Toxicology Final Exam Material Flashcards
T/F: Emetics are recommended in dogs and cats to prevent further absorption of petroleum products
False
Emetics and gastric lavage are generally contraindicated (aspiration pneumonia)
Ingestion of kerosene is most likely to cause:
severe aspiration pneumonia
Signs of aspiration pneumonia such as shivering, incoordination, anorexia, weight loss, fever, coughing, dyspnea, and abnormal lung sounds
Signs of chronic cyanide poisoning in horses are mainly due to:
neuronal degeneration of the spinal cord and brain
What is the toxic principle in this plant?
Tannic acid
Pictured: White Oak tree (Quercus alba)
Mechanism of action: tissue damage including GI lesions and kidney damage; mainly GI lesions and kidney damage in ruminants; mainly GI lesions in monogastric animals
Sternal recumbency while standing on the hind limbs is a clinical sign of what food and water related toxicant?
NPN (Urea)
Signs include restlessness, aggression, muscle tremors, salivation, teeth grinding, colic, bloat, rumen stasis, sternal recumbency while standing on the hind limbs, usually no diarrhea, convulsions and death within 1-2 hours
Sudden onset of signs of hepatic insufficiency such as weight loss, icterus, incoordination, head pressing, aimless wandering, walking in circles and other signs of mania, GI distress, tenesmus, are MAINLY signs due to ingestion of:
- Halogeton (Halogeton spp.)
- Oleander (Nerium oleander)
- Ragwort (Senecio spp.)
- Cottonseed (Gossypium spp.)
- Pigweed (Amaranthus retroflexus)
Ragwort (Senecio spp.)
What three toxic plants are associated with forage-induced photosensitization?
moldy alfalfa, red clover, moldy wheat
Mechanism of action: Secondary photosensitization is due to liver damage. (The photoreactive substance is a metabolite of chlorophyll)
Alsike clover and red clover are in the legume family and cause hepatotoxicity and secondary photosensitization in what species?
horses only
A dog that is showing autonomic signs including vomiting, colic, diarrhea, mydriasis, dyspnea; nervous signs including convulsions; locomotor signs including ataxia; then recovers to show signs of liver failure and metabolic acidosis 2-3 days later is most likely intoxicated with:
Metaldehyde
What is the primary effect of pyrrolizidine alkaloids?
Hepatotoxicity
Which is more toxic: pentavalent arsenic or trivalent arsenic?
Trivalent arsenic
- Inorganic trivalent is more toxic than pentavalent, which is more toxic than organic*
- Trivalent > Pentavalent > Organic*
Poisoning caused by ingestion of large amounts of rhubarb (Rheum rhaponticum) is most likely associated with damage to what organ?
kidney
Toxic principle in rhubarb: soluble oxalates
Mechanism of action: Hypocalcemia and precipitation of insoluble calcium oxalates in soft tissues and kidney damage
What is the toxic principle in this plant?
Insoluble calcium oxalates
Pictured: Chinese evergreen (Aglaonema spp.)
**All parts of the plant are toxic**
What is the main blood carrier for iron?
Transferrin
Which of the following is least likely an effect of marine toad (Bufo marinus) toxins?
- irritation of the mucous membranes
- hepatotoxicity
- cardiototoxicity
- hallucination
hepatotoxicity
The diagnosis of lead toxicosis in dogs is best established on the basis of:
blood levels of lead
What is the toxic principle in this plant?
Calcinogenic glycosides (Vitamin D analog)
Pictured: Day-blooming jessamine (Cestrum diurnum)
Mechanism of action: Hypercalcemia; calcification of the elastic tissues of the arteries, tendons, and ligaments as well as generalized increased density of the bones causing lameness
Chronic selenium in horses mainly causes:
hoof and hair abnormalities
Lameness, hoof abnormalities, emaciation, and loss of hair in cattle most likely suggest toxicosis with:
chronic selenium
What is the toxic principle in this plant?
Lectins (phytotoxins, toxalbumins)
Pictured: Castor bean (Ricinus communis)
What is the toxic principle in this plant?
