Unit 2 - Venoms and Poisons II Flashcards
Are male or female black widow spiders associated with envenomation?
females
What do female black widow spiders look like?
Shiny black with red or orange hourglass mark on the ventral abdomen
T/F: Juvenile black widow spiders have different patterns from adults.
True
What species are sensitive to black widow spider envenomation?
Camels, horses, cats, and dogs
In what species is mortality commonly associated with black widow spider envenomation?
Cats
T/F: A single bite from a black widow spider can deliver a lethal dose.
True
What are the problematic components in black widow spider venom?
Alpha-latrotoxin, other neuroactive proteins, and proteolytic enzymes
What does alpha-latrotoxin do?
It is a neurotoxin which binds presynaptically creating a stable Ca pore - this results in increased presynaptic vesicle trafficking and release of neurotransmitters (NE and ACh)
When do black widow spider clinical signs typically manifest?
In the first 8 hours post-envenomation
What clinical signs are associated with black widow spider envenomation?
Muscle fasciculation, severe abdominal pain may occur, ataxia, and flaccid paralysis
How are black widow spider envenomations treated?
Antivenon
Ca gluconate for muscle fasiculations
Narcotics or benzos
Limit IV fluids if hypertensive
What is the prognosis for black widow spider envenomations?
Generally good
What does a brown recluse spider look like?
Violin-shaped pattern on cephalothorax with the neck of the fiddle extending caudally
When do brown recluse spider bites typically occur?
When the spider becomes trapped in undisturbed clothing or bedding
What does brown recluse venom contain?
Sphingomyelinase D and hyaluronidase
What does sphingomyelinase D do?
Damages plasma membranes of endothelia, erythrocytes, and platelets
Neutrophil recruitment
Reduction in expression of epidermal growth factor
What clinical signs are associated with brown recluse spider envenomation?
Local pain and stinging followed by pruritus and soreness
Targetoid lesion
Occasional hemolytic anemia with hemoglobinuria
Systemic loxoscelism with DIC
What does the targetoid lesion caused by brown recluse spiders look like?
An ischemic area with a dark central eschar and erythematous background
How is brown recluse spider envenomation treated?
Routine wound care, supportive care, and surgical debridement of necrotic lesions
What does the scorpion toxin do?
It is neurotoxic and leads to depolarization of the neuromuscular junction
What is a good way to detect if a scorpion is in a room?
Use UV light - scorpions will fluoresce bright cyan-green
What clinical signs are associated with scorpion envenomation?
Sharp local pain
Tachycardia
Hyperactivity, trashing, writing
What treatment is recommended for scorpion toxicosis?
Supportive
Antivenom
What may individual stings from hymenoptera result in?
Immediate hypersensitivity reaction/anaphylaxis
How can hymenoptera cause death in non-allergic animals?
Via massive envenomation - > 20 stings
What is the main component of bee and wasp venoms?
Protein that acts as allergens
What is fire ant venom composed of? Why are they problematic?
Alkaloids - cytotoxic, hemolytic, fungicidal, bactericidal, and insecticidal properties
What are the four possible reactions to hymenoptera stings?
Local, regional systemic/anaphylaxis, delayed-type hypersensitity
What clinical signs are associated with hymenoptera stings?
Edema, erythema, pain at the site of the sting, regional response is an extension of local, anaphylaxis
How are local or regional hymenoptera stings treated?
Antihistamines, ice or cool compresses, topical corticosteroid lotions
How are anaphylactic hymenoptera stings treated?
Epinephrine
IV crystalloid fluids to prevent shock
Antihistamines, corticosteroids as indicated
What toad species are associated with serious clinical signs following oral exposure?
B. marinus and B. alvarius
What toxic principle do toads have?
Bufotoxins
What do bufotoxins contain?
Bufogenins and bufotenins
Where are bufogenins secreted from?
Parotid glands
What is the MOA of bufogenins?
They are digitalis-like cardioactive compounds that bind to Na/K ATPase pump and alter heart rate and rhythm
What do bufotenines do?
Vasoactive and neuroactive agents
What clinical effects does toad poisoning cause?
Immediate salivation, headshaking, and hyperemic mucous membranes
Acute onset of neurologic signs - convulsions, ataxia, nystagmus, and stupor
Trembling, tachypnea, abnormal cardiac rate, and arrhythmias
How is toad poisoning treated?
On-the-spot decontamination
Emetics if the whole toad is consumed and only ptyalism is observed
How is toad posioning treated when there are advanced clinical sings?
