Urethral Shaft Abnormality in Cats
Ectopic Ureter in Cats
An ectopic (displaced) ureter is a congenital abnormality in which one or both ureters open into the urethra or vagina. Bilateral ectopia affects both ureters, and unilateral ectopia affects one ureter. In cats affected with ectopic ureter, the ureter completely bypasses the bladder and enters the urethra from outside of the bladder walls (extramural type).
This condition is rare, and when it does occur it may be asymptomatic, with no apparent urination problems. When symptoms are apparent, they often present as occasional or continuous incontinence, and inflammation of the vagina (vaginitis) from urine scalding the vaginal tissue.
Ectopic ureter has an unknown mode of inheritance, but there does appear to be a component of breed predisposition.
Your veterinarian will use a diagnostic technique called urethrocystoscopy, which uses an insertable tube with an attached camera. In this way, your doctor will be able to examine the bladder internally, and visualization of the urethral opening into the urethra or vagina will be more apparent. Your veterinarian will also be looking to identify holes (perforations) in the structure of the urethra (urethral fenestrations), depressions, striping (or streaking), and tenting in the bladder. When this diagnostic method is performed skillfully, a more accurate diagnosis can be made than with external imaging techniques, such as radiography. Another technique, urethral pressure profilometry, measures surface variations to detect coexistent urethral muscle (sphincter) incompetence. There remains the possibility that a displaced ureter will confound the results of this test, however.
Treatment and Care
Treatment for repairing an ectopic ureter will involve surgically creating a new ureteral opening into the bladder, or removing a blocked or severely infected kidney. A portion of the displaced ureter will need to be removed, if feasible, and the ureter opening (ureterocele) into the bladder then repaired. Incontinence may continue if your cat also has urethral muscle incompetence, and will be weakened to some degree during recovery from surgery. Keeping the litter box close and easily accessible will help your cat to regain its composure over time.
Living and Management
Your veterinarian will need to evaluate the effectiveness of the surgery in a follow-up visit. Internal imaging of the urinary organs and bladder using dye injection through the vaginal canal (for female animals) will follow the track of the fluid and will make it possible to visually inspect the healing of the surgical site. Surgically elevating the vagina to support the bladder neck (where the urethra and bladder join) using the colposuspension technique may correct the incontinence.
If incontinence persists, phenylpropanolamine, an alpha-blocker, may be prescribed to enhance urinary flow, or to relieve tension and pain, a tricyclic antidepressor agent such as imipramine can be prescribed. Reproductive chemical hormone therapy may increase the naturally occurring sensitivity of urethral stress response receptors. Reproductive hormone therapy is not advised in immature animals.
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