07 October, 2018
animals - dogs, cats, hamsters, guinea pigs, turtles & rabbits
A swollen glans penis is seen after
and cystotomy for calcium oxalate urolithiasis in a dog
First written: 20 Sep 2011 Update: 10 Oct 2018
Sing Kong Yuen, BVMS (Glasgow), MRCVS
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
In the following case
of calcium oxalate urolithiasis, the Miniature Schnauzer dribbled
urine. X-rays showed the urethra
was blocked by more than 10
small stones 3x5 mm in diameter. The catheter was obstructed and could not
be passed into the bladder.
1. Retrograde urohydropropulsion
and cystotomy. 3. Retrograde urohydropropulsion without
surgery. This is possible if the stones are small as
detected by X-rays and/or ultrasound is early. The small
stones (<5 mm) are syringed from the urethra into the
bladder and sucked out using the syringe.
1. Using Prescription Diet to dissolve the urinary
stones cannot be done in calcium oxalate
urolithiasis. For struvite urolithiasis, this may be
successful if the stones are small, preferably <1cm
When there are too many stones inside
the urethra, 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
normal saline to push
all the urethral stones
from the urethra into the bladder).
I will make a 0.5 mm
cut behind the os penis (urethrostomy), take out the stones with a
forceps, close the urethra and skin. Then I take out the the bladder
stones via the cystotomy. In my experience, the
urethral wound heals well if proper post-op care is
given. The urinary cathether must be
inside the urethra for around 14 days to prevent
closure of the urethra.
However, in some cases, the dog is sent home within 2
after surgery, either by the vet or the
insistence of the owner. There is a lack of care by the owner due
to inexperience in animal nursing. The
urinary catheter is pulled out, 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.
and Cystotomy. 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 this approach.
Repeated flushing of the urethra to push the stones into
the bladder is needed. In this case, Vet 1 preferred the first approach.
are more than one surgical approaches in treating
urethral obstruction, depending on the
size of the stones. 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
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 as an
anchor point in the process of
Numerous small urinary stones
inside the os penis (penile bone)
were removed via flushing
the stones back into the
(retrograde urohydropropulsion) and removed
them via the bladder incision (cystostomy).
Calcium oxalate stones were
removed in this
The Miniature Schnauzer
dribbled urine for the past
2 weeks. Partial urethral
obstruction with >10 small
stones were seen in the X-rays.
and cystotomy removed
was not able to pass through more than 10 cm inside the
penis as its passage was obstructed by the numerous
stones inside the penile urethra. To prevent it being
dislodged as normal salinewas pumped into the catheter to push
the stones back into the bladder for removal.
penis has been gripped by Vet 1 as an anchor point, resulting in
swelling. Gripping the penile bone may not be practical
but would be preferred.
In any case, the outcome was
excellent in the sense that after 3
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.
Although the dog has a big size 20 elizabeth
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
owner told me that there was no way her dog could
have licked that area since he had the
biggest collar. I said it was possible
that the dob could have rubbed the
penile glans on the flooring to relieve his pain.
Within 24 hours of the prednisolone injection, the glans penis had shrunk by 50% and
was much less inflamed (see picture). He peed normally
and had a good appetite. He went
home the next day.
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. NSAID does not work very well in such cases
although they are standard offers for pain killer
effect. NSAID was
prescribed for the home stay.
MANAGING CALCIUM OXALATE
and X-rays regularly.
If the urine SG >1.020, give
canned food or add water
to the dry food.
Give 300 - 400 ml water daily if the small-breed
dog does not eat the dry food with water.
If the urine pH <6.5, consider diets that produce less
acidic urine e.g.
Hills' U/D or use urinary alkalinizers
eg. Potassium citrate.
If the urine pH>6.5, urine SG <1.020,
urinary crystals present, repeat
urinalysis monthly, then every
Repeat X-rays every 6-12 months
to detect urolith
Repeat urine test and X-rays if signs - haematuria, pollakiuria
and dysuria recur.
For calcium oxalate prevention:
1. Diets promoting urine pH <6.59 were at
risk for recurrence.
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.
You will need to do urine pH tests regularly.
4. Consider hydrochlorothiazide (2mg/kg q 12 hr)
with highly recurrent urolithiasis in dogs
5. Consider potassium citrate (75mg/kg q 12-24 hr)
if urine pH is consistently <6.5.
Many dog owners in Singapore stop doing regular
X-rays and urine tests, leading to recurrence of
urinary stones and surgeries or euthanasia.
Feeding Hills' C/D is not advised in
calcium oxalate urolithiasis as it is an urine
acidifying diet. There is no Prescription Diet to
dissolve calcium oxalate stones.
In Singapore in 2018, Hills' C/D diet is no longer
available. Royal Canin still produces Urinary S/0
diets. These diets are acidifying diets used
mainly for struvite stone prevention.
It is best to consult your veterinarian to prevent
recurrence of calcium oxalate urolithiasis as each
case is different. E-mail
firstname.lastname@example.org or SMS +65 9668-6468 to
make an appointment for consultation of your case
or for a second opinion.