Editing Pediatrics: Vesicoureteral Reflux (section)

== Causes of VUR ==

* '''<span style="color:#ff0000">Classified (2): primary vs. secondary'''

=== Primary Reflux ===
* '''<span style="color:#ff0000">VUR due to fundamental deficiency of the longitudinal muscle of the intravesical ureter resulting in an inadequate valvular mechanism while the remaining factors (bladder and ureter) remain normal or relatively noncontributory'''
** VUR may be a normal variant in the population but becomes clinically relevant only in some because of a predisposition to UTI. This is supported by the observation that VUR without infection is of questionable clinical significance
* '''Risk Factors'''
**'''Genetics'''
*** Tendency for an '''autosomal dominant pattern of inheritance'''; probably many genes are involved
***'''Prevalence of VUR in'''
****'''Offspring: ≈65%'''
**** '''Siblings: ≈30%'''
***** Screening in siblings
******Because the renal consequences of VUR are at issue, rather than reflux itself, siblings may be better served by non-invasively (ultrasound) screening for cortical abnormalities first, and screening for VUR if history of compounding factors such as UTI or bowel and bladder dysfunction are manifested.
******* By taking into account the imaging of the kidneys first, as well as the patient’s age and history of UTI, a rational top-down approach to sibling reflux screening emerges.
******* It cannot be assumed that all cortical abnormalities in siblings with VUR are acquired. The lack of prospective studies should temper the notion of mass screening of siblings
******* In any sibling, however, in whom reflux is diagnosed, the indications for treatment remain the same as for general reflux in the pediatric population.

=== Secondary Reflux ===
* '''<span style="color:#ff0000">VUR due to overwhelming the normal function of the UVJ'''
** May be of an anatomic or functional origin in the UVJ, bladder, or bladder outlet
*Reflux is also considered secondary if its absence was documented at some point before its detection.

==== Causes (5) ====

#'''<span style="color:#ff0000">Bladder dysfunction'''
#*Can be of a congenital, acquired, or behavioral nature
#*Often the cause of secondary VUR
# '''<span style="color:#ff0000">Posterior urethral valve'''
#* '''Most common cause of bladder outlet obstruction in infants'''
#** '''In females, anatomic bladder obstruction is rare. The most common structural obstruction in females is from a ureterocele that prolapses into the bladder neck.'''
#* Reflux is present in 48-70% of patients with PUV patients
# '''<span style="color:#ff0000">Neurogenic bladder'''
#* '''<span style="color:#ff0000">Spina bifida, in particular, is at risk for VUR'''
#** '''Special attention for the potential for occult spinal dysraphism is warranted during evaluation of any child with UTI'''
#* '''Urodynamic risk factors for VUR:'''
#*# '''Overactivity'''
#*#* '''Most common urodynamic abnormality associated with VUR in neurologically normal children'''
#*#* Overactive bladder frequently can be responsible for reflux
#*# '''Inadequate or obstructive voiding patterns'''
#*# '''Higher voiding pressures (may be due to inadequate sphincter relaxation)'''
# '''<span style="color:#ff0000">Urinary Tract Infection'''
#* UTIs and their accompanying inflammation can also cause reflux by:
#*# Lessening compliance
#*# Elevating intravesical pressures
#*# Distorting and weakening the ureterovesical junction
# '''<span style="color:#ff0000">Bladder and bowel dysfunction (BBD)'''
#* In older children, acquired abnormalities in bladder and bowel function commonly known as bladder and bowel dysfunction (BBD'')'' have been associated with reflux