Toxicology

Question 1

MOA of Tetanus toxicity

Answer 1

Clostridium tetani
Toxin interferes with release GABA and glycine

Enters the motor nerve endplates and ascends retrograde into CNS

Question 2

MOA of Botulism toxicity

Answer 2

Prevent Ach release from NMJ

Question 3

Alabama rot

Answer 3

Cutaneous/renal glomerulonephropathy of Greyhounds (Alabama Rot)

E. coli toxin due to fed raw meat
shiga like toxin

CS:

• thrombocytopenia due to arteriole thrombosis.glomerular ischemia
• limbs skin are often affected due to arteritis/thrombosis causing deep skin ulcers

Tx: antibiotic, pentoxyfilline

Question 4

Organophosphate toxicity
Symptoms?
Tx?

Answer 4

Symptoms: Showing nicotinic signs such as tense muscle
Tx: 2-PAM treats nicotinic signs, atropine treats muscarinic signs

Question 5

Dogs with 50 nRBC and tremors. What toxicity is this and Tx?

Answer 5

Lead

Succimer (meso-2,3-dimercaptosuccinic acid)

Question 6

What toxicity is Silibinin effective to?

Answer 6

Amanita phalloides mushroom
It causes lethal hepatotoxicity
Also Tx includes cyclopeprides, silymarin milk thistle, NAC

Question 7

Rodenticides/Warfarin (Coumadin) toxicity

Answer 7

Vitamin K antagonist
Factors 2, 9, 7, 10
Protein C and protein S in the liver
CS: cavitary bleeding, blood loss anemia, prolonged PT then ACT/PTT
Tx: Give Vit K

Question 8

Characteristics of blood work abnormality in Lily toxicity?

Answer 8

Creatinine&raquo_space; BUN

Question 9

Ethylene glycol toxicity
Each toxic material and CS in each phase
What is Tx?

Answer 9

1st phase: glycoaldehyde = neurotransmitter sign/depress

2nd: glycolic acid (via aldehyde dehydrogenase) = acidosis/cardiopulmonary sings
3rd: oxalic acid = Ca oxalate monohydrate stones, renal failure

Tx: 4-PM (4-methylpyrazole) and ethanol competitively inhibits alcohol dehydrogenase to to prevent nephrotoxic metabolite formation

Dx: EG test kit is ONLY for DOG, thus cats can get false negative results since they are so sensitive. Any detectable levels of EG warrants Tx in cats.

Question 10

Carbamates

Answer 10

Organophosphate insecticides
Reversibly inhibits acetylcholine esterase
Adrenergic symptoms: Tachycardia, hypertension, mydriasis

Question 11

Minoxidil (Rogaine)

Answer 11

Hair growth meds
Alters K channel
Oral: hypotension, pulmonary edema
Dermal: safe

Question 12

Marijuana

Answer 12

Tetrahydrocannabinol (THC), major Cannabinoids in Marijuana

CS: depress, disorientation, lethargy, ataxia, vomiting, tremor, mydriasis, hypothermia, urine dribbling

Question 13

Acetaminophen CS and Tx

Answer 13

Oxidative damage to Hb which causes metHbemia and Heinz bodies in RBCs and hemolysis and anemia
Also hepatotoxicity
Tx:
1. N-acetylcystein (increases glutathione synthesis which binds hepatotoxic metabolites)
2. Cimetidine (may slow metabolism into toxic metabolites by P-450)
3. Ascorbic acid = Vit C (enhances reduction of methemoglobin back to hemoglobin)
4. SAMe (gets metabolized to thiol donor in liver and can act as glutathione donor)

Question 14

Strychnine

Answer 14

It is in pesticide.
Inhibits postsynaptic buffering effect of glycine on motor neuron and interneurons, and leading to increased nerve stimulation.
CS: hyperthermic, extensors rigidity, seizures

Question 15

Pyrethrins/pyrethroids

Answer 15

CS: reversibly prolong Na conductance, producing increased depolarizing afxterpotentials that cause repetitive deuce firing

Question 16

Barbiturates toxicity can be treated with ____

Answer 16

Urine alkalization can trap the barbiturates in urine and increases the excretion 5-10X to treat. (forced alkaline diuresis)

Question 17

Copper

Answer 17

Inherited copper toxicosis in Bedlington terriers has COMMD1 gene mutation.

CS: IV hemolysis, MetHbemia, liver failure

Tx: Copper chelation with penicillamine, trientine, Zink would improves the grade of histologic damage of hepatocytes