Patient information from the BMJ Group Kidney stones Having a kidney stone can be painful and distressing. Most stones pass out of the body without any treatment. But for those that don't, there are good treatments available. What are kidney stones? Kidney stones are solid, stone-like lumps that can form in your kidneys. They are made from waste chemicals in your urine. Stones can also form in your bladder and the tubes that carry urine from your kidneys to your bladder (these are called ureters). Stones can stay in your kidneys without causing problems. But some might travel out of your body in the flow of urine. If they are very small, they can pass out of your body without you noticing. But larger ones can rub against the tubes or even get stuck. This can be extremely painful. There are four types of kidney stones. • The most common type contains calcium. These stones are called calcium oxalate stones. • Uric acid stones form if there is too much uric acid in your urine. Uric acid is a waste product made when food is digested. • Struvite stones develop after a urinary infection, such as cystitis. • Cystine stones are caused by a rare inherited condition called cystinuria. It is important to know what kind of stone you have, as this will affect your treatment to prevent future stones. What are the symptoms? The main symptom is pain. This can be a dull ache in your back or side, or an extremely sharp, cramping pain. The pain usually comes on suddenly. It might spread down to your tummy or groin. You might also: • Feel sweaty or sick • Be sick • Find blood in your urine. This is caused by the stone rubbing against the walls of the ureter • Need to urinate more often or feel a burning sensation when you urinate. © BMJ Publishing Group Limited 2014. All rights reserved. page 1 of 3 Kidney stones Your doctor is likely to suspect you have a kidney stone if you have sudden, severe pain in your side and blood in your urine. You'll probably be sent to hospital for an x-ray. If you have a kidney stone, these tests may show how big the stone is and where it is stuck. If the x-ray does not show a kidney stone, you will probably have more tests to find out what's causing the pain. You may not get any symptoms with a kidney stone. You might find out you have one when you have an x-ray for another reason. What treatments work? Stones that are less than 1 centimetre across often pass out of the body without any treatment. It can take two days to four weeks for this to happen. You can help the process along by drinking plenty of water to increase the flow of urine. You'll also need to take strong painkillers for the pain. If you have a stone stuck in a tube (ureter), your doctor might recommend taking a medicine called an alpha-blocker. This type of drug is often used to treat high blood pressure or symptoms of an enlarged prostate, but studies show it can also help stones to pass through the ureters faster. You'll probably be able to stay at home during this time, although you may need x-rays to check on the progress of the stone. Your doctor may ask you to catch the stone with a tea strainer or something similar as it comes out. This is so your doctor can see what type of stone you have. Knowing the type of stone will help them work out what you can do to prevent more stones. Surgical treatments Larger stones and those that don't pass out of the body need treatment. All the following treatments work well. • Shock wave therapy uses shock waves to break up stones into small pieces that can pass out of the body. Many stones are dealt with this way and it avoids any operation. You might sit in a tub of water or lie on a table to have this treatment. You'll have a local anaesthetic in the area that's being treated.You may need several treatments to break up hard or large stones. The risk of side effects after this treatment is small. But you could get an infection in your kidney or a stone stuck in your ureter afterwards. • You may need a minor operation if a stone in your kidney is large or in an awkward place. It's called a percutaneous nephrolithotomy (PCNL).You need a general anaesthetic for this, and you will probably have to stay in hospital. The doctor makes a small cut in your back and passes a needle and a very thin tube into your kidney to remove the stone. Like all operations, there can be problems (complications). The main ones are constipation and infections. © BMJ Publishing Group Limited 2014. All rights reserved. page 2 of 3 Kidney stones • If the stone is stuck in a tube (ureter), you may have a ureteroscopy. You don't need any cuts made in your body for this, and you can probably go home the same day. You can have a local or general anaesthetic. The doctor feeds a long, thin wire up through your bladder and into the ureter to reach the stone.The doctor then either removes the stone or breaks it up with shock waves. This procedure works well, but it does have risks. In one study, about 1 out of 10 people who had this treatment had a damaged or torn ureter afterwards. What will happen to me? If you've had a kidney stone you have about a 1 in 2 chance of getting another one within five years to seven years. Your doctor can prescribe medicines to help stop you getting some types of stones. The type of medicine you get depends on the type of stone you've had. For example, you may need to take diuretics (water pills) to reduce calcium in your urine if your stone contained calcium. Or if you have too much uric acid in your urine you might be given a drug called allopurinol (the brand names are Caplenal, Cosuric, and Zyloric). Your risk of getting more stones may also be affected by what you eat and drink. To reduce your risk, you can: • Drink more than two litres of water a day • Eat a healthy diet, including calcium but not calcium supplements. Foods rich in calcium include milk and other dairy products, peas and beans, leafy green vegetables, nuts, and bony fish like sardines and salmon • Avoid using lots of salt • Eat more vegetables. Vegetables make the urine less acidic. If you've had a calcium oxalate stone, you may need to reduce the amount of oxalate in your diet. This means cutting down on chocolate, nuts, rhubarb, strawberries, spinach, coffee, and tea. But changes in diet don't work for everyone, and there is not a lot of evidence to show how well they work. So it's important to talk to your doctor before making big changes to what you eat. This information is aimed at a UK patient audience. This information however does not replace medical advice. If you have a medical problem please see your doctor. Please see our full Conditions of Use for this content. For more information about this condition and sources of the information contained in this leaflet please visit the Best Health website, http://besthealth.bmj.com . These leaflets are reviewed annually. © BMJ Publishing Group Limited 2014. All rights reserved. page 3 of 3 Kidney stones © BMJ Publishing Group Limited 2014. All rights reserved. Last published: Sep 05, 2014 page 4 of 3