Editing Stones: Epidemiology and Pathogenesis (section)

== Uric acid stones ==
'''<span style="color:#ff0000">Determinants of uric acid stone formation (3):</span>'''
# '''<span style="color:#ff0000">Low urine pH (<5.5) (most important)</span>'''
#* Urine pH remains the most cost-effective means of screening for this condition and monitoring therapy.
# '''<span style="color:#ff0000">Low urine volume</span>'''
# '''<span style="color:#ff0000">Hyperuricosuria</span>'''

=== Causes ===

* '''Classified: congenital vs. acquired'''

==== Congenital ====
* Disorders associated with uric acid stones involve renal tubular urate transport or uric acid metabolism, leading to hyperuricosuria

==== Acquired ====
# '''<span style="color:#ff0000">Diabetes'''
#* '''Diabetic stone formers have a lower urine pH''' compared with non-diabetic stone formers '''due to insulin resistance'''
#** In normal individuals, insulin stimulates ammoniagenesis in renal tubule cells by promoting gluconeogenesis from glutamine and by stimulating ammonium excretion by the proximal tubular sodium/hydrogen exchanger. Failure of the renal tubule cells to respond to insulin '''results in defective ammonia production and/or excretion, thereby leading to a reduction in urinary pH and uric acid stone formation'''.
#* '''Diabetic stone formers are approximately 6x more likely to develop a uric acid stone'''.
#** Uric acid stones are found in 34% of stone-forming patients with diabetes mellitus compared to 6% of non-diabetic stone formers
# '''<span style="color:#ff0000">Obesity</span>'''
# '''<span style="color:#ff0000">Metabolic syndrome</span>'''
# '''<span style="color:#ff0000">Tumour lysis syndrome</span>'''
# '''<span style="color:#ff0000">Volume depletion</span>'''
# '''<span style="color:#ff0000">High animal protein intake</span>'''
# '''<span style="color:#ff0000">Chronic diarrhea</span>'''
# '''<span style="color:#ff0000">Uricosuric drugs</span>'''
# '''<span style="color:#ff0000">Idiopathic</span>'''
* '''<span style="color:#ff0000">All 11 conditions associated with hyperuricosuria listed above</span>'''