Cycasin
Pictured: Sago palm (Cycas revuluta)
Mechanism of action - cycad palms have three toxins:
- Cycasin is a glycoside that causes GI irritation and liver damage and it is also teratogenic, mutagenic and carcinogenic
- β‐methylamino‐L‐alanine (BMAA) is a neurotoxic amino acid
- Unknown toxin that may cause axonal degeneration in the CNS
[sahy-kuh-sin]
What is the toxic principle in this plant?
Piperidine alkaloids (and pyridine alkaloids)
Pictured: Tobacco (Nicotiana tabacum)
Mechanism of action: start with ganglionic and neuromuscular stimulation followed by ganglionic and neuromuscular blockade. Neuromuscular blockade prevents fetal movement resulting in birth defects
What domestic species is most sensitive to ethylene glycol toxicity?
Cats
T/F: This is a dog
True
Nice job! Finals week hasn’t gotten you yet :)
Deferoxamine is the chelating agent of choice for:
iron
What is the toxic principle in this plant?
Carboxyatractyloside (sulfated glycoside)
Pictured: Cocklebur (Xanthium strumarium)
Mechanism of action: Hepatotoxicity, excessive salivation, maybe renal damage and hypoglycemia
The presence of an odor of rotten garlic in a fresh carcass is suggestive of acute __________ toxicosis
selenium
What is the toxic principle in this plant?
Colchicine
Pictured: Glory lily (Gloriosa superba)
Mechanism of action: Antimitotic by binding to tubulin and inhibiting spindle formation during cell division
(Pronounced kol-chuh-seen)
T/F: Cats are the most susceptible species to toad intoxication
False
Ingestion of plants that have been sprayed with the recommended levels of 2,4-D herbicides may cause poisoning in livestock mainly as a result of:
accumulation of toxic levels of nitrate or cyanide by the plant
The toxic principles of which of the following poisonous plants act mainly by blocking nicotinic receptors at the neuromuscular junction?
- Castor bean (Ricinus communis)
- Lily-of-the -valley (Convallaria majalis)
- Larkspur (Delphinium spp.)
- Milkweed (Asclepias spp.)
Larkspur (Delphinium spp.)
Toxic Principle: Diterpene alkaloids
Mechanism of action: Competitive blockade of the nicotinic receptors at the muscle endplate similar to curare
- Castor bean (toxic principle: lectins) inhibit protein synthesis resulting in cell death
- Lily-of-the-valley and Milkweed (toxic principle for both: cardiac glycosides) are cardiotoxic by inhibiting Na/K ATPase
What plant part accumulates the highest amount of nitrate?
Stalks
The stalks (closest to the ground) contain the highest concentrations. Leaves contain less than stalks or stems
T/F: Seizures associated with strychnine toxicosis and water deprivation/sodium ion toxicosis are elicited by external stimuli
False
- Seizures associated with strychnine toxicosis are elicited by external stimuli.*
- Seizures associated with water deprivation/sodium ion toxicosis are not elicited by external stimuli!!*
What is the mechanism of action of glucosinolate (thiocyanate glycosides)?
Antithyroid
Which of the following is least likely a clinical sign of marine toad (Bufo marinus) intoxication?
- slow onset clinical signs (2-3 days)
- foaming of the mouth
- seizures
- tachycardia or bradycardia
slow onset clinical signs (2-3 days)
What anionic detergent is considered to be the most toxic?
Automatic Dishwashing Detergents
Even though they are anionic detergents (moderately toxic), they often contain alkali (NaPhos, NaCarb, etc.), which increases the risk of toxicity
What is the toxic principle in this plant?
Xanthine alkaloids
Pictured: Cocoa (Theobroma cocao)
Mechanism of action: block adenosine (A) receptors, inhibition of phosphodiesterase
T/F: Sodium nitrite IV is useful for treating hydrogen sulfide toxicity
True
Sodium nitrite IV forms methemoglobin that binds the hydrated sulfide radical to reduce toxic effects and reactivate cytochrome oxidase
Ragwort or senecio (Senecio spp.) is a common plant in western Oregon and Washington that causes losses in livestock mainly because it has this toxic principle:
pyrrolizidine alkaloids
What is the toxic principle in this plant?
