Page 516 - Problem-Based Feline Medicine

508 PART 7 SICK CAT WITH SPECIFIC SIGNS

Anti-coagulant rodenticide poisoning may occur ● Mucosal surface bleeding (petechiation, melena,
from either ingesting the poison (primary toxicosis) hematochezia) may also occur.
or a poisoned rodent (secondary toxicosis). Secondary
Sudden death may occur due to cerebral hemorrhage,
toxicosis is unlikely with warfarin, but may occur
hemopericardium, pulmonary or mediastinal hemor-
with second-generation products, and indeed may be
rhage, or exsanguination into the pleural or abdominal
the most common cause of anti-coagulant rodenti-
cavities.
cide poisoning in cats. Secondary toxicosis was sus-
pected as the cause of poisoning in a recent case
series.
Diagnosis
Cats with cardiomyopathy may be treated with vitamin
Anti-coagulant poisoning is less common in cats than
K antagonists as prophylaxis for thromboembolism.
dogs because of difference in eating habits.
Feces may be colored (e.g. green) from dye in bait
with primary toxicosis.
Clinical signs
Measuring hematocrit and total protein may help
Signs appear 2–5 days after exposure.
identify blood loss as a cause of lethargy, bearing in
● Severity and time to onset of signs depends on
mind that in the first few hours of bleeding these
amount of poison ingested and the animal.
parameters may not change appreciably.
– The higher the dose of poison the earlier and
more severe the signs. For a given amount of Reticulocytes will appear after 4 days of the onset of
poison, exposure over several days is more hemorrhage, but this is late in the disease process and not
toxic than a single large exposure. usually useful to identify blood loss as a cause of acute
– Because cats put less physical stress on their tis- anemia.
sue compared to dogs, signs tend to appear later
Radiographs and ultrasound examinations may detect
in cats after exposure than in dogs.
fluid accumulation in organs and body cavities.
– Signs appear earlier and are more severe in very
young and old animals. Maintaining a high index of suspicion when a cat at risk
● The newer generation poisons do not necessarily has appropriate signs will lead to hemostatic testing.
cause earlier onset of signs. ● PT is the most valuable routine test.
– Factor VII has the shortest half-life of the vita-
Signs of acute anemia and hypovolemia are present.
min K dependent factors and is in the extrinsic
Other non-specific signs include depression (which
system. The other vitamin K dependent factors
may appear before detectable anemia), non-localizable
have longer half-lives and are in the intrinsic or
pain and fever.
common system.
Localizing signs of hemorrhage include scleral hemor- – PT becomes prolonged before aPTT does, but by
rhages, otic hemorrhages, epistaxis, cough, hemoptysis the time a cat is presented with clinical bleeding,
and dyspnea (pulmonary hemorrhage), inspiratory both PT and aPTT are usually prolonged.
dyspnea or restrictive breathing (hemothorax), abdom- – If PT is not prolonged, then a prolongation of
inal pain (presumably due to hemorrhage within aPTT is not due to vitamin K antagonism.
organs), abdominal distention (hemoabdomen), lame- ● Platelet count is normal, or may be mild to moder-
ness, muscle pain and stiffness (hemorrhage into mus- ately decreased if there is marked hemorrhage.
cles), lameness and joint swelling (hemarthrosis), BMBT should be normal, but rebleeding may
neurologic signs (cerebral hemorrhage), ecchymoses, occur.
subcutaneous hematomas and excessive bleeding from ● Response to vitamin K1 (see Treatment, below).
wounds. ● PIVKA time is increased (see Tests of hemostasis,
● Pleural hemorrhage, mediastinal hemorrhage, and above). PIVKA time is more sensitive than PT to
subcutaneous hematomas appear to be most vitamin K antagonism, but is not necessary to make
common. the diagnosis in the bleeding animal, nor, despite its