Exam 1--LA Toxins Flashcards
Blister beetles are associated with which type of feed stuff & what toxin do they release?
Alfalfa Hay
Cantharidin
In addition to GI effects in horses, what other system might appear compromised with blister beetle toxicity and why?
Renal–cantharidin is excreted in urine
*dysuria, nephrosis, cystitis
Buttercups:
1) which system do they affect
2) which spp?
1) GI
2) livestock
Pokeweed:
1) system affected?
2) toxic principle?
1) GI
2) Saponin
Quercus can cause toxic effects in which systems?
What are 2 characteristic clinical signs?
GI
Renal
Bloody or dark diarrhea with acute renal failure
Which 2 plants can cause both GI and neuro signs?
Chinaberry
Nightshades (Jimson weed is neuro)
Toxic principle for chinaberry?
Tetranortriterpenoids
*Tetra-nor-tri-terpenoids
What are the 3 toxic principles found in nightshades & general effect of each?
1) Solanine (GI & neuro toxic)
2) Tropane alkaloids (anticholinergic)
3) Nicotine (cholinergic)
MOA of toxalbumins?
Which part of plant is typically toxic?
Which spp. most affected?
1) inhibition of protein synthesis (ribosomal inhibiton)
2) SEEDS (intact seed= not absorbed)
3) HORSES
Violent purging (bloody diarrhea with straining) along with other GI signs would be suggestive of?
Toxalbumin toxicity (i.e. Castor beans)
Toxic principle in castor beans? It’s MOA?
Ricin–inhibits 60s ribosomal subunit
Toxic principle of Rhododendron spp. and its MOA?
Grayanotoxin
Increases membrane permeability to Na
In addition to vomiting in goats (GI), which other system can rhododendrons affect?
Cardio
*can lead to fatal bradycardia
A unique treatment option for animals that have eaten persimmons?
Carbonated cola
Describe where nitrates are located in the plant and what can cause it to accumulate?
Bottom 1/3 of stalk (grains and leaves are less toxic)
accumulates in stressful conditions–plants stops growing and metabolizing it
Which spp. is most susceptible to nitrates and why?
Describe nitrate MOA
Ruminants (convert it to nitrite in rumen)
*Nitritie oxidizes hemoglobin to methemoglobin, which cannot bind O2
T/F: finding blue/brown MM in a cow can confirm nitrate toxicity
FALSE
**brown MM only SUGGESTIVE
Nitrates:
1) what sample is taken to measure for nitrate/nitrite levels?
Plasma
2 treatment options for nitrate/nitrite
Methylene blue (converts MetHgb–>Hgb)
Rumen lavage with cold water (slows microbial activity=less nitrite produced)
Name 2 plants that can accumulate nitrates?
Pigweed
Johnson grass
Wild black cherry & choke cherry impact which system?
Toxic principle?
Hematologic;
Prussic acid (cyanide)
Bright red MM and sudden death are common clinical manifestations of which toxin?
Cyanogenic glycosides (cyanide)
What 2 drugs are used in combination when treating cyanide toxicity?
Sodium nitrate followed by sodium thiosulfate
Copper toxicity:
1) most susceptible spp.
2) most common type of exposure
1) Sheep!
2) chronic dietary exposure
Because copper causes _____ hemolysis, an expected UA finding would be _______
intravascular; hemoglobinuria
Since red maples causes _______ damage to RBCs, you would expect _____ _____ anemia
Oxidative;
Heinz body
Bracken Fern:
1) Which spp. are susceptible—which is most?
2) toxic principle
3) System(s) affected
1) CATTLE* (also sheep & horses)
2) Ptaquiloside
3) Hematologic & Renal
What are the 3 clinical syndromes associated with Bracken Fern?
Which is most common?
1) Hemorrhagic disease
2) Enzootic hematuria (MOST COMMON)
3) Neurologic disease
In which spp. does Bracken fern typically cause neuro disease? Why?
Horses–can’t synthesize thiamine like ruminants can
*Thiaminases
Sweet clover toxicity MOA?
*include toxic principle in description
Dicourmarol inhibits vitamin K epoxide reductase
Decreased synthesis/activity of vit K-dependent factors (2,7,9,10)
Describe the pathogenesis of ABPEE?
Rapidly changed to lush forages containing L-tryptophan, which is converted in rumen to 3-methylidole (3-MI)
3-MI absorbed, metabolized by clara cells in lungs–>damage–>difficult to transport O2 across thickened endothelial cells
Perilla Mint:
1) system affected
2) toxic principle
1) Respiratory
2) perilla ketone
What spp. of fungus infects sweet potatoes?
