Crotalids: Pit Vipers

Southern Copperhead, Cottonmouth Moccasin, Timber Rattlesnake, Eastern Diamondback, Pygmy Rattlesnake, Massasauga, Mojave, Western Diamondback, Ridgenose, Sidewinder

Enzymatic spreading factors cause necrotic lesions (metalloproteases, hyaluronidase, phospholipase A)

Enzymatic myotoxins that open Na+ channels to cause myocyte necrosis

Antivenin available

Elapids: Corbras

Eastern Coral Snake, Texas Coral Snake, South Florida Coral Snake

Neurotoxic polypeptide irreversibly binds post-synaptic nicotinic ACh receptors to prevent ACh from binding causing ascending flaccid paralysis

Enzymatic spreading factors

Antivenin available - Most effective before neuro signs are present

Bufodienolides are digitalis-like steroids that inhibit Na+/K+ ATPase causing potentially fatal arrhythmia

Bufotenin has hallicinogenic and GI effects

Spingomyelinase D2 and enzymatic spreading factors cause necrotic, ulcerative lesions and hemolysis

α-latrotoxin binds axon membrane at neuromuscular junction and opens cationic ion channels to release neurotransmitters - Initially muscle fasciculations but then can't repolarize so there is flaccid paralysis

Antivenin available

Hymenoptera: Bees, Wasps, Hornets

Bee venom: melittin causes pain and hemolysis by hydrolyzing cell membranes, peptide 401 causes mast cell degranulation/hypersensitivity, and apimin neurotoxin (requires a lot of stings to see effects)

Wasp venom: Antigen 5 (allergen), mastoparans cause weak mast cell degranulation, phospholipase A/hyaluronidase, and pheromones to trigger swarming behavior

Anaphylaxis is biggest problem

Alkaloid solenopsins are cytotoxic, hemolytic, and pain inducing; Enzymatic factors; Antigenic proteins stimulate IgE response - Massive envenomation possible (can be fatal to small animals)

Found in green or red dyed milo rodent baits and illegal coyote baits - Relay toxicity possible in raptors that eat poisoned rodents

Glycine Receptor Inhibitor: Prevents glycine from shutting off muscle response to stimulus resulting in tetanic seizures/hyperthermia

*Calycanthus and gelsemium plant species also inhibit glycine receptors*

Ionize the ingested substance so that it can't cross cell membranes - When urinary pH favors ionized form, the compound can't be reabsorbed

For weak acids, alkalinize urine with bicarbonate

For weak bases, acidify the urine with ammonium chloride or vitamin C

Stomach pump to remove contents - Not as effective as emesis, but needed if there is an aspiration risk, massive ingestion, or high toxicity substance

Requires anesthesia

Adsorbs compounds in the GI tract (not alcohols, heavy metals, or lithium)

Loading dose often given with cathartic (sorbitol), but subsequent doses are given alone

*Clay is less effective that activated charcoal, but it's gastroprotective

Decrease GI transit time to remove substance faster

Saline cathartics: Sodium sulfate, magnesium sulfate aka epsom salt

Psyllium aka metamucil

Mineral oil and castor oil

*Contraindicated if patient is dehydrated or has diarrhea

Glycine Release Inhibitor Produced by Clostridium tetani: Inhibits glycine release to prevent muscle relaxation and cause spastic paralysis; Inoculated into puncture wounds

GABA inhibitor mycotoxin produced by Penicillium species that can grow in refrigerators, silage, compost piles, etc. 

