Toxicities

Question 1

Acetaminophen toxicity in cats

Answer 1

Results in Heinz body anemia, cats can die from oxidative damage and methemoglobin within 1-2 days of ingestion. Immediate gastrointestinal decontamination is needed if ingestion was within 2-3 hours. Treat with N-acetylcysteine, SAMe, vitamin C, and aggressive fluid therapy

Question 2

Alfalfa

Answer 2

Nitrate Accumulating Plant

Question 3

Aflatoxin

Answer 3

produced by certain fungi that are found on agricultural crops such as maize (corn), peanuts, cottonseed, and tree nuts

Turkeys are extremely susceptible to aflatoxicosis. Recent studies have revealed that this is due to the efficient cytochrome P450 mediated metabolism of aflatoxin B1 in the liver of turkeys and deficient glutathione-S-transferase mediated detoxification

Question 4

Amsinckia intermedia

Answer 4

Fiddleneck, Fireweed, tarweed: Secondary photosensitization due to liver failure - contains pyrrolizidine alkaloids. Cause megalocytosis, biliary duct hyperplasia, and fibrosis. As a result of liver damage, the liver will be unable to clear normal chlorophyll breakdown products such as phylloerythrin, which causes photosensitization secondary to liver failure.

Question 5

Anaranthus (pig weed)

Answer 5

nitrate

Question 6

Astragalus

Answer 6

“loco weed”

Question 7

Avacado

Answer 7

toxic to parrots

A toxin, know as persin, is a phytochemical found in the Guatemalan type of avocado which causes myocardial necrosis in the budgerigar, parrot and possibly other pet bird species.

Question 8

Azalea - Rhododendron

Answer 8

Cardiotoxic plant Contains andromedotoxins, which bind membrane sodium channels, leading to excitation and movement of calcium intracellularly for an effect similar to digitalis

Question 9

Black Walnut - Juglans nigra - Toxicity - Equine

Answer 9

• horses bedded on black walnut shaving can cause laminitis within 24 hours of exposure - signs: reluctance to move, increased digital pulses and shifting-weight lameness - exact toxin yet to be identified - treatment: remove source and decontaminate GI tract with mineral oil or activated charcoal, wash legs and feet, and treat for laminitis

Question 10

Blister Beetle Toxicity - Equine

Answer 10

• exposed to dead blster beetles entrapped in alfalfa hay during harvesting - contain cantharidin - highly irritant substance - causes severe irritation to tissues it contacts (GIT and kidney) - signs: variable, lethargy, anorexia, polyuria, colic, tachycardia, diarrhoea, sweating - diagnosis: clinical signs plus beetles in hay, cantharidin in urine and stomach contents - treatment: supportive care

Question 11

blue-green algae - Microcystis sp

Answer 11

Secondary photosensitization due to liver failure

Question 12

Bracken fern - Pteridium aquilinum

Answer 12

Neurotoxic glycoside plant Poisons cattle, sheep, pigs and horses Contains thiaminase which cleaves vitamin B1, and also contains up to 1% ptaquiloside which alkylates DNA leading to carcinogenicity and bone marrow suppression (only in ruminants) Thiamine deficiency leads to polioencephalomalacia Clinical signs in all large animals - incoordination, standing with legs apart - depression - muscle tremors, ataxia - blindness, retinal degeneration Clinical signs of ptaquiloside in ruminants - bone marrow destruction, hemorrhage - anemia, elevated pyruvic acid - tumors in bladder and other organs Treatment: injectable thiamine, no Rx for ptaquiloside

Clinical sign in horse: opisthotonos

Question 13

Brodifacoum

Answer 13

highly lethal 4-hydroxycoumarin vitamin K antagonist rodenticide - in dogs supplement Vit K for 6 weeks post ingestion

Cat recently ingested: gastric lavage, activated charcoal, vitamin K for 30 days. Clinical signs occur 3-5 days after ingestions and hemorrhaging results. PT should be checked 48 hours after the last dose of Vitamin K.

