What are kidney stones?

Your kidneys filter your blood and takes out the water soluble waste products that you do not need. The kidneys make urine (pee) by dissolving these waste products in water. The bladder stores the urine until you are ready to go toilet and pee.

Kidney stones are hard little crystals that form in your kidney. They are usually made from calcium, sometimes they are made from uric acid. These types of chemicals are always in your urine but when you don’t drink enough they become more concentrated and form crystals that can grow to become kidney stones.

People often do not realise they have a kidney stone until it moves from the kidney into the tube that connects the kidney to the bladder.

Signs, symptoms and treatments

Once the kidney stone moves it can be painful. Most stones will pass out of your body in your urine when you pee. For this reason if the doctor knows you have a kidney stone they often suggest waiting to see if it will pass by itself. You might need to take pain relief medicine when they are passing and drink lots of water.

If the stone gets stuck or completely blocks the tube that joins the kidney to the bladder (the ureter) it will be really, really painful. The kidney stone can cause severe pain in your back and side. It might hurt to pee and there might be blood in your urine. You might need to pee often, or you might not be able to pee at all.

If the stone does not pass or if it causes an infection then you might need to go to hospital for treatment to dissolve or remove the stone.

There are a range of options available including laser treatment. It is uncommon to require surgery.

What causes them?

Dehydration (not enough water in your body) is the major reason for people developing a kidney stone. You can become dehydrated by living somewhere really warm, or doing heavy work or lots of exercise and not taking fluid replacement.

Remember if you have runny bowel motions you are losing more water from your body than usual. It is important to replace the fluids you lose from your body. This is especially important if you have any medical condition that means you regularly have loose motions (runny poo). Medical conditions like Chon’s disease and ulcerative colitis often mean lose motions. 

Things that increase your chance of developing a kidney stone:

• dehydration
• insulin resistance
• high protein diet (too much meat)
• too much salt or sugar in your diet
• being overweight
• gastric bypass surgery
• inflammatory bowel disease (like Chron’s or ulcerative colitis)  
• chronic diarrhoea

Men are about three times more likely to get kidney stones than women.

See your doctor.

Make sure you see your doctor if

• you have significant pain bad enough that you cannot sit still or find a comfortable position
• the pain is in your side and back and it came on suddenly
• as well as pain you have fever and chills
• as well as pain you have nausea and vomiting
• you cannot pass any urine (pee)
• you have blood in your urine

Anything on the above list means you need to see a doctor today.

How to reduce the chance of developing a kidney stone

Nearly half of all people who get one kidney stone develop a second kidney stone. If you have already had a kidney stone, make sure you talk to your doctor about whether you need any adjustments to what you eat and drink to reduce the chance of getting a second kidney stone.

Make sure you replace fluids after lots of sweating e.g. from sport or heavy manual work. Replace fluids lost from lose bowel motions. We should all drink 8 – 10 cups of water per day. This is about two litres. If you have had a kidney stone and are risk of developing another, you need to drink 3 litres of water every day.

Ministry of Health NZ say that plain tap water is best. “Tea and coffee are ok but have no more than 7 cups of tea or instant coffee or 3 single-shot espresso-type coffees a day.” It is important to keep fruit juices and fizzy drinks to a minimum as they contain lots of sugar.

Written by Linda Caddick

This blog provides general information and discussion about medicine, health and related subjects. The information contained in the blog and in any linked mate­ri­als, are not intended nor implied to be a substitute for professional medical advice.