Vomiting (protective and removes toxic substance), muscle tremors and seizures

Toxin in snail/slug bait with unknown toxic principles

Salivation, anxiety, vomiting, ataxia, and tremors followed by seizures, hyperthermia, tachycardia, acidosis, blindness, liver failure, elevated muscle enzymes, hyper or hypoglycemia, metabolic acidosis

-Give within 2 hours of ingestion; Works best with food in stomach

-Vomiting begins in ≤ 40 min and can continue 30-40 min

-Contraindications: Severe CNS signs (aspiration risk), ingestion of oily or irritating compounds, antiemetics have been given, already vomiting

-For Dogs: Apomorphine, naloxone, metoclopramide, hydrogen peroxide (tissue irritant)

-For Cats: Xylazine, dexmedetomidine

Methylxanthines

Caffeine, Theophylline (Asthma Meds), Theobromine (Chocolates)

Sympathomimetic toxin that antagonizes adenosine

Vomiting, diarrhea, and restlessness followed by diuresis, hyperactivity, tremors, seizures, tachycardia, hypertension, weakness, coma, and possible hyperthermia

Sympathomimetic toxin that increases catecholamine and dopamine release

Mydriasis, salivation, vomiting, hyperactivity, tremors, seizures, ataxia, mental obtundation, vocalization, hyperthermia, tachycardia

Sympathomimetic toxin that triggers release of norepinephrine, dopamine, and serotonin

Agitation, hypermetria, tremors, seizures, hyperthermia, tachycardia, hypertension, retinopathy, dry mouth, nausea, tachypnea, piloerection, mydriasis, myoglobinuria and renal failure

Insecticide and repellent that acts as an α-2 agonist and H1 receptor inhibitor that is toxic if ingested (ex: flea collar ingestion)

Obtundation and intestinal stasis in horses

Depression, ataxia, disorientation, coma, respiratory suppression, seizures, hypotension, bradycardia, hyperglycemia, glycosuria in dogs and cats

Extracted from chrysanthemum flower and used in insecticides (Pyrethroid = synthetic form)

Death in fish/amphibians

Hypersalivation, paresthesia (ear twitching/paw flicking), ± vomiting/diarrhea in cats - usually mild and self-limiting

Synthetic insecticide of the pyrethroid class

Salivation, hyperesthesia, hiding, reluctance to move, ataxia, mydriasis, twitching, tremors, seizures, pyrexia (very severe in cats)

Body makes a hydrophobic, lipid soluble compound into a more polar, hydrophilic compound that can be excreted in urine

Phase I Reactions: Oxidation, Reduction, and Hydrolysis

Phase II Reactions: Conjugation to glucuronide by glucuronidase (limited in cats so hard to clear toxins)

Experimental treatment in which IV lipids are given to create a lipid sink and decrease bioavailability of a lipid soluble toxin

Adverse Effects: Lipemia, pancreatitis, pulmonary emboli, phlebitis

Organochlorine Insecticide that inhibits K+ channels to inhibit K+ outflow which inhibits Na+ inflow resulting in partial depolarization of neurons; Affects Ca metabolism in birds resulting in weak egg shells; Selective adrenal necrosis of zona fasciculata and reticularis

Signs: Tremors, salivation, ataxia, depression, ± vomiting, seizures in cats

Type of organochlorine insecticide found in moth balls

Relatively low toxicity 

Organochlorine Insecticide With Low LD50

Tremors, salivation, ataxia, depression, ± vomiting, seizures in cats

Toxin used for bird control and put in corn baits; Relay toxicosis possible because bait stays in GI tract

Blocks K+ channels and increases ACh at neuromuscular junction resulting in salivation, hyperexcitability, incoordination, tremors, tonic-clonic seizures, tachycardia, horses and cows walk backwards

Ataxia, tremors, ± seizures, and opisthotonus (normal at rest) caused by mycotoxins on Paspalum, Bermuda, Rye, Corn and Crab grasses

Anticholinergic Toxidrome

Signs, Anticholinergic Plants

"Blind as a bat, dry as a bone, red as a beet, mad as a hatter, hot as a hare"

Signs: Dry mouth, mydriasis, hyperthermia, flushed skin, urine retention or PU/PD, GI atony (constipation/colic), bradycardia followed by tachycardia, agitation, delirium, hallucinations, coma, tremors, seizures, pyrexia, paralysis, respiratory failure

