Poisonous Plants Flashcards
What are cyanide containing plants?
Chokecherry, Vetch, Hydrangea, Johnson grass (sorghum)
What is the toxic principle of cyanide?
Inhibits mitochondrial cytochrome oxidase
How does cyanide affect the cells?
Cannot release O2 for transport, leads to cellular hypoxia
How soon after ingestion of a cyanide containing plant will clinical signs begin?
Within 10-15min
What is commonly the first clinical sign of cyanide-containing plant tox?
Acute death
What are other potential signs of cyanide-containing plant tox?
Excitement/tremors, dyspnea, salivation
What is a key finding on investigations of a cyanide-containing plant tox?
Bright red blood (cherry colored)
How will cyanide gas in the rumen smell?
Faint bitter almond smell
How do you treat cyanide toxicity?
Sodium thiosulfate or small amount of sodium nitrite
How does sodium nitrite treat cyanide tox?
Has greater affinity for cyanide so it strips cyanide from cytochrome oxidase
How does sodium thiosulfate treat cyanide tox?
Reacts w/cyanide to form thiocyanate which is excreted in urine
What are nitrate accumulating plants?
Pigweed, Nightshades, oat hay, Sorghum, rye, alfalfa
Why are nitrate accumulating plants particularly a problem in ruminants?
Reduction to nitrite by microbes in rumen
What color blood will nitrate poisoning produce?
Chocolate brown (diminished O2 carrying capacity)
What does nitrate cause in the blood?
Methemoglobinemia
What are clinical signs of nitrate poisoning?
Dyspnea, tremors, ataxia, tachycardia
How do you treat nitrate poisoning?
1% methylene blue
How does methylene blue help treat nitrate poisoning?
Reduces methemoglobin
Which plant contains cardiac glycosides, oleandrin, and neriine?
Oleander
Which plant contains cardiac glycosides that prolong diastole?
Foxglove
Which plant contains >20 cardiac glycosides and has a digitalis-like action?
Lily of the Velley
What plant contains taxine alkaloids A and B?
Yew
How does yew affect the heart?
Inhibits cardiac depolarization
Which plant contains andromedotoxins?
Rhododendron (azalea)
What do andromedotoxins do?
Bind membrane Na channels = excitation and digitalis
What are clinical sings of cardiotoxic plants?
Salivation, nausea, weakness, bradycardia, AV block, collapse
How do you treat cardiotoxic plant tox in small aimals?
Emesis, activated charcoal, supportive care
How do you treat bradycardia assoc. w/cardiotoxic plant tox?
Atropine
How do you treat AV blocks assoc. w/cardiotoxic plant tox?
Isoproterenol, procainamide, quinidine
What plant causes primary photosensitization?
St. John’s wort
What plants cause 2* photosensitization?
Brassica spp. (rape), Blue-green algae, Groundsel
What is photosensitization?
Increases susceptibility to UV light damage
What areas of the body are most affected by photosensitization?
White/light skinned areas, thin/non-pigmented areas
When ingested/absorbed, the agent is or is metabolized to become photodynamic
Primary photosensitization
Is primary or secondary photosensitization have a better prognosis?
Primary
Effects of _____ photosensitization are usually restricted to the skin
Primary
Causes damage to the liver along with skin lesions
Secondary photosensitization
What are clinical signs of photosensitization?
Erythema, edema, sunburn, pruritus, hyperesthesia
What are neurotoxic plants?
Lupine, poison hemlock, Larkspur, Nightshade, Bracken fern
Which neurotoxic plant most commonly affects sheep?
Lupine
What is the MoA of lupine?
Quinolizidine alkaloid induces nicotinic effects
What are clinical signs of lupine?
Salivation, incoordination, head-pressing, wandering, tremors/seizures
In which species is lupine a teratogen?
Cattle
At what age gestation is lupine teratogenic in cattle?
40-70d gestation
What plant causes “crooked calf syndrome”?
Lupine
How do you treat lupine and poison hemlock?
No specific treatment
Contains coiine and pyrididine-type alkaloids
Poison hemlocks
What are clinical signs of poison hemlock?
Salivation, V/D, tremors/convulsions
How can poison hemlock cause death?
Respiratory failure
Contains polycyclic diterpene alkaloids
Larkspur
What is the MoA of larkspur?
Neuromuscular blocker = cholinergic/nicotinic antagonist
Which species is most susceptible to larkspur?
Cattle
What are clinical signs of larskpur?
Bloat, excitability, arrhythmias, tremors/seizures
How can larkspur cause death?
Respiratory paralysis
What are the two toxins Nightshade contains?
Glycoalkaloid and aglycone (GI and neuro)
What are clinical signs of nightshade?