Fusarium solani
The mold on moldy sweet potatoes causes production of what toxic substance?
4-ipomeanol
Name 3 noxious gases that can affect cattle?
Maure gase Nitrogen Dioxide (silos) Zinc oxide (welding)
What two plants are included with Senna spp.? What system do they affect?
Coffeeweed
Sicklepod
Musculoskeletal
Which enzymes, associated with muscle, would you expect to be elevated with Senna spp. toxicity? (3)
1) CK
2) AST
3) cardiac troponin
Bedding containing the shavings from which plant can be toxic for HORSES?
Black walnut (Juglans nigra)
**if >20% black walnut shavings
Alkali disease is an excess of?
Selenium
MOA of selenium toxicity?
2 Most common clinical signs?
Replaces sulfur in amino acids (glutathione depletion & free radical formation)
Hoof deformities
Loss of tail/mane hairs
Indicator plants can be used for detection of?
High Se levels in soil
Which 2 systems can fescue impact?
Musculoskeletal
Repro
Fescue:
1) toxic principle?
2) most clinical signs occur due to what effect of fescue?
1) Ergot alkaloids
2) vasoconstriction (dry gangrene or extremities & summer slump)
Oleander & Rhododendrons are what type of cardiac toxins?
Yew?
Cardiac glycosides
Cardiac alkaloid
Which spp. is most susceptible to ionophore toxicity?
Horses
Name the muscle preference for ionophores in the following species:
1) horses
2) cattle
3) sheep/swine
1) cardiac»_space; skeletal
2) cardiac = skeletal
3) skeletal > cardiac
In which cotton products can the toxin (gossypol) be found?
whole cottonseed
cottonseed meal
Which two systems can be impacted by gossypol?
Cardio (monogastrics)
Repro (male ruminants)
Myocardial damage
decreased milk production
olive-colored eggs
decreased spermatogenesis
All above signs can be related to?
Gossypol
Name 4 effects of the cardiac glycosides on the heart
1) Blocks Na/K ATPase
2) increased vagal tone
3) increased myocardial contraction
4) decreased coronary artery blood flow (vasoconstriction)
For which toxicity would atropine be indicated and why?
Oleander–to combat increased vagal tone
Toxic principle of Yew? MOA?
Taxines
block Na movement through membrane, depressing cardiac conduction
The repro effects of fescue are primarily seen in which spp.?
The ergot alkaloids decrease secretion of?
Horses
Prolactin
When should the mare not graze fescue to avoid clinical signs?
First and last 30-45 days of gestation
An estrogenic mycotoxin that infects corn?
What spp. of fungus produces it?
Zearalenone
Fusarium spp.
Which group of animals is most susceptible to Zearalenone? Prominent clinical sign?
Pre-pubertal gilts
Vulvar edema
Phytoestrogens interact with specific estrogen receptors and are called _____ _____ _______ _______
Selective estrogen receptor modulators (SERMs)
Toxic principle of locoweed?
As it relates to repro disease
Swainsonine
*interferes with glycoproteins
In addition to repro, which other system does locoweed PRIMARILY affect?
Neuro (locoism)
Which signaling pathway does Veratrum disrupt?
Sonic hedgehog
Cyclopia associated with Veratrum commonly occurs if ingested on day ___ of gestation
14
Which “syndrome” is associated with lupine intoxication?
Crooked calf syndrome (arthrogryposis of forelimbs–elbows)
Lupine: where in the plant are toxins highest? Why is this bad?
Seed pods
bad because seed pods are palatable!
In addition to teratogenic repro effects, Lupine can also affect which other system?
Neuro
*nicotinic effects
When differentiating poison hemlock from water hemlock, what feature can you use?
Where the veins terminate
Water hemlock–veins terminate BETWEEN teeth
Poison hemlock–veins terminate at ends of teeth
Ponderosa pine has what effect on which species?
Abortion in cattle
Describe how ponderosa pine causes abortion
Powerful vasoconstrictor of uterine/caruncular vascular bed–> reduced blood–> decreased O2 & nutrient delivery to fetus
Why might you see abortions with nitrate toxicity?
methemoglobin formation leads to asphyxiation of fetus
Describe the pathogenesis of food related ammonia poisoning… include how the presence of liver disease is a risk factor
NPN converted to ammonia in rumen via ureases
not enough ketoacids present to combine with all ammonia–>excess ammonia absorbed into circulation
Usually can be detoxified by the liver (liver dz); if not it can travel to brain and impair astrocyte K buffering
What two factors make urease more efficient? How does this relate to our treatment of food related ammonia poisoning?