Question 14

Cantharidin (blister beetle)

Answer 14

Results in endotoxic shock and renal failure. Horses affected may be found dead, colicing, or in cardiovascular shock. Vesicles may form in the mouth and tongue, and if the animal lives long enough, you can expect to see watery feces. Renal tubular damage will be profound, and you will probably observe cardiac arrhythmias.

Question 15

Cardiotoxic Plants

Answer 15

Oleander, Foxglove, Lily-of-the-Valley, Yew, Azalea - signs: salivation, nausea, vomiting (risk of aspiration), hematochezia, weakness, bradycardia, hypotension, A/V block, collapse, and acute death - treatment: in small animals - emesis, activated charcoal, supportive care (IV fluids, supplemental oxygen), atropine for severe bradycardia, isoproterenol/procainamide/quinidine for A/V block

Question 16

Castor bean - Ricinus communis

Answer 16

Contains ricin - a highly toxic glycoprotein Clinical signs (may have lag period before onset): - anorexia, vomiting, diarrhea - weakness, thirst - muscle spasm, uremia, death - sweating, ataxia (horses) - extensive organ edema and damage

Question 17

Chocolate toxicity

Answer 17

Methylxanthines (specifically theobromine and caffeine) can cause CNS excitation, tachycardia, and vasoconstriction. Signs include vomiting, diarrhea, hyperactivity, polyuria, polydipsia, lethargy, tachycardia, cardiac arrhythmias, seizures, and death.

Question 18

Chokecherry - Prunus sp.

Answer 18

Cyanide/Cyanogen Containing Plant

Question 19

Cholecalciferol-based rodenticide

Answer 19

Cholecalciferol gets converted to activated vitamin D to cause increased bone resorption of calcium and gut absorption of calcium leading to a sometimes fatal hypercalcemia (-> organ mineralization). Nutirional secondary hyperparathyroidism results when an anima’s diet contains too much phophorus resulting in cedreased serum calcium.

Question 20

Copper Toxicity

Answer 20

Sheep highly susceptible, goats and cattle less susceptible.

Causes acute hemolytic crisis, most common signs are acute death, icterus, depression, hemoglobinuria, increased respiratory rate, and weakness.

Pathology often shows dark, hemoglobin-filled kidneys (“gun metal blue”)

Question 21

Cottonseed - Gossypium sp.

Answer 21

May contain gossypol which is cardiotoxic, particularly to very young animals (cattle, sheep and pigs) Clinical signs: - sudden death due to heart failure may occur - anorexia, red urine, thin pot-bellied appearance - poor performance in adult animals

Question 22

Crotalaria sp

Answer 22

Secondary photosensitization due to liver failure Pyrrolizidine Alkaloid Toxicity

Question 23

Cyanide/Cyanogen Containing Plants

Answer 23

Chokecherry, Vetch, Hydrangea, Johnson grass - hydrogen cyanide absorbed from GIT and inhibits mitochondrial cytochrome oxidase. oxyhemoglobin cannot release oxygen for electron transport in cytochrome system leading to cellular hypoxia - signs: excitement, muscle tremors, dyspnea, salivation, urination, defecation, sudden death, bright red blood and mucous membranes - treatment: methylene blue, sodium nitrite, and sodium thiosulfate

Question 24

Cynodon

Answer 24

One of the causes of grass staggers

Question 25

Dumbeane - Dieffenbachia

Answer 25

Clinical signs: - ataxia, hypermetria - clicking of the dewclaws (“cracker heels”), conscious proprioceptive deficits - emaciation - emphysema (sheep) - abortions, teratogenesis (contracted tendon)

Question 26

Erodium

Answer 26

Geranium - Pelargonium species and are toxic to both cats and dogs. Geraniums contain geraniol and linalool, which are both poisonoussubstances. Animals that have consumed geraniumstypically exhibit symptoms such as vomiting, lethargy, dermatitis and loss of appetite

Question 27

Ethylene glycol

Answer 27

4-methylpyrazole antidote

Causes hypocalcemia due to chelation of calcium by metabolites of ethylene glycol such as oxalate.

