3. Pesticide poisoning

Question 1

Fumigation

Answer 1

Only done by trained person
CO2, HCN, zinc or aluminium phosphide gases are used

Pulmonary oedema

Question 2

Bait

Answer 2

• anticoagulant rodenticides
• powdered corn cob (agricultural waste) - highly hydroscopic -> lots os water coming to GIT -> severe hypovolemia and hypovolemic shock

Question 3

Anticoagulant rodenticides. Source

Answer 3

• sweet clover (coumarin) -> dicoumarol

Coumarin is used in food industry, On its own doesn’t have hurtful effect
But during storage some coumarin will change to dicoumarol but it’d not be enough to cause problem.

From dicoumarol warfarin was produced. And belongs to 1st generation of anticoagulants. Rn is obsolete

Warfarin should be taken for several days to cause an effect. Resistance is developing.

Question 4

2nd generation of anticoagulants

Answer 4

• Brodifacoum
• Bromadiolone
• Difenacoum
• Difethialon
• Difacinon

Can be taken only once for effect. Toxicity is also higher comparing to 1st generation. Have longer half-life -> longer treatment in case of poisoning needed

Answer 5

Comparing to volume of product there is small amount of active ingredient
BUT
If product is flavoured, animal can consume product repeatedly -> consuming of enough amount of active substance to cause poisoning

Question 6

Toxicity of anticoagulant

Answer 6

In case of repeated consumption LD is much lower! More dangerous!

Question 7

LD50 of different anticoagulants

Answer 7

Brodifacoum is the most toxic !
If consumed more than 0.02 ml/bwkg -> observe
Check PTT. If ok -> check next day, if ok -> check in 3 days, if ok -> no need to treat

In first several days usually no signs

Question 8

Toxicokinetics

Answer 8

Absorption
- lipophilic, can be absorbed dermally
- accumulation in liver (esp. brodifacoum)
- high albumin binding

Metabolism, excretion
- long-half life (albumin, liver, EHC)
-

Question 9

Dose of activated charcoal for poisoning

Answer 9

1 GRAM per body weight

Question 10

Mechanism of action of anticoagulant rodenticides

Answer 10

Inhibition of blood coagulation factor activation ->
blood coagulation problems

Vitamin K should be reactivated after activation coagulation factors. Rodenticides inhibit work of reactivating enzyme => no active vit K -> coagulation factors are not activated

Damage of capillary endothel -> bleeding, haematomas, hypovolaemia

PT increase (24h)
Clotting time increase (in 4-6 days after poisoning)
Endothelial damage! (after some days)

Question 11

Clinical sign of anticoagulant poisoning

Answer 11

ACUTE:
Usually 3-6 days
- severe anaemia
- coagulation time increase (possibly icterus)
- bleeding (injuries, body cavities, eye, nose, gingiva, haematomas; damage of vessels in pregnant animal, rupture of vessels -> uterine bleeding, abortion)

Death of hypovolaemic shock

Question 12

Pathological changes

Answer 12

• inadequate clotting of blood
• anaemia
• haematomas, bleeding everywhere

Question 13

Diagnosis

Answer 13

Anamnesis + progressive blood clotting problems

Lab additional examinations:
- thoracic radiograph
- thoracic ultrasound
- blood clotting parameters

Question 14

Lab tests

Answer 14

• prothrombin time (PTT) elevated
• PIVKA (proteins induced by vit K antagonism)
• bleeding time
• clotting time
• activated partial thromboplastin time (APTT)
• trombocyte count is normal!!

Question 15

Treatment

Answer 15

• inducing emesis (<4h) (..morphine, xylazine,ropinirol)
• blood transfusion (or serum) 15-20ml/bwkg
• activated charcoal
• vitamin K1 (no vit K3!!)

Symptomatic therapy:
- vit C - for vessels
- Ca++ supplementation - for vessels
- tranexamic acid - inhibition of the fibrinolysis

Question 16

Vitamin K1 dose

Answer 16

Dog,cat: 3-5mg/kg (IV?, IM?, PO, SC) - but because of damaged vessels not a good idea. Not to give PO if activated charcoal is applied.
Large animals: 0,5-1 mg/kg SC, PO
Recovery period: PO

Treatment protocol:
3-5 mg/kg for 14 days
1-2 mg/kg for 7 days
1-2 mb/kg every other day for 14 days