Plants: Datura species (jimsonweed, angel's trumpet); Brugmansia species

Competitively inhibit H1 histamine receptors, anticholinergic activity, and block fast Na+ channels (tachycardia) resulting in salivation, vomiting, diarrhea, CNS depression (excitation/hyperactivity in young animals)

Caused by toxins that mimic ACh at nicotinic receptors 

SLUD: Salivation, Lacrimation, Urination, Diarrhea

DUMBBBELLS: Diarrhea, Urination, Miosis, Bradycardia, Bronchorrhea, Bronchospasm, Emesis, Lethargy, Lacrimation, Salivation

Mycotoxin produced by Rhizoctonia (Black Patch Disease on Clovers)

Causes Slobbers

Inhibit acetylcholinesterase to prevent hydrolysis of acetylcholine resulting in buildup of acetylcholine at synapses leading to continued nerve firing in the CNS, in glands, and in skeletal muscle

Signs: Cholinergic toxidrome, tremors, tetany, clonic seizures, ataxia, paralysis, tachycardia

Carbamate is bound and hydrolyzed by acetylcholinesterase - Takes the place of acetylcholine so acetylcholine accumulates

Cholinergic toxidrome, tremors, tetany, clonic seizures, ataxia, paralysis, tachycardia

*Can still be fatal because the animal can die before all carbamate is hydrolyzed

Mimic ACh at sympathetic and parasympathetic ganglia, neuromuscular junctions, and in the CNS (acts on emetic chemoreceptors and stimulates vomiting) - Low doses are stimulating, but high doses are depolarizing followed by blockade

Signs: Vomiting, salivation, defecation, miosis, sweating, salivation, bradycardia followed by tachycardia, vasoconstriction (via sympathetic ganglia), excitement, tremors; Vasodilation, seizures, descending paralysis, respiratory failure and cardiovascular collapse with high dose (poor prognosis)

*Associated with teratogenesis - Limbs don't develop properly because nicotine slows fetal movement

Anatoxin-a: Nicotinic alkaloid causes tremors to paralysis (very fast death factor)

Anatoxin-a(S): Organophosphorous acetylcholinesterase inhibitor causes SLUD but no CNS signs because doesn't cross blood brain barrier

Thiamine depletion disrupts the Krebs cycle leading to lactic acidosis in the brain (edema, disruption of blood brain barrier, neuronal death)

Signs: Blind due to swelling of optic disk, head pressing, agression, muscle fasciculations, seizures, death

Destroys thiamine resulting in thiamine deficiency (PEM)

Treatment: Feed clean diet, thiamine (start parenterally because if thiaminase is still in GI tract it will destroy administered thiamine), symptomatic care

*Fish contain thiaminase so an all-fish diet can be problematic*

Thiaminase

Ptaquiloside: Carcinogen, bright blindness in sheep, bone marrow suppression in cattle

T

Sulfur

Inhibits cell respiration - Blocks cytochrome c oxidase and inhibits electron transport resulting in neuronal necrosis

Signs: Feed/water refusal, diarrhea, PEM (also colic and icterus in horses)

Intereferes with enzyme -SH, affecting RBC production; Competes with calcium resulting in nerve/myocte depolarization; Inhibits GABA transmission; Inhibits Na/K pumps; Disrupts blood brain barrier

Signs: Normocytic, normochromic anemia, increased erythropoiesis with RBC basophilic stippling

Cows: Muscle fasciculations/seizures, blindness, swelling of optic disk, head pressing, bruxism, agression, bloat, diarrhea

Horses: Depression, weight loss, laryngeal paralysis, facial nerve deficits

Dogs/Cats: GI signs, anorexia, ataxia, seizures, PU/PD, blindness, aggression

Birds: Anorexia, depression, weight loss  

Causes direct tissue necrosis (GI, renal); Concentrates in CNS and kidney; Binds SH and disrupts protein synthesis; Disrupts ion channels; Disrupts mitochondrial electron transport

