Tox-3 Flashcards
Which form of arsenic is more toxic?
Inorganic arsenic
Which form of arsenic is highly associated with CNS effects?
Pentavalent
Which form of arsenic is associated with blood and CV effects?
Trivalent
Where is pentavalent arsenic metabolized?
Reduced and metabolized in the rumen
How is trivalent arsenic metabolized?
Binds to -SH groups, disrupting cell metabolism and inhibits oxidative phosphorylation
What clinical signs are associated with an arsenic toxicosis?
Intense abdominal pain, gastroenteritis, vomiting, weakness, staggering gait, PU/PD progressing to oliguria and anuria, dehydration, thirst
What differentials must you consider when observing the blood-related clinical signs of arsenic?
Ergot
What blood-related clinical signs are expected with arsenic toxicity?
Cold extremities due to poor perfusion and subnormal temperature
What CNS related clinical signs are expected with arsenic toxicity?
Salivation, trembling, depression, and posterior paresis
What characteristic lesion in the abomasum is associated with arsenic toxicity?
Brick red gut
Which toxin must you consider whenever there is sudden onset of GI or sudden death, especially dead animals found in or near water?
Arsenic
How do you treat arsenic toxicity?
GI decontamination (only if acute!), chelation therapy, supportive therapy (demulcents, fluids)
What is the classic chelating antidote for arsenic toxicosis?
Dimercaprol (complete with -SH groups for available arsenic)
What can you use for chelation therapy for arsenic toxicosis before displaying clinical signs?
Sodium thiosulfate
What is the prognosis for arsenic toxicosis?
Guarded to poor
Pennies made before what year are 96% zinc?
1982
What is the mechanism of action of zinc toxicosis?
Free zinc is released in the stomach’s acidic environment forming zinc salts leading to corrosive effect to stomach and intestinal mucosa; oxidative damage
What are the “big three” clinical signs of zinc toxicity seen in both acute and chronic toxicity?
GI tract bleeding, renal failure, and hemolysis
How do you diagnose zinc toxicosis?
Serum zinc levels >10ppm, regenerative anemia, thrombocytopenia, elevated liver, kidney, and pancreatic enzymes, hemoglobinuria
Is emesis indicated in zinc toxicosis?
Yes! As quickly as possible if the animal hasn’t already vomited (unless an exploded battery)
How do you treat zinc toxicosis?
Remove foreign body, symptomatic (fluids, blood products), proton-pump inhibitors (omeprazole) or H2 blockers
At what pH are you worried about the caustic effects and damage to the GI tract?
High (alkaline) pH
What clinical signs do you expect with soap/shampoo toxicosis?
GI distress
How do you treat soap/shampoo toxicosis?
Dilution with milk or water
What type of necrosis does scouring powder/bleach cause?
Liquefactive necrosis
What are the clinical signs of scouring powder/bleach toxicosis?
Vomiting, drooling, and abdominal pain
What is the gold standard treatment for scouring powder/bleach toxicosis?
Milk or water, gastrointestinal protectants
Is emesis or lavage contraindicated in scouring powder/bleach toxicosis?
Yes! Caustic
What is the mechanism of action of phenols?
Denatures and precipitates cellular proteins thus destroying all contacted cells
What are the clinical signs of phenol toxicosis?
Corrosive burns of oral-esophageal pathway, vomiting, hypersalivation, ataxia, panting -> shock, cardiac, arrhythmias, methemoglobinemia, hepatic and renal damage, coma
How are pine oils detoxified?
Glucuronidation (cats more susceptible to toxicosis!)
What are the clinical signs of pine oils?
Nausea, hypersalivation, blood vomit, abdominal pain, ataxia, hypotension, respiratory depression, acute renal failure, pulmonary edema
What are the clinical signs of automatic dishwasher detergents toxicosis?
Vomiting, diarrhea, salivation, GI pain, and oral, esophageal, gastric erosions
How do you treat automatic dishwasher detergents toxicosis?
Dilution with milk or water, analgesics and possibly steroids for inflammation
What is the pH of toilet bowl cleaner?
Low pH (acidic)
What mycotoxin is a metabolite of Fusarium spp. That is a reproductive toxicant?
