Kidney stones can develop in one or both kidneys. They're quite common. They most often affect people aged 40 to 60. This page has information on kidney stones including symptoms, causes and treatment.
Symptoms of kidney stones
Very small kidney stones are unlikely to cause many symptoms. They may even go unnoticed and pass out painlessly when you urinate (pee).
Symptoms usually occur if the kidney stone:
- gets stuck in your kidney
- starts to travel down the ureter (the tube that attaches each kidney to the bladder) – the ureter is narrow and kidney stones can cause pain as they try to pass through
- causes an infection
In these cases, the symptoms of kidney stones can include:
- a persistent ache in the lower back, which is sometimes also felt in the groin – men may have pain in their testicles and scrotum
- periods of intense pain in the back or side of your abdomen, or occasionally in your groin, which may last for minutes or hours, with intervals of no pain or dull ache
- feeling restless and unable to lie still
- nausea (feeling sick)
- needing to urinate (pee) more often than normal
- pain when you urinate (dysuria)
- blood in your urine (haematuria) – this may be caused by the stone scratching the kidney or ureter
Blocked ureter and kidney infection
A kidney stone that blocks the ureter can lead to a kidney infection. This is because waste products can’t get past the blockage. This 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 (fever) of 38C (100.4F) or over
- chills and shivering
- feeling very weak or tired
- cloudy and bad-smelling urine
Diagnosing kidney stones
Your GP will usually be able to diagnose kidney stones from your symptoms and medical history.
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 urine
- blood tests to check that your kidneys are working properly, and to also check the levels of substances that could cause kidney stones, such as calcium
Your GP will want to diagnose and treat any infection. Depending on how severe your symptoms are, your GP may simply treat you to relieve the pain.
When to seek urgent medical attention
You should seek urgent medical attention if:
- you have a high temperature (fever) of 38C (100.4F) or over and symptoms of kidney infection/a kidney stone
- you have an episode of shivering or shaking and symptoms of kidney infection/a kidney stone
- the pain gets worse, particularly if it's a sudden, severe pain
You may be admitted to the hospital if:
- you are in shock or have signs of a bad infection
- you are at increased risk of damaging your kidneys (for example, if you have pre-existing chronic kidney disease)
- you are pregnant
- you are dehydrated and cannot take fluids due to vomiting
- there is uncertainty about the diagnosis
- you don’t respond to treatment within one hour (or sooner depending on clinical judgement), or there is sudden and recurring severe pain
If you don’t need admission to hospital, you will likely be referred to a urologist for investigation, to be seen as soon as possible.
This is so investigations can be done to confirm the diagnosis and to assess the likelihood of your body passing it when you go to the toilet (in your pee).
A urologist is a specialist in treating urinary problems.
Causes of kidney stones
The waste products in the blood can occasionally form crystals. These crystals 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:
- don't 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 go to the toilet (in your pee). This means it will often travel through the urinary system (the kidneys, kidney tubes and bladder).
Treating and preventing kidney stones
Most kidney stones are small enough to be passed in your urine. It may be possible to treat the symptoms at home with medication.
Larger stones may need to be broken up using ultrasound or laser energy. Occasionally, keyhole surgery may be needed to remove very large kidney stones directly.
It's estimated that up to half of all people who have had kidney stones will experience them again within the following five years.
The best way of preventing kidney stones is to make sure you drink plenty of water each day to avoid becoming dehydrated.
Keeping your urine (pee) diluted 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.
The kidneys are two bean-shaped organs that are roughly 10cm (four inches) in length. They're at the back wall of the abdominal cavity (the belly) on either side of the spine.
The kidneys take away waste products from the blood, acting like a filter on the blood, as it flows through the kidney. The waste products are passed out of the body in your urine (pee) when you go to the toilet.
More useful links
The information on this page has been adapted from original content from the NHS website.
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