Toxicology 2

Question 1

Anticoagulant rodenticide toxicity

Answer 1

 Anticoagulant rodenticide toxicity
 Toxins inactivate the enzyme required to activate vitamin K
 Active vitamin K is needed to produce coagulation factors II, VII, IX, and X
 Depletion of coagulation factors leads to abnormal hemostasis

Question 2

Depletion of coagulation factors leads to abnormal hemostasis

Answer 2

 First-generation rodenticides (e.g. warfarin, pidone, diphacinone, chlorophacinone) decrease clotting factor levels for 7-10 days
 Second-generation rodenticides(e.g. brodifacoum, bromdiolone) decrease clotting factor levels for 3-4 wks.

Question 3

Clinical signs Anticoagulant rodenticide toxicity

Answer 3

lethargy, vomiting, anorexia, ataxia, diarrhea, hemorrhage, melena, dyspnea, epistaxis, external hemorrhage/bruising, pale mm’s, sudden death from excessive internal hemorrhage

Question 4

Diagnosis Anticoagulant rodenticide toxicity

Answer 4

hx, clinical signs, prolonged bleeding time tests (PT, aPTT, ACT), response to vitamin K therapy

Question 5

Treatment Anticoagulant rodenticide toxicity

Answer 5

 Vitamkin K1 is the antidote for anticoagulant rodenticide toxicity
 Administered at 5 mg/kg SC initially, than PO q24h or divided q12h for 3-4 weeks
 Symptomatic and supportive therapy

Question 6

Bromethalin

Answer 6

 (Assault, Trounce, Vengeance)
 Formulated as greet pellets in a packet
 Potent neurotoxin causing hyperexcitability, muscle tremors, seizures, and death

Question 7

Cholecalciferol

Answer 7

 (Ortho Mouse-B-Gone, Rampage)
 Rodenticide converted to vitamin D3 causes calcium reabsorption leading to hypercalcemia
 Calcium deposition in soft tissues (e.g. blood vessels, kidney, stomach wall) can lead to hemorrhaging and renal failure. High calcium levels can lead to cardiac dysrhythmias and death

Question 8

Zinc phosphide

Answer 8

 (Acme Mole and Gopher Killer, Mr. Rat Guard, Phosvin)
 Formulated as meal, pellet or strip
 Reacts with HCl acid in stomach to form toxic phosphine gas-> smells like garlic/rotten fish, damages capillary endothelium and RBC’s within the kidneys, liver, and lungs
 Supportive therapy including oxygen supplementation and IV fluid administration
 If vomiting is induced, it should be done outside or in a well ventilated area

Question 9

Clinical signs of Zinc phosphide

Answer 9

lethargy, salivation, vomiting, abdominal distension, pulmonary edema, cyanosis, hypotension, shock, seizures, death

Question 10

Metaldehyde toxicity

Answer 10

 snail/slug bait toxicity
 Toxin causes serious CNS abnormalities in animals, its mechanism of action is unknown
 Death may occur from respiratory failure as disease progresses

Question 11

Clinical signs Metaldehyde toxicity

Answer 11

anxiety, hypersalivation, hyperesthesia, ataxia, muscle tremors, tachycardia, seizures, hyperthermia

Question 12

Treatment Metaldehyde toxicity

Answer 12

 No specific antidote
 Treatment is supportive and symptomatic
 Administration of sodium bicarbonate IV may be needed for severe metabolic acidosis

Question 13

Ethylene glycol (antifreeze) toxicity

Answer 13

 Toxin is metabolized by liver into metabolites that cause metabolic acidosis and renal failure
 One of the metabolites, oxalic acid, may combine with calcium to form calcium oxalate crystals in the renal tubule

Question 14

Ethylene glycol clinical signs appear in three progressive phases

Answer 14

 Stage I– CNS abnormalities (depression, ataxia, knucking, seizures, coma, death), anorexia, vomiting hypothermia
 Stage II– Cardiorespiratory abnormalities (tachypnea, tachycardia)
 Stage III– Renal abnormalities (severe depression, vomiting, diarrhea, dehydration, azotemia, oliguric renal failure)

Question 15

Ethylene glycol Diagnosis is based on…

Answer 15

hx, clinical signs, laboratory tests (metabolic acidosis, calcium oxalate monohydrate crystals in urine), and ethylene glycol poison test kit

Question 16

Ethylene glycol Treatment

Answer 16

 Administer antidote for ethylene glycol poisoning
 Fomepizole (4-methypyrazole) IV at time of presentation and then at 12, 24, and 36 hrs.
 Ethanol IV as a CRI until renal function can be stabilized
 Supportive and symptomatic treatment– including diuresis and possible peritoneal dialysis

Question 17

Acetaminophen (Tylenol) toxicity

Answer 17

 Common OTC analgesic medication used by humans
 Cats are unable to metabolize acetaminophen efficiently enough to prevent the formation of a toxic metabolite
 Toxic metabolite causes methemoglobinemia, Heinz body formation, hemolytic anemia, hepatic necrosis
 Toxic dose in cat 50-60 mg/kg, dog 160-600 mg/kg

Question 18

Clinical signs

Answer 18

salivation, vomiting, hypothermia, depression, brown or cyanotic mucous membranes, dark/chocolate colored blood and urine, respiratory distress, swelling of face and paws, death

Question 19

Treatment

Answer 19

 Oxygen supplementation
 Administer antidote– N-acetylcysteine (Mucomyst) IV or PO
 Administer S-adenosyl-methionine (SAMe) and vitamin C
 Supportive therapy

Question 20

Lead toxicosis

Answer 20

 Found in paint, batteries, linoleum, plumbing supplies, improperly glazed ceramic water bowls, fishing sinkers, shotgun pellets
 Diagnose by measuring lead levels in blood
 Treat with calcium EDTA SC and D-penicillamine PO

Question 21

Causes and signs of Lead toxicosis

Answer 21

GI and CNS abnormalities
(vomiting, abdominal pain, anxiousness, compulsive pacing, chomping of jaws, vocalizing, muscle tremors, seizures, blindness)

Question 22

Zinc toxicosis

Answer 22

 Found in pennies, zinc oxide skin preparations, galvanized metal
 Causes intravascular hemolysis
 Diagnose by measuring lead levels in blood
 Treat with calcium EDTA SC and D-penicillamine PO

Question 23

Zinc toxicosis- Clinical signs

Answer 23

depression, anorexia, vomiting, diarrhea, abdominal pain, hemolytic anemia with hemoglobinuria and icterus, renal failure