Rodenticide Toxicity Flashcards
What is the most common type of rodenticide used in N. America?
Anticoagulant rodenticide
What are examples of an anticoagulant rodenticide?
Warfarin, brodifacoum
What is the toxic effect of anticoagulant rodenticide?
Prevents activation of Vit K-dependent coagulation factors
What are clinical signs assoc. w/warfarin toxicity?
Hemorrhagic shock signs
Where do warfarin cases usually bleed?
Into body cavities (internal)
How soon after warfarin ingestion do clinical signs appear?
3-7d
How long can warfarin compounds persists in the body after ingestion?
4-6wk
What coagulation pathway will be most prolonged with warfarin toxicity?
Prothrombin time (PT)
Why is PT prolonged with warfarin toxicity?
Factor 7 has shortest half life of K-dependent coag factors
How long after warfarin ingestion does it take for PT to increase?
36-72h
How long after warfarin ingestion will you see aPTT (activated partial thromboplastin time) increase?
3-5d
How do you treat warfarin toxicity?
Emesis w/in 2-4h
Activated charcoal +/- sorbitol w/in 8-12h
Vit K1 for 4wk
If you know an animal has ingested warfarin, what is your plan when that animal presents to the clinic?
Check PT, induce emesis if PT is normal, Vit K1 for 4wk
How do you treat a dog presenting w/hemorrhage 2* to coagulopathy d/t warfarin tox?
Plasma transfusion (+RBC if indicated)
Vit K1
Thoracocentesis, O2 may be needed
What is the toxic principle of bromethalin rodenticide?
Inhibits oxidative phosphorylation of ATP
What happens when neurons’ ATP malfunctions?
Can’t maintain osmotic gradients, cerebral edema, increased ICP
What are clinical signs of high dose bromethalin rodenticide toxicity?
Tremors, seizures, hyperexcitability, and hyperthermia <12h after ingestion
What are clinical signs of low dose bromethalin rodenticide toxicity?
Ascending paralysis beginning in hind limbs days-weeks after ingestion
How do you treat bromethalin rodenticide toxicity?
GI decontamination if acute, seizure tx/prophylaxis
How do you treat increased ICP?
Mannitol/furosemide and incline plane 30*
What is the toxic principle of cholecalciferol rodenticide?
Precursor converted to active Vit D after ingestion
What does cholecalciferol rodenticide result in?
Increased intestinal absorption of Ca and mobilization from bones
What e-lyte abnormalities result from cholecalciferol rodenticide ingestion?
Severe hyperCa and hyperP
When do cholecalciferol rodenticide toxicity clinical signs occur?
Usually within 36h of ingestion
What are clinical signs of cholecalciferol rodenticide toxicity?
Acute renal failure, arrhythmias, PU/PD, GI upset
What biochem parameters help you diagnose cholecalciferol rodenticide toxicity?
HyperP (12h), hyperCa (24h), and azotemia (36-48h post ingestion)
How do you treat cholecalciferol rodenticide toxicity?
Activated charcoal if actue
Renal failure supportive care
HyperCa treatment
How do you treat hyperCa?
Furosemide, bisphosphonates, corticosteroids
How do bisphosphonates help treat hyperCa?
Inhibit osteoclast activity and bone re-absorption
How do corticosteroids help treat hyperCa?
Decrease intestinal Ca absorption and urinary retention
How does furosemide/diuretics help treat hyperCa?
Promote urinary Ca excretion
If renal failure results from cholecalciferol rodenticide, what is the prognosis?
Guarded to grave
What are Vit K-dependent coag factors?
2, 7, 9, 10
Which rodenticide inhibits epoxide reductase, and therefore causes a loss of vitamin K?
Brodifacoum (D-con)
Which vegetation produces a vit K antagonist like warfarin and can be dangerous to large animals that eat it?
Moldy sweet clover
What is the toxin produced by moldy sweet clover?
Dicumarol
What does dicumarol/warfarin cause?
Hemorrhage (NOT hemolysis)
