Envenomation Flashcards
Black Snake
Mulga - large, painful bite, potentially lethal
Red-bellied black - usually non-lethal
Coagulopathy: Anticoagulant
Neurotoxicity: nil unless Death Adder
Myotoxicity: Common Mulga, uncommon red-bellied black
Systemic Symptoms: Common
Thrombotic Microangiopathy: nil
Cardiovascular: nil
Brown Snake
Most common cause of severe envenomation and death due to VICC.
Coagulopathy: VICC Neurotoxicity: Rare and Mild Myotoxicity: Nil Systemic Symptoms: <50% Thrombotic Microangiopathy: 10% Cardiovascular: Collapse 25%, Arrest 5%
Tiger Snake
Coagulopathy: VICC Neurotoxicity: Uncommon Myotoxicity: Uncommon Systemic Symptoms: Common Thrombotic Microangiopathy: 5% Cardiovascular: Rare
Taipan
Envenomation is rare but frequently lethal without antivenom. Papuan Taipan in PNG is the worst.
Coagulopathy: VICC Neurotoxicity: Common Myotoxicity: Rare Systemic Symptoms: Common Thrombotic Microangiopathy: 5% Cardiovascular: Uncommon
Diagnosis of VICC
Elevated INR / PT with elevated D-Dimer
will often have low fibrinogen as well
Signs of Neurotoxiciy
Descending Flaccid Paralysis:
Ptosis Bulbar palsy opthalmoplegia Respiratory muscle paralysis Limb Paralysis
Diagnosis of Myotoxicity
Local or genralised myalgia / weakness with CK > 1000
Non-specific systemic symptoms
Nausea / vomiting abdominal pain headache diaphoresis diarrhoea
Antivenom Tasmania
Tiger only
Antivemon Victoria
Brown and Tiger
Antivenom dosing
Dose is always 1 vial
monovalent if can identify based on signs/symptoms and geography.
polyvalent if unsure.
in Cardiac arrest - undiluted as slow bolus
Otherwise - dilute 1 in 10 with N Saline and given over 15 minutes
Systemic Hypersensitivity reaction in 20%, only severe in 5%. Most common with polyvalent and tiger.
Premedication not supported by evidence.
Blood products for VICC not supported by evidence.
Local pain, headache, nausea and vomiting, with mild anticoagulant coagulopathy.
Which snake?
BLACK
How to differentiate between Taipan, Tiger and Brown?
All three cause VICC
Tiger and Taipan have neuro and myotoxicity but Brown usually doesn’t.
Tiger neurotoxicity is usually delayed in onset whereas Taipan is early and rapid.
Early Collapse after a snakebite
Which snake?
BROWN
Painful bite site associated with descending flaccid paralysis, but normal blood tests
Which snake?
DEATH ADDER
Sea Snake (hydrophiidae)
small painless bite sites, potentially lethal envenomation
no coagulopathy
systemic features present
neurotoxicity present
myotoxicity present
Treatment is Sea Snake Antivenom
Bluebottle Jellyfish (Physalia)
local pain and errythema
no systemic envenomation
treatment: hot water immersion provides relief
Stonefish (Syanceia)
dorsal spines contain venom
Immediate pain
local swelling bruising, retained spines
Systemic envenomation is rare
Treatment:
do not apply pressure bandage
Hot water immersion
IV opioids
Regional anaesthesia e.g. foot or wrist block
Antivenom indicated in treatment of severe refractory pain or systemic envenomation
Box Jellyfish (Chironex fleckeri)
Can cause severe envenomation and death - often within 5minutes of the sting probably due to cardiac toxicity
immediate severe pain, linear welts in a crosshatched pattern. adherent tentacles present may be present.
Systemic envenomation - collapse or sudden death - hypertension/hypotension, tachycardia, dysrhythmias
Delayed local hypersensitivity reactions 1-2 weeks later
Mx: Resuscitation - push undiluted antivenom 6 vials in cardiac arrest, or else 3 vials diluted over 20mins in systemic envenomation. Large amounts of vinegar to sting sites do not apply pressure bandage IV morphine for pain local ice packs for pain
Irukandji Syndrome (Carukia barnesi)
minimal local signs
systemic symptoms develop 30 to 120minutes later
-sense of impending doom/agitation/dysphoria
-vomiting/sweating
-severe pain in back/limbs/abdomen
-Hypertension and tachycardia
Complications ?2nd to uncontrolled hypertension - cardiomyopathy/cardiogenic shock/APO/intracranial haemorrhage
Mx: Do not apply pressure bandage apply liberal volumes of vinegar Resus as needed - mechanical ventilation for APO Large doses IV fentanyl (cardiac stable) treat refractory HTN with GTN infusion no Antivenom available
Blue Ringed Octopus (hapalochlaena)
usually not painful bite
envenomation = rapid progressive symmetrical descending flaccid paralysis which usually manifests within minutes
Mx:
DO apply a pressure immobilisation bandage
treatment is mainly assisted ventilation for 24hrs
no antivenom available
Redback spider
local pain 5-10mins later
envenomation = proximal regional spread to limbs then general pain to back/chest etc
nonspecific headache, nauesa, vomiting, dysphoria
localised sweating and piloerrection.
symptoms may last 1-4 days or longer
Mx:
ice pack, simple analgesia
do not apply PBI
antivenom is 2 units IV but envenomation is not life threatening
Funnel-Web Spider (big black spider)
painful bite
severe systemic envenoming usually develops within 30mins to 2hrs
general - headache, aggitation, vomiting, abdo pain
Autonomic - sweating, salivation, piloerection, lacrimation
CVS - HTN, tachycardia, hypotension, bradycardia, APO
Neuro - muscular fasiculation, oral paresthesia, muscle spasm and coma
Mx:
Apply PBI
Resuscitation - hypo/hypertension, APO, Coma, Resp failure
cardiac arrest - undiluted antivenom at least 4 vials as a push. otherwise give 2 vials then assess response
atropine for secretions
