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1cm
STONE
Ureteral
Stone - Lower (Distal)
Classification:
There are three physiologic narrowing of the ureter where stones
may obstruct. The first narrowing of the ureter is the location
where the renal pelvis of the kidney meets the ureter or the uretero-pelvic
junction (UPJ). The next level of narrowing is where the ureter
crosses the iliac vessels. At this point, the diameter of the ureter
is narrowed to about 4 mm and urinary obstruction by a calculus
can commonly occur. The third ureteral narrowing exist where the
intramural portion of the ureter meets the bladder known as the
ureteral vesico-junction, or UVJ, which measures approximately 1
- 5 mm. in size. The majority of stones become stuck at this level.
Once a calculus reaches the distal ureter and approaches the bladder,
symptoms of vesicle irritation are frequently noted.
Clinical
Presentation:
The usual manifestations of a kidney stone small enough to pass
into the ureter are ureteral colic and hematuria. This patient presents
with a stone in the upper ureter will frequently experience acute
onset of a sharp, spasmodic pain localized to the flank (side).
As the stone progresses downward to the level of the bladder, the
pain remains sharp and intermittent, corresponding to the ureteral
peristalsis. The pain will frequently radiate to the lateral flank
and abdominal area and may be accompanied by nausea and vomiting.
If infection accompanies obstruction, then the patient may develop
fever and/or chills associated with an infection of the kidney,
also known as pyelonephritis.
As
the stone passes into the distal ureter, the pain remains sharp.
In males, pain may frequently radiate to the inguinal canal into
the groin and to the corresponding testicle. In females, the pain
may radiate to the ipsilateral labia.
It
is not uncommon for patients with ureteral colic to present with
nausea and vomiting. Abdominal distention due to a reflex ileus
may be present and may potentially confuse the diagnosis. These
symptoms may mimic the presentation of other disease processes,
including gastroenteritis, acute appendicitis, colitis, diverticulitis,
salpingitis, cholecystitis and bowel obstruction.
Less
frequently, the passage of the stone may be less dramatic with patients
describing a dull ache in the flank (side) that may be present for
weeks without interfering with his or her routine. This pain is
not as localized as that of acute colic and may be confused with
other complaints. Other patients may present with microscopic hematuria
or gross hematuria and/or a urinary tract infection (UTI).
Once
the calculus reaches the distal ureter and approaches the bladder,
symptoms of bladder irritation, frequency, and nocturia may be present.
Diagnosis:
| UVJ
stone |
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| Ureteral
stone. Plain abdominal film (a) shows a radiopaque stone
in the pelvis. This patient was also found to have stones
in both kidneys (yellow arrowheads). Unenhanced CT scan
(b) shows stone in the distal ureter (red arrow). Following
removal of the stone, stone analysis revealed calcium
oxalate stone |
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Treatment
options:
UVJ stone
Ureteroscopy is a technique utilized for accessing the distal ureter.
Rigid or semi-rigid ureteroscopy is used to access the ureter below
the iliac vessels so that various lithotripsy options are available
for fragmenting stones (see treatment section of text). In addition,
shock wave lithotripsy can be used for distal ureteral stones. This
is done while the patient is placed in the prone position. However,
it should be noted that the success rate for distal ureteral stones
is less than the success rate for upper ureteral stones or renal
calculi.
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