Kidney Stones

What are kidney stones?

Kidney stones are small hard pieces that form in the kidneys when certain salts and minerals in the urine clump together. They can stay in the kidney, or travel down the tube that connects the kidney to the bladder (the ureter).

They are common, and they can be very painful when they move.

Common symptoms

• Sharp pain in the side or back, often spreading to the groin.
• Nausea or vomiting.
• Blood in the urine.
• Wanting to pass urine more often, or burning when passing urine.

See a doctor straight away if you have a fever as well as these symptoms. A blocked, infected kidney is a medical emergency and needs to be drained quickly.

How are they checked?

The doctor will usually arrange:

• A urine test, to look for blood and check for infection.
• A CT scan, which is the most accurate test for finding kidney stones. The scan shows where the stone is, how big it is, and whether it is causing a blockage.
• Sometimes blood tests to check kidney function and other levels.

What are the treatment options?

The right treatment depends on the size and location of the stone, your symptoms, and whether the stone is causing a blockage or infection.

Watchful waiting

Small stones (around 4 mm or less) often pass on their own. The plan is then pain relief, plenty of fluids, and a follow-up scan after a set time to check that the stone has passed.

Lithotripsy (shockwave treatment)

Shockwaves are sent from a machine outside the body, aimed at the stone. The shockwaves break the stone into small pieces that can pass in the urine. This is usually done under a light anaesthetic. Some stones need more than one session, and not all stones respond.

Ureteroscopy

A thin telescope is passed through the urine tube, the bladder, and up to the stone. The stone is broken up using a laser or a small "mini jackhammer", and the pieces are removed with a tiny basket.

For stones high up in the kidney, a flexible telescope can bend around to reach them. After the procedure, a small plastic tube called a stent is often left for one to two weeks to help urine drain.

Percutaneous nephrolithotomy (PCNL)

For very large kidney stones (sometimes called "stag horn" stones), keyhole surgery may be used. A small puncture is made in the side, the surgeon goes into the kidney, breaks up the stone, and removes the pieces. Hospital stay is usually a couple of days.

Keyhole or open surgery

Rarely, very large stones in the kidney's drainage system or ureter may be removed using keyhole surgery. Open surgery for stones is now very rarely needed.

Stopping stones from coming back

If you have had stones, simple steps can lower the chance of more:

• Drink plenty of fluids - aim for clear urine and to pass urine every two to three hours.
• Get the type of stone analysed if possible, and have blood and urine tests to check for things like high uric acid or calcium levels.
• If you keep getting stones, you may be referred to a kidney physician for a more detailed check-up.