Zearalenone
What makes zearalenone hard to get rid of in the environment?
Heat stable and resistant to most mold retardants (even if the fungus is killed, the toxin is still active)
Which species are resistant to zearalenone toxicosis?
Chickens
What is the mechanism of action of zearalenone?
Estrogen receptor agonist
What syndrome does zearalenone toxicosis cause?
“Hyperestrogen” syndrome - vulvovaginitis and estrogenic responses
How do you diagnose zearalenone toxicosis?
Presence of toxin in feed
What is the difference between venomous and poisonous animals?
Venomous animals actively inject toxins and poisonous animals secrete poisons which are passive defense mechanisms
What three classes of compounds comprise venom?
LMW substances (PG, histamine, epi), peptides/proteins (direct toxic effects), enzymes (cause toxicity and allergy)
What is the difference between bee and wasp/hornet stings?
Bees can only sting one, wasps/hornets sting repeatedly
What is the mechanism of action of bee venom?
Mellitin causes pain and histamine release, phospholipase A2 destroys membranes
What is the mechanism of action of wasp/hornet venom?
Some contain neurotoxins, kinins induce pain
What is the mechanism of action of ant venom?
Piperidine causes dermal necrosis and formic acid causes burning sensation and pain
What are the clinical signs of bee, wasp, hornet venom toxicosis?
Swelling, redness, and edema at the site, anaphylaxis, systemic toxicity
How do you treat bee, wasp, hornet, fire ant venom toxicity?
Scrape retained stinger to remove, cold compress, antihistamines and corticosteroids, monitor for anaphylactic reactions (Epi, IV fluids PRN)
What two species of ticks are venomous?
Dermacentor and Ixodes
What is the toxin produced in the salivary glands of ticks?
Holocyclotoxin
What is the mechanism of action of holocyclotoxin?
Impairs acetylcholine release at neuromuscular junction (results in weakness and paralysis)
What other mechanism of action is associated with Dermacentor toxin?
Acts on Na+ channels
After how long after attachment of a tick do you observe clinical signs?
6-14 days
What are the clinical signs of holocyclotoxin toxicosis?
Loss of appetite and voice, incoordination, ascending flaccid paralysis, excessive salivating and vomiting, respiratory distress, death due to respiratory paralysis
How do you diagnose holocyclotoxin toxicosis?
No definitive diagnosis! History or presence of ticks
What are the 2 major clinical signs that suggest holocyclotoxin toxicosis?
Ascending paralysis and loss of voice
What medication can be used to reverse the mechanism of action of holocyclotoxin toxicosis?
Atropine sulfate
What is the prognosis of holocyclotoxin toxicosis?
Good if treated
Which species of Bufo toad is found in Florida?
B. Marinus
What is the mechanism of action of toad poisoning?
Secretions from the toad include biogenic amines (histamines) and Bufogenins (bufotalin)
What is the mechanism of action of bufogenins (bufotalin)?
Inhibit sodium-potassium ATPase; produce toxic cardiac arrhythmias
What should you differentiate from when suspecting Bufo toad toxicosis?
Cardiac glycoside producing plant toxicosis
What clinical signs can be present in Bufo toad toxicosis?
Hypersalivation and/or foaming at the mouth; head, shaking, vomiting; hyperemic gums; arrhythmias; neurological signs (convulsions, ataxia, hallucinations)
What electrolyte abnormality is present with Bufo toad toxicosis?
Severe hyperkalemia
What treatment is indicated in Bufo toad toxicosis?
GI and oral decontamination, seizure control, antiarrhythmics, fluid replacement therapy, digoxin-specific antigen-binding fragments
How do you treat the severe neurologic signs/hyperkalemia associated with Bufo toad toxicosis?
Digoxin-specific antigen-binding fragments (may be cost prohibitive)
What toxin does the venom from female black widow spiders contain?
Alpha-latrotoxin
What is the mechanism of action of alpha-latrotoxin?
Creates pores in membranes allowing Ca++ entry and releasing massive amounts of neurotransmitter -> sustained muscle spasms
What clinical signs are associated with black widow spider venom toxicosis?
Muscle cramping and spasms, rapid weight loss, abdominal rigidity, restlessness, writhing, vocalization, hypertension, tachycardia, respiratory collapse
Which species is most sensitive to the venom of black widow spiders?
