How to treat kidney stones

Around one in five adults in the UK will develop kidney stones at some point in their lifetime. Kidney stones are hard deposits of minerals and salts, most commonly calcium oxalate and calcium phosphate, which collect in your kidneys. 

They are often caused by dehydration, which produces very concentrated urine and consequently, increases your risk of these deposits forming. Other factors that increase your risk of kidney stones include metabolic conditions such as hyperparathyroidism, inflammatory bowel disease, urine infections and certain genetics. 

Kidney stone symptoms 

In a small number of cases, kidney stones don’t cause any symptoms. 

Usually, symptoms occur when a kidney stone dislodges or breaks off and passes into the narrow tube that runs from your kidney to your bladder (ureter), causing a blockage. 

This makes it painful to pass urine, often described as a burning sensation, and can cause blood to appear in your urine as the kidney stone scratches the lining of your ureter. 

In some cases, you may also develop an infection as a result of your kidney stones, with symptoms including fatigue, fever, chills, foul-smelling urine and severe pain. 

If the kidney stone passes into the lower part of your ureter, it can cause an increase in your urge to urinate and how often you urinate. In men, it can also cause discomfort in and around the penis and testes, and in women, it can cause discomfort in and around the womb (uterus).

If you’re experiencing symptoms of kidney stones, see your GP for treatment. If needed, they may refer you to a specialist (a urologist) for treatment.  

How to treat kidney stones

Surveillance and medication

If you have a small kidney stone and your pain can be well-controlled with over-the-counter painkillers, your doctor may recommend surveillance until your kidney stone naturally passes out of your body. They may prescribe a medication, an alpha-blocker, to help your kidney stone pass. 

If your doctor suspects you have a uric acid kidney stone, they will prescribe a medication to help dissolve it. This medication works by making your urine more alkaline. Only uric acid stones can be treated in this way as all other kidney stones are calcium-based and consequently, aren’t vulnerable to dissolving with an alkali. 

You will have an X-ray, ultrasound scan or CT scan four weeks later to check if your stone has passed or has been dissolved. An ultrasound scan or CT scan is used if you have a uric acid kidney stone, as these are difficult to detect via an X-ray. 

In the meantime, you will be given dietary advice to reduce your risk of developing further kidney stones. 

Shockwave lithotripsy (SWL)

If you have a large kidney stone that can’t, therefore, pass out of your body naturally without intervention and the stone is visible on an X-ray, your doctor may recommend SWL. 

This is a non-invasive procedure during which you will be awake. However, as it can be uncomfortable, you will usually be given pain relief medication beforehand. 

High-frequency soundwaves will be passed into your kidney to break up the large kidney stone into smaller pieces, which can then pass out of your body naturally. 

If SWL isn’t appropriate or effective, your doctor may recommend surgery, specifically ureteroscopy or percutaneous nephrolithotomy (PCNL).

Ureteroscopy

If your kidney stone is stuck in your ureter, a ureteroscopy is performed under a general anaesthetic to remove the kidney stone. This usually involves an overnight stay in hospital. 

A thin, telescope-like device, with a light and a camera on the end, called a ureteroscope will be passed into your urethra (the tube that carries urine away from your bladder and out of your body). The ureteroscope is then passed through your bladder and up into your ureter, where a special instrument is used to remove the kidney stone or a laser is used to break it up into smaller pieces before removal.

The procedure can irritate your ureter, causing it to swell. If this occurs, a temporary stent may be placed into your ureter to allow urine to flow out more easily. The stent is attached to thin black threads that will be left hanging out of your urethra — you can still pass urine as normal but shouldn’t pull on the threads. Once you’ve recovered, the stent will be removed during an outpatient appointment by pulling on the threads. 

If your ureter is too tight for the ureteroscope to pass through easily, a stent without strings may be placed and left for three to four weeks to stretch the ureter, so surgery can be performed later. 

Percutaneous nephrolithotomy (PCNL)

If you have a very large kidney stone, your doctor may recommend PCNL. This surgery is performed under a general anaesthetic and involves making a cut in your back through which a thin, telescope-like device, with a light and a camera on the end, called a nephroscope is passed. 

The nephroscope is passed into your kidney and a special instrument is then used to remove the kidney stone or a laser is used to break it into smaller pieces before removal.

Dietary changes

Once you have formed a kidney stone, your risk of developing another kidney stone in the next five years if you don’t change your diet is one in two. Over the next 10 years, your risk of needing emergency medical treatment for a kidney stone is one in four. 

If you have been diagnosed with a kidney stone, it is, therefore, important to make dietary changes even after your kidney stone has passed or been removed. This usually involves eating less animal protein (ie meat, fish and dairy products) and reducing how much salt you add to food. 

If you have calcium oxalate stones, you will also need to go on a low-oxalate diet. This involves reducing the amount of high-oxalate foods you eat, such as chocolate, soy products, raspberries, oranges, spinach, potatoes, walnuts, kidney beans and brown rice.

If you have uric acid stones, you will also need to go on a low-purine diet. This involves reducing the amount of high-purine foods you eat, such as red meat, liver, kidneys, anchovies, shellfish and tuna.  

You will need to stay well-hydrated too. Aim to drink two to three litres of fluids every day depending on your activity levels and the weather. You should avoid fluids that dehydrate your body, such as alcohol and caffeinated drinks.