Signs: Stomatitis, gastroenteritis, flu-like pulmonary signs, multiorgan failure, pulmonary edema, oliguria, azotemia, peripheral myopathy, encephalopathy

Lesions: Laminar necrosis, peripheral demyelinating neuropathy

*cerebellar hypoplasia in neonate cats

Increased osmotic pressure causes cells to shrink → Sudden water intake causes water to diffuse down its concentrtion gradient into the CNS → Cerebral edema

Cattle - Gastroenteritis, weakness, gait disturbances, paddling, opisthotonus, death

Poultry - Depression, weakness, thirst, dyspnea, nasal discharge, ascites, diarrhea, hind limb paralysis, death

Dogs - Vomiting, diarrhea, depression, lethargy, PU/PD, tachycardia, tremors, ± tonic-clonic seizures

Swine - Restlessness, thirst, pruritis, anorexia, constipation, polyuria progressing to anuria, CNS signs

Inhibits sphingolipid production by ceramide synthase  Sphingolipids important for cell membrane integrity, cell membrane receptors, cell messengers, and folate metabolism in horses

Neurotxic syndrome/cerebral edema/leukoencephalomalacia

Hepatotoxic syndrome with hepatomegaly and centrilobular lipidosis/necrosis

Toxin produced by endophytes in Astragalus and Oxytropis plants (locoweeds) that inhibits manosidase leading to oligosaccharide accumulation, lysosomal storage, and cellular dysfunction

Abortion

Teratogenesis (arthrogyrposis, weak neonates)

Males have decreased fertility/vacuolated spermatocytes

Water Deprivation/Sodium Toxicosis

Lesions - Swine, Poultry, Cattle

Swine - Transient eosinophilic meningoencephalitis, cerebral edema, laminar necrosis, Alzheimer type II cells

Poultry - Tissue edema, urate nephritis, ± eosinophilic meningoencephalitis

Cattle - NO eosinophilic meningoencephalitis, gastroenteritis, pulmonary edema, hydropericardium

Locoism

Miserotoxicosis/Nitrotoxicosis

Selenium Toxicosis

Cell vacuolation

Non-specific gross lesions

Glycosides of 3-NPA and 3-NPOH in locoweeds that inhibit succinate dehydrogenase in the Krebs cycle resulting in decreased ATP production and myelin/neuronal degeneration

Signs:Acute incontinence, incoordination and salivation; Chronic poor thrift, diarrhea, clicking dewclaws ("cracker heel")

Lesions: Multifocal necrosis, white matter spongiosis, Wallerian degeneration of spinal cord and sciatic nerve

Inhibits oxidative phosphorylation resulting in decreased ATP production, failure of Na+/K+ pumps, loss of osmoregulation, vacuolation of myelin, and cerebral edema leading to acute hyperexcitability, tremors/seizures, hyperthermia, death due to respiratory paralysis; Chronic hindlimb ataxia, paresis, paralysis, tremors/seizures

Emesis, salivation, vocalization, ataxia, hyperesthesia, weakness, tremors, mydriasis, blindness, retinal edema, hypothermia

Acts on CB1 receptors in the nervouse system

Signs: Emesis, ataxia, depression, urinary incontinence, mydriasis, head bobbing, seizures, behavioral changes, vocalization, salivation

Excess serotonin due to increased production, decreased reuptake, or decreased breakdown resulting in GI upset, sedation, agitation, seizures, muscle rigidity, nystagmus, head tilt, hyperthermia, hypertension, and tachycardia

Selective serotonin reuptake inhibitor used to treat depression and anxiety

Most common drug overdose in cats - Serotonin Syndrome

Narcosis, behavior change, respiratory suppression, acidosis

e

Salivation, weakness, ataxia, muscle tremors, seizures, dermatitis, altered hepatic/renal function

Can be ingested or absorbed orally - mostly affects cats because they can't glucuronidate

