Kidney stones


Kidney stones
Kidney stones

Kidney stones can develop in 1 or both kidneys and most often affect people aged 30 to 60.

They're quite common, with more than 1 in 10 people affected.

Kidney stones are usually found in the kidneys or in the ureter, the tube that connects the kidneys to your bladder.

They can be extremely painful, and can lead to kidney infections or the kidney not working properly if left untreated.

Symptoms of kidney stones

You may not notice if you have small kidney stones. You'll usually pee them out without any discomfort.

Larger kidney stones can cause several symptoms, including:

  • pain in the side of your tummy (abdomen)
  • severe pain that comes and goes
  • feeling sick or vomiting

When to get urgent medical help

You should contact a GP or NHS 111 immediately if:

  • you're in severe pain
  • you have a high temperature
  • you have an episode of shivering or shaking
  • you have blood in your urine

What causes kidney stones?

Waste products in the blood can occasionally form crystals that collect inside the kidneys.

Over time, the crystals may build up to form a hard stone-like lump.

This is more likely to happen if you:

  • do not drink enough fluids
  • are taking some types of medication
  • have a medical condition that raises the levels of certain substances in your urine

After a kidney stone has formed, your body will try to pass it out when you pee.

Treating and preventing kidney stones

Most kidney stones are small enough to be passed in your pee, and it may be possible to treat the symptoms at home with medication.

Larger stones may need to be broken up or removed with surgery.

It's estimated up to half of all people who have had kidney stones will experience them again within the following 5 years.

To avoid getting kidney stones, make sure you drink plenty of water every day so you do not become dehydrated.

It's very important to keep your urine pale in colour to prevent waste products forming into kidney stones.

The kidneys

The kidneys are 2 bean-shaped organs that are roughly 10cm (4 inches) in length.

They're located towards the back of the abdomen on either side of the spine.

The kidneys remove waste products from the blood. The clean blood is then transferred back into the body and the waste products are passed out of the body when you pee.


Very small kidney stones are unlikely to cause many symptoms. They may even go undetected and pass out painlessly when you pee.

Larger kidney stones can cause symptoms, including:

  • pain in the side of your tummy (abdomen) or groin – men may have pain in their testicles
  • a high temperature
  • feeling sweaty
  • severe pain that comes and goes
  • feeling sick or vomiting
  • blood in your urine
  • urine infection

Blocked ureter and kidney infection

A kidney stone that blocks the ureter, the tube that connects your kidney to your bladder, can cause a kidney infection.

This is because waste products are unable to pass the blockage, which may cause a build-up of bacteria.

The symptoms of a kidney infection are similar to symptoms of kidney stones, but may also include:

  • a high temperature
  • chills and shivering
  • feeling very weak or tired
  • diarrhoea
  • cloudy and bad-smelling urine

Who can get it

Kidney stones are usually formed following a build-up of certain chemicals in the body.

Certain medical conditions can lead to an unusually high level of these chemicals in your pee.

You're also more likely to develop kidney stones if you do not drink enough water and other fluids.

Types of kidney stones

Kidney stones come in a variety of sizes, shapes and colours. Some are like grains of sand, while in rare cases others can grow to the size of a golf ball.

The main types of kidney stones are:

  • calcium stones, the most common type of stone
  • struvite stones, usually caused by an infection, like a urine infection
  • uric acid stones, usually caused by a large amount of acid in your urine

Recurrent kidney stones 

People who keep getting kidney stones include those who:

  • eat a high-protein, low-fibre diet
  • are inactive or bed-bound
  • have a family history of kidney stones
  • have had several kidney or urinary infections
  • have had a kidney stone before, particularly if it was before they were 25 years old


Certain medicines may increase your risk of developing recurrent kidney stones.

These include:

  • aspirin 
  • antacids 
  • diuretics (used to reduce fluid build-up)
  • certain antibiotics
  • certain antiretroviral medicines (used to treat HIV)
  • certain anti-epileptic medicines


Your GP will usually be able to diagnose kidney stones from your symptoms and medical history.

It'll be particularly easy if you have had kidney stones before.

You may be given tests, including:

  • urine tests to check for infections and pieces of stones
  • an examination of any stones that you pass in your pee
  • blood tests to check that your kidneys are working properly and also check the levels of substances that could cause kidney stones, such as calcium

You may be told what equipment you need to collect a kidney stone. Having a kidney stone to analyse will make a diagnosis easier, and may help your GP determine which treatment method will be of most benefit to you.