Insoluble Ca2+ oxalate
Pictures: Dumbcane (Dieffenbachia spp.)
Mechanism of action: hypocalcemia and preceipitation of insoluble oxalates in soft tissue and kidney damage; produces proteolytic enzymes which cause _release of histamine_ and kinins by the body increasing the mechanical damage
What is the toxic principle in this plant?
Pyrrolizidine alkaloids
Pictured: Rattlebox (Crotolaria spp.)
Mechanism of action: hepatotoxic
Which of the plants pictured is a soluble oxalate-containing plant?
Sorrel (Oxalis spp.)
What are the general signs you’d expect to see associated with chronic fluoride poisoning in cattle?
lameness, exostoses, and excessive dental wear
You may also observe anorexia, emaciation, rough haircoat, reduced milk production and reproduction
What is the toxic principle in this plant?
Triterpene acids
Pictured: Lantana (Lantana camara)
Mechanism of action: liver damage and hepatogenic photosensitization
T/F: Selenium deficiency causes blind staggers in cattle
False
Selenium _toxicosis_ causes blind staggers in cattle
T/F: Ethylene glycol is known to cause heinz body anemia in cats
False!
Propylene glycol is known to cause heinz body anemia in cats
….dummy
T/F: Phytonadione is the treatment of choice for anticoagulant rodenticide toxicity
True
Phytonadione is Vitamin K1 (oral route is recommended)
Identify this selenium indicator plant that is grown widely in the west:
Prince’s Plume
Stanleya pinnata
A dog that was treated in the ER for tremors and hyperthermia related to metaldehyde ingestion was doing fine on discharge but now, a few days later, is showing inappetence and vomiting.
What organ/body system is most important to assess at this time?
Liver
A reddish-brown gas that produces bronchial constriction and pulmonary edema is:
nitrogen dioxide (NO2)
What species are most susceptible to soluble oxalate poisoning?
Sheep & Cattle
- Sheep and cattle are the most susceptible (although the rumen microflora can detoxify oxalates to carbonates and bicarbonates)*
- Sheep may be poisoned by 0.55% of body weight. Starved sheep or water deprived can be killed by only 0.1% of body weight.*
What is the toxic principle in this plant?
Isocupressic acid
Pictured: Ponderosa Pine (Pinus ponderosa)
Mechanism of action: Maybe vasoconstriction and decrease uterine blood flow that stimulates release of fetal cortisol and abortion
Clinical signs: abortion in cattle
If a patient ingests an antifreeze product that contains a rust inhibitor, what biochemistry value may rise in the first few hours post-ingestion but not be related to renal injury?
phosphorous
T/F: As low as 0.1g/kg Xylitol can cause hyperglycemia
False
- As low as 0.1g/kg Xylitol can cause hypoglycemia*
- Xylitol is a potent promoter of insulin release in dogs, resulting in hypoglycemia. Large doses can cause liver failure, GI hemorrhage, and DIC*
- Hypoglycemia can occur within 30-60 minutes or may take several hours depending on the amount ingested*
T/F: Petroleum products with low boiling points, low viscosity, and low surface tension usually have more pneumotoxic potential
True
Generally products with high boiling points (low volatility) such as asphalt, mineral oil or waxes are relatively non-toxic because of poor absorption
What is the toxic principle in this plant?
Anthraquinones
Pictured: Coffee Senna (Senna occidentalis)
Mechanism of action: Purgative, and coffee weed also has an unknown principle that causes skeletal and cardiac muscle degeneration and the urine may be coffee colored due to myoglobinuria which may cause kidney damage
Horses usually die from liver failure and not muscle degeneration
[an″thrah-kwin´ōn]
Which of the following poisonous plants is most likely to produce a photodynamic substance that causes photosensitivity?
- Horsetail (Equisetum hymenale)
- Cottonseed (Gossypium spp.)
- Johnsongrass (Sorghum spp.)
