Symptoms usually occur if the kidney stone:
In these cases, common symptoms of kidney stones include:
Rarely, if a stone blocks the ureter, this can lead to a kidney infection and pus building up in the kidney. This is a medical emergency.
Symptoms may include:
Kidney stones are hard mineral deposits that form inside the kidneys.
This build-up may consist of:
You are at a greater risk of developing recurrent (returning) kidney stones if:
Kidney stones can develop as a result of a number of different factors. The causes of the four main types of kidney stone are outlined below.
Calcium stones are the most common type of kidney stone. They are caused when there is too much calcium in the urine. High amounts of calcium could be a result of:
Calcium stones are usually very hard.
Struvite stones are often caused by recurrent urinary tract infections.
They are more common in women than in men.
They can form very large stones that fill the entire kidney. These are called "staghorn" stones. They tend to from slowly over time and are not really painful. Patients may just notice a dull ache in their back or loins.
Uric acid stones often form when there is a high amount of acid in your urine.
Dalmations are the only other animal to get uric acid stones.
Uric acid stones may be caused by:
Cystine stones are the rarest form of kidney stone.
They are caused by an inherited condition called Cystinuria, which affects the amount of Cysteine that passes into the urine.
Treatment often involves surgery to clear the stones and then medication to try and stop them re-forming.
Diagnosing kidney stones
You can try and collect your kidney stone if it passed by urinating through some gauze or a stocking. This will allow the stone type to be analysed and allow more tailored advice to be given about lifestyle changes to prevent further stone formation in the future.
Treating ureteric stones
If the stone is small (<4mm), the pain has settled and your blood tests are normal there is a chance that the stone will pass by itself without any need for intervention.
You will be given:
If the pain returns and is not controlled by pain killers or if you develop a fever you will need to contact me urgently or return to Accident and Emergency for further treatment.
You should maintain a high fluid intake and try and filter the urine with gauze to look for the kidney stone.
Usually after 4 weeks we will repeat a scan to make sure that the stone has passed by itself. Even if the symptoms settle this does not mean that the stone has gone. You may not even notice the stone passing out in the urine, especially if it is small.
Cystoscopy and insertion of JJ stent
A JJ stent is a thin piece of hollow plastic that has curls at each end. It is usually placed as an emergency procedure to unblock a kidney due to some form of obstruction in the ureter (tube that drains urine from the kidney into the bladder). It is inserted under a general anaesthetic using an endoscopic technique. A telescope is placed into the bladder and a wire passed into the kidney under X-ray screening control. The stent is the deployed over the wire. The top end of the stent will form a curl in the kidney and the bottom end a curl in the bladder, these help to hold the stent in place. Once things have settled and the ureter has had time to dilate around the stent a further procedure will be planned to deal with the stone.
Side effects of the stent:
Extracorporeal shock wave lithotripsy (ESWL)
It involves using X-rays or ultrasound to pinpoint the position of the stone. A machine then produces sound waves to fragment the stone into smaller pieces so it can be passed in your urine.
ESWL can be an uncomfortable though is usally well tolerated. It feels like an elastic band is being flicked against the skin.
It usually requires several treatments to clear a stone.
Possible side effects:
If a kidney stone is stuck in your ureter (tube that carries waste products from your kidneys to your bladder) you may need to have ureterorenoscopy. This involves being taken to theatre and given a general anaesthetic. A long, thin telescope called a ureteroscope is then passed through your urethra (the tube urine passes through out of the body) and into your bladder. It is then passed up into your ureter to where the stone is stuck. If possible, the stone is broken with a laser and the fragments removed. You will most likely end up with a JJ stent in after the procedure which will require another small opeartion which can be performed under a local anaesthetic to remove it.
Percutaneous nephrolithotomy (PCNL)
PCNL is a procedure that is usually reserved for larger stones (>1.5cm) or those in a walled off area within the kidney called a diverticulum.
PCNL can be performed with the patient lying on their front (prone) or on their back (supine). I am one of a selected number of surgeons in London who can perform the latter procedure. This has significant anaesthetic advantages as it puts less strain on a patient's heart and lungs whilst they are under anaesthetic.
A thin telescopic instrument called a nephroscope is inserted into the kidney via a 1cm incision. Guiding the position of the kidney puncture is performed by a radioogist using both ultrasound and X-ray guidance. The stone is either removed intact using graspers or broken into smaller pieces using pneumatic energy.
Nowadays, it is rare for people to have open surgery for kidney stones (<1% of cases require this type of surgery). It is usually used if there is a very large stone or abnormal anatomy.
Preventing kidney stones
The best way of preventing kidney stones is to make sure you drink plenty of water each day to avoid becoming dehydrated.
It is very important to keep your urine dilute to avoid waste products forming into kidney stones.
You can tell how dilute your urine is by looking at its colour. The yellower 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 has produced overnight. After the first void all other urine should be colourless.
Fluid intake will depend on the environment and each individual patient. Aiming at two litres per day is reasonable. Drinks such as tea, coffee and fruit juice can count towards your fluid intake but water is the healthiest option and is best for preventing kidney stones.
It may be sensible to have 1l of water when you get out of bed with a fresh lemon squeezed into it. This will help to hydrate the body and fresh lemon contains Citrate which helps prevent stone formation.
You should also make sure that you drink more when it is hot or when you are exercising to replenish fluids lost through sweating.
If your kidney stone is made up of calcium oxalate, you may be advised to reduce the amount of oxalate in your diet.
You should continue to eat foods containing calcium as this prevents oxalate being absorbed into the body and stones forming
Foods that contain high levels of oxalate include:
You should also avoid:
Medication can be used in certain circumstances to try and prevent kidney stone recurrence.
For example, if you have: