Toxicology PDF

TOXICOLOGY Chapter 26 Managing Poisoning Emergencies • Address the following questions: • • • • • • • • • Clinical status of the animal? Substance & route, if known? Actions already taken by owner? Signalment (minimum: age, weight, female (nursing/pregnant))? How much was animal exposed to? When...

TOXICOLOGY Chapter 26 Managing Poisoning Emergencies • Address the following questions: • • • • • • • • • Clinical status of the animal? Substance & route, if known? Actions already taken by owner? Signalment (minimum: age, weight, female (nursing/pregnant))? How much was animal exposed to? When did it occur? Current medical issues/recent surgery? Current medications? Any other animals exposed? POISON CONTROL CONSULTATION Assessment of the Animal’s Condition • TPR, CRT, MM • Respiratory rate, heart rate • Obvious signs of intoxication • • • • • • GI signs—V/D Ataxia Unconscious Shock Seizing Cardiovascular or respiratory distress Patient Stabilization • “Treat the patient not the toxin” • Start with your ABCs (airway, breathing, circulation) • Establish patent airway • Start artificial respiration if necessary • Dyspnea or cyanosis • Monitor cardiovascular system • Place IV cath • For medications • IV fluids Decontamination • Performed to prevent absorption of toxins • Dependent on the agent and the status of the patient • Clinical signs? • Timeframe? • Ocular exposure • • • • Flushed repeatedly w/tepid water or saline solution Minimum 20-30 minutes Should be initiated by pet owner if possible Exam for corneal damage, excessive redness, lacrimation, pain Decontamination • Dermal exposure • Bathed in mild liquid dishwashing detergent • Repeated if oily product & until completely stripped • Monitor body temperature after bathing • Wear gloves to prevent personal exposure • Oral ingestion • Dilution • Corrosive or irritant ingested • Milk or water • Dosage 1-3mL/lb • Exotic animals juicy fruits or vegetables in place of milk Decontamination • Oral ingestion (cont) • Emesis • Determined by length of time since ingestion, species, medical conditions, type of poison • Dogs, cats, pigs, ferrets able to vomit • Contraindicated rodents, rabbits, birds, horses, ruminants • Not indicated if any of the following: • Cardiovascular abnormalities, poorly controlled epilepsy, recent abdominal surgery, severely debilitated • Ingestion of corrosive materials (cationic detergents, acids, alkalis) • Generally only vomit 40-60% stomach contents • Need to inspect vomit for substance • Make sure patient or any other animal doesn’t reingest vomit Decontamination • Oral ingestion (cont) • Emesis (cont) • Apomorphine • Preferred in dogs • Injectable or capsule (powder given in conjunctival sac of eye) • Hydrogen peroxide-3% • Dosage 5mL/5 pound body weight up to 45mL • Vomiting typically occurs 15-20 minutes • Can be repeated 1x • Not recommended in cats due to hemorrhagic gastroenteritis • Alpha-2 adrenergic agonists • Xylazine, dexmetdetomidine • Cats • Clevor (Ropinirole Ophthalmic Solution) • New eye drop • Dogs (may now be preferred for dogs) Decontamination • Oral ingestion (cont) • Activated Charcoal • Adsorbent that binds to toxins • Prevents absorption into bloodstream • Facilitates toxin excretion via feces • Administered orally • Dosage: 1-3g/kg body weight • May need to be repeated depending on toxin • Contraindicated if ingested following • Caustic agents, ethanol, methanol, fertilizer, fluoride, petroleum distillates, heavy metals, iodides, nitrates/nitrites, sodium chloride, chlorate Decontamination • Oral ingestion (cont) • Gastric lavage • Gentle stomach pump • Contraindicated w/caustic agents/petroleum distillate • Requires general anesthesia, cuffed endotracheal tube • Pass fenestrated stomach tube • Lavaged repeatedly w/physiologic temperature water until fluid is clear Supportive Care • Continue to monitor vital signs • Collect blood samples to monitor body systems • CBC, Chemistry, clotting times • Blood, vomitus, urine can be used to check for some toxins • Nutritional support may be needed • Continued care will depend on clinical signs, side effects, recovery Chocolate • Toxic component: methylxanthines • Theobromine & caffeine • Stimulants • Toxicity: baking chocolate › dark chocolate › milk chocolate • Darker/more bitter the more toxic • Clinical signs: Lethargy, polydipsia/polyuria, V/D, restlessness, excitation, increased heart rate, tremors/seizures, potentially death Muscle Tremors Chocolate • Lethal dose • 100-200mg/kg • Mild GI signs • >20mg/kg • Cardiovascular effects • >40mg/kg • Neurologic signs • >60mg/kg • Treatment • Decontamination • Emetics and activated charcoal • Supportive • Monitor cardiovascular system • Fluid diuresis Onions • Allium sp. • Includes garlic, onions, leeks, scallions, shallots, chives • Toxic principle n-propyl disulfide • Fresh, dried, powder, cooked • Cats more susceptible than dogs • Causes hemolytic anemia • Oxidative damage to the RBCs Onions • Signs: lethargy, weakness, vomiting, pale mucous membranes, red/brown urine (hemoglobinuria) • Treatment: • Decontamination if recent: • Emesis/activated charcoal • Monitor development hemolysis, azotemia, +/- hematuria • May take 3-7 days to develop • Whole blood transfusion • Fluid diuresis w/hemoglobinuria • Supportive care as needed Xylitol • Artificial sweetener in gum/candy • Also found in dental products, chewable medications, cough drops, (some) peanut butter • Causes • Severe low blood sugar (hypoglycemia) • Reports of liver failure & secondary coagulopathy (not well understood) • Doses over 100 mg/kg need tx Xylitol • Clinical signs: • • • • Occur soon after ingestion of baked goods/candy Gum up to 8 hours later Weakness, depression, ataxia, vomiting (think hypoglycemia) Increased liver enzymes/liver failure 18-72 hrs later • Treatment: • Emesis, even if asymptomatic • 5% dextrose for hypoglycemia (IV) • Blood transfusions with severe liver dz to replace clotting factors Grapes/Raisins • Unknown etiology • Dogs only • Causes acute kidney failure • Clinical signs: vomiting, lethargy, anorexia, signs of abdominal pain • Treatment: • Decontamination-emesis/activated charcoal • Fluid diuresis for 48 hours • Monitor for azotemia Moldy Food • Tremorgenic mycotoxins • Neurotoxins • Clinical signs: • Muscle tremors, ataxia, convulsions • Can last for several days • Treatments: • Minimize absorption • Emesis/lavage/activated charcoal • Use w/caution if seizing-risk aspiration pneumonia • Control tremors • Methocarbamol-muscle relaxant • Supportive care Seizures/Convulsions Zinc • Sources: galvanized hardware (wire, screws, bolts, nuts) & U.S. pennies • Minted since 1983 • Contain 99.2% zinc/0.8% copper • Ingestion of 1 penny can cause poisoning • Causes oxidative damage to RBCs • Clinical signs: • Hemolytic anemia, hemoglobinuria, weakness, renal failure, death • Radiographs reveal metallic objects in GI tract • Remove source via endoscopy or surgery • May need blood transfusion • IV fluids to protect kidneys from hemoglobin ZINC Dangerous Plants Cardiotoxic Kidney Failure Liver Failure Multiple Effects Oral Irritation •Lily of the valley •Oleander •Rhododendron, azalea, yew •Foxglove •Kalanchoe •Certain species of lilies in cats •Rhubarb (leaves) •Grapes & raisins •Cycads (Sago palm) •Amanita phalloides •Crocus – bloody V/D, shock, kidney failure, bone marrow suppression •Castor beans – lethal •Mushrooms •Calcium oxalatecontaining plants: Philodendron Peace lily Pothos Mother-inlaw’s tongue Cycad/Sago Palm • Cycas, Zamia • Toxic principle: cycasin • All parts of the plant are toxic • Seeds contain the largest amount of toxin • Clinical Signs: • Hepatic & GI signs • Liver failure • V/D • Seizures/neuro signs horses/livestock that eat foliage • Treatment: decontamination and supportive care • Guarded prognosis Lilies • Lilium spp.—daylilies, Easter lilies, Stargazer lilies, Tiger lilies, Japanese lilies • Cats only • Causes acute kidney failure & death • Toxic principle is unknown • Even minor exposures (few bites of leaf, ingestion of pollen) can be toxic Lilies • Clinical signs: • • • • • Depression Vomiting Anorexia Urinary changes progressing to oliguria or anuria Dehydration • Elevations in kidney values as early as 12-18 hours • Within 24-72 hours renal failure develops • Death from acute kidney failure w/in 3-6 days of ingestion • Treatment: • Decontamination-emesis, activated charcoal, cathartic • Fluid diuresis • Delayed treatment typically results in death Permethrin • Cats extremely sensitive • OTC topical flea control • Spot-on products labeled for “use in dogs only” • Inappropriate application on cats • Cats in close contact w/or grooming a dog that had it applied • Clinical signs: • Seizures/tremors • Treatment: • Controlling muscle tremors w/methocarbamol • Seizure control: diazepam, propofol, barbiturates, inhalant anesthetics • Bathed using mild liquid dishwashing detergent • Supportive care: thermoregulation, IV fluids, nutritional support • May have symptoms for up to 3 days Rodenticides • Multiple types available commercially • Anticoagulants • Bromethalin • Cholecalciferol Anticoagulant Rodenticide • Ex: D-Con • Dogs more than cats but both susceptible • Block activation of Vitamin K dependent clotting factors • Results in generalized hemorrhage • Clinical signs may not be observed for 3-10 days Anticoagulant Rodenticide • Clinical signs: • • • • • • • Pale mm Bruising Weakness Exercise intolerance Lameness Dyspnea/Coughing Swollen joints • Treatment: • If observed ingesting induce emesis • Decontamination if