A urinary stone is a solid mass which can form in the kidneys and pass down to the ureter or form in the ureter itself. If a stone has initially formed in the kidney it is normally referred to as a kidney stone until it passes in to the ureter.
Urinary stones are formed from normal substances within urine which form crystals leading to the mass.
Urinary 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.
Urinary 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
- When formed in the ureter it may often be as a result of a urinary tract infection (UTI).
The treatment of urinary stones is normally dependent on the size of the stone. In the cases of small urinary 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 urinary stones in to smaller masses and allow them to be passed.
In rare cases surgery may be needed to remove a urinary stone. When a stone is located in the ureter a specialist will treat this with a ureteroscopy. Alternatively, this surgery is sometimes referred to as a retrograde intra-renal surgery (RIRS).
The surgery involves passing a telescopic tube down the ureter and once the urinary stone is visualised the stone can be broken up to be passed or can be extracted using tools.
Depending on the underlying cause of a urinary stone or in repeated cases of urinary 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.