Toxins

Toxins

1. Small animals

   • Human drugs (NSAIDS, ibuprofen)
   • Rat Bait = Vit K antagonist
     • inhibit Vit K epoxide reductase enzyme = clotting factors not activated
       • Internal bleeding, pale MM, high HR, high clotting indices
       • Tx = reduced form of Vit K Has to be oral not IV
   • Snail Baits = metaldehyde
     • GIT + neurological signs
   • Organophosphates (cholinesterase inhibitors)
   • Permethrin (cats)
   • Dark choc (theobromine)
   • Paints (lead poisoning)
   • Plant toixicities
     • Cats - lilies
     • Dogs - berry plants (Brunfelsia)

2. Large animals

   • Nitrate poisonings
     • Some plants, too much fertiliser
   • Cyanide poisoning
     • Common in ruminants - have enzymes that can release toxins in GIT
       • Initial seizures + staggering Bright pink MM + cherry-red blood
     • Sorghum crop - reduces O2 carrying capacity + accumulate toxin
   • Urea poisoning
     • Poor effluent disposal
       • Allow microbes in faeces to convert ammonia to urea
     • Seizures
   • Plant toxicities
     • Nitrate/nitrite
       • Converts Hb to Met-Hb Lowers O2 carrying capacity
         • Grey/dark brown MM Decreased Appetite Liver damage & photosensitization
     • Cardiac glycosides in plant oleander
       • Arrhythmic effect
     • Oxalates
       • Chelates w/ GIT calcium
         • Bone resorption + lameness
     • Grass tetany (rye grass)
       • Hypo-Mg
         • Muscle twitching, stiff gait, jumpy movements
     • Fluoroacetates
       • Inhibit ATP production
         • Brain damage and sudden death
     • Dicoumarol toxicity
       • Mouldy clover
         • Inhibits Vit L epoxide reductase
           • Bleed out due to anti-coagulopathies
     • Pyrrolizidine alkaloids
       • usually during drought periods
         • Liver damage