Please select the country or location you would like to see content from.
country picker icon
condition icon


Renal calculi

Written by Healthwords's team of doctors and pharmacists based in UK | Updated: 26.01.2023 | 4 min read

Renal calculi, commonly as kidney stones, are crystals formed from the naturally occurring salts in urine that bulk together to form a solid lump. They are common, and affect around 1 in 10 people - but slightly more men than women.

Renal calculi, also known as renal lithiasis or nephrolithiasis, can cause pain when they are stationary in the kidney itself, but the real problems occur if they move out from the kidney and into the pipe connecting the kidney and bladder (the ureter). If this happens, along with causing severe pain, they can block the pipe, leading to potential infection and difficulty passing urine. They carry the risk of preventing the kidneys working effectively, either in the short or with long term consequences.

The typical pain associated with kidney stones is a loin-to-groin pain. This is from the back on the side, round to the front lower part of the abdomen. People sometimes feel the pain radiating to the vagina, testicle or tip of the penis.

Most people report kidney stone pain to be excruciating, coming in waves and spasms to double them over until it passes after a few seconds or minutes. This is when your ureter is blocked but this muscular tube is trying to force the stone down by squeezing.

If you have classical-sounding pain, along with blood in your urine, your doctor may arrange a scan to see whether there is any evidence of kidney stones.

What causes the stones?

Renal calculi form because there is an imbalance in certain chemicals produced in your urine, such as calcium. This can be due to a medical problem or certain regular medications.

Stones are more likely if you are dehydrated or don’t drink enough fluids, as this dilutes the stone-forming chemicals, to be passed out in the urine. Medical textbooks sometimes describe a typical kidney stone patient being a middle-aged chef who works in a hot environment and doesn’t drink enough water during a busy evening of work. The moral of that story is to carry your bottle and stay hydrated.

When should I see a doctor?

If you think you have a renal calculus, you will need to see or speak to your doctor. You may be looking for some pain relief, and if it is the first time you have had a suspected kidney stone then you will need some sort of imaging to confirm the diagnosis. Scans can include X-rays, ultrasound and CT scans.

If you have had renal calculi before, and have spoken to your doctor about managing them at home if the pain is controlled – you should take care to know when you may need to escalate things.

If you get a fever, you should immediately attend the emergency department as this can indicate a blocked and infected kidney due to the stone. If you are unable to pass urine for several hours, you should attend the emergency department urgently.

If you don’t notice the stone pass, you will need to see your doctor to arrange some imaging to check that the stone has passed and is not stuck and potentially causing long term kidney damage by blocking the tube connecting the kidney and bladder.

Your doctor will, of course, consider other causes of tummy pain, including a urine or kidney infection, appendicitis, pelvic inflammatory disease in women or prostatitis in men, or simple severe lower back pain.

How is it treated?

In many cases, no treatment is needed to pass renal calculi. Even stone sizes up to around half a centimetre in diameter can pass out by themselves. They can be painful, so pain relief can be the only thing required to help get through it. You can take paracetamol or ibuprofen (if just for short term relief). Any stronger pain relief can be prescribed by your doctor.

If the stone is large, or there are other complications such as infection or damage to the kidney and its filtering effects then other treatments may be required.

These include shock wave therapy to break up stones that are still in the kidney. Operations can include collecting and removing stones from the kidney or ureter.

In emergency situations, when stones get stuck and completely block the ureter, a stent can be placed to keep the person safe in the short term. A stent is a tube that is passed from the bladder to the kidney to ensure no blockage or complications occur due to the stone, and urine can pass freely down the ureter and around the stone due to the presence of the stent.

How can I prevent renal calculi?

Staying hydrated is key to putting yourself in the best place possible for avoiding renal calculi formation. Make sure that you keep your water intake at least at the minimum of 2.5L to 3L per day will ensure that you are doing everything possible to dilute down the stone-forming products in the urine.

You can take stock of your hydration by checking in on your thirst levels, tracking your daily intake of water and also monitoring the colour of your urine – aim for pale straw-coloured urine at all times.

If you take regular medications, you can speak to your doctor to check that none of the medications could be linked to kidney stone formation. You should avoid drinking excessive amounts of tea, coffee, salt, fizzy drinks and beer which can predispose to certain types of stone formation.

Was this helpful?

Was this helpful?

Newsletter icon
Subscribe to our Newsletter
to get monthly notified about our latest health and wellness topics.
By clicking Subscribe, I agree to the Healthwords Terms & Conditions and Privacy Policy and understand that I may opt out of the newsletter subscription at any time.