- St. John’s wort (Hypericum perforatum)
- Milkweed (Asclepias spp.)
St. John’s wort (Hypericum perforatum)
The mechanism of action for St. John’s wort is primary photosensitization. The photodynamic substance comes directly from the plant.
- Horsetail (toxic principle: thiaminase) produces signs of thiamine deficiency
- Cottonseed (toxic principle: gossypol) causes heart and liver damage
- Johnsongrass (toxic principle: cyanogenic glycosides) inhibits the citric acid cycle, cytochrome oxidase, cellular respiration, and glycolysis
- Milkweed (toxic principle: cardiac glycosides) causes cardiotoxicity and irritation of nervous tissue
What toxic plants act by a mechanism similar to vitamin D?
Day-blooming Jessamine (Cestrum diurnum) and turkey berry (Solanum torvum)
Both contain calcinogenic glycosides (Vitamin D analog)
What is the specimen of choice to confirm a diagosis of chronic fluoride poisoning?
bone
- Bone is the best specimen - either by biopsy or necropsy (metatarsals, metacarpals, ribs, pelvis, mandible, or coccygeal vertebrae)*
- Levels >1500 ppm are significant*
- Elevated urine levels confirm recent exposure (15-20 ppm)*
What is the most common source of Naphthalene toxicity?
Ingestion of mothballs
What is the toxic principle in this plant?
Soluble oxalate
Pictured: Halogeton (Halogeton glomeratus)
\ˌha-lə-ˈjē-ˌtän\
T/F: In general, nonionic detergents are the most toxic, while anionic detergents are more toxic than cationic detergents.
False
- Nonionic detergents are the least toxic, anionic detergents are moderately toxic, and cationic detergents are highly toxic*
- nonionic (least toxic) < anionic < cationic (most toxic)*
What is the toxic principle in aster (Aster spp.) and woody aster (Xylorrhiza spp.)?
Selenium
When would you expect to see late signs associated with ethylene glycol toxicity in the cat?
12-24 hours post-ingestion
What is the name of the disease in horses that is caused by this plant?
Equine Nigropallidal Encephalomalacia (ENE) or ‘chewing disease’
Pictured: Yellow starthistle (Centaurea solstitialis)
Clinical signs: Sudden onset of inability to eat or drink, drowsiness interrupted by excitation, head down, and dehydration
What is the toxic principle in this plant?
Quinones
Pictured: St. John’s Wort (Hypericum perforatum)
Mechanism of action: primary photosensitization
Identify deez nuts:
Macadamia nuts
(Macadamia integrifolia, Macadamia tetraphylla)
Main toxic Principle: Unknown
Clinical Signs: Dogs ingest 3-60 g/kg nuts show clinical signs within 12 hours of ingestion which include weakness especially in hind limbs, depression, ataxia, tremors, hyperthermia, lameness, recumbency, vomiting, colic, diarrhea, pale mucous membranes, full recovery is within 2 days
Inhibition of lipoic acid which results in inhibition of citric acid cycle is the mechanism of action of:
trivalent arsenic
As you’re casually strolling through your pasture, you notice your dumbest horse eating this plant. Desperately you yell out “don’t eat that,” but the son-of-a-mare, engrossed in his mastication, doesn’t listen and continues on.
You continue to try to persuade him to cease his incessant chomping with a heartfelt speech about how he’ll likely die from muscle degeneration when out of nowhere your annoyingly conversant stable-hand interrupts.
He says, “you’re wrong. Your horse is not very likely to die from muscle degeneration… The horse is MUCH more likely to die from __________”
liver failure
The plant pictured is Coffee Weed (Senna occidentalis), which has an unknown principle that causes skeletal and cardiac muscle degeneration. The urine may be coffee colored due to myoglobinuria which may cause kidney damage.
In horses, death is typically due to liver failure and NOT muscle degeneration.
Stupid horse.
What is the toxic principle in this plant that results in hemorrhage?
Coumarin glycosides
Pictured: Sweet clover (Melilotus spp.)
