Toxicities Flashcards

Question

Belladonna alkaloids exposure:

Answer 1

seed contamination of grain, plant contamination of forage all plant parts are toxic

Answer 2

Belladonna alkaloids = antimuscarinic: Belladonna (Atropa) --> atropine Mechanism: competitive antagonism at muscarinic receptors preventing acetylcholine binding

Answer 3

mostly toxic to ruminants Antimuscarinic: tachycardia, tachypnea dry skin, ↓salivation, mydriasis (can be topical), blurred vision, hyperthermia, ↓feed, tremors, bloat, recumbancy

Answer 4

(1) Physostigmine (2) Emetic/AC CS resolve within 24hrs – death is rare

Answer 5

(Centauria solstitialis) Russian Napweed

Answer 6

Unknown NOT HIGHLY TOXIC **only toxic to horses signs after grazing 30-90d (hundreds of ##) Contains a neurotoxin destroys dopaminergic nigrostriatal pathway – inhibiting effects on cerebral cortex pathways that control prehension and chewing (CN’s V, VII, IX)

Answer 7

Mixed CNS: hypertonic facial/lip mm, tongue lolling, head tossing, dysphagia, immerse head in water to drink  death 2’ starvation Lesions: pathognomonic bilaterally symmetric nigropallido-encephalomalacia – liquefactive necrosis in globus pallidus and substantia nigra “Sardonic grin” is class term used to describe facial lesions

Answer 8

Irreversible once symptomatic euthanize

Answer 9

(Astragalus spp, Oxytropis sericea)

Answer 10

locoweed whole plant is toxic

Answer 11

Locoism:alkaloid swainsonine inhibits mannosidase  brain accumulation of oligosaccharides (generalized lysosomal storage disease of CNS)

Answer 12

Methemoglobinemia  fetlock knuckling (cracker heels), dyspnea, cyanosis, death (24hrs); abortion (fetal Hgb sensitive); brown blood Locoism:  CNS dep, dullness, emaciation, ataxia, then excitement; reduced fertility (cattle); abortion Teratogen: skeletal problems

Answer 13

Selenosis: no tx; allow to excrete; soft bedding; change diet Locoism: improve feed; horses = euthanize

Answer 14

Inhibit membrane sodium-Potassium-ATPase pumps – intracellular sodium increases and potassium decreases – changes in ions flux decreases electrical conductivity = arrhythmias Used therapeutically to increase myocardial contractility (by decrease intracellular sodium, increases intracellular calcium through Na:Ca Exchanger – more calcium available to actin-myosin apparatus

Answer 15

Oleander | Toxin = cardiac glycoside

Answer 16

ruminants on ionophores are MORE susceptible

Answer 17

Early (GI) = projectile vomiting, diarrhea; bloating, salivation Later (CV): hypotension, bradycardia,Vtach, SVT, conduction probs Even later: sudden death Death hrs or days after ingestion Lesion: cardiac mm necrosis

Answer 18

MEDICAL EMERGENCY (1) Emetics (2) AC + SC (3) AVOID K+ in tx (4) Manage cardiac effects for 1-3d (drugs designed for animals w/ pre-existing cardiomyopathy) = unless lethal arrhythmia, don’t be too aggressive w/ heart Treating arrhythmias: Bradycardia: atropine Heart block: phenytoin Tachyarrhythmia: propranolol Digitalis Abs (FAD antibody): Digibind (works well but $$$)

Answer 19

Asclepias spp Toxin = Cardenolides (Cardiac glycoside) AFFECTS SHEEP

Answer 20

Cardio toxins

Answer 21

Japanese yew Toxin = Taxine A and B cardio toxic

Answer 22

Black snakeroot Death camas Toxin = steroidal alkaloids cardio toxic

Answer 23

teratogen in sheep toxin = cyclopamine, veratramine

Answer 24

hepatotoxins

Answer 25

Pyrrolizidine alkaloids --> pyrrole derivatives (must be bioactivated) --> irreversible liver damage (hepatocyte DNA alkylation, megalocytosis)

