Most kidney stones are small enough (less than 4mm in diameter) to be passed out in your urine and can probably be treated at home.
But even small kidney stones can be painful, although this usually only lasts a couple of days and disappears when the stone has been passed.
If you are in severe pain, your GP can give you pain relief by injection. A second dose can be given after half an hour if you're still experiencing pain.
Medication can also be injected to treat the symptoms of nausea (feeling sick) and vomiting. This is called an anti-emetic (anti-sickness) medication.
You may also be given a prescription for painkillers, anti-emetics, or both, to take at home.
You may be advised to wait until you pass your kidney stone when you go to the toilet, and to try to collect it from your urine. You can do this by filtering your urine through gauze or a stocking.
Give the stone to your GP so that they can have it analysed to help determine any further treatment you may need.
You should drink enough water to make your urine colourless. If your urine is yellow or brown, you're not drinking enough.
Admission to hospital
If your kidney stone has moved into your ureter (the tube that carries waste products from the kidneys to the bladder), and it's causing severe pain, your GP may admit you to hospital for treatment.
This may be necessary if:
- you're at an increased risk of your kidneys failing (for example, because you only have one kidney)
- your symptoms don't improve within an hour of being given painkillers or anti-sickness medication
- you're dehydrated and vomiting too much to keep fluids down
- you're pregnant
- you're over 60 years of age
Treating large kidney stones
If a kidney stone is too big to be passed naturally – 6-7mm (about 0.23 to 0.27in) in diameter or larger – you may need treatment to remove it another way.
This could include:
- extracorporeal shock wave lithotripsy (ESWL)
- percutaneous nephrolithotomy (PCNL)
- open surgery
These procedures are explained in more detail below. The type of treatment you have will depend on the size and location of your stones.
Extracorporeal shock wave lithotripsy (ESWL)
ESWL is the most common way of treating kidney stones that can't be passed in the urine.
It 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.
ESWL can be an uncomfortable form of treatment, so it's usually carried out after giving painkilling medication.
You may need more than one session of ESWL to successfully treat your kidney stones. ESWL is up to 99% effective for stones up to 20mm (0.8in) in diameter.
If a kidney stone is stuck in the ureter, you may need to have a ureteroscopy, which is also sometimes known as retrograde intrarenal surgery (RIRS).
It involves passing a long, thin telescope called a ureteroscope through your urethra (the tube urine passes through on its way out of the body) and into your bladder. It's then passed up into your ureter to where the stone is stuck.
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 that it can be passed naturally in your urine.
Ureteroscopy is carried out under general anaesthetic (where you're unconscious), so you shouldn't drive or operate machinery for up to 48 hours after the procedure.
For stones up to 15mm (0.6in), a ureteroscopy is effective in 50-80% of cases.
A plastic tube called a stent may need to be temporarily inserted inside you to allow the stone fragments to drain into the bladder.
Percutaneous nephrolithotomy (PCNL)
PCNL is an alternative procedure that may be used for larger stones. It may also be used if ESWL isn't suitable – for example, because the person being treated is obese.
PCNL involves using a thin telescopic instrument called a nephroscope. A small 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, so you shouldn't drive or operate machinery for up to 48 hours after the procedure.
PCNL is 86% effective for stones that are 21-30mm (0.8-1.2in) in diameter.
Nowadays, open surgery for kidney stones is rare (less than 1% of cases require this type of surgery). It's only usually used if there's a very large stone or abnormal anatomy.
During open surgery, an incision will be made in your back so that your surgeon is able to access your ureter and kidney. The kidney stone can then be removed.
Treating uric acid stones
If you have a uric acid stone, you may be advised to drink around three litres (just over five pints) of water each day to try to dissolve it.
Uric acid stones are much softer than other types of kidney stone, and they can be made smaller if they're exposed to alkaline fluids.
You may need to take some medication to make your urine more alkaline before the uric acid stone starts to dissolve.
Complications of treatment
Complications can occur following 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
- bleeding during surgery
It's estimated that 5-9% of people may experience complications after having a ureteroscopy.