Kidney stones

What are kidney stones?

The waste products in the blood can occasionally form crystals that collect inside the kidneys. Over time, the crystals may build up to form a hard stone-like lump. The medical term for kidney stones is nephrolithiasis, and if they cause severe pain it’s known as renal colic.

Kidney stones are quite common and can develop in one or both kidneys. Around three in 20 men, and up to two in 20 women, develop them at some stage of their lives. Kidney stones often affect people aged 30 to 60.

Small kidney stones may go undetected and be passed out painlessly in the urine. Larger stones may block part of the urinary system, such as:

  • The ureter – the tube connecting the kidney to the bladder
  • The urethra – the tube urine passes through on its way out of the body.

It may be possible to treat the symptoms at home with medication but larger stones may need to be broken up using ultrasound shock waves. Occasionally, keyhole surgery may be needed to remove very large kidney stones directly.

Ultrasound treatment (known as Extracorporeal Shockwave Lithotripsy) is a non-invasive outpatient treatment that focuses ultrasound shock waves on renal stones to break them up so that they pass out of the body naturally.

This treatment can have some side effects and most patients have some blood in the urine for a few days. The shattered stone fragments may also cause discomfort as they pass through the urinary tract. Sometimes, if the stone is not completely shattered, additional treatments may be needed.

Patient eligibility criteria

There is good evidence that if a kidney stone does not cause symptoms such as infection or severe pain, it may remain stable. Therefore, ultrasound treatment should not be required.

Larger stones may cause blockages and therefore the CCG will fund ultrasound treatment if the kidney stone (renal calculus) is 5mm or larger AND the patient is suffering from symptoms like obstruction, infection, or severe pain.

This means (for patients who DO NOT meet the above criteria) the CCG will only fund the treatment if an Individual Funding Request (IFR) application proves exceptional clinical need and that is supported by the CCG.

Advice and guidance

  • For more information, search for ‘kidney stones’ at
  • Choosing Wisely UK is part of a global initiative aimed at improving conversations between patients and their doctors and nurses.

Or visit the following websites:

Treatment policy for patients covered by NHS Birmingham and Solihull CCG

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