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Anticoagulant Rodenticide Toxicity (view source)
Revision as of 16:45, 23 August 2010
, 16:45, 23 August 2010→Laboratory Tests
Laboratory tests are unlikely to show abnormalities until 36-72 hours after exposure, due to the delay in onset of haemorrhagic signs. Prothrombin time (PT) is a measure of functionality of the extrinsic (and common) pathway, and because factor VII has the shortest half life and thus becomes depleted most rapidly, this parameter is generally the first to become prolonged. Partial thromboplastin time (PTT) and activated clotting time (ACT) are related to the function of the intrinsic and common pathways, and usually become prolonged by 48-72 hours post-ingestion when levels of factor IX are reduced. Platelet count and buccal mucosal bleeding time assess platelet function, and since only secondary haemostasis is affected by vitamin K epoxide reductase antagonism, these measure are usually within normal limits.
Laboratory tests are unlikely to show abnormalities until 36-72 hours after exposure, due to the delay in onset of haemorrhagic signs. Prothrombin time (PT) is a measure of functionality of the extrinsic (and common) pathway, and because factor VII has the shortest half life and thus becomes depleted most rapidly, this parameter is generally the first to become prolonged. Partial thromboplastin time (PTT) and activated clotting time (ACT) are related to the function of the intrinsic and common pathways, and usually become prolonged by 48-72 hours post-ingestion when levels of factor IX are reduced. Platelet count and buccal mucosal bleeding time assess platelet function, and since only secondary haemostasis is affected by vitamin K epoxide reductase antagonism, these measure are usually within normal limits.
The 'proteins induced by vitamin K antagonism'(PIVKA) are acarboxylated proteins that form as a result of anticoagulant rodenticide toxicity. PIVKAs are not normally detected in the circulation and are increased in the plasma of intoxicated animals. However, PIVKAs are rapidly cleared following adminstration of vitamin K, and so samples should be obtained before therapy is initiated.
It may also be possible to assay vitamin K epoxide and specific anticoagulant in the blood, but these tests are not normally necessary.
===Pathology===
===Pathology===