Mechanism of action: form dicoumarol in spoiled plants; hemorrhage due to antagonism of vitamin K by inhibiting vitamin K epoxide reductase resulting in deficiency of coagulation factors II, VII, IX, and X
T/F: Vitamin K1 should always be given IV
False
Vitamin K1 should pretty much always be given orally. If given IV there is a high risk of anaphylaxis
Ragwort or senecio (Senecio spp.) is a common plant in western Oregon and Washington that causes many losses in livestock mainly because it has this toxic principle:
pyrrolizidine alkaloids
Mechanism of action: hepatotoxic
What species is most sensitive to monensin toxicosis?
Horses
Ionophores are rapidly metabolized by P-450 oxidative demethylation enzymes in the liver and excreted mainly in bile. Horses have the lowest levels of oxidative demethylases out of the other domestic species, so the compound is metabolized slowly
What is the toxic principle of this plant responsible for its enterotoxicity and neurotoxicity?
Meliatoxins
Pictured: Chinaberry (Melia azedarach)
T/F: You’re more likely to see reticulocytosis associated with zinc toxicity than with lead toxicity
True
What species is most frequently affected by marijuana toxicosis?
Dogs
Cats are also susceptible
Oh snap. Your pet cow just ate this!! What is the best treatment option?
Physostigmine or neostigmine are the antidotes
Pictured: Monkshood, Aconite (Aconitum spp.)
Toxic principle: Diterpene alkaloids
How quickly would you expect to observe clinical signs associated with urea toxicosis?
0.5 - 3 hours (rapid onset)
Signs include restlessness, aggression, muscle tremors, salivation, teeth grinding, colic, bloat, rumen stasis, sternal recumbency while standing on the hind limbs, usually no diarrhea, convulsions and death within 1-2 hours
T/F: In addition to the effect on the kidneys, an important effect of ethylene glycol is the production of systemic alkalosis
False
In addition to the effect on the kidneys, an important effect of ethylene glycol is the production of systemic _acidosis_
DEET concentration of ____ppm is considered diagnostic for DEET toxicity
20 ppm
What is the general mechanism of action (MOA) of anticoagulant rodenticides?
Inhibit Vitamin K epoxide reductase
(Vitamin K epoxide reductase is the enzyme that converts Vit K epoxide to reduced form). This inhibition leads to depletion of reduced Vit K and reduced activation of clotting factors II, VII, IX, and X.
T/F: Fomepizole is used in the treatment of both ethylene glycol and propylene glycol
False
Fomepizole is only used in the treatment of ethylene glycol
What is the specimen of choice for diagnosis of nitrate poisoning in an animal that has been dead for several hours?
Ocular fluid
(>30 ppm indicates excessive exposure)
A dog showing gastrointestinal signs followed by a phase of apparent recovery, which deteriorates into multi-organ failure is most likely poisoned with oral
iron
What is the toxic principle in this plant?
Insoluble Ca2+ oxalate
Pictured: Flamingo plant (Anthurium spp.)
Adding 20% ferric chloride to urine samples to observe a purple color change in the urine is useful for detecting what toxicant?
Phenol
What is the mechanism of action of diterpene alkaloids?
Competitive blockade of the nicotinic receptors at the muscle endplate similar to curare
T/F: Methylene blue IV is the antidotal treatment for 2,4-D
False
Methylene blue IV is the antidotal treatment for nitrates
Which three insecticides that we covered in class are CNS depressants?
Amitraz, Ivermectin, D-limonene
*Financial AID can be depressing*
What is the toxic principle in this plant?
Tetradymol
Pictured: Horsebrush (Tetradymia spp.)
Mechanism of action: Tetradymol from horsebrush causes liver damage that decreases elimination of phylloerythrin, a metabolite of chlorophyll
- Phylloerythrin is a photodynamic substance that causes damage in microcirculation areas exposed to ultraviolet light and hepatogenic photosensitization in white skin or lightly pigmented skin*
- **Sheep are the most susceptible animals***
Poisoning by which of the following toxicants is least likely to cause convulsive seizures in cattle?
