Kidney stones are formed from crystals of substances found in urine, and can vary in size from tiny particles to large, smooth or irregular lumps. The stones are formed in the kidney, but can pass into the bladder and the ureters (the two tubes connecting the kidneys to the bladder).
Kidney stones are especially common in ADPKD. They affect around one in four people with ADPKD compared to one or two in a hundred people without ADPKD.
Treatment of kidney stones depends on their size and position. Small stones can sometimes be passed in the urine without causing problems or discomfort, but larger stones may cause severe pain, blood in the urine, or may obstruct the flow of urine, and may have to be treated with surgery.
Causes of kidney stones
Kidney stones are formed from substances found in the urine, such as calcium and uric acid. It is unclear why people with ADPKD are more likely to develop kidney stones, but the possible causes include:
- Cysts may slow the flow of urine from the kidney, forming the crystals that lead to kidney stones
- Low levels of citrate in the urine appears to be more common in ADPKD. Citrate is a substance that prevents the formation of kidney stones.
Symptoms of kidney stones
You may not have symptoms until a stone moves down from the kidney into one of the ureters. When this happens, symptoms may include:
- Severe pain in the back, side or groin
- The pain may start and may go away suddenly
- Blood in the urine
- Chills and fever
- Nausea and vomiting.
Diagnosing kidney stones
Your doctor will examine you physically, and test your blood and urine to check the levels of stone-forming substances such as calcium and uric acid.
To confirm that your symptoms are caused by a kidney stone, you will also need one or more of the following tests:
- X-ray of your kidneys
- CT scan
- Kidney ultrasound
- Intravenous pyelogram (IVP, a special X-ray of the kidneys, ureters and bladder).
Treating kidney stones
You may be able to pass small stones without treatment (if possible, strain your urine so that you can save the stone for testing).
Large stones need to be removed. Possible approaches include:
- If the stones are in the bladder, they may be removed using a cystoscope. This instrument is passed from the outside, up the urethra and into the bladder
- Shattering the stone with a special machine that delivers shockwaves from outside the body (extra-corporal shockwave lithotripsy). This breaks up the stone into small pieces that can be passed in the urine
- ‘Keyhole’ surgery, through a very small cut in the skin (percutaneous nephrolithotomy)
Preventing kidney stones
Having one kidney stone increases your chances of having another one in the future. Your doctor may advise you to avoid certain foods if you form a particular type of stone, but you can reduce your general risk by:
- Keeping up your intake of fluids and avoiding dehydration. (But check with your doctor in case you have been advised to restrict fluids because of your kidney function.)
- Eating a healthy diet with plenty of vegetables and cutting down on salt.
- Avoiding calcium supplements, but make sure that you eat calcium-containing foods such as dairy products.
Your doctor may also prescribe medication that reduces the amount of stone-forming substances in your urine.
- Edren, the website of the Edinburgh Renal Unit, has information on kidney stones.
- The UK Royal College of Radiologists website has leaflets for patients on having a CT scan, ultrasound scan, IVP and percutaneous nephrolithotomy.
The information on this page is under review by the PKD Charity using the accredited Information Standard process.
PKD Charity Helpline: The PKD Charity Helpline offers confidential support and information to anyone affected by PKD, including family, friends, carers, newly diagnosed or those who have lived with the condition for many years.
Disclaimer: This information is primarily for people in the UK. We have made every effort to ensure that the information we provide is correct and up to date. However, it is not a substitute for professional medical advice or a medical examination. We do not promote or recommend any treatment. We do not accept liability for any errors or omissions. Medical information, the law and government regulations change rapidly, so always consult your GP, pharmacist or other medical professional if you have any concerns or before starting any new treatment.
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