Question 28

Fescue Toxicosis - Equine

Answer 28

• not a problem on its own, but most infected with Neotyphodium coenophialum - fungus produces numerous toxins including ergopeptine alkaloids which act as dopamine agonist (blocks prolactin release) - clinical signs: prolonged gestation, placental thickening and agalactia - diagnosis empiric - treatment: remove infected grass/hay, administer dopamine antagonist (Donoeridone)

Question 29

Fleet enemas

Answer 29

high in phosphorus and lead to a decrease in serum calcium due to the law of mass action. Hypocalcemia can cause weakness, lead to shock, and cause muscle tremors or seizures. Treatment is to correct the electrolyte disturbance and correct the dehydration. IV fluid therapy and calcium gluconate are the initial treatments, and many times phosphorus binders are helpful to more quickly decrease the serum phophorus.

Question 30

Foxglove - Digitalis purpurea

Answer 30

Cardiotoxic plant Contains cardiac glycosides, which increase contractility and decrease heart rate via vagal stimulation, prolonging diastole

Question 31

Gossypol toxicity

Answer 31

Found in cotton seed in varying amounts. Cardiotoxic and can kill calves less than 4 months of age. In adults, if fed at high levels, it usually causes sterility in bulls and decreased conception in cows.

Question 32

Groundsel - Senecio sp

Answer 32

Secondary photosensitization due to liver failure Pyrrolizidine Alkaloid Toxicity

Question 33

Heliotropium sp.

Answer 33

Pyrrolizidine Alkaloid Toxicity

Question 34

Hydrangea

Answer 34

Cyanide/Cyanogen Containing Plant

Question 35

Ionophore Toxicity - Equine

Answer 35

Lasalocid, monensin, salinomycin - antibiotics with ability to bind and transport ions across biological membranes - used as growth promotants and coccidiostats in ruminants but are toxic to horses - cytotoxicity due to disruption of mitochondria -> loss of aerobic energy production (muscle and neurologic tissue) Signs: - acute: weakness, ataxia, anorexia, tremors, tachycardia, hypotension, dyspnea, recumbancy, death - chronic: damage to heart, poor performance, exercise intolerance, arrythmia

Question 36

Jimsonweed - Datura stramonium - Devil’s snare

Answer 36

Dangerous levels of tropane alkaloids, hyoscyamine, and scopolamine Deliriant and anticholinergic Produces delirium, hyperthermia, tachycardia, bizarre behavior, and severe mydriasis which results in painful photophobia that can last for several days.

Treatment for horse post ingestion: Physostigmine (a parasympathomimetic), activated charcoal, laxatives, diazepam to control convulsions

Question 37

Johnson Grass (Sorghum)

Answer 37

Cyanide/Cyanogen Containing Plant Nitrate Accumulating Plant

Question 38

Larkspur - Delphinium

Answer 38

Neurotoxic Plant Contains polycyclic diterpene alkaloids - neuromuscular blocker, cholinergic and nicotinic antagonist Cattle are most susceptible Clinical signs: - bloat - excitability - muscletremors, stiffness, paresis, seizures - arrhythmias - death from respiratory paraylsis Treatment: - physostigmine may reverse neuromuscular blockade - relieve bloat if present - decontaminate and supportive care

Question 39

Lead poisoning

Answer 39

treated with Ca-EDTA to chelate and excrete lead, Succimer can also be given orally. D-penicillamine has also been used to chelate lead, copper, iron and mercury.

Clinical signs are primarily gastrointestinal and neurologic. Lead blood levels can be measured but do not necessarily correlate with severity of clinical signs. Toxic blood levels are greater than 0.4 ppm. Blood work can show an elevated number of nucleated RBCs without anemia. Basophilic stippling is a classic finding with lead toxicity but not specific.