no clinical signs present • DO NOT decontaminate if the patient hemorrhaging • Stabilize • Blood transfusions • Vitamin K1 supplementation • Duration depends on type ingested but often 30 days or longer Bromethalin • Ex: Tomcat • Cats more sensitive than dogs • Becoming more common due to EPA regulations • Causes uncoupling of oxidative phosphorylation in CNS • Leads to cerebral edema/neuro signs • Clinical signs occur 8-96 hours after exposure Bromethalin • Clinical signs: • • • • • • • • Muscle tremors/seizures Hyperexcitability Forelimb extensor rigidity Ataxia CNS depression Loss of vocalization Paresis/paralysis Death • Treatment: • Aggressive decontamination • Repeated doses of activated charcoal (every 8-12 hours) • Prognosis poor for animals w/severe signs • Vitamin D3 • Ex: Rat-B-Gon, Quintox • Cats and Dogs • Causes serum calcium elevations due to increased intestinal absorption of calcium, bone/kidney resorption of calcium Cholecalciferol • Results in kidney failure, soft tissue mineralization, death • Delayed onset of signs • 18-36 hours after ingestion Cholecalciferol • Clinical signs: • • • • • V/D PU/PD Inappetence Depression Dehydration • Treatment: • Decontamination • Repeated doses activated charcoal • Monitor calcium, phosphorus, BUN/Crea • Elevated calcium • IV fluids (0.9% NaCl) • Prednisone • Furosemide • May need treatment for weeks Antifreeze • Toxic component: Ethylene glycol • LD for dogs 4.4-6.6mL/kg; cats 1.4mL/kg • Peak blood levels w/in 1-4 hours after ingestion • Causes CNS depression & acute kidney failure • Progresses very quickly • Commercial test kits available • Cage side diagnosis • Accurate for 3-12 hours after ingestion • Blood sample obtained prior to any tx Antifreeze • Clinical signs: • W/in first few hours • Vomiting • W/in 1-6 hours • • • • • Depression Ataxia Weakness Tachypnea Polyuria/polydipsia • By 18-36 hours • Acute renal failure • Calcium oxalate monohydrate crystals on urinalysis • Treatment: • Decontamination if recent ingestion: emesis/activated charcoal • Goal is to slow/block metabolism • Ethanol or fomepizole (4methylpyrazole) used to block production of toxic metabolites • IV fluid therapy • Sodium bicarbonate to correct acidosis • Once renal values elevated prognosis is poor Dihydrate Monohydrate CALCIUM OXALATE CRYSTALS Ibuprofen and others • NSAID toxicity • Ibuprofen, naproxen, diclofenac, carprofen, deracoxib • Cats more sensitive than dogs • B/c limited ability to metabolize NSAIDs • Clinical signs: • Vomiting, stomach ulcers, acute renal failure • High doses (ibuprofen/phenylbutazone) CNS effects like seizures, ataxia, coma • Treatment: • • • • Decontamination IV fluids Antiemetics Gastric ulcer prevention/treatment • GI protectants Acetaminophen • Affects cats and dogs; cats more sensitive • Causes methemoglobinemia & liver failure • Dogs: • Liver injury at 100mg/kg • Methemoglobinemia at 200mg/kg • Cats: • 10mg/kg can produce toxicity • Lack the enzyme detoxifies acetaminophen Acetaminophen • Clinical signs: • • • • • • • • • Lethargy/Depression Weakness Tachypnea/dyspnea Vomiting Pale or muddy mucous membranes Hypothermia Facial/paw edema Hepatic necrosis Death • Treatment: • Decontamination • Antidote: N-acetylcysteine • Denamarin (liver protectant) *** Methemoglobinemia=too little oxygen is delivered to your cells • Methemoglobin can’t bind oxygen, can’t carry oxygen to tissues Pseudoephedrine/Amphetamines • Cold/flu medications such as nasal decongestant • Similar to amphetamines • Also contained in many attention deficit hyperactivity disorder medications • Clinical signs: • • • • • • Increased BP Tachycardia Ataxia Mydriasis Hyperactivity Tremors/seizures • Treatment: • Acepromazine-sedate • Beta blockers • IV fluids Marijuana • Toxicity increases when plant damaged by heating, drying, smoking or aging • Dogs onset clinical signs 30-90 minutes after ingestion • May last for up to 72 hours • Clinical signs: • Initially: • Nervousness • Disorientation • Depression (lasts up to 18-36 hours) • Mydriasis, hypothermia, nystagmus, urinary incontinence, ataxia Nystagmus Marijuana • Treatment: • • • • • • Decontamination attempted but cannabis has antiemetic properties Activated charcoal if asymptomatic IV fluids Thermoregulation Assisted respiration Diazepam if agitated • Urine drug test confirm exposure Bufo toads • Salivary glands on toads excrete bufotoxin (similar to cardiac glycosides) • Dogs and cats susceptible, dogs more likely to ingest the toad • Primarily occurs in Florida • Clinical Signs: • • • • Hypersalivation Head shaking/face rubbing Seizures Cardiac arrhythmias • Treatment: • • • • • Wash mouth with water immediately Only decontaminate if safe to do so/ based on clinical signs IV fluids Seizure control Cardiac arrhythmia control