V

vesicoureteral reflux A condition in which URINE
backflows from the BLADDER into the ureters
toward the KIDNEYS. Vesicoureteral reflux may
result from congenital anomalies in the structure
of the ureters, such as short ureters or ureters that
enter the bladder wall in an unusual location or at
an unusual angle. Normally the URETER forms a
short, flattened tunnel within the bladder wall
that functions like a valve to keep urine from
reentering the ureter from the bladder. Structural
anomalies may prevent the valvelike action of
the ureter’s entrance into the bladder from func-
tioning properly, such that when the bladder fills

with urine the ureter is open and allows urine to

enter.

Vesicoureteral reflux may also develop second-

ary to an obstruction that blocks the flow of urine

from the bladder, such as bladder stones (UROLITHI-

ASIS) or an enlarged PROSTATE GLANDin a man. Such

an obstruction causes the bladder to overdistend,

which causes the ureteral tunnels to open and

allow urine to enter the ureters. INFECTIONthat

inflames and narrows the URETHRA also can

obstruct the flow of urine out of the bladder. Vesi-

coureteral reflux presents a high risk for INFLAM-

MATION and bacterial infection of the kidneys

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VESICOURETERAL REFLUX GRADING

Reflux Grade Extent of Urine Reflux Effect on Kidneys
grade 1 part way up URETERbut not into the kidney increased risk for NEPHRITIS

grade 2 completely up ureter to renal pelvis increased risk for nephritis

grade 3 URINEbacks up into the renal pelvis and renal mild dilation of renal pelvis and ureters
calyces mild nephritis likely

grade 4 urine distends the renal pelvis and renal significant dilation of ureters
calyces nephritis
HYDRONEPHROSISwith mild to moderate impaired renal
function
risk of permanent kidney damage

grade 5 as much or more urine refluxes as passes from extensive and persistent dilation of ureters, renal pelvis,
the URETHRA and renal calyces
nephritis
hydronephrosis with significant impaired renal function
secondary problems such as HYPERTENSION
permanent kidney damage likely