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Anticoagulant Rodenticide Toxicity (view source)
Revision as of 12:32, 23 August 2010
, 12:32, 23 August 2010→Laboratory Tests
===Laboratory Tests===
===Laboratory Tests===
Coagulation screening tests are unlikely to reveal abnormalities
until at least 36 to 72 hours post-exposure. The
prothrombin time (PT) generally becomes prolonged
first (by 36 to 48 hours), since F-VII, a component of the
tissue factor-mediated coagulation pathway, has the
shortest half-life (about six hours) and is therefore the
first factor to become depleted. The partial thromboplastin
time (PTT) and activated clotting time (ACT) are
usually prolonged by 48 to 72 hours post-exposure. The
thrombin clotting time (TCT), platelet count and buccal
mucosal bleeding time (BMBT) (an assessment of
platelet function) are usually normal (see table below).
The so-called 'proteins induced by vitamin K antagonism'
(PIVKA) are acarboxylated proteins formed as a
result of anticoagulant rodenticide toxicity. While not
normally detected in the circulation, these increase in the
plasma of poisoned animals and can be detected using
the PIVKA test which is available through some veterinary
diagnostic laboratories. PIVKA are usually cleared
within 12 hours of administration of vitamin K. Samples
for coagulation testing should be collected before initiating
vitamin K therapy.
Other possible confirmatory tests include quantitation
of vitamin K epoxide concentrations and determination
of the specific anticoagulant in the blood, liver and/or
stomach contents.
===Pathology===
===Pathology===