Editing Pediatrics: Vesicoureteral Reflux (section)

==== Upper Urinary Tract ====
* '''Rationale for Serial Assessment of Upper Tracts'''
** '''Pyelonephritis propagated by VUR causes:'''
**# '''Renal scarring'''
**# '''Impedes attainment of full renal growth potential'''
**# '''Increases risk for renovascular hypertension'''
** '''Most parenchymal abnormalities are detected after the first episode of pyelonephritis'''
** A fundamental goal in serial upper tract imaging with VUR is to ascertain whether abnormalities are due to ongoing or resolved reflux and differentiate them from intrinsic developmental disturbances, medical renal disease, or antegrade flow resistance.
** Intensity of upper tract studies should be proportional to the propensity for renal damage
** The challenge in imaging is to differentiate congenital reflux–associated renal dysmorphism from scarring acquired after infection
*** VUR, particularly of higher grades, may result in renal maldevelopment that often appears scintigraphically or sonographically identical to postinfection pyelonephritic scars
* '''Renal US'''
** The mainstay of renal imaging in VUR management
** '''The appearance of the kidneys on ultrasound does not correlate with the absence or presence of reflux, or with its grade'''
** '''Renal resistive index measurements are significantly increased in higher grades of reflux'''
* '''Renal Scintigraphy'''
** '''The gold standard for imaging functioning renal parenchyma is scintigraphy using 99mTc-labeled DMSA.'''
*** The radiotracer is taken up only by functioning proximal tubular tissue mass, where it binds for several hours.
**** Because pyelonephritis impairs tubular uptake of radiotracer, these areas will fail to radioemit photons and appear as unexposed or underexposed regions in the resultant renal cortical images
**** DMSA scanning provides 98% sensitivity and 92% specificity for scar detection
*** The uptake of DMSA provides a good proportional representation of glomerular filtration
*** No consensus exists on the precise use of DMSA scanning in reflux management.
* DMSA and ultrasonography are often used complementarily, particularly when knowledge of relative renal function is desired since all DMSA defects are not necessarily scars.