- lead
- urea
- chlorinated hydrocarbon insecticides
- nicotine
- chronic selenium
chronic selenium
T/F: White clover and alfalfa cause infertility in females and decreased libido and feminization in males
True
T/F: Urea toxicosis is associated with ↑ ammonia, ↑ blood urea nitrogen (BUN), ↑ blood glucose, ↑ blood lactate, ↑ blood pH, ↑ transaminases (ALT, AST), and ↑ PCV
False
Urea toxicosis is associated with ↑ ammonia, ↑ blood urea nitrogen (BUN), ↑ blood glucose, ↑ blood lactate, ↑ transaminases (ALT, AST), and ↑ PCV
Urea toxicosis is NOT associated with ↑ blood pH. Blood pH will decrease due to the circulating acids.
Rumen pH is expected to increase (>7.5 is highly suggestive of urea toxicosis)
Fluoride reacts with a variety of other organic and inorganic compounds, and has an especially strong affinity for __________
calcium
This is what is responsible for abormal teeth and bones in chronic fluoride toxicosis
T/F: Cyanide and hydrogen sulfide both cause sudden death mainly due to preventing tissue oxygen utilization
True
Which of the following is LEAST likely a clinical sign of marine toad (Bufo marinus) intoxication?
- foaming of the mouth
- seizures
- tachycardia or bradycardia
- hemolysis
hemolysis
Methylene blue IV is the antidotal treatment for
Nitrate
What is the toxic principle in this plant?
Indolizidine alkaloids
Pictured: Locoweed (Astragalus spp.)
Mechanism of action: inhibit lysosomal enzymes essential for formation of glycoproteins; alteration of cellular function in the brain and many other organs including endocrine and reproductive organs, heart, and immune system
- Astragalus and Oxytropis also have nitropropanol glycoside and selenium. Niropropanol causes peripheral neuronal degeneration and respiratory signs. Selenium causes abnormal hoof and hair*
- The disease is called locoism and shows neuronal signs and is more common in horses than cattle or sheep*
If anticoagulant rodenticide intoxication is suspected but you do not know what specific rodenticide was ingested, how long should you treat with Vitamin K1?
4 weeks (28 days)
How does carbon monoxide cause asphyxia?
Changes oxygen-carrying capacity of hemoglobin
In a chemical analysis, the result is expressed as 67 µg/g. What is the equivalent to this value in %?
0.0067%
1 µg/g = 0.0001%
Fun fact, right? Wrong - That fact isn’t even a little bit fun.
What is the toxic principle in this plant?
Lycorine
Pictured: Narcissus (Narcissus poeticus)
Mechanism of action: emetic and purgative
**the bulb is the most toxic portion**
What is the toxic principle in this plant?
Ergot alkaloids
Pictured: Ergot (Calviceps spp.)
Mechanism of action: vasoconstriction and gangrene; uterine contraction
What toxic plant is associated with neoplasia in the urinary tract causing enzootic bovine hematuria?
What is the toxic principle responsible?
Bracken fern (Pteridium aquilinum)
Toxic principle: ptaquiloside
What sample do you think is most appropriate for antemortem testing for lead toxicosis?
- Serum
- Plasma
- Whole Blood
- Brain tissue
Whole Blood
- > 90% of circulating lead is bound to erythrocyte membranes*
- Blood lead more than 0.4 ppm along with clinical signs is considered diagnostic (Blood lead >0.6 ppm are considered diagnostic regardless of correlation with clinical signs)*
In which US states do we see selenium rich soil?
North Dakota, Kansas, Utah, Nebraska, New Mexico, Wyoming, South Dakota, Colorado, Montana
_N_ancy _K_ept _U_ttering _N_onsensical _N_otions _W_hile _S_ally _C_rapped _M_arshmallows
T/F: Fomepizole (4-methyl pyrazole) is used in the treatment of ethylene glycol in dogs and cats and acts by competitive inhibition of alcohol dehydrogenase
True
Alcohol dehydrogenase is the enzyme that catalyzes the initial steps in the metabolism of ethylene glycol and methanol to their toxic metabolites
What is the name of the disease associated with ingestion of this plant?
