Page 200 - Basic Monitoring in Canine and Feline Emergency Patients

hemorrhage, platelet counts are typically higher transfusion with clotting factors alone (i.e. a plasma-
than immune-mediated cases (often 50,000– containing product without red blood cells) is indi-
VetBooks.ir 150,000/hpf). Regardless if immune-mediated cated. Typically, fresh frozen plasma (plasma frozen
for <1 year) or frozen plasma (plasma frozen for
destruction or consumption of platelets secondary
to another disease is suspected, it is important to
neither of these products have functional platelets.
try to diagnose the underlying condition to stop the >1–3 years) can be used in these cases. Note that
destruction. This usually involves a systemic Also, frozen plasma may contain lesser amounts of
workup including testing for tick-borne (Rickettsial) factors V and VIII than fresh frozen plasma
diseases, imaging of the thorax and abdomen look- depending on duration of storage, and therefore
ing for underlying neoplasia or other disease, and may be more limited in its efficacy.
potentially performing a bone marrow biopsy to Once hemorrhage is controlled and any anemia
evaluate the megakaryocytes and other platelet is corrected, more diagnostic tests can be con-
precursors. While attempting to look for the under- ducted to look for the underlying cause of the dis-
lying disease, both primary and secondary immune- order. The first step is often to look critically at the
mediated destruction is controlled by administration degree of PT prolongation versus aPTT prolonga-
of immunosuppressive drugs including steroids, tion to try to narrow down the possible etiologies.
cyclosporine, mycophenolate mofetil, and azathio- See Table 9.2 for an approach to evaluating the PT
prine. Further treatments to apprehend the immune and aPTT. Subsequently, further diagnostics might
system (intravenous immunoglobulin) or stimulate include testing for specific clotting factors, investi-
megakaryocyte platelet release (vincristine) can gation into possible anticoagulant rodenticide
also be attempted. In many cases, while test results exposure, or evaluation of liver function. The
for Rickettsial disease are pending, animals are also reader is referred to the Further Reading section for
prophylactically treated with doxycycline. The more information on evaluating specific clotting
reader is referred to the Further Reading section for factors and liver function. Longer term treatment
more information on the specific treatments for and outcomes for these cases are dependent upon
ITP. If another underlying disease is diagnosed that the underlying cause. For example, a case of antico-
is causing platelet consumption, platelet counts agulant rodenticide intoxication can be treated
should improve once that disease is addressed. with vitamin K supplementation until the toxin is
cleared from the body (1–6 weeks depending on
the product ingested). In contrast, liver functional
Secondary hemostatic disorders
failure needs to be managed long term and may not
Secondary hemostatic disorders have only limited be reversible.
treatment options, which are again somewhat
dependent upon the cause of the clotting factor
disorder. As with platelet disorders, the first clinical 9.5 Pitfalls of the Monitor
decision is whether or not the animal requires All laboratory testing is subject to various causes
emergent treatment to stop bleeding. This is argu- for error. Please see Box 9.1 for a summary of the
ably more important in secondary coagulation most common reasons for alterations in the typical
disorders than primary disorders since secondary coagulation tests. Further detail related to each of
disorders often involve larger volumes of hemor- the reasons listed in Box 9.1 is found in the text
rhage than primary disorders. within this section.
If an animal is clinical for either anemia (typically
packed cell volume <12–15%) or hypovolemia
(tachycardia, weak peripheral pulses, obtundation, Primary hemostasis
pale mucous membranes), it requires emergent
transfusion of plasma with functional clotting fac- Platelet counts
tors as well as red blood cells. Typically, whole When interpreting platelet counts, the most common
blood or multicomponent therapy (packed red spurious finding is a pseudothrombocytopenia that
blood cells AND fresh frozen plasma) is indicated in occurs secondary to platelet clumping. Attention to
these cases. Otherwise, if the animal has prolonga- atraumatic venipuncture, gentle sample handling,
tions of coagulation tests (e.g. prolonged PT, aPTT, and reducing the delay in placing the blood in an
or ACT) without severe anemia or hypovolemia, anticoagulant may help reduce clumping. Despite

192 E.J. Thomovsky and A.C. Brooks