1) high rumen pH
2) elevated body temperature
This means that treatment involves lowering pH (acetic acid) and lowering rumen temperature (cold water)
Which 2 plants are included in Centauria spp.?
Yellow starthistle
Russian knapweed
Centauria:
1) system affected
2) main spp. affected
3) general MOA
1) neuro
2) horses
3) degeneration of dopaminergic neurons (equine parkinsonism)
Name 2 major neurotoxic principles associated with Locoweed
1) swainsonine
2) Misertoxin
Species most susceptible to locoweed?
Horses
Which toxin of Locoweed:
1) is associated with behavioral changes (i.e. hyper-reactive to handling)
2) is associated with HL ataxia (cracker heels) & posterior paralysis
1) swainsonine
2) miserotoxin
What can be used for aversion therapy against locoweed?
Single oral dose of lithium chloride
Which plants are included in Aesculus spp.?
Buckeye (pointy leaf) Horse chestnut (round leaf)
Toxic principle of Aesculus spp?
Triterpenoid saponins
Toxin associated with bovine bonker’s syndrome?
Source?
4-methyl-imidazole
Ammoniated feeds
Name 4 grasses that can be associated with grassland staggers?
Perennial rye grass
Dallis grass
Bermuda grass
Annual rye grass
toxic principle in grassland staggers? MOA?
Tremorgens
impair inhibitory pathways in nervous system (GABA & lysine)
Toxic principle of water hemlock? MOA?
Cicutoxin
GABA antagonist–prevents influx of Cl–>CNS stimulation and seizures
Toxic principle of white snake root? MOA?
Tremetol–inhibits TCA cycle
A horse that’s BAR, shows ataxia of only the hindlimbs, and also dribbles urine could be suspected of grazing on?
Sorghum
Larkspur toxic principle & MOA?
Polycyclic diterpene alkaloids
neuromuscular blocking agent at cholinergic and nicotinic receptors
Which toxic principle of Jimson weed (nightshade) causes neuro signs?
Tropane alkaloids
*non-depolarizing muscarinic blockers
Briefly describe Physostigmine’s MOA as it relates to treatment of toxicities that block cholinergic receptors
competitively inhibits cholinesterase–>ACh builds in synapse to compete with toxic compounds
Toxic principle of poison hemlock? Which 2 systems does it affect?
Piperidine alkaloids
Repro & neuro
Lupine MOA?
mimics ACh at sympathetic and parasympathetic ganglia
Photosensitization secondary to liver dz is associated with which compound in the skin?
Phylloerythrin
Cocklebur (Xanthium):
1) system affected
2) spp. affected
1) hepatic
2) swine»_space; cattle, sheep > horses
In addition to clinical signs, what clinc path findings would correlate with Xanthium toxicity?
severe hypoglycemia
elevated liver enzymes
decreased electrolytes (normal kidneys)
Which 2 plant spp. are associated with PA toxicity?
Ragwort-groundsel
Crotalaria
Blue-green algae is associated with stagnant ponds high in ____
phosphorus
Blue-green algae MOA?
inhibits cytoskeleton intermediate filaments–>intrahepatic hemorrhage and necrosis
Sneezeweed:
1) system affected
2) susceptible spp.
1) Hepatic
2) sheep, goats > cattle, horses
Bitterweed
1) system affected
2) susceptible spp.
1) hepatic
2) sheep, goats >cattle, horses
Kochia
1) system
2) susceptible spp.
1) hepatic
2) ruminants
Which hepatotoxic plant is associated with birefringent crystals in bile ducts?
Panic grasses
Which hepatotoxin primarily affects HORSES (find it palatable)
Alsike clover
Vetch:
1) system affected
2) susceptible spp.
1) dermal
2) cattle
Toxic principle of St. Johnswort?
Hypericin (fluorescent pigment)
Which dermal toxin is associated with hyper-reactivity to cold water?
St. Johns wort (Hypericum)
Cestrum diurnum:
1) system affected
2) susceptible spp.
1) Urinary
2) cattle & horses
Cestrum diurnum mimics what other toxicosis?
Vitamin D intoxication
*acts like free vitamin D
Name 4 plants that contain soluble oxalates
1) beets
2) Curly dock
3) Lamb’s Quarter
4) Rhubarb
Soluble oxalate MOA?
combine with serum Ca to form insoluble Ca-oxalates that block renal tubules
Clinical pathologic changes expected with soluble oxalate toxicity?
Hypocalcemia
Hyperkalemia
Elevated BUN
Toxic principle of Halogeton?
Na & K oxalates
Though primarily hematologic, pigweed may also affect?
Renal (contains oxalates)
