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VSCD profiles interesting and instructive cases and pet owner
stories as they present.
| Microscopic
Ureter Surgery Canidates |
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Name: Cleopatra
Breed: Himalayan
Age: 10
years
Condition: Renal
Failure |
“Bella” is a 3 year old spayed female Siamese cat
who presented with a history of acute onset of frequenting the
litter box, straining to urinate and producing small drops of
bloody urine. Radiographs and ultrasound diagnosed bilateral
hydronephrosis and hydroureter secondary to ureteral stone obstruction. Significant
laboratory values included BUN of 126 and creatinine of 10.6.
“Cleopatra” is a 10 year old spayed female Himalayan
cat who presented with a history of chronic renal failure with
acute decompensation. Ultrasound revealed left unilateral
hydronephrosis and hydroureter seconday to ureteral stone obstruction. Relevant
laboratory values included BUN of 62 and creatinine of 5.2.
Though their presentation differed both cats were successfully
treated with microscopic ureter surgery by Dr. Carlson.
These patients underscore the need to perform thorough diagnostics
when assessing kidney disease. Bilateral ureteral stones (which
are almost always composed of calcium oxalate) may be present
in as many as 25% of cats affected with chronic renal failure. Partial
or complete ureteral obstruction will lead to the progressive
loss of nephrons and consequent renal function: because it essential
that every effort be made to preserve nephrons in these patients
both the obstruction and/or the underlying disease process must
be addressed. Fixing the obstruction does not fix the
underlying disease process. Since obstructive nephropathy
is potentially correctible, it is important to recognize its
occurrence before extensive and irreversible renal damage takes
place. Other factors to consider include:
- Many cats with chronic kidney failure demonstrate relatively
stable renal function over time: progressive declines in these
values should prompt investigation of ureteral obstruction.
- The principle concern in managing uroliths in cats with renal
disease is to minimize the risk that the urolith may cause
further loss of renal function.
- Over time, the reversibility of obstructive renal injury
declines: early detection maximizes the value of surgical intervention.
- In general, ureteroliths that are not associated with urinary
obstruction and do not cause clinical signs can be left in
place but should be monitored.
- Nephroliths, however, are rarely associated with obstruction
unless they move into the ureter and most remain within the
renal pelvis.
- Not every ureterolith requires surgical intervention. Some
will move down the ureter and ultimately exit to the bladder. Evidence
of progressive movement toward the bladder, with stable renal
function, generally suggests delaying surgery.
- Surgical intervention should be based on contemporary alterations
in renal structure and function using serial laboratory diagnostics
and ultrasonography. If surgery is indicated, the precise
technique is dictated by the location of the stone within the
ureter.
For more information on these cases or ureter surgery in general
please contact Dr. Carlson.
Kimberly R. Carlson, DVM
Diplomate of the American College of Veterinary Surgeons
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