limit excess salt, because higher sodium intake may increase the risk of some types of stones.
  • Do not restrict dietary calcium or whole food groups without knowing the stone type and receiving specialist guidance.
  • Recommendations about animal protein or oxalate may differ according to the stone type and assessment results.
  • In hot weather or during activity, monitor urine colour and avoid dehydration.
The most important advice The best prevention plan is personal. What suits calcium oxalate stones may not be the same as what suits uric acid or cystine stones.

What should you bring to your appointment?

Bring previous imaging and test reports, medication names, and a short record of when the pain began, how often it returns, and which symptoms accompany it. If you pass a stone, ask whether it can be analysed, because its type may help guide prevention.

Reliable medical sources

This educational content was prepared using patient information from the U.S. National Institute of Diabetes and Digestive and Kidney Diseases , the UK National Health Service , and the European Association of Urology .

This article is for general education and does not provide an individual diagnosis or replace medical advice.