Kidney Stones
Kidney stones can cause severe pain, urinary obstruction or infection, but not every stone requires surgery. Assessment helps determine the size and location of the stone, whether it is causing a problem, and which treatment pathway may be appropriate.
An infected and obstructed kidney can be a medical emergency. Seek urgent medical care rather than waiting for a routine appointment if you are acutely unwell, have fever with suspected kidney obstruction, or are unable to pass urine.
What is a kidney stone?
A kidney stone is a solid deposit that forms from substances within the urine. Stones can remain within the kidney or travel into the ureter — the tube connecting the kidney to the bladder.
Some kidney stones are discovered by chance and cause no symptoms. Others can obstruct urine drainage or move through the ureter, producing the severe pain commonly called renal colic.
Kidney stones vary considerably in their size, location, composition and likelihood of passing without treatment. These differences are important when deciding whether a stone should be monitored or treated.
What can a kidney stone feel like?
Symptoms vary depending on where the stone is located and whether it is obstructing the kidney or ureter.
Severe side or back pain
Renal colic can cause sudden severe pain in the side or back that may come in waves.
Pain travelling toward the groin
Pain may move from the flank toward the lower abdomen or groin as a ureteric stone moves.
Blood in the urine
Stones can cause visible blood in the urine or microscopic blood found during urine testing.
Nausea or vomiting
Severe renal colic is commonly associated with nausea and sometimes vomiting.
Urinary symptoms
A stone close to the bladder can sometimes cause urinary urgency, frequency or discomfort.
No symptoms at all
Some kidney stones are found incidentally during imaging performed for another reason.
How are kidney stones investigated?
Imaging helps determine whether a stone is present and provides information that may influence treatment. Depending on the clinical situation, investigations may include ultrasound, CT imaging, urine testing and blood tests.
A non-contrast CT can provide detailed information about stone size, location and density, as well as whether there is obstruction of the urinary tract.
- Stone size and location
- Number and overall stone burden
- Whether the kidney is obstructed
- Signs of urinary infection
- Kidney function
- Previous stone episodes or treatment
Does every kidney stone need surgery?
No. Some kidney stones can be monitored, while others are more likely to benefit from active treatment.
When observation may be reasonable
Selected stones that are small, stable and not causing symptoms, infection or obstruction may sometimes be monitored rather than treated immediately.
A ureteric stone may also have a reasonable chance of passing without surgery depending particularly on its size and location.
When treatment may be considered
Active treatment becomes more relevant when a stone is causing significant symptoms, persistent obstruction or infection, is increasing in size, or is unlikely to pass spontaneously.
Individual circumstances also matter, including kidney function, urinary anatomy, previous stone problems and patient preference.
What are the treatment options?
Treatment is selected according to the stone rather than using the same procedure for every patient.
Observation & Follow-Up
Selected kidney stones can be monitored when immediate treatment is not required. Follow-up may include repeat imaging to assess for stone growth, movement or obstruction.
Ureteroscopy, Pyeloscopy & Laser
Fine endoscopic instruments can be passed through the urinary tract to reach selected ureteric or kidney stones. Laser energy can then be used to fragment the stone where appropriate.
Learn about ureteroscopy & laserShock Wave Lithotripsy
Shock wave lithotripsy uses externally generated energy to fragment suitable stones. Whether it is appropriate depends on factors such as stone size, position, density and patient anatomy.
PCNL
Percutaneous nephrolithotomy accesses the kidney through a small tract created through the back and is an important treatment option for larger or more complex renal stone burdens.
Learn about PCNLWhich treatment is right for me?
There is no single best treatment for every kidney stone. The most appropriate approach depends on the characteristics of the stone and the individual patient.
Existing CT imaging is particularly useful when planning treatment because it can show the size, position and density of a stone as well as surrounding urinary anatomy.
What if my kidney stones keep coming back?
Recurrent kidney stones may warrant further investigation to identify factors contributing to stone formation. Depending on the situation, assessment may include stone analysis, blood testing and specialised urine testing such as a 24-hour urine collection.
Prevention should be individualised because different stone types and metabolic abnormalities may require different strategies.
Explore Recurrent Stones & PreventionAlready had a scan for a kidney stone?
Bringing previous investigations can make your assessment more useful and may avoid unnecessary duplication.
Helpful information to bring
- CT, ultrasound or other imaging
- Radiology reports
- Recent blood test results
- Urine test or urine culture results
- Details of previous stone procedures
- Previous stone-analysis results if available
- Previous 24-hour urine results if performed
What will be considered?
Your symptoms and previous stone history can be reviewed together with the imaging. This helps establish whether the stone is suitable for observation or whether treatment should be considered.
If an intervention is appropriate, the advantages and limitations of the relevant treatment options can then be discussed.
Kidney Stone FAQs
Can a kidney stone pass by itself?
Yes. Some ureteric stones pass spontaneously, particularly smaller stones. The likelihood of passage depends on factors including stone size and its position within the ureter.
Does every kidney stone need to be removed?
No. Some asymptomatic stones can be monitored. Treatment may become appropriate if a stone grows, causes symptoms or obstruction, is associated with infection, or for other individual clinical reasons.
What size kidney stone needs surgery?
Size is important, but there is no single size that automatically means surgery is required. Location, symptoms, obstruction, infection, stone composition, anatomy and the likelihood of spontaneous passage are also considered.
What scan is used for kidney stones?
Ultrasound can identify some stones and urinary obstruction. Non-contrast CT provides more detailed assessment and is commonly used to confirm suspected urinary stones and help plan treatment. The most appropriate imaging depends on the clinical situation.
Is blood in the urine normal with a kidney stone?
Kidney stones can cause blood in the urine. However, blood in the urine can have many other causes and should not automatically be assumed to come from a stone without appropriate assessment.
When is a kidney stone an emergency?
An obstructed urinary system associated with infection can require emergency drainage. Fever, chills or significant illness with suspected kidney obstruction should therefore be assessed urgently. Inability to pass urine also requires urgent medical attention.
Will I need a ureteric stent?
Not every patient requires a stent. Ureteric stents are used in selected circumstances to maintain drainage between the kidney and bladder, including around some stone procedures.
Why do kidney stones keep coming back?
Stone recurrence can be influenced by urinary chemistry, fluid intake, diet, metabolic conditions, medications, stone type, genetics and urinary anatomy. Recurrent stone formers may benefit from a more detailed metabolic assessment.
Have you been diagnosed with a kidney stone?
Existing scans and investigations can be reviewed to determine the stone's size and location, whether it is causing obstruction, and whether observation or active treatment may be appropriate.
This information is general educational information and does not replace individual medical advice. Kidney stone investigation and treatment depend on factors including stone size and location, symptoms, obstruction, infection, kidney function, urinary anatomy and individual clinical circumstances.