Locoism
Pictured: Locoweed (Astragalus spp.)
The disease is called locoism and shows neuronal signs and is more common in horses than cattle or sheep. Primary signs include depression, incoordination, ataxia, circling, and abnormal behavior
The most likely pathognomonic evidence of water deprivation/sodium ion toxicosis in swine is
eosinophilic meningoencephalitis
What is the toxic principle in this plant?
Cardiac glycosides
Pictured: Oleander (Nerium oleander)
Mechanism of action: Cardiotoxic by inhibiting Na/K ATPase
**BE AWARE THAT OLEANDER CAN BE A NUMBER OF DIFFERENT COLORS! ALL OF THE PICTURES BELOW ARE EXAMPLES OF OLEANDER**
What is the toxic principle in agave?
Steroidal saponins
Mechanism of action: Liver damage and inability to eliminate phylloerythrin, a metabolite of chlorophyll that acts as a photodynamic substance
Leads to hepatogenic photosensitization
In what types of animals do we most commonly see chronic fluoride toxicosis?
herbivores (mainly dairy cattle)
D-penicillamine is the chelating agent of choice for:
copper
T/F: Organophosphates and Carbamates undergo storage activation
False
Carbamates do not undergo storage activation
Reduced cytochrome oxidase in cattle can be used as a diagnostic test in toxicosis with:
molybdenum
If chelation therapy is recommended for a toxicant when levels reach 5mg%, will a blood level of 900mcg/dL require therapy?
No
5mg% = 5000 mcg/dL
Therefore, 900 mcg/dL is not high enough to require therapy
What is the toxic principle in this plant?
Cyanogenic glycosides
Pictured: Wild cherries (Prunus spp.)
Mechanism of action (acute): Inhibition of cytochrome oxidase, inhibition of cellular respiration, vasoconstriction, inhibition of glycolysis, inhibition of citric acid cycle, irritation of mucous membranes
Mechanism of action (chronic): neuronal degeneration
Chronic poisoning with this toxic principle in plants is most likely to cause abortion in cattle due to a decrease in progesterone production:
Nitrate
What is the toxic principle in this plant?
Muscarine
Pictured: Poisonous mushrooms (Amanita muscaria)
Mechanism of action: stimulation of muscarinic cholinergic receptors causing CNS stimulation
Which of the following plants is very toxic because it has a phytotoxin?
- Oleander (Nerium oleander)
- Castor bean (Ricinus communis)
- Marijuana (Cannabis sativa)
- Black nightshade (Solanum niger)
Castor bean (Ricinus communis)
Toxic principle: lectins (phytotoxins, toxalbumins)
Other plants in this category: precatory bean, coral plant, sandbox tree, block locust, soybeans, kidney beans, pinto beans
- Oleander (toxic principle: cardiac glycosides) is cardiotoxic by inhibiting Na/K ATPase
- Marijuana causes irritation of the nervous or muscle tissue
- Black nightshade (toxic principle: solanine and solanidine alkaloids) cause GI, CNS, respiratory, and cardiac issues
The diphenylamine test is a quantitative test for __________ in forages (hay, pasture, silage), rumen contents, and water
nitrate
Positive results indicate greater than 5,000 ppm nitrate
Dark blue color indicates a positive result
What is the toxic principle in this plant?
Taxine alkaloids
Pictured: English Yew (Taxus spp.)
Cardiotoxic & GI
What is the toxic principle in this plant?
Tropane alkaloids
Pictured: Jimsonweed (Datura stramonium)
T/F: Emetics and gastric lavage is generally contraindicated in treatment of a patient that has ingested phenolic compounds
True
Milk, egg whites, followed by activated charcoal (maybe) and saline cathartics
What is the specific treatment for organophosphate toxicity?
2-PAM
“Cholinesterase reactivating oxime”
What substance that is commonly added to ethylene glycol antifreeze may show up on the fur, mucous membranes, or in urine when inspected with a Wood’s lamp that can provide support for a diagnosis?
