Can renal stone formation be prevented?
Q: I am a 37-year old male.In a diagnosed case of prostrate hypertrophy, when and how frequently should one test for PSA levels? If we maintain the urine pH alkaline of a person having a history of renal calculi, apart from proper hydration, will it prevent stone formation? If yes, then can we use urinary alkaliser for a longer duration? Which will be a better preparation, potassium citrate monohydrate or citric acid monohydrate?
A:It is advisable to have Serum PSA done annually after the age of 50 years as a part of annual health check. Evaluation may be started annually after the age of 45 years in people with a family history of prostate cancer. If you have been advised PSA by some physician, or labelled as having prostatic hypertrophy, at your age of 37 years, he must have very compelling reasons to do so as an exceptional case. Very often, the sonologists report prostatic hypertrophy a routine abdominal ultrasound as a radiological diagnosis, and recommend PSA as a standard reporting format to everybody without looking at the age. If that were the case, you need to see a clinician before getting into this PSA-mania. An alkaline pH will not prevent stone formation in all cases, and is a dangerous generalisation. Solubility of uric acid and cystine calculi is higher in alkaline pH, and, thus, these stone formers would benefit from alkalanisation, and make primary indication of use of citrates for stone prevention. Incidence of these stones is less than 5% in Indian population. More than 85% of Indian stone-formers have calcium oxalate stones. Some of the latter stones are associated with hypocitrauria (low citrates in urine, citrates inhibit calcium oxalate crystallisation), or associated with uric acid epitaxy (common crystallisation of uric acid and oxalate crystals. Citrates may be specific therapy for these groups of oxalate stone formers. Industry has promoted citrates as blind therapy for all calcium oxalate stones, but one has to be careful that potassium content of such self-induced therapy could be lethal in cardiac and renal patients. Alkalinisation of urine could be counter-productive in struvite stone formers, and may in fact promote such stone formation. It would be thus advisable to start such therapy only on your physician’s advice that would take your original urine pH, urine cultures, stone type and possibly a metabolic evaluation into consideration before advising therapy. All urinary alkalisers are either potassium or sodium citrates, alone or in combination with citric acid. A choice of salt is dependent on associated diseases like hypertension, oedema, renal failure or cardiac disease. These would differ in risks in different diseases, and not efficacy.