Kidney Stones
Update in Diagnosis and Management
Calcium Phosphate is Very Insoluble at High pH!
February 2010
Calcium phosphate stones are the exact opposite, since calcium phosphate precipitates in urine with an alkaline pH > 6.3. Many of these patients have a defect in renal acidification, or renal tubular acidosis.
Causes include autoimmune diseases affecting the kidney such as Sjogrens disease, monoclonal protein diseases with peritubular deposits, and certain drugs (for example toperimate or acetazolamide which both block carbonic anhydrase).
In patients with renal tubular acidosis, in addition to a high urinary pH, they also develop hypocitraturia because of the associated systemic acidosis, as well as hypercalciuria, probably due to effects of bone buffering of the acid load. All of these also favor calcium phosphate precipitation.
Treatment often consists of citrate repletion with potassium citrate, although this can potentially make things worse if the urinary pH goes up further. Therefore, it is very important to watch serial urinary supersaturation profiles to monitor treatment effect in these patients.
Calcium Phosphate Insoluble |
Jump to section:
- Introduction
- Kidney Stones
- Why do Kidney Stones Form?
- Genetics and Environment
- Not All Stones are Created Equal: Stone Analysis is Very Helpful
- Laboratory Evaluation
- Supersaturation Index
- Components of the Urinary Supersaturation Profile
- Uses of Urinary Supersaturation
- Common Features Increase Urinary Supersaturation in Patients with Idiopathic Calcium Oxalate Nephrolithiasis
- "Conservative" Dietary Recommendations for Calcium Oxalate Stone Formers
- Causes of Hypercalciuria
- Genetic Hypercalciuria
- Genetic Hypercalciuria: Treatment
- What is Oxalate?
- Hyperoxaluria: What is the Relevant Concentration?
- Oxalate Balance on a Typical Western Diet
- Enteric Hyperoxaluria is Caused by Fat Malabsorption
- Control of Urinary Citrate: Largely Due to Systemic Acid Base Balance
- Treatments for Enteric Hyperoxaluria
- Low Urinary Citrate
- Hyperuricosuria is a Risk Factor for Calcium Oxalate Stones
- Uric Acid is Very Insoluble at Low pH
- Calcium Phosphate is Very Insoluble at High pH!
- Cystine Stones
- Struvite stones
- Questions?
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