Question 40

Leukoencephalomalacia - Equine

Answer 40

Moldy corn toxicity - ingesting moldy corn with mycotoxin fumosisin (metabolite) can develop neurologic deficits and (less common) liver damage - sings: incoordination, anorexia and lethargy to blindness, head pressing, hyperexcitability, profuse sweating and delirium - toxin causes liquefactive necrosis and degeneration of cerebral hemispheres and other portions of the brain - diagnosis based on history, clinical sings and postmortem - treatment is supportive care

Question 41

Lidocaine toxicity

Answer 41

muscle tremors & seizures

Question 42

Lily-of-the-Valley - Convallaria majalis

Answer 42

Cardiotoxic plant Contains >20 cardia glycosides, has a digitalis-like action

Question 43

Locoweed

Answer 43

Of the genera Astragalus, Oxytropis, and Swainsona, and many species contain a chemical which inhibits alpha-mannosidases and causes widespread neurovisceral cytoplasmic vacuolation and emaciation, as well as abortion and nervous system abnormalities. They tend to grow in the arid west, and are often eaten when other forage becomes scarce. Horse can also be affected

Question 44

Lolium

Answer 44

One of the causes of grass staggers

Question 45

Lupine - Lupinus so

Answer 45

Neurotoxic Plants Most commonly affects sheep Contains lupinine, a quinolizidine alkaloid - induces nicotinic effects Clinical signs: - salivation, incoordination, head-pressing, aimless wandering, excitement, muscle tremors, seizures, dyspnea A teratogen in cattle but not sheep - in calves exposed in utero day 40-70 gestation - causes “crooked calf syndrome” - toricollis, scoliosis, carpal flexufe No soecific treatment

Question 46

Moldy sweet clover

Answer 46

Inhibits vitamin K and causes coagulopathy.

especially in horses

Question 47

Moldy Sweet Potatoe

Answer 47

4-ipomeanol

Question 48

Neurotoxic Plants

Answer 48

Lupine, Poison hemlock, Larkspur, Nightshade, Bracken fern

Question 49

Nightshade - Solanum sp

Answer 49

Neurotoxic Plant In addition to potentially accumulating nitrates, Solanum sp can contain varying amounts of 2 toxins, a GI irritant (glycoalkaloids) and neurotoxin (agkycone) Clinical signs: - anorexia, nausea, abdominal pain, vomiting, diarrhea - apathy, paresis/paralysis, protration, unconsciousness

Question 50

Nightshades - Solanum

Answer 50

Nitrate Accumulating Plant

Question 51

Nitrate Accumulating Plants

Answer 51

Pigweed, Nightshade, Oat hay, Sorghum, Rye, Alfalfa - primarily ruminants (esp. cattle) due to reduction to nitrite by microbes in the rumen - nitirite causes methemogloinemia -> dark brown blood (“chocolate coloured”) which has diminished oxygen carrying capacity - signs: “muddy” mucous membranes, dyspnea, tremors, convulsions, ataxia, tachycardia - treatment: 1% methylene blue, reduces methemoglobin

Question 52

Oat Hay

Answer 52

Nitrate Accumulating Plant

Question 53

Oleander - Nerium oleander

Answer 53

Cardiotoxic plant Contains cardiac glycosides - oleandrin and neriine

Question 54

Organophosphate Toxicity

Answer 54

• used as insecticides, inhibit acetylcholinesterase -> accumulation of acetylcholine at postsynaptic receptor -> excessive synaptic neurotransmitter activity - in horses clinical signs result from overstimulation of muscarinic cholinergic receptors (‘SLUD’ salivation, lacrimation, urination, defecation, can also see diarrhea, colic, bradycardia, and miosis), carbamates cause similar signs - treat with atropine (same for sheep) - antidote: pralidoxime chloride
• treatment in sheep: Atropine
• causes severe vertebral and long bone abnormalities as well as generalized stunting of embryonic development

Question 55

Oxytropis

Answer 55

“loco weed”

Question 56

Paspalum

Answer 56

One of the causes of grass staggers

Question 57

Perilla Mint

Answer 57

pneumotoxin Contains perilla ketone which causes pulmonary edema and pleural effusion Clinical signs: - respiratory distress (on exhalation) due to atypical interstitial edema and emphysema - nasal discharge Treatment: usually ineffective once severe pulmonary edema or emphysema is present

Question 58

Permethrin toxicity

Answer 58

common cause of poisoning in cats. May result from inappropriate application of spot-on formulations intended for use in dogs, from cats who are in close contact with dogs after application, or from cats who come into contact with the applicator after use. Permethrin is excreted following oxidation and glucuronidation. Cats have a reduced capacity for glucuronidation, which may be attributed tot he accumulation of metabolites and a less efficient detoxification process. Permethrin passes through the blood-brain barrier and can cause CNS signs, including seizures. Dermal decontamination should be instituted immediately with dishwashing detergent.

