| Symptoms vary depending on the degree of the shunt. It appears that
with an intrahepatic shunt it is unlikely that, if left untreated, the
puppy will survive; in the case of partial shunts it has been known that
the dog lives a longer, albeit, sickly life span, usually being managed
with antibiotics and special low protein diet. However, these cases are
in the minority and long-term prognosis has been uncertain to say the
least. There are cases where the shunt isn't diagnosed until the hound
is older and this may be due to partial shunting where symptoms are less
obvious.
When do the symptoms show? Some people say they can
spot a shunt puppy in a litter early on, and it is true that badly affected
puppies often show signs of weakness, staring coats and a general failure
to thrive, as early as 6 weeks. However, these are in the minority and
the more usual pattern is for the pup not to begin showing symptoms
until after 10 weeks of age.
In the case of partial shunts it has been known for
a puppy to be several months old before symptoms show, due to a more
gradual build up of symptoms.
Without treatment, observations have been that the
dog is unlikely to survive very long, and will be in distress.
Testing Methods
To date the most reliable method of testing for PSS
is the Bile Acid Test. Ammonia testing has proved to be an unreliable
method in Wolfhounds and is not advised. Ammonia levels in Wolfhounds
have been found to be naturally higher than the normal dog population
and are transient.
Bile Acid Tests have to date been a reliable method
for detecting PSS, it is stated that "Postprandial SBA concentrations
are consistently abnormal and are a good screening test for animals
suspected to have PSS & concentrations typically exceed 100 :mol/l"
( Ettinger).
The double Bile Acid test entails fasting the litter
for 12 hours (usually overnight), taking a blood sample (pre-prandial),
feeding the puppies their morning meal and then taking the postprandial
sample 90 - 120 minutes after feeding.
This method is still used in cases where the result
is indicative of an affected puppy or if the test is inconclusive for
any reason.
After some 7 years of testing in the UK we now take
only the postprandial blood test. These tests are done through a dedicated
Laboratory who has now developed a testing index for Wolfhounds. Other
breeds may need their own index as each breed can differ as to what
a normal Bile Acid reading would be.
A puppy affected with PSS would be expected to have
a post feeding Bile Acid reading in excess of 40, in actual fact it
is usually considerably higher than the pre feeding result for example
a difference from 20/155 or even 22/390 (actual readings). However there
is a grey area of lower scores and one test did prove positive at only
18/44. This is in the minority (so far only one), but does highlight
the need to be careful when testing, to use facilities where the vets
are experienced in testing for that particular breed, and to retest
if the result is uncertain.
It is impossible for any test like this to be 100%
accurate but on current information it must be said that it is 99%.
The main difficulties have been with the samples themselves either because
the blood has clotted before reaching the laboratory.
A rarer occurrence is the some of the samples being
too fatty to test. A spate of this prompted us to investigate what type
of food the litters involved were being given. There was no common factor
in the feeding of the litters which ranged from various complete foods
to meat and rice.
Very occasionally, and I can number four occasions
for this, a puppy may return a high Bile Acid score, but on re-test
the score drops to normal levels. Again, there is no explanation for
this but it does reinforce the necessity for a re-test if a positive
result is returned. This is ALWAYS recommended by us and by Idexx.
Further diagnostic methods
Aside from the more accessible testing methods as mentioned
above also available are Rectal Portal Scintigraphy, Ultrasonography
or Contrast Radiography. Ultrasonography has been used in the UK to
identify the location of a shunt prior to surgery, but is very dependent
upon the skill of the operator. It is non invasive and does not require
anaesthesia, referral by the Veterinary Surgeon is required. Rectal
portal scintigraphy again does not require anaesthesia; it uses a radioactive
substance which is rapidly absorbed from the colon into the blood stream.
Radioactivity is first detected in the liver then the heart, in PSS
the radioactivity reaches the heart before or at the same time as it
reaches the liver. The expense and availability of equipment means that
this method is only available by referral to a specialised institution.
In the UK, it has recently been used in post operative care to ascertain
the status of the shunt.
Treatments
Surgery has to be the preferred means of repairing
a Shunt and has been very successful.
Dietary management can help in dogs who have a partial
shunt and is beneficial in reducing symptoms in dogs awaiting surgery.
Success with managing Livershunt by diet will depend
on the severity of the shunt itself. Managing the condition medically
includes a low protein prescription diet, usually Hills Science KD or
UD. Potatoes, rice can also be included. Periodic treatment with antibiotics,
and a laxative i.e. Lactulose.
Dramatic improvement can often be seen in the dog
after treatment as above, but as the toxins build up again, the symptoms
return and further ongoing treatment is required, it is possible that
if the shunt is partial, the dog can continue a reasonably normal life
with periodic treatments.