Anorexia, abd pain, V/D, apathy, prostration, unconsciousness
Which plant is poisonous to cattle, sheep, pigs, and horses?
Bracken fern
What is the MoA of bracken fern?
Thiaminase cleaves Vit B1; ptaquiloside alkylates DNA
What does a thiamine deficiency result in?
Polioencephalomalacia
What are clinical signs of bracken fern?
Standing with legs apart, depression, tremors, blindness
What are clinical signs of ptaquiloside from bracken fern in ruminants?
Bone marrow destruction (anemia) and hemorrhage
How do you treat bracken fern?
Inj thiamine, none for ptaquiloside
What animal is susceptible to black walnut toxicity?
Horses
What is the most common source for black walnut tox in horses?
Sawdust/shavings from black walnut trees used in bedding
What are clinical signs of black walnut tox?
Acute laminitis, distal limb edema
How do you treat black walnut tox?
Remove source, wash legs, tx for laminitis
Which poisonous plant contains ricin and what is it?
Castor bean, glycoprotein
What are clinical signs of castor bean?
Anorexia, V/D, thirst, mm spasms, sweating, organ edema
What plant contains cardiogenic gossypol?
Cottonseed
What age group does cottonseed most affect?
Very young cattle sheep and pigs
What are clinical signs of cottonseed tox?
Sudden death, red urine, pot-belly
How does cottonseed cause death?
Heart failure
What are clinical signs of dumbcane?
Ptyalism, tongue/lip edema, difficulty swallowing/breathing
What is the MoA of dumbcane?
Irritation of the mucous membranes
What are clinical signs of locoweed?
Clicking dewclaws, emaciation, contracted tendon, ataxia
Which plant causes “cracker heels”?
Locoweed
What is one of the most toxic plants known to cattle and horses?
Waterhemlock
What does waterhemlock contain that is highly contagious to cattle and horses?
Cicutoxin
What are clinical signs of waterhemlock?
Acute violent tetanic seizures
What species is affected by yellow star thistle?
Horses
What plant causes “chewing disease” in hoses?
Yellow star thistle
What does yellow star thistle cause in horses?
Nigropallidal encephalomalacia
What is the main clinical sign of yellow star thistle tox in horses?
Chewing and dropping food, chewing motions in an empty mouth
What is the MoA of perilla mint?
Perilla ketone causes pulmonary edema and pleural effusion
What are clinical signs of perilla mint?
Nasal discharge, exhalation resp distess
Which plant contains cyclopamine and mainly causes stillborns in sheep?
Western false hellebore
At what age gestation will W. false hellebore cause “monkey faced lambs”
Day 14
When will lambs develop craniofacial deformities if affected by W. false hellebore?
Day 12-30 gestation
How are lambs affected by W. false hellebore at day 30-36 gestation?
Shortened legs and MT bone hypoplasia
Which plant affecting horses and cattle contains ketone and trematone which is passed to the young via milk?
White snakeroot
What are clinical signs of white snakeroot in horses?
Myocardial necrosis and CHF
What are clinical signs of white snakeroot in cattle?
Ataxia, depression, tremors, “acetone breath”
What plant causes RBC lysis in horses?
Red maple
A depressed horse with icterus, anemia, hemoglobinemia/uria likely has what plant poisoning?
Red maple
Which plant causes abortions characterized by weak contractions, excessive discharge, small calves, and retained fetal membranes?
Ponderosa pine
What plant contains atropine and causes CNS signs?
Nightshade
Which part of a water hemlock plant is most toxic?
Leaves
Which plant causes grand mal seizures?
Water hemlock
Loss of globus pallidus and substantia nigra
Nicropallidial encephalomalacia (yellow star thistle)
What is the px for yellow star thistle tox?
Grave
What is the teratogen of false hellebore?
Cyclopamine
What plants cause abortions, weak lambs, and bent legs?
Locoweeds
What is the MoA of locoweed?
Inhibit alpha-mannosidases
What is the result of a-mannosidase inhibition caused by locoweed?
Neurovisceral cytoplasmic vacuolation
What conditions/region does locoweed grow in?
West - dry conditions of Rocky Mtns
Which plant causes arthrogryposis?
Lupine
During which trimester does ponderosa pine cause abortion?
Last trimester
Which plant causes enzootic hematuria d/t hemorrhagic cystitis that progresses to neoplastic changes in the bladder?
Bracken fern
This plant causes ataxia/tremors as a result of GABA activation when infected with endophytic fungus
Perennial ryegrass
How does blue-green algae cause neuro signs?
Absorbed through mms and causes post-synaptic depolarization block
If you find dead birds or cattle next to a pond, what toxicity should you suspect?
Blue-green algae
What cells are affected by perilla mint?
Type 1 pneumocytes and bronchiolar epithelial cells