Question 59

Phalaris Spp Grass (Canary Grass)

Answer 59

grass staggers - accumulate toxic alkaloids, can also cause acute death. Most sheep affected by Canary grass staggers will slowly recover if removed from the offending pastures

Question 60

Pigweed - Amaranthus

Answer 60

Nitrate Accumulating Plant

Question 61

Plants Causing Photosensitization

Answer 61

Primary: St. John’s wort Secondary: any plant causing liver failure (Rape, Blue-green algae, Groundsel, Crotalaria and Amsinckia intermedia - increased susceptibility to ultraviolet light damage - damage generally is most prominent on the least protected areas of the body such as: - white skin areas of the dorsum and lateral body wall - thin and non-pigmented areas (sclera, udder, muzzle) - most common in regions and seasons of more intense sunlight Two types: - primary - when ingested or absorbed agent is or is metabolized to become photodynamic (becomes a high energy molecule when exposed to ultraviolet light, causing membrane and free radical damage) - effects usually restricted to skin - better prognosis - secondary - when impaired hepatic function reduces excretion of plant pigments (such as phylloerythrin, a chlorophyll breakdown product) - damage to liver along with skin lesions Clinical signs: - erythema, edema, peeling (sunburn) - pruritus - hyperesthesia - may progress to exudation, ulceration

Question 62

Poison Hemlock - Conium masculatum

Answer 62

Neurotoxic Plant Contains coniine and pyridine-type alkaloids Clinical signs (develop very rapidly) - salivation - vomiting and diarrhea - muscle tremors, weakness, convulsions - death from respiratory failure No specific treatment

Question 63

Ponderosa Pine - Pinus ponderosa

Answer 63

Causes abortion in last trimester (“pine needle abortion”) characterized by weak contractions, excessive discharge, a small calf and retained fetal membranes

Question 64

Pyrethrins toxicity in cat

Answer 64

treat with methocarbanol

Question 65

Pyrrolizidine Alkaloid Toxicity

Answer 65

Chronic progressive consumption of plants containing pyrrolizidine alkaloids: Senecio sp., Crotalaria sp., and Heliotropium sp. Toxin absorbed by GI and transported to liver where it is metabolized by hepatocytes to pyrroles Pyrroles cross-link DNA causing an anti-mitotic effect Hepatocytes cannot divide and from megalocytes (large cells) as cytoplasm expands without nuclear division Cells subsequently die and are replaced by connective and fibrous tissue Clinical signs: non-specific signs of liver disease includeing weight loss, icterus, and photosensitization Diagnosis: history of consumption of PA-containing plants. Definitive diagnosis of observation of fibrosis, megalocytosis and bile duct proliferation(hyperplasia) on microscopy Treatment: remove PA-containing plants and provide supportive care Prognosis: dependent on degree of hepatic change

Question 66

Rape - Brassica sp

Answer 66

Secondary photosensitization due to liver failure

Question 67

Red Maple Leaf - Acer rubrum - Toxicity - Equine

Answer 67

Heinz body anemia

• ingestion of wilted leaves causes an acute hemolytic anemia - fresh leaf material is not toxic - toxic principle unknown but produces oxidative damage to erythocyte membranes - signs: lethargy, anorexia, dysnea, pale mucous membranes, tachycardia, dark-colored urine, icterus and colic, pigment nephropathy can cause acute renal failure - treatment: supportive care, blood transfusion and vitamin C - prognosis: guarded to poor

Question 68

Rye

Answer 68

Nitrate Accumulating Plant

Question 69

Scopolamine

Answer 69

Atropine-like alkaloid and causes depression and is parasympathetic to the autonomic nervous system. It can cause convulsions, respiratory failure, incoordination, mydriasis, and constipation. Treatment consists of activated charcoal, laxatives, diazepam to control convulsions and physostigmine (a parasympathomimetic)