Toxin produced by Clostridium botulinum that binds synaptotagmin and cleaves SNARE proteins to prevent ACh vesicle release; Can be ingested or colonize wounds/necrotic tissue

Signs: Vomiting, dysphagia, and xerostomia followed by flaccid paralysis - Animals remain aware and able to sense pain; Death from respiratory paralysis

*AKA limberneck in birds or Shaker foal syndrome*

Female Dermacentor andersoni/variabilis release holocyclotoxin from salivary glands that inhibit ACh release at neuromuscular junction causing ascending paresis, facial nerve paresis/paralysis, remain bright and alert, death from respiratory paralysis

Treatment: Remove ticks 

Signs: Progress through mild tremors, difficulty standing, inability to stand, sternal recumbence, lateral recumbence, and death due to respiratory failure

Treatment: Physostigmine and symptomatic/supportive care

Dopamine Inhibitors

Signs: Paralysis of tongue and lips causing difficult eating and drinking - Poor prognosis

Lesions: Bilaterally symetrical malacia, cavitation, globus pallidus, substantia nigra

Organophosphorous Induced Delayed Neuropathy (OPIDN)

Signs, Lesions

Signs: Sensation deficits, ataxia, weakness, flaccid paralysis progresses to spastic paralysis, incomplete recovery

Lesions: Bilaterally symmetrical axonal injury/demyelination starting with large nerve fibers first (ex: peripheral nerves to hindlimbs)

Causes oxidative damage in the liver resulting in hepatic failure

Ulcerative gastroenteritis followed by apparent recovery and then liver failure

Pyrrolizidine Alkaloids

(Senecia/Ragwort, Crotolaria/Rattle box, Heliotropium)

Hepatocytes grow without dividing resulting in megalocytosis with necrosis, fibrosis, regeneration and extrahepatic lesions (pulmonary)

Staggers, walking disease, hepatic encephalopathy

Cycasin: Hepatotoxin (Nutmeg Liver - Centrilobular necrosis, fibrosis, and bile duct proliferation)

BMAA: Neurotoxin causing proprioceptive defects and progressive weakness due to axonal and myelin degeneration

Sugar substitute that stimulates a rapid increase in insulin release leading to hypoglycemia, hypokalemia, and liver failure in dogs

Bile duct obstruction results in inability to excrete phylloerythrin (photoactive chlorophyll pigment) so it leaks into circulation and reacts with light

Yellow-green-brown liver with portal fibrosis and bile duct proliferation; Also causes head edema in sheep (big head)

Fluorescent pigments are absorbed through the GI tract or integument and react with light resulting in skin erythema/edema, sloughing and crusting

St. John's Wort, Fagopyrum (Buckwheat), and Heracleum (Giant Hogweed)

Polyhalogenated Aromatic Hydrocarbons (PHAHs)

PCBs, PBBs, and 2,3,7,8-Tetrachlorodibenzodioxin (2,3,7,8-TCDD/dioxin)

Immunosuppression, thymus atrophy, nonregenerative anemia, hypothyroidism, hepatopathy, epidermal hyperkeratosis, sebaceous atrophy, weight loss, behavioral changes, reproductive failure, teratogenesis

Chick edema disease

Chloracne, hepatopathy, abortion, and cancer in humans

Vicia villosa (Hairy vetch)

Citrus Pulp

Pale myocardium with necrosis and hemorrhage

Pulmonary edema

Hydrothorax

Mild Hepatomegaly

Chronic selenium toxicosis

Lameness, hoof deformities, alopecia, achromotrichia 

Cardiomyopathy, effusions, hepatic/renal/pancreatic/myocyte necrosis

White muscle disease - Humans, horses, ruminants

Mulberry heart disease - Swine

Hepatosis dietica - Swine

Exudative diathesis - Chicks

Keshan disease - Humans

*Deficiency is more common than toxicosis*

Dietary micromineral that complexes with copper resulting in a functional copper deficiency

