Page 1 - Ureteropelvic Junction Obstruction

Urological Health
Ureteropelvic junction
obstruction
A ureteropelvic junction obstruction is a partial blockage of the drainage system of the kidney.
our kidneys filter blood to eliminate waste
Yproducts and excess water that are excreted in
the urine. A drainage system carries urine from each
kidney to the bladder where it is stored until emptying
is appropriate. Each kidney drains into a renal pelvis,
which funnels urine into a ureter, the long, narrow
muscular tube that conducts urine to the bladder.
Your doctor has found a partial blockage of the
connection of a renal pelvis with the ureter, the
ureteropelvic junction (UPJ). This ureteropelvic junction
obstruction impedes drainage and causes urine to
back up in the kidney leading to increased pressure,
flank pain and, in some cases, kidney damage.
Imagine a partially clogged sink drain: when water is
running slowly, drainage is adequate, but when water
is flowing more rapidly, it backs up.
Most often, this blockage is the result of an
abnormality of kidney development occurring prior
to birth (congenital). The muscle of the obstructed
ureteropelvic junction is poorly developed and,
sometimes, replaced with scar tissue. Both kidneys are
involved in 10% of cases. In some, the obstruction may
have occurred after an injury or inflammation related
to a kidney stone. Occasionally, a blood vessel
crossing over the UPJ can contribute to blockage.
UPJ obstruction may be diagnosed at any age.
Routine ultrasound during pregnancy can detect
fullness of the developing child’s renal pelvis
(hydronephrosis). Some infants are found to have UPJ
obstruction when abnormal swelling in the abdomen
or flank is discovered or urinary infection develops. In
adults, it may be identified during the investigation
of intermittent flank or abdominal pain often made
worse by drinking large volumes of fluid. Some patients
develop bloody urine or stones in the affected kidney.
Investigation
Once UPJ obstruction is suspected, investigations are
required to determine the exact site and severity of
the blockage. Blood and urine tests assess overall
kidney function and the possibility of infection.
Ureteropelvic junction obstruction
kidney
renal
pelvis
obstructed
ureter ureteropelvic
junction
with dilated
renal pelvis
Roula Drossis
bladder
urethra
Ureteropelvic Junction Obstruction
Imaging studies are used to clarify the drainage
system anatomy and assess the degree of obstruction.
Ultrasound or CT scan will show fullness in the renal
pelvis and any loss of functioning kidney tissue.
Intravenous pyelography (IVP) involves the injection
of contrast material into a vein followed by a series of
x-rays. The “dye” is excreted by the kidneys outlining
the drainage system and gives an indication of
function.
A nuclear renal scan can evaluate kidney function
more accurately. In some cases, a diuretic is
given during the scan to promote increased urine
production. The scanner will show increasing nuclear
marker buildup in the kidney in the presence of
obstruction while the marker washes rapidly out of a
normal drainage system.
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