Venoms & Poisons

Question 1

What are LMW substances?

Answer 1

They are endogenous substances like epinephrine, histamines, or prostaglandin that cause pain, inflammation, and hypotension

Question 2

What are peptides?

Answer 2

They are toxins that cause allergic reactions and many direct toxic effects

Question 3

What are 3 types of toxic enzymes and what do they do?

Answer 3

Hyaluronidase (spreading and potentiating factor) catalyzes the cleavage of glycoside bonds
Collagenase breaks down capillary walls
Protease degrades proteins and causes necrosis

Question 4

What are the 3 man components of bee venom?

Answer 4

1) 50% Mellitin - detergent and hemolytic, causes pain, histamine release, cortisol release
2) 12% Phospholipase A2 - destroys membranes (major allergen
3) 3% hyaluronidase – disrupts cell membranes

Question 5

What is the primary pain inducing substance in hornet and wasp stings?

Answer 5

Kinins

Question 6

What does Piperidine do and in which insects is it found?

Answer 6

It is a fireant venom that has cytotoxic, hemolytic, fungicidal, insecticidal and bactericidal properties and causes dermal necrosis when injected into the skin

Question 7

What are the severe systemic signs that can arise from delayed hypersensitivity to bee/wasp/hornet stings?

Answer 7

Shock, hemolysis, rhabdomyolysis, hepatic and renal injury

Question 8

What chemical causes the pain at the site of a fire ant sting?

Answer 8

Formic acid

Question 9

What are clinical signs of fire ant envenomation?

Answer 9

Erythematous puritic papules that generally resolve within 24 hrs

Question 10

What is the mechanism of Holocyclotoxin and in what insect is it found?

Answer 10

It is produced in the salivary glands of Ixodes and Dermacenter ticks and it decreases ACh release and affects Na channels at neuromuscular junction resulting in weakness and paralysis.

Question 11

What are the clinical signs of Holocyclotoxin?

Answer 11

Tick paralysis - ataxia -> ascending flaccid paralysis -> salivation/vomiting -> respiratory faliure

Question 12

How do you treat Holocyclotoxin (tick paralysis)?

Answer 12

Use of atropine to stop the SLUDGE signs, anti-emetics, oxygen and supportive therapy

Question 13

What are the two main components of Bufo toxin, and what are their mechanisms?

Answer 13

1) Biogenic amines - these mimick histamine and serotonin to cause vasoconstriction, hypotension (due to shock?), hallucination, and GI effects
2) Bufogenins - Inhibit sodium-potassium ATPase activity similar to cardiac glycosides to cause arrythmias

Question 14

What are the clinical signs of Bufotoxin?

Answer 14

Immediate hypersalivation and vomiting, brick-red gums, arrythmias, ataxia, convulsions, hyperkalemia

Question 15

How do you treat bufotoxin?

Answer 15

GI decontamination and activated charcoal in case of tadpole ingestion
Diazepam/barbituates for seizures
Atropine if bradycardia
Propanolol/esmolol or lidocane for arrythmias
Digoxin antigen binding substance - if CNS signs and hyperkalemia are bad, but $$$

Question 16

What is the mechanism of Black widow venom?

Answer 16

Alpha-latrotoxin- creates pores in membranes allowing Ca++ entry and massive release of neurotransmitter causing sustained muscle spasms followed by paralysis.

Question 17

What are clinical signs of Black Widow envenomation?

Answer 17

Muscle rigidity, spasms, vocalization, pain/writhing, hypertension, tachycardia

Question 18

How do you treat Black Widow envenomation?

Answer 18

Diazepam or methocarbamol for muscle spasms
Calcium Gluconate for muscle cramps
Supportive care + ventilator if necessary
Antivenom, but $$$

Question 19

What is the substance that causes tissue necrosis in Brown Recluse venom?

Answer 19

Sphingomyelinase D - binds to cell membranes and cleaves head off lipids

Question 20

What are clinical signs of a Brown Recluse bite?

Answer 20

Blister that leaves a “bulls-eye” pattern and a non-healing ulcer.
Hemolytic anemia, fever, weakness, leukocytosis

Question 21

How do you treat a Brown Recluse bite?

Answer 21

Dapsone - inhibits neutrophil migration to treat dermal lesion
Fluids + bicarb for hemoglobinuria & resulting acidosis
Antibiotics for secondary infections
Analgesics (NSAIDs)
Debriding and flushing of lesion with Burrow’s solution (Aluminum acetate) or H2O2

Question 22

What is the mechanism of Coral Snake venom?

Answer 22

Bungarotoxin stops ACh by binding irreversibly to postsynaptic ACh receptor causing paralysis

Question 23

What are clinical signs of Botulinum toxin?

Answer 23

Weakness, dropping food, weak vocalization, constipation, urinary retention, flaccid paralysis

Question 24

What are clinical signs of endotoxin poisoning?

Answer 24

Endotoxin from phospholipase in G- bacteria causes lethargy, fever followed by hypothermia, diarrhea, abdominal pain, shock, and extremely bad smelling feces.