Diarrhea, periostosis, osteochondrosis, reproductive failure, anorexia, achromotrichia, alopecia, anemia, ataxia

Spear shaped crystals released from plant cell vacuoles after mechanical damage causing pain ± vomiting

Present in Arcaceae (Dieffenbachia, philodendron), tulips, hyacinths, and Narcissus (daffodils)

Veratranines: Cardiotoxin that delays closing of voltage gated Na+ channels resulting in bradycardia and hypotension

Jervanines: Inhibits sonic hedgehog singaling pathways resulting in birth defects

Toxin with anti-estrognic effects that causes decreased uterine blood flow resulting in abortions, potentially decreased milk production, retained placenta and severe endometritis

In Pinus, Cupressus and Juniperus plants

Setae of ingested eastern tent caterpillars migrate through intestinal mucosa and are distributed to other tissues in the blood spreading bacteria as they go 

Fetal Lesions: Placentitis, funisitis

Mare Lesions: Panophthalmitis,pericarditis, encephalitis

Mycotoxin produced by Fusarium species that stimulates estrogen receptors

Males: Decreased testosterone, testicular atrophy, feminization, sertolli cell tumors

Females: Decreases LH, FSH, and progesterone preventing ovulation

Produced by Trifolium and Medicago plant species and then undergo hepatic bioactivation

Males: Decreased testosterone, testicular atrophy, feminization, sertolli cell tumors

Females: Decreases LH, FSH, and progesterone preventing ovulation

Fusarium Trichothecene Mycotoxins:

 DON/Vomitoxin, T-2, DAS

Inhibit peptidyl transferase so there is no protein production and stimulate vomiting via medullary vomiting centers

Feed refusal, diarrhea, vomiting, immunosuppression, oral mucosa and GI tract mucosa necrosis/hemorrhage, and lymphoid necrosis

Lectins

(Ricin)

Antibiotics kill normal GI flora and leave room for Clostridium difficile and other pathogenic bacteria to grow resulting in catarrhal to hemorrhagic typhlocolitis

Toxin A: Disrupts cell permeability and attracts neutrophils

Toxin B: Cytoskeletal action

Inhibit Na+/K+ pumps and inhibit Na+/Ca++ channels leading to positive inotropic effects followed by a bradycardia and arrhythmia as well as GI signs 

Found in oleander, digitalis, milkweed, and bufodienolides toxin from bufo toads

K+ potentiator in Gossypium (cottonseed) that interferes with cardiac conductance, creates reactive oxygen species, reduces fertility, and binds nutrients

Acute heart failure and sudden death with possible myocardial necrosis/streaking and lesions consistent with heart failure

Reversibly bind ions and form lipid-soluble complexes that can cross membranes resulting in ion imbalance and changes in pH; Used as coccidiostats and growth promoters in livestock

Depression, dyspnea, ataxia, jugular pulses, tachycardia, polyuria, sweating and recumbency in horses

Lesions: Cardiac myonecrosis, pulmonary edema, ascites, hepatic congestion, myonecrosis, axonal degeneration

Hypoglycin

Seasonal Pasture Myopathy in Horses

Box elder toxin that causes vacuolation of cardiac and skeletal myocytes 

Poor prognosis

Ergot Alkaloids

4 Syndromes

Endophyte toxin produced by Neotyphodium coenphialum in grasses (fescue) and grains that mimics biogenic amines resulting in vasoconstriction, decreased prolactin/agalactia, and other hormonal changes that can affect dam and fetus

Summer Slump: Vasoconstriction inhibits heat dissipation

Fescue Foot: Vasoconstriction in cold temps lead to edema and erythema that progress to gangrene

Fat Necrosis: Adipose becomes saponified and forms hard masses in the abdomen that can cause dystocia, obstruction, bloat, etc.

