There are primary and secondary bladder stones. Primary bladder stones develop in sterile urine. A possible cause is loss of larger amounts of fluid as for example diarrhea. Most of these stones sonsist of ammonium urate. Secondary bladder stones usually develop on the grounds of a chronic urinary infection and/or the presence of residual urine as for example with BPH or a stenosis of the urethra. Stones can also form on foreign objects in the bladder such as indwelling catheters. These stones are usually composed of uricacid or magnesium phosphates.
Primary bladder stones are found mostly in underdeveloped countries and here most often in malnourished children. Secondary bladder stones may be found all over the world in elderly patients, especially men.
Mostly voiding problems occur. This may sometimes be accompanied with blood in the urine, especially at the end of micturition, so-called terminal macrohaematuria. Typically there is an abrupt interruption of urinary flow, whereby the patient can void another portion of urine after changing position, so-called staccato micturition.
As a rule, a presumptive diagnosis can be made based upon the patients symptoms. Definite proof of a bladder stone can then be made by sonography, X-ray of the abdomen or most certainly by cystoscopy.
Small and middle size stones can usually be made smaller with a stone disintegration forceps and then be flushed out. The forceps is introduced through the urethra. Large stones must often be removed by open surgery.
Prognosis is, as a rule, good. For secondary bladder stones the obstruction of urine flow should be eliminated in addition to the stone disintegration. This may involve the resection of an enlarged prostate or incision of a urethral narrowing, otherwise there is the danger of renewed stone building.