Neurotoxic range plants Flashcards
Water hemlock
-one of the most acutely toxic plants in world
-found near water bodies
-most toxin in the root
Target organ and mechanism
CNS
-noncompetitive GABA antagonist causing acute neuroexcitation /sitmulation
Water hemlock clinical signs
-Animals found dead with signs of violent struggle
-salivation, twitching, running fit, tonic-clonic seizures,
-death from resp failure
-PM: muscle necrosis (skeletal and myocardial)
Management of water hemlock toxicity
Peracute so often hard to intervene
-seizure control and supportive care
Diagnosis of water hemlock toxicity
-found dead where water hemlock is present
-plant in rumen/stomach
-lesions in heart and skeletal muscle
-detection of toxin in rumen
Poison hemlock
-grows in moist sites with frequent disturbance (ditches, flood plains, pastures; can out compete native plants)
-Spring
-look like carrot leaves, purple specks on stem
-all parts toxic esp. seeds and flowers; seeds can contaminate feed
Poison hemlock target and mechanism
Target: CNS (acute), fetus (chronic)
Mechanism: nAChR agonists= initial CNS stimulation followed by depression
Poison hemlock clinical signs
-Sublethal =weak, CNS depression= recover over 6-10hrs
-High dose= initial CNS stimulation followed by depression and paralysis
death from resp failure
**poor prognosis with high dose, acute poisoning
Management of poison hemlock
-no antidote
-Move herd to differnt area
-seizure/tremor control
-low stress handling
Diagnosis of poison hemlock
-plant in rumen/stomach
-pasture with plant present
-detection of piperidine alkaloids in rumen/stomach contents
Larkspur
-Delphinium spp
-most common in mtn areas, less in pastures and meadows
-tall varieties more toxic
Mechanism of larkspur toxicity
nAChR antagonists = neuromuscular blockade and paralysis
Clinical signs of larkspur toxicity
-animals found dead on pasture
-restless, agitated, weak, dyspnea, tachypnea, tachycardia
-lateral recumbency and bloat
-death from rsp paralysis or bloat
Management of larkspur
-antidote= neostigmine
-positioning to avoid bloat
*can be poor to grave depending on how quick cattle are found and treated
Diagnosis of larkspur toxicity
-evidence of plant on pasture or in stomach/rumen contents
-send out test for larkspur alkaloids
DDx for larkspur toxicity
-toxic hemlock
-nicotine
-aute selenium toxicity
-cardiotoxic plants
-acute lupinosis
-Pb
-salt
-organochlorine insecticides
-OP/carbamate insecticides
Prevention of larkspur toxicity
Avoid larkspur pastures during toxic window
*can use sheep to graze larkspur