Reproductive Toxicosis

Fresh shavings used as bedding cause depression, hind limb edema, laminitis, and increased TPR in horses

Possible lethargy, vomiting, and weakness in dogs

Peripheral vasodilation leading to hypotension, pulmonary edema, and myocardial degeneration in cats

Poor prognosis

Taken up by pneumocytes and react with oxygen to cause oxidative damage resulting in epithelial necrosis, edema, hemorrhage, pulmonary fibrosis with firm parenchyma, type II pneumocyte proliferation, pneumomediastinum, and renal epithelial necrosis

Poor Prognosis

Replace O₂ in air so that animal suffocates because they don't get O₂ when they breathe

CO₂, CH₄, N₂, etc.

Irritant Gasses

Ammonia and Nitrogen Dioxide

High water solubility allows them to dissolve in tear films, mucous membranes, etc. and cause cellular necrosis on contact - Can lead to secondary bacterial infection and/or bronchiolitis obliterans

Polytetraflouroethylene

(Teflon)

Severe respiratory distress and death in birds 

Pulmonary hemorrhage ± particulate 

Cause dissolution of cell membranes

Highly volatile so eructated and aspirated after ingestion - Aspiration pneumonia and bloat common in cattle

Damage feathers and fur of aquatic animals in oil spills - Hypothermia, reproductive failure, hepatic encephalopathy, CNS signs, aspiration, hemolytic anemia, hepatic and renal damage

Competes with oxygen for hemoglobin and shifts the oxygen dissociation curve left which impairs tissue release resulting in tissue anoxia

Cherry Red Blood

Cytochrome inhibitors that react with ferric iron to form ferrous iron which prevents electron transport and ends aerobic respiration so cells are unable to use oxygen resulting in tissue anoxia causing cherry red blood and dyspnea

 H₂S also paralyzes respiratory centers by interacting with chemoreceptors

Contain cyanogenic glycosides spatially separated from β-glycosidase but when the plant is damaged, the enzyme is released and frees cyanide

Cherry, plum, peach, apricot, almond, Sudan grass, Johnson grass, arrow grass, white clover, flax, vetch, elderberry, birdsfoot trefoil, apple seeds

Uncouple mitochondrial electron transport from ATP production resulting in hyperthermia 

Restlessness, panting, tense abdomen, bright red mucous membranes, tachypnea, tachycardia, seizures, apnea, elevated CK and dark brown urine

Depletes α-ketoglutarate leading to Kreb's cycle inhibition so anaerobic glycolysis must replace aerobic respiration

Urea and dietary NPNs can cause ammonia toxicosis in ruminants because bacteria produce urease that converts urea to ammonia - Sudden death, trembles, rumen atony, dyspnea, bloat (head pressing in horses)

Acidify rumen (acetic acid/vinegar) to reduce ammonia absorption

Illegal rodenticide that may be used in livestock collars by USDA and EPA to target coyotes

Inhibits aconitase leading to citric acid build up which results in CNS excitation, vomiting and diarrhea

Relay toxicosis possible

Oxidizes hemoglobin so it can't carry oxygen resulting in methemoglobin/brown blood

Dyspnea, exercise intolerance, weakness, tachycardia, cyanosis, tremors

Brown blood disease/new tank syndrome in fish

Treat with methylene blue to reduce iron

Ethylene Glycol - 3 Stages

(Antifreeze)

Gastric irritation, CNS depression, respiratory depression and possibly calcium oxalate crystals in renal tubules

Stage 1: Hypersalivation, emesis, inebriation, PU/PD, dehydration

Stage 2: Acidosis, progressive CNS signs, hypothermia, hypocalcemia, cardiac changes, possible death

Stage 3: Oliguric renal failure, enlarged/painful kidneys, dehydration, oral ulcers, vomiting, anorexia, depression, and seizures

Oxalate nephrosis and possibly pulmonary edema - Often lethal

Beets, Rheum raponticum, Rumex, Halogeton, Greasewood

Added to pet foods to increase apparent protein content because of its high nitrogen content

