FASAVA Congress 2017

The cat is a unique creature who seems to do things differently to what we expect or want, and the same goes for their response to diseases. Although they share many disease with their canine cousins, they often are affected in different ways, and many times they present dissimilarly; certainly their defence mechanisms behave in a disparate fashion to the dog. Many medications have exclusive uses in the cat, and there are many drugs for which cats have increased susceptibility, hence caution in their use is paramount – these will be discussed.                                                             
Transfusion therapy underlines major differences between the dog and cat, with felines having just three major blood groupings – A, B, AB. That being so, most cats have naturally occurring antibodies against foreign RBC, therefore must be crossmatched prior to transfusions – there are no universal donors – as giving a cat an incompatible transfusion can be fatal. Further, in 2007 there was identified a novel RBC Ag (Mik Ag), an alloantibody that’s not identified during traditional Ab blood typing, which helped explain why it is in the patient’s interest to type-specific cross-match. Curiously, Xenotransfusion (giving dog’s blood to cats) has received positive prominence where compatible feline blood is unobtainable, transfusion with canine blood may be considered as a life-saving procedure – benefits, although profound, are very short-lived (<4 days), and any repeated infusion with canine blood >4-6 days after the first transfusion causes anaphylaxis (frequently fatal).                              
As a case example, in acute urethral obstruction, both cats & dogs present as acute emergencies with similar organ system derangements, notably azotaemia and hyperkalaemia. However the cat doesn’t often show the classic ECG changes that we have learnt from the textbooks with increasing levels of serum potassium. This condition highlights how we must tailor our treatment and monitoring to allow for the idiosyncrasies of the feline patient.                                                              
Sepsis is another disease where the cat seems to process and manifest in a disparate fashion to the dog. Distributive shock in the feline is likely to be associated with bradycardia, and a septic cat is more likely to present pale & hypodynamic (hypothermia, bradycardia, hypotension)