Sedatives/anticonvulsants to control neuro signs
Cardiac support
Fluids and other supportive therapy as indicated
What is the toxic principle of blister beetles?
Cantharidin
Where is cantharidin contained?
In hemolymph and repro glands
What does cantharidin do?
Induces erosions and ulcers on all mucous membranes
Mycoardial necrosis
What is the MOA of cantharidin?
It induces the release of serine proteases which causes disintegration of desmosomes which leads to acantholysis
How does blister beetle toxin get ingested?
With hay - they are trapped in hay during harvest and the crimping process releases the toxin
What species is most commonly affected by blister beetles?
Horses
It has been reported in cattle and sheep
T/F: Blister beetle toxin decreases over time with storage.
False - it does not decrease with storage
What clinical signs are associated with blister beetle poisoning?
Dose depenent: colic, polyuria, hematuria, lesions in oral, GI and urogenital mucosae, dehydration, and shock
What clin path abnormalities are associated with blister beetle poisoning?
Hypocalcemia and hypomagnesemia
What lesions are associated with blister beetle poisoning?
Sloughing of gastric and other mucosae
Hyperemic mucous membranes - stomach, intestine, renal pelvis, ureters, and bladder
Myocardial necrosis
How are blister beetle poisonings diagnosed?
History, observation of beetles in hay, ID of cantharidin
In what biologic samples can cantharidin be found in?
Urine, GI contents
How is blister beetle poisoning treated?
Symptomatic - fluids for shock, dehydration
Mineral oil
Analgesics
Remove all suspect feedstuffs
How is blister beetle poisoning prevented?
Use first cutting hay
Scout for beetles
Control grasshoppers and crickets
Most mushroom poisonings occur as a result of ingestion of ______ mushrooms.
wild
During what time of year does mushroom poisoning typically occur?
Fall
What clinical signs are associated with hallucinogenic mushroom poisoning?
Vomiting, diarrhea Panting, dyspnea Muscle spasms Collapse Cyanosis Death
How is hallucinogenic mushroom poisoning diagnosed?
History of exposure
Observation of mushroom parts in vomitus
T/F: The Amanita/Galerina group of mushrooms are composed of the most lethal poisons known.
True
What toxins do the Amanita/Galerina group of mushrooms create?
Phallotoxins
Amatoxins
Why are amatoxins so bad?
They are highly active, rapidly absorbed
Resistant to stomach acid
Thermostable
What is the MOA of the Amanita mushrooms?
Amatoxins interfere with RNA polymerase which results in decreased mRNA and protein synthesis
What body systems are affected by Amanita mushroom poisonings?
The liver, kidneys, and intestine
What clinical effect does Amanita mushroom toxicosis?
Acute hepatic failure +/- hepatoencephalopathy and coma
What are the 4 phases of Amanita mushroom poisoning?
- Initial latent period
- Gastroenteric phase
- Second latent period
- Organ failure phase
How long does the 1st phase of Amanita mushroom poisoning last?
6-24 horus
What occurs during the 2nd phase of Amanita mushroom poisoning?
Sudden sharp colicky abdominal pains
Nausea, vomiting, and watery diarrhea
Stools with blood and mucous shreds
What occurs during the 3rd phase of Amanita mushroom poisoning?
Apparent recovery - ‘false hope’
When does the 4th phase of Amanita mushroom poisoning occur?
36-84 hours post exposure
What occurs during the 4th phase of Amanita mushroom poisoning?
Fulminant hepatic, renal, and multiorgan failure
What laboratory results are associated with Amanita mushroom poisoning?
Albuminuria, hematuria
Elevated liver enzymes, and serum bilirubin
Rapid decrease in coag factors
Hypoglycemia
How is Amanita mushroom poisoning diagnosed?
History of exposure
Detection of amanitin by LC-MS
What is the ideal antemortem sample for Amanita mushroom poisoning diagnosis?
Urine
Serum can be used
What is the ideal post mortem sample for Amanita mushroom poisoning?
Fresh kidney and/or liver
What is the toxic principle of Cortinarius mushrooms?
Orellanine
What is poisoning by Cortinarius mushrooms often characterized by?
Severe oliguric renal failure
How is Cortinarius mushroo toxicosis diagnosed?
Detection of orellanine in renal biopsies by LC-MS/MS
Why should you treat the patient not the mushroom?
Many mushrooms contain several toxins in varying concentrations
Toxic or non-toxic mushrooms grow side by side so mixed exposure is possible
Likely not all toxins have been ID
How are mushroom poisonings treated?
Emesis
Activated charcoal after vomiting or gastric lavage
Catharic if no diarrhea
