Envenomation

Question 1

Black Snake

Answer 1

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

Question 2

Brown Snake

Answer 2

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%

Question 3

Tiger Snake

Answer 3

Coagulopathy:     VICC
Neurotoxicity:     Uncommon
Myotoxicity:     Uncommon
Systemic Symptoms:     Common
Thrombotic Microangiopathy:     5%
Cardiovascular:      Rare

Question 4

Taipan

Answer 4

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

Question 5

Diagnosis of VICC

Answer 5

Elevated INR / PT with elevated D-Dimer

will often have low fibrinogen as well

Question 6

Signs of Neurotoxiciy

Answer 6

Descending Flaccid Paralysis:

Ptosis
Bulbar palsy
opthalmoplegia
Respiratory muscle paralysis
Limb Paralysis

Question 7

Diagnosis of Myotoxicity

Answer 7

Local or genralised myalgia / weakness with CK > 1000

Question 8

Non-specific systemic symptoms

Answer 8

Nausea / vomiting
abdominal pain
headache
diaphoresis
diarrhoea

Question 9

Antivenom Tasmania

Answer 9

Tiger only

Question 10

Antivemon Victoria

Answer 10

Brown and Tiger

Question 11

Antivenom dosing

Answer 11

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.

Question 12

Local pain, headache, nausea and vomiting, with mild anticoagulant coagulopathy.

Which snake?

Answer 12

BLACK

Question 13

How to differentiate between Taipan, Tiger and Brown?

Answer 13

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.

Question 14

Early Collapse after a snakebite

Which snake?

Answer 14

BROWN

Question 15

Painful bite site associated with descending flaccid paralysis, but normal blood tests

Which snake?

Answer 15

DEATH ADDER

Question 16

Sea Snake (hydrophiidae)

Answer 16

small painless bite sites, potentially lethal envenomation

no coagulopathy
systemic features present
neurotoxicity present
myotoxicity present

Treatment is Sea Snake Antivenom

Question 17

Bluebottle Jellyfish (Physalia)

Answer 17

local pain and errythema
no systemic envenomation

treatment: hot water immersion provides relief

Question 18

Stonefish (Syanceia)

Answer 18

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

Question 19

Box Jellyfish (Chironex fleckeri)

Answer 19

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

Question 20

Irukandji Syndrome (Carukia barnesi)

Answer 20

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

Question 21

Blue Ringed Octopus (hapalochlaena)

Answer 21

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

Question 22

Redback spider

Answer 22

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

Question 23

Funnel-Web Spider (big black spider)

Answer 23

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