Question 70

Skunk Cabbage

Answer 70

Sheep: craniofacial deformities is consumed on 14th day of gestation

Question 71

St. John’s wort - Hypericum perforatum

Answer 71

Contains hypericin, causes primary photosensitization and hepatotoxicity

Question 72

Strychnine toxicity

Answer 72

in snail bait treat with methocarbamol

Strychnine competitively antagonizes the action of glycine and causes a loss of impulse control in the spinal cord and brainstem. Clinical signs can begin suddenly and progress from anxiety to tetanic convulsions spontaneously or response to stimuli. Affects all striated muscles.

Question 73

Sudan Grass

Answer 73

Nitrate poisoning, treat with Methylene blue

Question 74

Sweet pea

Answer 74

in horses

Question 75

Tansy ragwort

Answer 75

pyrrolizidine alkaloid and causes liver disease

Question 76

Veratrum californicum

Answer 76

It is a source of jervine and cyclopamine, teratogens which can cause prolonged gestation associated with birth defects[5] such as holoprosencephaly and cyclopia in animals such as sheep, horses, and other mammals that graze upon it. These substances inhibit the hedgehog signaling pathway

California corn lily, white or California false hellebore) is a poisonous plant native to mountain meadows at 3500 to 11,000 ft elevation in southwestern North America, the Sierra Nevada and Rocky Mountains, and as far north as Washington State and as far south as Durango

Question 77

Vetch

Answer 77

Cyanide/Cyanogen Containing Plant

Question 78

Waterhemlock - Cicuta

Answer 78

One of the most toxic plants known Contains cicutoxin which is highly toxic to cattle and horses Clinical signs: - acute violent tetanic seizures (resembles strychnine poisoning) - rapid progression from salivation to muscle twitching, seizures, coma, and death

Question 79

Western False Hellebore - Veratrum californium

Answer 79

Contains several teratogenic compounds including cyclopamine Mainly affects sheep and many affected lambs are stillborn Teratogenic effects depend on stage of gestation when eaten - day 14 - classic cyclopean deformity (“monkey faced lambs”) - day 17-18 - hind limb motor nerve patalysis - day 12-30 - craniofacial deformities (cleft palate, harelip, brachygnathia) - day 30-36 - shortened legs from metacarpal and metatarsal bone hyooplasia

Question 80

White Snakeroot - Eupatorium ragosum

Answer 80

Affects horses and cattle Contains the ketone, trematone, which is passed to young in milk Clinical signs: - weakness, depression - horses develop myocardial necrosis and congestive heart failure (ventral edema, jugular pulse, tachycardia) - cattle develop ataxia, depression, and muscle tremors and may have “acetone breath”

Question 81

Yellow Star Thistle - Centaurea solstitialis

Answer 81

Affects horses Causes nigropallidal encephalomalacia (“Chewing Disease”) Toxin is unknown Clinical signs - usually occur over time and are generally irreversible - inability to eat or drink because of dystonia to muscles in lips and tongue - continuous chewing motions with an empty mouth, or jam food into mouth in desperstion - behaviorial changes - chewing and dropping food - may appear similar to early symptoms of rabies

Question 82

Yew - Taxus sp. including cuspidata

Answer 82

Cardiotoxic plant Contains taxine alkaloids A and B, which inhibit cardiac depolarization

Question 83

Zinc toxicity

Answer 83

Heinz body anemia and hemolysis

Question 84

Vitamin D

Answer 84

Excessive intake of vitamin D is associated with an increase in 25-hydroxyvitamin D3 levels. At high levels, 25-hyfroxyvitamin D3 competes with 1,25-duhydroxyvitamin D3 for its receptors on the intestines and bone causing increased absorption of Ca and P from the intestinal tract and resorption of bone causing increased levels of circulating Ca and P. A common source of confusion in that this is in contrast to PTH which causes high Ca but generally caused unchanged or normal phosphorus because it also enhances renal phosphorus excretion.