Kidney stones (renal calculi) are solid masses which form over time anywhere in the urinary tract system. Most kidney stones form within the kidneys themselves but a small percentage form in the bladder or urethra. Kidney stones are formed from normal substances within urine which form crystals leading to a kidney stone.
Kidney stones often give rise to a characteristic pain referring in to the lower back or abdomen recognisable by healthcare specialists. To confirm the diagnosis your specialist may request any of the number of tests including an ultrasound scan, x-ray or CT scan.
Kidney stones are caused when the substances within the urine including uric acid, oxalate and calcium are present in high concentrations. Causes of high concentration of these substances may include:
- Certain types of medication
- Genetic factors
- High protein diet
- Other medical conditions (including recurrent urinary tract infections)
The treatment of kidney stones is normally dependent on the size of the stone. In the cases of small kidney stones your specialist will encourage you to attempt to pass the stone normally even if this is a painful procedure.
In cases where this is not possible your specialist will normally request a treatment known as extra-corporeal shockwave lithotripsy. This treatment uses shock-waves which are a much stronger form of waves than ultrasound waves (which have historically been used widely within medicine). Shockwaves are strong enough to break up many kidney stones in to smaller masses and allow them to be passed.
In rare cases surgery may be needed to remove a kidney stone. This may be done in two ways and your specialist will choose the suitable surgery depending on the location and size of the kidney stone.
A ureteroscope is a telescopic tube that can be passed down the ureter and once the kidney stone is visualised the stone can be broken up to be passed or can be extracted using tools.
A nephrolithotomy procedure is sometimes needed for very large stones located in the kidneys themselves. This involves making a small incision in the lower abdomen to access the kidneys to directly remove the stone.
Depending on the underlying cause of kidney stones or in repeated cases of kidney stones, your specialist may recommend changes to diet and fluid intake or may prescribe certain medication to reduce the concentration of crystal forming particles in the urine to prevent further problems.