KIDNEY STONE SYMPTOMS AND DIAGNOSIS

1. What symptoms can kidney stones cause?

Kidney stones sometimes cause no symptoms at all and are found by chance when you have a scan for another reason.

When they do cause symptoms, common ones are:

• Sudden, severe pain in the side or back (often called renal colic)

  • The pain may spread from the back towards the tummy, groin or, in men, towards the testicle.

• Blood in the urine (sometimes visible, sometimes only seen on a urine test)

• Needing to pass urine more often or burning when passing urine

• Nausea and vomiting

• A feeling of bloating or discomfort in the abdomen

The nerves that supply the kidneys and urinary tract share pathways with those from the stomach and intestines, so stone pain is often mistaken for “stomach pain”, “gas cramp” or “bowel colic”.

2. When should I go to A&E (emergency)?

If you have a known or suspected kidney stone and any of the following, you should seek urgent medical help:

• High temperature (38 °C or above) together with stone pain

• Shivering, shaking, feeling very unwell

• Only one working kidney (born with one kidney, one kidney removed, or one kidney not working)

• Possible blockage of both kidneys

• Severe pain that does not improve with strong painkillers

• Not passing any urine at all

These can be signs of a serious infection or severe blockage. A stone plus infection is a urological emergency and can be life-threatening if not treated quickly.

3. How are kidney stones diagnosed?

It is not safe to rely only on symptoms to diagnose a kidney stone. The stone must be seen on a scan.

Common tests used are:

• Ultrasound scan

  • Usually the first test done.

  • Looks at the kidneys, ureters and bladder.

  • Shows if there is a stone, swelling of the kidney (hydronephrosis) or other problems.

  • Advantages: quick, painless, no radiation.

  • Limitations: small stones or stones in certain positions may be missed, and the exact size and location are not always clear.

• CT scan (non-contrast CT, often called a “stone CT”)

  • This is the gold-standard test for kidney stones.

  • Shows the exact size, number and position of stones.

  • Shows how much blockage there is in the urinary tract.

Other tests may be used in special cases:

• Nuclear medicine scans (renal scintigraphy) to measure how well each kidney is working

• Older tests like intravenous urography are now rarely used

• What tests should be done if I have a kidney stone?

Most people with kidney stones will need:

• Urine tests

  • Routine urine test to look for blood, infection and crystals

  • Urine culture if infection is suspected

• Blood tests

  • Urea and creatinine to check kidney function

  • Electrolytes (such as sodium, potassium)

  • Uric acid, calcium and other relevant tests

• Imaging

  • Ultrasound and/or CT scan, depending on the situation

People who have:

• Recurrent stones

• Stones at a young age

• A single kidney

• A strong family history of stones

should usually have more detailed “metabolic” tests. These may include:

• A 24-hour urine collection (you collect all urine you pass over 24 hours, which is then analysed in the lab)

• Stone analysis (chemical analysis of any stone that is passed or removed)

These tests help to plan long-term prevention.