If you're in severe pain

If you have severe pain that could be caused by kidney stones, your GP should refer you to hospital for an urgent scan:

  • adults should be offered a CT scan
  • pregnant women should be offered an ultrasound scan
  • children and younge people under 16 should be offered an ultrasound – if the ultrasound does not find anything, a low-dose non-contrast CT scan may be considered


Most kidney stones are small enough to be passed out in your pee and can probably be treated at home.

Treating small kidney stones

Small kidney stones may cause pain until you pass them, which usually takes 1 or 2 days.

A GP may recommend a non-steroidal anti-inflammatory drug (NSAIDs) to help with pain.

To ease your symptoms, a GP might also recommend:

  • drinking plenty of fluids throughout the day
  • anti-sickness medicine
  • alpha-blockers (medicines to help stones pass)

You might be advised to drink up to 3 litres (5.2 pints) of fluid throughout the day, every day, until the stones have cleared.

To help your stones pass:

  • drink water, but drinks like tea and coffee also count
  • add fresh lemon juice to your water
  • avoid fizzy drinks
  • do not eat too much salt

Make sure you're drinking enough fluid. If your pee is dark, it means you're not drinking enough. Your pee should be pale in colour.

You may be advised to continue drinking this much fluid to prevent new stones forming.

If your kidney stones are causing severe pain, your GP may send you to hospital for tests and treatment

Treating large kidney stones

If your kidney stones are too big to be passed naturally, they're usually removed by surgery.

Surgery for treating kidney stones

The main types of surgery for removing kidney stones are:

  • shockwave lithotripsy (SWL)
  • ureteroscopy
  • percutaneous nephrolithotomy (PCNL)

Your type of surgery will depend on the size and location of your stones.  

Shock wave lithotripsy (SWL)

SWL involves using ultrasound (high-frequency sound waves) to pinpoint where a kidney stone is.

Ultrasound shock waves are then sent to the stone from a machine to break it into smaller pieces so it can be passed in your urine.

SWL can be an uncomfortable form of treatment, so it's usually carried out after giving painkilling medication.

You may need more than 1 session of SWL to successfully treat your kidney stones. 


Ureteroscopy involves passing a long, thin telescope called a ureteroscope through the tube urine passes through on its way out of the body (the urethra) and into your bladder.

It's then passed up into your ureter, which connects your bladder to your kidney.

The surgeon may either try to gently remove the stone using another instrument, or they may use laser energy to break it up into small pieces so it can be passed naturally in your urine.

Ureteroscopy is carried out under general anaesthetic, where you're asleep.

Percutaneous nephrolithotomy (PCNL)

PCNL involves using a thin telescopic instrument called a nephroscope.

A small cut (incision) is made in your back and the nephroscope is passed through it and into your kidney.

The stone is either pulled out or broken into smaller pieces using a laser or pneumatic energy.

PCNL is always carried out under general anaesthetic.

Complications of treatment

Complications can occur after the treatment of large kidney stones.

Your surgeon should explain these to you before you have the procedure.

Possible complications will depend on the type of treatment you have and the size and position of your stones. 

Complications could include:

  • sepsis, an infection that spreads through the blood, causing symptoms throughout the whole body
  • a blocked ureter caused by stone fragments (the ureter is the tube that attaches the kidney to the bladder)
  • an injury to the ureter
  • a urinary tract infection (UTI)
  • bleeding during surgery
  • pain


The best way to prevent kidney stones is to make sure you drink plenty of water each day to avoid becoming dehydrated.

To prevent stones returning, you should aim to drink up to 3 litres (5.2 pints) of fluid throughout the day, every day.

You're advised to:

  • drink water, but drinks like tea and coffee also count
  • add fresh lemon juice to your water
  • avoid fizzy drinks
  • do not eat too much salt

Keeping your urine clear helps to stop waste products getting too concentrated and forming stones.

You can tell how diluted your urine is by looking at its colour. The darker your urine is, the more concentrated it is.

Your urine is usually a dark yellow colour in the morning because it contains a build-up of waste products that your body's produced overnight.

Drinks like tea, coffee and fruit juice can count towards your fluid intake, but water is the healthiest option and is best for preventing kidney stones developing.

You should also make sure you drink more when it's hot or when you're exercising to replace fluids lost through sweating.

Find out more about preventing dehydration

Depending on the type of stones you have, your doctor may advise you to cut down on certain types of food.

But do not make any changes to your diet without speaking to your doctor first.

The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website
Last Updated: 26/05/2023 10:15:36