Causes renal failure, azotemia, crystalluria, hemorrhage and corticomedullary junction, renal tubules dilated with inflammatory cells/necrotic epithelium/brown green crystals

Renal toxin associated with blister bettles that causes acantholysis of epithelial cells and causes a direct necrotizing effect on cardiac myocytes

Mostly affects horses - Insects get crushed into alfalfa hay

Starling bait that causes acute hepatic and renal necrosis

Possible methemoglobinema and paralysis in mammals

Aspergillus/Penicillium mycotoxin associated with grain that causes gastroenteritits, pyrexia, PU/PD, and dehydration or slow onset renal disease with chronic low doses

Retained in meat even if cooked

Increases calcium by stimulating intestinal absorption and bone resorption, decreasing PTH and decreasing renal calcium excretion

Tissue mineralization and cell necrosis due to altered membrane permeability (decreased energy production)

Unknown toxic principle - Contains tannins, gallic acid, and phenolics

Causes GI edema/ulceration, pale enlarged kidneys with tubular necrosis and casts, effusion, subcutaneous edema and hepatic degeneration

Unknown renal toxin that affects cats - Possibly proximal convoluted tubule mitochondrial damage

Perirenal edema, PCT necrosis, granular casts, evidence of regeneration, pancreatitis

Unknown renal toxin that affects dogs

PCT necrosis, casts, mineralization, arteritis, and pancreatitis

Gastroenteritis, testicular necrosis, bone deformities, and renal failure

(found in artisit paint, sewage, batteries, etc.)

Normally metabolized by p450 enzymes to glucuronide byt cats lack sufficient glucuronidase so reactive NAPQI  is formed and it disrupts hepatocellular membranes causing anorexia, salivation, vomiting, methemoglobinemia, face/paw edema, and liver failure

NEVER GIVE TO CATS

Isothiocyanate: Causes GI irritation

Goitrin: Prevents iodine uptake by the thyroid so it can't be incorporated into thyroxine

S-methyl Cysteine Sulfoxide: Oxidizes hemoglobin

Gallic acid is metabolized to pyrogallol by GI microbes which can then cause Heinz body anemia and hemolysis in horses

Pyrexia is a GOOD prognostic indicator

Corrosive and cytotoxic effects in GI tract and pancreas, competes with copper for absorption resulting in copper deficiency and causes oxidative damage/hemolysis

Also crop stasis and anorexia in birds

Usually removing zinc is sufficient for recovery

Hepatic lysosome are overwhelmed with copper resulting in oxidative damage to cells and fibrosis - Chronic liver failure with brown nodular liver, intraheptocytic pigment, multifocal necrosis with minimal inflammation, portal to bridging fibrosis, and nodular regeneration

Most common in Bedlington terriors, Westies, dalmations, labs, dobermans, and skye terriers

Chelated with D-penicillamine, low Cu diet, and Zn supplements

Slow accumulation of copper in hepatocytes until hepatocyte necrosis releases the copper into the bloodstream where it damages RBC membranes leading to intravascular hemolysis, anemia, and tissue anoxia

Gun-metal kidneys, friable hepatomegaly, periportal fibrosis, bile duct proliferation, and centrilobular necrosis

Treated with molybdenum but poor prognosis if symptomatic 

Anticoagulant Rodenticides 

(Warfarin, brodifacoum, bromadiolone, difethialone, difenacoum)

Inhibit vitamin K epoxide reductase required for hepatic vitamin K recycling needed for clotting factors 

Blue/green rodenticide may be found in vomit/feces

Treated with vitamin K, exercise restriction and transfusion if needed (K3 contraindicated in horses)

Stored in calcified tissues (bone/teeth) and accumulates over time resulting in soft bones/teeth, enamel hypoplasia, staining, rapid wear/pitting of teeth, bilateral osteoperosis, bridging spondylosis, lameness

Treat with aluminum to bind fluoride