1 in 10 Kiwis Will Get Kidney Stones. But What Are They?

Recognised to be one of the most painful physical experiences, with sufferers making comparisons to childbirth or being stabbed, kidney stones affect around 1 in 10 New Zealanders in their lifetime. The condition leads to over 4,000 hospital visits annually.¹ Some people may not even know they have a kidney stone, as the stones can be very small and pass through the urinary tract without causing any symptoms. For the unlucky people who end up with a large kidney stone, the pain can be so severe as to cause nausea and vomiting, and they may need medical intervention to help break up the stone so that it can pass.

What are kidney stones?

Kidney stones are clusters of crystals that form from minerals and other substances in the urinary tract such as salts like calcium and sodium, oxalates and uric acid.

There are various types of kidney stones, the most common being calcium-oxalate and calcium-phosphate stones. Calcium containing kidney stones occur when you eat high-oxalate or low-calcium foods and don’t drink enough fluids. Other types of stones that form are uric acid stones formed from eating high amounts of animal protein, struvite stones and cystine stones.

Why do kidney stones cause such severe pain?

Kidney stones can form into sharp or jagged shapes which can irritate the ureter (the narrow tube between the kidney and bladder). If a stone is large enough it can get trapped in the ureter and block urine flow. As urine backs up, the ability of the kidney to filter waste is limited. This causes high pressure and spasms within the kidney and ureter. The severe pain, called ‘renal colic’, comes in waves that can feel very sharp and intense as the stone moves through the ureter. The pain is usually felt in the side or lower back just below the ribs, and moves to the lower abdomen and groin as the stone moves. Stones can range from the size of a grain of rice, to the size of an apple!

Are there other symptoms apart from pain?

Kidney stones can also cause other symptoms:

• Blood in the urine
• Cloudy urine
• Pain when peeing
• A constant need to pee
• Inability to pee
• Fever, if an infection is present.²

Kidney stones can be prevented

People who have had kidney stones are likely to have them recur, so prevention is very important. Prevention tips include:

• Stay hydrated – you need to drink enough water (around 2.5 to 3 litres per day), so that the urine is pale or clear.
• Squeeze lemon or orange juice into the water you drink – citrate in these juices can help block stone formation.
• Decrease salt intake – high salt can increase calcium in the urine which can lead to stones.
• Limit animal protein in the diet – decreasing consumption of red meat, poultry, fish and pork can help to lower uric acid levels.
• Avoid high oxalate foods – spinach, rhubarb, nuts, beetroot and chocolate can make people more prone to calcium oxalate stones.
• Limit added sugars – avoid sugary drinks, especially those sweetened with high fructose corn syrup.

Treatment for smaller stones

Small stones don’t usually require a trip to the hospital. Your healthcare provider will ask you to drink lots of water. You may also be prescribed pain relief and sometimes a medication to help the muscles of your ureter to relax so that is easier for the stone to pass.

Treatment for larger stones³

Uteroscopy and laser of stones: Ureteroscopy and laser of stones is an incision-free operation to remove or break up a stone from the ureter. A small telescope is passed up the ureter and usually a laser is used to shatter the stone. Sometimes a stone can be removed in one piece with a basket.

Extracorporeal shock wave lithotripsy (ESWL): This is a non-invasive procedure done under sedation or anaesthetic. It uses high energy acoustic pulses that pass through the skin to disintegrate the stones. Stone fragments can then pass out of the body in the urine.

Percutaneous removal of kidney stones (PCNL): PCNL is keyhole surgery where the stone is removed under general anaesthetic by passing a small telescope through your side directly into the kidney. The stone is broken up and the fragments are removed.

If you suspect you have a kidney stone

It is important to make an appointment with your healthcare provider if you think you may have a kidney stone so they can rule out a blockage or infection. Keep up with a steady intake of fluid and use pain relievers like paracetamol, ibuprofen or naproxen until you are able to be seen by your doctor.