Envenomation Flashcards
What routes can toxins take on the body?
- Intravenous
- Inhalation
- Intraperitoneal
- Subcutaneous
- Intramuscular
- Intradermal
- Oral
What types of toxins are there?
- Neurotoxins
- Postsynaptic toxins
- Myotoxins
- Locally acting toxins
- Haemotoxins
What are the 3 basic workings of neuro toxins?
- Block/prevent nerve conduction
- Spontaneous action potentials
- Abnormalities of acetylcholine release – pre-synaptic toxins
What are some effects of neurotoxins?
- Neuromuscular paralysis associated with respiratory failure
How do the toxins found in blue ring octopus and puffer/toad fish work on the body system?
- TTX released prevents the action potential propagation by Na+ channel blockade.
What effects are seen from the Sydney funnel web spider?
- The Atraxotoxin will cause
o Gross muscle twitching
o Catecholamine release and glandular hypersecretion
The above is due to the development of spontaneous action potentials that are uncontrollable. These occur throughout the skeletal and autonomic nerves.
What spider is the alpha-latrotoxin seen in?
- The red back spider
What does the alpha-latrotoxin do to the body?
- Depletion of the pre-synaptic vesicles
- The above results in patchy muscle paralysis and catecholamine release.
What type of toxin is seen in all Australian snakes?
- Postsynaptic toxins
- They will block post-synaptic acetylcholine receptors causing paralysis
- Has rapid onset – but also rapid relief if anti-venom is administered.
What are the effects of Myotoxins?
- They affect the muscles
- May cause rhabdomyolysis and potential for renal failure
- Common in Australian snakes
How are locally acting toxins seen in snake venom affect the body?
- Result in the following o Local pain o Oedema o Necrosis o Possible headaches o Systemic myalgia – pain in muscle/group of muscle
How are locally acting toxins seen in marine venoms affect the body?
- Sever pain
- Ischemia
- Cyanosis – blueish apperance
- Necrosis
What is necrotising arachnidism?
- The area around the bite becomes oedematous and necrotic over a couple days.
- Seen in the white tail spider.
What is seen in Haemotoxins?
- Pro-coagulation
- Anti-coagulant activity
- Haemolysis
- Platelet effects
What is the process of envenomation?
- Snake strike occurs and venom is deposited in the form of an avascular liquid or blobs.
- Depending on the venom type – pain/tissue damage will occur at site of the bite.
- For the venom to move centrally It must enter through the following:
o Blood vessels
o Lymphatic system
o Tissue planes. - Regional lymph nodes become enlarged and tender after a venomous bite.
What are you more likely to die from in a snake bite? Anaphylaxis or the venom?
- Anaphylaxis
What venomous effects does the Australian brown snake have?
- Pro-coagulation, Nephrotoxicity, Paralysis, Haemolysis
What venomous effects does the Australian Tiger snake have?
- Rhabdomyolysis, Pro-coagulation, paralysis, Haemolysis
What venomous effects does the Australian Red bellied black snake have?
- Rhabdomyolysis, pro-coagulation, paralysis
What venomous effects does the Australian copperhead snake have?
- Rhabdomyolysis, Anticoagulation, Paralysis
What are common signs of a snake bite wound?
- One ore two small puncture wounds approx. 1cm apart.
- Bleeding and venom residue – will appear as milky fluid.
- Pain, swelling and redness around bite site.
- Bite site may not be visible to naked eye or will present as a scratch.
How will a Pt present with a snake bite?
- N + V
- Difficulty in breathing
- ACS, headache, visual disturbances
- Loss of consciousness
- Chest and abdominal pain
- Paralysis and convulsions
- Acute renal failure
- Rhabdomyolysis
- Ptosis – dropping of upper eyelid.
S&S <1-hour post snake bite if left untreated?
- Headache
- N+V
- Abdo pain
- Hypotension with confusion
- LOC
- Regional inflammation
- Tender lymph nodes
S&S 1-3 hours post snake bite if left untreated?
- Cranial nerve paralysis
- Haemorrhage from mucosal surfaces / puncture site
- Tachycardia / hypotension
- Tachypnoea / shallow tidal volume
S&S >3 hours post snake bite if left untreated?
- Paresis/paralysis of truncal and limb muscles
- Paresis/paralysis of respiratory muscle
- Peripheral circulatory failure
- Hypoxaemia/cyanosis
- Rhabdomyolysis
- Dark urine
Do you wash the site of a snake bite?
- No
- The venom @ site can be absorbed into bandage and be used to match the venom
What should be done if bite site is not located in an area were pressure bandaging will be effective?
- Sit Pt as still as possible
Indications for PIT?
- All Australian snake species (including sea)
- Funnel web spider
- Blue ringed octopus
- Cone fish
Contras for PIT?
- Any other spider bites
- Jelly fish stings
- Stone fish and other fish stings
- Scorpion, centipede and beetle bites
What pressure do you want to do a PIT?
- Same as a sprained ankle
What treatment should be used for a redback spider bite?
- Apply cold pack for pain relief.
Why do you not apply pressure to a redback spider bite?
- Its venom is tissue necrotic and will cause severe necrosis of surrounding tissue if held in place under pressure.
What will the venom of the Red back spider do to the victim?
- It is a multi-component venom
- Will cause stimulation of neural synapses – wide ranging effects
What does the Atraxotoxin from them Sydney funnel web spider do to the body?
- Will cause an autonomic storm with SNS or PNS dominance or both.
- May cause severer life threat within 10 minutes
What symptoms will a bite from the SFW cause?
- Gross muscle twitching
- Catecholamine release
- Glandular hypersecretion due to development of uncontrollable spontaneous action potential and autonomic nerves.
- Tachycardia/hypertension
- Anxiety
- Abdo pain
- Mouth tingling
- Breathing difficulty
- ↓ GCS = unconsciousness
What is the treatment for the SFW spider?
- PIT bandage
- Atropine can be sued to reverse cholinergic symptoms
- Anti- venom – hospital
What does the TTX toxin found in blue ringed octopus do?
- Blockade of nerve conduction
- Prevents action potential propagation by Na+ channel blockade leading to paralysis
S&S of Blue Ringed Octopus bite?
- Painless bite
- Numbness in lips and tongue
- Dyspnoea resulting in cessation of breathing
Treatment of a blue ringed octopus?
- PIT bandage
- Tx to hospital
