Kidney Stones
Kidney stones are small, hard masses made of minerals and salts that form inside the kidneys. They develop when urine becomes concentrated, letting crystals stick together. Many small stones pass on their own, while larger ones may need medical treatment to remove or break apart.
Overview
What are kidney stones?
Kidney stones are hard, pebble-like pieces of material that form inside one or both kidneys. They are made of minerals and salts that crystallise out of the urine and clump together. Stones can be as small as a grain of sand or grow large enough to fill part of the kidney, and they may stay in place or travel into the urinary tract.
How common are kidney stones and who do they affect?
Kidney stones are a common condition that can affect people of any age, though they most often appear in adults. They are more frequent in men than in women, and someone who has had one stone has a higher chance of developing another. Diet, body weight, climate and fluid intake all influence how often they occur.
Symptoms and Causes
What are the symptoms of kidney stones?
Small stones may cause no symptoms at all. Larger stones or those that move into the urinary tract can cause sudden, severe pain in the side, back or lower abdomen that may come in waves. Other signs include blood in the urine, pain when passing urine, cloudy or strong-smelling urine, nausea and a frequent urge to urinate.
What causes kidney stones and who is at risk?
Stones form when urine contains more crystal-forming substances, such as calcium or uric acid, than the fluid can dilute. Not drinking enough water, a diet high in salt or animal protein, being overweight, certain medical conditions and a family history of stones all raise the risk. Some medicines and repeated urinary infections can also contribute.
Diagnosis and Tests
How are kidney stones diagnosed?
A doctor usually starts by asking about symptoms and may arrange urine and blood tests to check kidney function and look for substances linked to stones. Imaging such as an ultrasound or CT scan can confirm a stone, show its size and location, and help guide treatment. If a stone is passed, it may be analysed to identify what it is made of.
Management and Treatment
How are kidney stones treated or managed?
Treatment depends on the size and type of stone. Small stones often pass on their own with plenty of fluids and pain relief. Larger stones may need procedures that use sound waves to break them apart, a thin telescope passed through the urinary tract, or, less often, surgery. Care also focuses on relieving symptoms and preventing future stones.
Prevention
Can kidney stones be prevented or their risk reduced?
The risk of kidney stones can often be lowered by drinking enough fluid each day to keep urine pale, reducing salt, and eating a balanced diet. Depending on the stone type, a doctor may suggest specific dietary changes or, in some cases, medication. Treating underlying conditions and staying a healthy weight also help reduce recurrence.
Additional Common Questions
How long does it take to pass a kidney stone?
It varies with the size and position of the stone. Small stones may pass within a few days to a few weeks, while larger ones can take longer or may not pass without treatment. A doctor can advise on what to expect in your situation.
Are kidney stones dangerous?
Most kidney stones are not life-threatening, but they can be very painful and sometimes block the flow of urine or lead to infection. Seek prompt medical care for severe pain, fever, or difficulty passing urine.
Do kidney stones come back?
They can. People who have had a kidney stone are more likely to form another over time. Staying well hydrated and following any dietary advice from your doctor can help reduce the chance of recurrence.
This health topic is for general information and is not a substitute for professional medical advice. Always consult a qualified clinician about your individual situation. See our medical disclaimer.