What are kidney stones?
Kidney stones are very similar to pieces of gravel formed from concentrated minerals in the urine. They range in size from a few millimetres to over ten centimetres. About 1:12 people will get a stone, and the chance of a stone recurring is approximately 50% in ten years. Some people form recurrent stones more quickly and this requires investigation.
What problems can kidney stones cause?
- Renal colic: Kidney stones may become lodged in the thin muscular tube (ureter) that drains urine from the kidney to the bladder. This causes severe pain requiring hospital admission. Small stones may pass spontaneously, larger stones require treatment.
- Loin pain: Kidney stones may also cause a dull back pain by blocking portions of the kidney, and also when they become lodged in the flesh of the kidney.
- Infections: Kidney stones often contain bacteria, and can cause recurrent urine infections.
- Blood in the urine: Kidney stones are sharp and can scratch the inside of the kidney and causing bleeding. Infections caused by stones are associated with bleeding.
- Kidney damage: When a stone blocking the ureter is untreated the kidney can be damaged. Large stones in the kidney can slowly destroy the kidney from the inside.
How are kidney stones treated?
- Ureteric stent: When a stone becomes lodged in the ureter a ureteric stent may need to be inserted in hospital. This allows the urine to drain. The stent can cause troublesome symptoms however.
- Shock wave treatment (ESWL): This is an outpatient procedure that involves sending shock waves through the skin focused on the stone. It avoids an operation, but may leave fragments in the kidney which grow to form more stones later.
- Laser ureteroscopy (URS): This involves an operation to break up the stone using a tiny laser fibre. The fragments are removed and can be sent for analysis which can help subsequent stone prevention.
- Percutaneous nephrolithotomy (PCNL): When stones grow to over 2cm they are removed by an operation through the back. This involves an overnight stay.
- Metabolic testing: Recurrent stone formers require detailed testing to identify and correct biochemical abnormalities in the urine.
Author: Mr Andrew Ballaro MSc, MD, FRCS (Urol). Consultant Urologist and Specialist Stone Surgeon at Highgate Private Hospital.