Editing Stones: Epidemiology and Pathogenesis (section)

== Infection Stones (magnesium ammonium phosphate) ==

* '''<span style="color:#ff0000">Struvite stones occur only in association with urinary infection by urea-splitting organisms.</span>'''
** '''Urease hydrolyzes urea, forming ammonium and carbon dioxide, which increases urinary pH.'''
*** Alkaline urine promotes supersaturation and precipitation of crystals of magnesium ammonium phosphate and carbonate apatite.
* '''<span style="color:#ff0000">Most common urease-producing pathogens (4):</span>'''
*# '''<span style="color:#ff0000">Proteus (most common)</span>'''
*# '''<span style="color:#ff0000">Klebsiella</span>'''
*# '''<span style="color:#ff0000">Pseudomonas</span>'''
*# '''<span style="color:#ff0000">Staphylococcus aureus</span>'''
** '''Some yeasts and mycoplasma species have the capacity to synthesize urease'''
** '''<span style="color:#ff0000">Although E. coli is a common cause of UTIs, only rare species of E. coli produce urease</span>'''
* '''Pathogenesis'''
** '''Occur more often in females''' than males by a ratio of 2:1 '''because infection stones occur most commonly in those prone to frequent UTIs.'''
*** '''Other populations at risk of recurrent infection include the diabetics, elderly, premature infants or congenital urinary tract malformation, urinary stasis as a result of urinary tract obstruction, urinary diversion, or neurologic disorders'''
** '''Spinal cord–injured patients are at particular risk for both infection and metabolic stones owing to neurogenic urinary tract dysfunction and hypercalciuria related to immobility'''
* '''Commonly produce staghorn stones; however, other crystals, including cystine, calcium oxalate monohydrate, and uric acid, can assume a staghorn configuration'''