Management in this way is so far uncommon (because
of the low success rate), and expensive. The highly expensive prescriptive
diet is only available from Veterinary Surgeries and the ongoing need
for antibiotics and lactulose is also costly.
Recorded so far have been one survivor to 18 months,
but died of the condition, one to 2 ½ years - died of cancer.
Still surviving one bitch at 3 ½ years, only one on record made
it to over 7 years, but it was stated that she was in a poor physical
condition.
See below for further information on Dietary Management.
Surgical Options
Surgery for the repair of a single intrahepatic shunt
is now extremely successful when undertaken by an expert surgeon. Great
benefit is derived from ultrasound to identify beforehand the type and
location of the shunt before surgery is considered an option. The earlier
the sugery is performed after diagnosis the better as this minimalises
damage to the liver, but a delay of two or three weeks in a young puppy
i.e. 8 weeks or so, will not usually be detrimental.
Total surgical ligation (i.e. the tying off of the
vessel), is preferred but due to the liver being unable to cope with
the volume of portal blood diverted back, causing portal hypertension,
partial ligation of 60 - 80% is often opted for. The immediate post
operative 24 hours is important and the dog us usually hospitalised
for a few days after the operation.
Post operative care usually consists of antibiotics
and diet management and lactulose. Depending on the progress of the
pup, normal food can gradually be introduced after a few days, it can
be expected that a normal diet can be fed on recovery. Bile Acid tests
can be carried out at a later date, but do not usually return to normal
even when the dog becomes clinically normal.
You may read elsewhere that surgery is not that successful.
This may be true in some countries or if the practitioner hasn't had
a great depth of experience - this is very intricate surgery. We are
very fortunate in the UK to have access to exceptional surgeons who
have many years experience now of operating successfully on many breeds
- particularly Irish Wolfhounds, and this means that we have a particularly
good success rate..
Contact us for
details of experienced surgeons in the UK
Prognosis
After successful surgery the outlook is usually excellent,
there is no reason why the dog should not live a normal life, and indeed
they are doing so. Surgery is extremely expensive >£2000, it
is very important that the puppy is diagnosed early for the best results
from the surgery option.
Dietary Management of Livershunt
While surgery is more often the best way of dealing
with a shunt it is possible to manage the condition by diet in certain
cases.
The diet follows the principle of low protein, but
in the case of a growing Wolfhound puppy, gentle restriction of protein
is required as long as the puppy is not showing neurological signs of
the condition, otherwise growth may be hampered Some suggested complete
foods would be:
Waltham Selected Protein
Hills Intestinal Diet
Eukanuba Intestinal Diet
Wafcol Fish and Corn
Cottage Cheese is the best source of additional protein
and this can be used to supplement the diet. Avoid normal puppy foods
as the protein is generally too high, you should be aiming at a level
of around 20 - 24% maximum.
The protein source should be high quality for maximum
digestibility. Meals should be given 4 times per day. The first 6 months
are critical for growth and it is suggested that every 3 months protein
levels are checked. This is done by taking a blood sample.
Lactulose, prescribed
by the Veterinary Surgeon, is usually required for life. This binds
ammonia and assists its elimination from the body.
Ampicillin can also be
given continuously, so far no negative side effects have been observed
from this.
If the puppy starts to show neurological signs, feeding
Hills K/D diet can reduce the protein further. This can be supplemented
with Pasta/ Rice and Cottage Cheese. The Hills UD diet has insufficient
protein to sustain normal growth.
Information provided by Penny Watson MRCVS - Cambridge
University
FAILED TESTS
If a puppy has a high score on Bile Acid Testing Vetlab
will request a re-test to be done. A second Bile Acid Test should always
be done as it is not unheard of for a high score to subsequently fall.
Please ensure that you do a DOUBLE BILE ACID TEST as
this is the most effective way of confirming a positive test.
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In 2007 Idexx Laboratories bought Vetlab
but have agreed to continue the relationship with our breed
and offer us a discounted rate on Bile Acid testing. This works
out at £7.05 inc VAT per puppy. If a puppy requires re-testing
and this is usually a double test i.e. before and after feeding,
this will cost £12.93 inc.
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-
In 2007 Idexx Laboratories bought
Vetlab but have agreed to continue the relationship with our breed
and offer us a discounted rate on Bile Acid testing. This works
out at £7.05 inc VAT per puppy. If a puppy requires re-testing
and this is usually a double test i.e. before and after feeding,
this will cost £12.93 inc.
Method:
Starve the puppy overnight.
Arrange for a blood sample to be taken by the Vet in the morning.
Feed the puppy in the presence of the Vet
Wait for 90 - 120 minutes
The Vet should take a second blood sample.
Clearly label the two samples as pre-feeding and post-feeding,
then submit to Idexx.
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