Snakebite…Now what?

A Talk by Chris Nickson

No $

“Julius Caesar and the Crossing of the Rubicon,” Francesco Granacci, 1494

Assessment

If so, what antivenom & treatment is needed?

Is the patient envenomed?

Photo by Iguana Joe

Snake bite

Lymphatics

Non-specific Systemic Features

Specific Envenoming Syndromes

Specific Envenoming Syndromes

Venom-inducedConsumptive Coagulopathy

Anticoagulation

Neurotoxicity

Myotoxicity

Others

Does he look sick?

Photo by JD Hancock

Life Threats

HypotensionRespiratory failure

SeizureHaemorrhage

AssessmentGeographic area

Anatomic site of biteNumber of strikes

Use of PIBPre-hospital course and treatment

Previous snakebitesSystemic features

Investigations

Brown snake Pseudonaja spp

Tiger snake Notechis spp

TaipanOxyuranus spp

Death AdderAcanthophis spp

Black snake Pseudechis spp

Sea SnakesHydrophiidae

Photo by Gnangarra

InvestigationsWhole blood clotting test

Coagulation profile (INR, APTT) Fibrinogen, D-Dimer, FDPs 

Full blood count  Creatine kinase  

Renal function and urinalysisLactate Dehydrogenase

Venom Detection Kit (VDK)

VDK does NOT tell you if a patient is

envenomed

If envenomed… VDK is an aid to

monovalent antivenom selection

First Aid

Pressure Immobilisation Bandage

PIB

Warrell DA. Treatment of bites by adders and exotic venomous snakes. BMJ. 2005 Nov 26;331(7527):1244-7.

Management

Not envenomed

Remove PIBSerial examination

Serial laboratory testsObserve for 12 hours

Envenomed

Address life threatsReplace PIB

Give AntivenomSerial assessment

Seek and treat complications

AntivenomIndications

CollapseCoagulopathy

ParalysisRhabdomyolysis

Protracted GI distress

1. Geography2. Clinical features

3. Laboratory findings

Which Antivenom to give?

http://www.kingsnake.com/aho/species/extras/budden.html

What about the snake?

How to give AntivenomResuscitation area

2 x IV lines

Give in 500 mL normal saline over 20 min

Give Monovalentif Possible

SevereAnaphylaxis

1% Monovalent

5% Polyvalent

Isbister et al. MJA 2008; 188: 437-476

Polyvalent Antivenom

Appropriate monovalent AV not available

Need >2 monovalent AVand

No SVDK or no time to wait

Premedication?Photo by Gaptone

DoesAntivenom

Work?

Isbister GK. Antivenom efficacy or effectiveness: the Australian experience. Toxicology. 2010 Feb 9;268(3):148-54.

Efficacy

Effectiveness

Inefficacious antivenom?Irreversible venom effect?Rapid onset venom effect?

Yeung JM, Little M, Murray LM, Jelinek GA, Daly FF. Antivenom dosing in 35 patients with severe brown snake (Pseudonaja) envenoming in Western Australia over 10 years. Med J Aust. 2004 Dec 6-20;181(11-12):703-5.

Isbister et al. Pathology (2006) 38(6) 568-572

Expect >8 hours until fibrinogen returns

FFP: Fuel for the Fire?

Don’t forget

ASP

THE END

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/education/toxicology/

Photo by Peter Firminger