Answer 26

Hepatic veno-occlusive dz --> icterus, ascites, edema--> fibrosis Liver necrosis and death: bipsy – triad of fibrosis, bile duct proliferation and megalocytosis

Answer 27

Pyrroles crosslink DNA – antimitotic effect and hepatocytes can’t divide = replaced by connective tissue = megalocytosis

Answer 28

Perilla mint

Answer 29

Perilla ketone (similar to 4-ipomeanol from moldy sweet potatoes) --> reactive metabolite in Clara cells --> lung damage (especially alveolar Type I cells; proliferation of type II pneumocytes = interstial pneumonia)

Answer 30

``` Acute bovine pulmonary emphysema & edema (ABPE) Respiratory distress (grunt on exhale), nasal discharge, cyanosis, hypersalivation ``` Lesions: pulmonary fibrosis, emphysema, edema, congestion

Answer 31

No specific antidote Hard to reverse once CS Supportive: steroids, antihistamines, abx Prevention: eliminate Ddx for ABPE: moldy sweet potatoes, lush pasture (3-methylindole)

Answer 32

bracken fern

Answer 33

Ptaquiloside – primary carinogen Causes bone marrow supp  ↓neut/plt/anemia SE: thiaminase  thiamine deficiency (horses and pigs = NOT cattle)

Answer 34

Bone marrow: hemorrhage on mucus membranes, hyphema, melena, anemia Thiamine deficiency: anorexia, wt loss, weakness, ataxia, crouching stance, arched neck in horses polioencephalomalacia (ruminants) Bladder neoplasia = Red water disease (cattle/sheep)

Answer 35

Hellebore Over 50 alkaloids – some are teratogenic Sheep: if consumed on 14th day of gestation = CYCLOPS LAMP (Boards ?) and monkey faced facial deformities After 30-35 days, shortened limbs

Answer 36

Common in South East US Exposure: fresh plant or dried in hay (young fronds palatable) More likely in dry years

Answer 37

give thiamine

Answer 38

Both are acetylcholinesterase (AChE) inhibitors w similar chemical effects Carbamates are esters of carbamic acid OPs are esters of phosphoric acid

Answer 39

Can enter body through oral, dermal or resp route Bind and inhibit the AChE (and other cholinesterases) within the nervous system, the neuromuscular junctions and blood, causing an accumulation of the acetyl choline neurotransmitter at postsynaptic receptors OP’s considered irreversible inhibitors of the enzymes, whereas carbamates are reversible inhibitors of AChE

Answer 40

vomiting, dyspnoea, colic, salivation, lacrimation, urination, diarrhoea, miosis, tracheobronchial secretion, lung oedema, cyanosis

Answer 41

twitching of muscles, tremors, followed by convulsions, and seizures which can finally progress to paresis and even paralysis

Answer 42

atropine test dose – preanaesthetic dose of 0.02 mg/kg IV à if HR decreases and mydriasis occurs, it is not an OP or carbamate poisoning antidote tx for OP: atropine sulphate and pyridine 2-aldoxime methochloride (2-PAM) - -atropine will control muscarinic R associated signs. 0.22 mg/kg (1/4 dose given IV, remainder IM or SC) - -2-PAM will control the nicotinic signs. 2-aldoxime methochloride reactivates the AChE enzyme and can control nicotinic and CNS associated signs. Has to be administered within 24 h of exposure. Dose in horses is 20 mg/kg slow IV, repeated q 4-6 h. Not recommended for carbamate toxicosis because this drug has less affinity for carbamates and the AChE inhibition is usu rapidly reversible

Answer 43

Cyclic tetramer of acetaldehyde Toxicity characterised by CNS signs, metabolic acidosis and resp alkalosis Exact mechanisms unknown, but decrease in the conc of the inhibitory NT GABA, noradrenaline and serotonin (5-hydroxytryptamine, 5-HT) as well as increased monoamine oxidase activity may be involved CS usu within 15 min to a few hours: agitation, ataxia, hypersalivation, hyperaesthesia, muscle spasms, profuse sweating, convulsions, tachycardia and hyperpnoea. Signs of severe and unrelenting colic also reported. Death, usu dt resp failure, can occur within a few hours of ingestion and oft preceded by violent convulsions