Editing Stones: Epidemiology and Pathogenesis (section)

== Anatomic predisposition to stones ==

* '''Ureteropelvic Junction Obstruction (UPJO)'''
** '''Correction of the UPJO does not prevent recurrent stones in most patients''', emphasizing the role of underlying metabolic abnormalities in the etiology of renal calculi in patients with UPJO
* '''Horseshoe kidneys'''
** Although urinary stasis likely contributes to a propensity toward stone formation in patients with horseshoe kidneys, an underlying metabolic abnormality is required for stone formation to occur
* '''Caliceal Diverticula'''
* '''Medullary Sponge Kidney'''
** '''Congenital disorder'''
** '''Characterized by cystic dilatation of the collecting tubules''' in one or both kidneys, '''resulting in stasis of urine and may eventually lead to calculi deposits'''
** '''May independently cause both nephrocalcinosis (see above) and distal RTA with associated RTA metabolic abnormalities including''' hypercalciuria, hypocitraturia and defective urinary acidification
** '''Increased risk for kidney stones and UTI'''
** Imaging: hyperechoic papillae with clusters of small stones on ultrasound examination of the kidney or with an abdominal x-ray.