Cats
How do you treat alpha-latrotoxin toxicosis?
Control muscle spasms and pain (methocarbamol), anti-venom, supportive care
What is the only proven treatment for alpha-latrotoxin toxicosis?
Anti-venom
What enzyme is present in the venom from brown recluse spiders that binds to cell membranes and cleaves heads off lipids?
Sphingomyelinase D
What determines the severity of the lesion caused by the brown recluse venom?
Victim’s immune response
What are the clinical signs of brown recluse envenomation?
Redness, swelling, tenderness, bulls eye non healing ulcer; hemolytic anemia, fever, weakness, leukocytosis
How do you diagnosis brown recluse envenomation?
Difficult if bite isn’t witnessed
How do you treat brown recluse envenomation?
Dapsone, fluids, anti-inflammatories, glucocorticoids, antibiotics, analgesics
All venomous snakes are members of the which two families?
Elapidae or Crotalidae
What determines the severity of the clinical signs observed with a venomous snake bite?
Size of victim and amount of venom delivered (as well as age of snake!)
What causes victims of venomous snake bites to die?
Respiratory paralysis
What is the mechanism of action of the venom from an Eastern Coral Snake?
Bungarotoxin is neurotoxic that prevents binding of ACh causing paralysis
What are the clinical signs of Eastern Coral Snake envenomation?
Salivation, dyspnea, weakness, hyporeflexia, CNS depression, paralysis, myoglobinemia in cats and hemolysis in dogs
What diagnostic test is used to diagnose Eastern Coral Snake envenomation?
No definitive diagnostic tests
Is there an anti-venom for Eastern Coral Snake envenomation?
Yes - administer if neurologic signs develop
How do you treat Eastern Coral Snake envenomation?
Anti-venom, ventilatory support, antibiotics and symptomatic wound care, monitoring for >/= 24 hours
What is the prognosis of Eastern Coral Snake envenomation?
Good
What pit vipers are part of the Crotalid family?
Copperhead,cottonmouth, rattlesnakes
What are the clinical signs of Crotalid (pit viper) envenomation?
Fang marks, swelling and bruising at site of bite, pain, hypotension, shock, tachycardia, tachypnea, anticoagulation, tissue necrosis
What is the only proven therapy for Crotalid (pit viper) envenomation?
Anti-venom
What is the mechanism of action of enterotoxins from garbage and carrion toxicity?
Bind to intestinal epithelium, increasing permeability and causing fluid loss (diarrhea) and decreased absorption of nutrients
What are the clinical signs of entertoxins from garbage/carrion toxicity?
Vomiting, diarrhea, abdominal pain, stasis with gas accumulation and bowel distension
What is the source of endotoxins in garbage/carrion?
LPS from gram negative cell walls
What are the clinical signs of endotoxins from garbage/carrion toxicity?
Lethargy, fever followed by hypothermia, diarrhea, abdominal pain, shock, extremely bad smelling feces
How do you treat endotoxin toxicity from garbage/carrion?
Emesis, support CV function, correct fluid and electrolyte imbalances, antibiotics
What is considered to be the most potent toxin on Earth?
Clostridium botulinum toxin
What is the mechanism of action of botulinum toxin?
Prevents release of ACh at neuromuscular junction causing paralysis
How do you diagnosis clostridium botulinum toxicosis?
Very difficult! Only circumstantial evidence (access to carrion, garbage, compost piles)
What are the clinical signs of clostridium botulinum toxicosis?
Decreased tongue and tail tone, dropping food from mouth, salivation, weakness, weak vocalization, progressive paresis, bradycardia, constipation, urinary retention
What other differential diagnoses must be considered when suspecting clostridium botulinum toxicosis?
Anticholinesterases, ionophores, lead, and nitrate poisoning
Is there an antitoxin for clostridium botulinum toxin?
Yes!
What is the prognosis of clostridium botulinum toxin toxicosis?
Poor
How do you treat clostridium botulinum toxin toxicosis?
Supportive therapy, IV fluids, respiratory support, O2 therapy, warm water enemas and bladder expression if necessary, antibiotics, and antitoxin
