Lifespan and Causes of Death in the Irish Wolfhound - Vetsuisse ...

Conservative therapy is also indicated to stabilise animals that exhibit signs of
hepatic encephalopathy before surgery is attempted and should additionally include
fluid therapy, normalisation of acid-base disturbances. Antibiotic treatment
(neomycin, metronidazole, ampicillin) is also indicated to reduce the production of
bacterial toxins in the intestine (Fossum and Hedlund 2002).
Surgery is the therapy of choice, but complication and mortality rates are high. For
intrahepatic PSS, postoperative complications have been reported in 77% of cases,
short-term mortality is reported to range from 11% to 28% and overall mortality from
23% to 63.6%. The one-year survival rate was reported as 61%, while the two-year
survival rate was 55% (Papazoglou, Monnet et al. 2002). The technique of choice is
reported to be direct posthepatic ligation for the left divisional shunt consistent with a
persistent Ductus venosus (White, Burton et al. 1998). Another reported technique is
cellophane banding, which was used in two Wolfhound puppies, one of which
survived (Connery, McAllister et al. 2002).
Recently, there have been reports of successful shunt attenuations through minimally
invasive coil embolisation and other occlusion techniques using a jugular venous
approach (Leveille, Johnson et al. 2003; Weisse, Mondschein et al. 2005). While
results seem to be promising to-date, these techniques should still be considered
experimental at the moment given the small number of described cases.
3.2.2 Epizootology
PSS incidence rates in the Irish Wolfhound population are reported to vary between
2.1 and 3.4% of all puppies and 18% of all litters. Smaller litters seem to have a
higher risk (Meyer, Rothuizen et al. 1995; Ubbink, van de Broek et al. 1998 b; Kerr
and van Doorn 1999). According to Hardy-Weinberg (p 2 +2pq+q 2 =1 ; p+q=1), these
numbers imply a healthy carrier frequency of 24.8% to 30.1% of all Irish Wolfhounds
given the mode of inheritance (see below).
Furthermore, PSS incidence rates in the direct descendants of certain individuals
have been measured to be as high as 15% (Ubbink, van de Broek et al. 1998 a).
3.2.3 Heredity and Control Measures
Intrahepatic PSS has been described to be passed on in a simple autosomal
recessive way (Rothuizen 2002). While the nature of the data used in the study at
hand made it impossible to determine a mode of inheritance, the hereditary nature of
PSS could also be demonstrated (see Chapter 7.2.4.2).
In this study, analysis of the data provided by White, Burton et al. (1998) showed that
all 9 Irish Wolfhounds in their sample of 58 dogs with intrahepatic portosystemic
shunts had a left divisional shunt consistent with a persistent Ductus venosus,
whereas such a shunt was diagnosed in only 57% of all other dogs (P=0.02; twosided
Fisher’s exact test). This fact provides further evidence of a hereditary
mechanism.
The first published recommendation was not to breed close relatives of affected
puppies (Skancke 1994). Later, it was shown that the Dutch breeders had not
realised the full potential to select against PSS and that the incidence of the disease
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