Fluorescein
What toxic plants are known to cause signs of vitamin B1 (thiamine) deficiency in monogastric animals?
Horsetail (Equisetum hyemale) and bracken fern (Pteridium aquilinum)
Toxic principle: Thiaminase
Mechanism of action: Thiaminase destroys thiamine in the diet and produces signs of thiamine (vitamin B1) deficiency in monogastric animals (neurotoxic)
What is the toxic principle in this plant?
Thiaminase
Pictured: Horsetail (Equisetum hyemale)
Mechanism of action: Thiaminase destroys thiamine in the diet and produces signs of thiamine (vitamin B1) deficiency in monogastric animals (neurotoxic)
Caladium is common house plant. What is the primary toxic principle in Caladium spp?
insoluble calcium oxalate
What toxicant causes elevated thiocyanate levels in urine?
Cyanide
Dogs that survive the acute phase of 3 hrs will develop liver failure from what toxicant?
metaldehyde
Name two antidotes for Amitraz toxicity. Which one is considered the better option?
Yohimbine and Atipamezole
Atipamezole is considered the better option because it has fewer cardiorespiratory effects than yohimbine
Which is more toxic: Sodium Fluoride (NaF) or Calcium Fluoride (CaF)?
Why?
Sodium Fluoride (NaF)
- Systemic toxicity depends on absorption which depends on solubility. Soluble sodium fluoride (NaF) is more toxic than calcium (insoluble) fluoride (CaF2).*
- It is really only NaF that is absorbed and causes systemic issues. Once it is absorbed it will go and look for Ca2+ in the blood, then Ca2+ will replace the Na+ and it will become CaF2.*
A toxicant that causes very rapid death, has a characteristic odor, and causes bright red mucous membranes and cherry red blood is:
cyanide
Cottonseed (Gossypium spp.) reduces male fertility by destroying __________
seminiferous tubules
A feedlot steer that survived an overdose of monensin in the feed was found dead 3 weeks later.
T/F: The most likely cause of death, if related to the monensin toxicosis is persistent depolarization and arrhythmias as a result of the sodium and calcium channel effects
False
The most likely cause of death in this case, if related to the monensin toxicosis is cardiac fibrosis and insufficiency as a result of cardiac muscle necrosis during acute monensin toxicosis
Enlarged yellow liver, enlarged friable and hemorrhagic kidneys, enlarged black spleen, and red wine-colored urine are lesions most likely associated with:
chronic copper toxicosis
What is the mechanism of action of this plant?
causes laminitis
Pictured: Black Walnut (Juglans nigra)
Ingestion of fresh shavings made from heartwood (used as bedding) causes laminitis
What is the toxic principle in this plant?
Xanthine alkaloids
(caffeine, theophylline, and theobromine)
Pictured: Coffee arabica (Coffea arabica)
Mechanism of Action: Blocks adenosine (A) receptors and inhibits phosphodiesterase
Clinical signs: Salivation, vomiting, colic, and diarrhea; CNS stimulation and convulsive seizures
**DO NOT CONFUSE THIS WITH COFFEE SENNA**
Dogs poisoned by ingesting large amount of chocolate will be expected to show which of the following clinical signs?
- Posterior paralysis and constipation
- CNS depression, skin rashes, and oliguria
- bleeding, vomiting, dehydration and shock
- convulsions, tremors, tachycardia, and urination
- reddening of the skin, alopecia, and lameness
convulsions, tremors, tachycardia, and urination
What type of drug would you use to treat tachyarrhythmias associated chocolate toxicity?
β-blockers
β-blockers such as propanolol or metoprolol to treat tachyarrhythmias. Metoprolol may exhibit less competition for urinary excretion – faster elimination than with propanolol
What is the toxic principle in this plant?
Grayanotoxins
Pictured: Azalea (Rhododendron spp)
Mechanism of action: Bind to sodium channels in excitable cells (nerve, skeletal muscle, cardiac muscle, CNS), Increase permeability of sodium ions and depolarization, irritation of GI mucosa
The irrational fear that somehow, somewhere, a duck is watching you is termed:
anatidaephobia
