Each vet has his own
way of handling a case of urethral obstruction in the
dog. The outcome may be similar in that the dog can pass
urine normally but the post-operation complications and
implications vary.
In the following case, the Miniature Schnauzer dribbled
urine. X-ray showed the urethra blocked by more than 10
small stones 3x5 mm in diameter. The catheter was obstructed and could not
pass into the bladder.
SURGICAL APPROACHES
1. Cystotomy and retrograde urohydropropulsion of the
stones into the bladder.
2. Cystotomy and urethrostomy.
When there are too many stones, I usually take the second
surgical approach. There will be less trauma to the
glans penis and urethra as the
urohydropropulsion (syringing 20-35 ml of water to push
back the stones into the bladder). I will make a 0.5 mm
cut behind the os penis, take out the stones with a
forceps, close the urethra and skin. Then I take out the
3 stones from the bladder. In my experience, the
urethral wound heals well if proper post-op care is
given.
However, in some cases, the dog is sent home within 2
days
after surgery. There is a lack of care by the owner due
to inexperience in animal nursing. The wound breaks down
and the urine leaks from the wound perpetually. This is
because some owners
do not bother to refer to the vet on seeing the wound
breakdown, owing to various reasons. So, the first
approach eliminates this post-op complication of an
unnatural urethral gap as the
penile urethra is not incised. All stones are taken out
via the bladder in the first approach.
In this case, Vet 1 preferred the first approach. There
are more than one surgical approaches in treating
urethral obstruction and each has its own pros and cons.
However, on Saturday (my day off and 24 hours after
surgery by Vet 1), I visited Toa Payoh Vets to check on
this Miniature Schnauzer in the afternoon. I noted the glans penis was
much swollen and so did the owner.
In this case, the dog was scheduled to go home 48 hours
after surgery. The owner was concerned about this
swollen glans penis - reddish and not able to get back
inside the prepuce. This swelling is a post-op
complication of retrograde urohydropropulsion in some
cases. What makes it occur? It is due to the traumatic
pressure of gripping the glans in the process of
retrograde urohydropropulsion via a catheter.
Numerous small urinary stones
inside the os penis (penile bone)
can be removed via a urethrostomy
or via flushing back into the
bladder and removed via cystostomy.
Calcium oxalate stones were
removed.
The catheter has not
been able to pass through more than 10 cm inside the
penis as its passage is obstructed by the numerous
stones inside the penile urethra. To prevent it being
dislodged as water is pumped into the catheter to push
the stones back into the bladder for removal, the glans
penis has been gripped as an anchor point, resulting in
swelling. Gripping the penile bone may not be practical
but will be preferred. In any case, the outcome was
excellent in the sense that after 3 irrigations, the
stones were pumped back into the bladder where they were
removed. So, the penile urethra was not cut open.
In this case, there
was a complication post-op. I had to intervene to resolve this
problem. I decided to give an anti-inflammatory pred
injection which is not normally used after surgery.
Leaving the glans penis to shrink will take many days
and any traumatic injury to it will lead to much
unhappiness for the owner as it will cost her money.
Although the dog has a big size 20 e-collar, the owner
disagreed with me that the dog could reach his
surgical area to bruise it. There was
a small bruised area near his sutures (see picture). The
lady owner told me that there was no way her dog could
have licked that area since he had the collar. I said it
was possible but there was no point arguing with an
owner as she had not seen incidents in other cases.
Within 24 hours of the injection, the glans penis had shrunk by 50% and
was much less inflamed (see picture). He peed normally,
had a good appetite and an excellent caregiver. He was
sent home on Sunday.
For dogs with swollen glans penis, it is best not to
send home till the dog has recovered but that would take
many days and trauma could still occur in the Surgery.
NSAID does not work very well in such cases if they are
given as the "first line of defence." NSAID was
prescribed for the home stay.
MANAGING
Calcium Oxalate Urolith prevention - do urinalysis
and X-rays.
If urine SG >1.020 give canned food or add water
to food
If urine pH <6.5, consider diets that produce less
acidic urine eg. u/d or use urinary alkalinizers
eg. K citrate If urine pH>6.5, USG <1.020, no
crystals, repeat urinalysis monthly, then every
3-6 months.
Repeat X-ray every 6-12 months to detect Urolith
recurrence early.
Repeat urine test and X-rays if signs -
haematuria, pollakiuria, dysuria recur.
For calcium oxalate prevention:
1. Diets promoting urine pH <6.59 were at highest
risk
2. Avoid risk factors like hypercalciuria due to
hypercalcaemia, metabolic acidosis, high sodium
consumption and Vit D excess.
3. Feed canned foods and/or add more water to food
so that urine pH is consistently <6.5
4. Consider hydrochlorothiazide (2mg/kg q 12 hr)
with highly recurrent urolithiasis in dogs
without hypercalcaemia.
5. Consider potassium citrate (75mg/kg q 12-24 hr)
if urine pH is consistently <6.5.
TOA
PAYOH VETS
In the following case, the Miniature Schnauzer dribbled
urine. X-ray showed the urethra blocked by more than 10
small stones 3x5 mm in diameter. The catheter was obstructed and could not
pass into the bladder. 
