Rodenticide Toxicosis, Anticoagulant

Rodenticide Toxicosis, Anticoagulant

Basic Information  image

Definition

Anticoagulant rodenticides are compounds that contain a coumarin or indandione group and act by inhibiting vitamin K recycling, thereby causing coagulopathy. Warfarin, a once common prototypical rodenticide, has a short half-life in the body. Newer anticoagulant rodenticides are more common and have prolonged half-lives.

Synonym(s)

Warfarin, brodifacoum, bromadiolone, difenacoum, chlorophacinone, diphacinone, pindone, or difethialone toxicosis

Epidemiology

Species, Age, Sex

• Anticoagulant rodenticide poisoning is not common in horses.

• Younger, more curious animals may be more likely to ingest rodenticides.

• Smaller individuals may be more likely to ingest a high enough dose to produce clinical signs.

Risk Factors

• Improper use of anticoagulant rodenticides around horses

• Storage of anticoagulant rodenticides in places horses can access

Clinical Presentation

Disease Forms/Subtypes

• Anticoagulant rodenticides cause coagulopathy.

• Presentation varies based on site of hemorrhage.

History, Chief Complaint

Signs vary depending on the site of hemorrhage but may include:

• Anemia

• Depression

• Anorexia

• Superficial swellings (hematomata)

• Evidence of excessive external bleeding

• Abdominal distension

• Dyspnea

• Central nervous system signs

• Lameness

Physical Exam Findings

• Pale mucous membranes

• Increased hemorrhage during phlebotomy or nasogastric tube placement

• Superficial hematomata

• Hemorrhage either externally or internally

Etiology and Pathophysiology

• Anticoagulant compounds inhibit vitamin K1 epoxide reductase enzyme.

• Prevent recycling of vitamin K1, needed for manufacture of clotting factors II, VII, IX, and X

• Cause depletion of clotting factors and coagulopathy

• Toxic dose varies for different anticoagulant rodenticides and has not been determined for all compounds.

image 0.125 mg of brodifacoum/kg body weight was associated with severe toxicosis in some horses but minimal clinical signs in others.
image 50 to 100 mg is the estimated lethal dose of brodifacoum for a mature horse.
image 1 to 2 kg of brodifacoum bait (0.005% brodifacoum) would be expected to cause toxicosis in a mature horse.

Diagnosis  image

Differential Diagnosis

Anticoagulant rodenticide poisoning may mimic a variety of diseases depending on the site of hemorrhage. Other causes of coagulopathy include:

• Disseminated intravascular coagulation

• Congenital coagulopathies

• Thrombocytopenia or thrombocytopathy

• Moldy sweet clover poisoning (caused by dicoumarol)

Related posts:

  1. Codocytes
  2. Rhabdomyolysis
  3. Albumin
  4. Protein-Losing Nephropathy

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Rodenticide Toxicosis, Anticoagulant

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