The top end. Envenomations Royal Darwin Hospital RMO education 29.09.2015 Laura K. reg ED.

The top end

Envenomations

Royal Darwin Hospital

RMO education

29.09.2015

Laura K.

reg ED

Northern Territory

Snakes

Spiders

Stingers

SNAKES

Sources

Article Bart Currie

RDH guideline

Pictures from the web and myself

Rural EM skills training syllabus, ACRRM

eTG

Article Bart Currie

Envenoming

All year but highest incidence during March to May

Highest rate among Top End rural Aboriginal adult males (45.2 per 100.000)

59% on foot / ankle, less bites on hands in Aboriginals

Continuing snake activity in evenings / nights

Three cases of overambitious feeding attempts

Average 2 deaths/yr in Au, > 70% no first aid or antivenom

4 Highly venomous snakes

Western brown = pseudonaja nuchalis = gwardar

Mulga (black snake) = pseudechis australis = king brown

Death adder = acanthophis praelongus

Taipan = oxyuranus microlepitodus / scutellatus

Symptoms 1

Symptoms 2

Bite swelling, lymphadenitis and non-specific systemic features are most prominent in Mulga snake

Myotoxicity is the major feature of Mulga snake

Early collapse with recovery in > 50% of syst env. from Wester Brown snakes (consumptive coagulopathy)

Neurotoxicity most important feature of Death Adder, this study in < 50% pts

Mulga and Brown snake have neurotoxins, but neurotoxicity uncommon = ‘brown snake paradox’

RDHguId.

Treatment bite Apply or reinforce with pressure bandage Eslet S

3A

Immobilize limb with splint

Fenestrate at bite site, take swab

Have snake identified if possible

Tetanus status check +/- ADT

Continuous cardiac monitoring

Hourly neuro obs

Investigations

Investigations

UA

VDK urine (hold if asymptomatic and WBCT < 10min)

VDK bite swab (ord.swab soaked in NS), same procedure

Bloods: WBCT, FBC, UEC, CK, LDH, Coags, D-dimer, Fibrinogen, serology tube

VDK high fals pos rate, esp for brown snake, esp on urine

WBCT = whole blood clotting time (no additive blue container)

VDK = venom detection kit, only on arrival

Bloods

On arrival

Immediately before administration of antivenom if > 30 min later than bloods taken on arrival

30 min after each antivenom infusion

4 hourly until normal results

8 hourly until discharge = 12h after bite when non-envenomed

Symptoms by snake type

Western brown

Transient early hypotension / collapse with procoagulation. Neurotox rare, no myotox

Mulga (King Brown = black snake group)

Early anticoagulant, marked myotox, occasionally neurotox

Taipan

Transient early hypotension / collapse, procoagulation, neurotox +/- myotox

Death adder

Neurotox only

Symptoms minor

N, V. abdo pain, headache

Tender regional lymph nodes +/- enlargement

DO NOT REQUIRE ANTIVENOM

Symptoms major

Coagulopathy 0-4h after bite

Neurotoxicity 1-6h after bite up to 24h in death adder

Myotoxicity 1-2h after bite

Cardiac

Also:

Thrombotic micro-angiopathy in ass with coagulopathy

Resulting in kidney damage

REQUIRE ANTIVENOM

Coagulopathy 0-4h after bite

WBCT > 10 min

Procoagulant = APPT, PT and D-dimer

Anticoagulant = APPT and PT D-dimer =

UA pos blood

Bleeding

Neurotoxicity 1-6h after bite up to 24h: ptosis, then ophtalmoplegia, then bulbar palsy,finally resp paralysis

Myotoxicity 1-2h after bite

Dark urine

Pos dipstick for blood can be true hematuria or myoglobinuria or haemoglobinuria (intravsc haemolysis)

Cardiac

Early transient hypotension +/- collapse within 30 min

Rarely arrhytmias 1-12h

Treatment envenomation

ACDE approach

Continuous cardiac monitoring

Neuro obs

CT brain in every pt with conc. head strike or headache

Contact consultant + Bart Currie / Geoff Isbister

Antivenom when major symptoms

Antivenom 1

All groups of poisonous elapids are possible, except tiger snake. Thus alle snake antivenoms available in RDH:

Polyvalent

Brown

Black

Taipan

Death adder

Sea snake

Antivenom 2

Administer in resus

In stable patients commence specific antivenom (snake identified or pos VDK result, takes 20-30 min)

In unstable patients give 1 vial polyvalent and change to specific when identified

In clin. significant bleeding from Brown snake give 2 vials

Dilute antivenom 1:10 with NS, infuse over 30 min

Antivenom 3

In anaphylaxis (25%) (5% severe) stop infusion, Tx normally (PM: Adrenaline im safer)

Same amount for children

Remove PBI towards the end of the antivenom infusion

Admit unless snake identified as non-venomous by reptile specialist

D/c pts bitten in Darwin urban area at 12h if asymptomatic and bloods normal, all others 24h (Death adder)

Sea snake

Treat bite as land snake bite

CSL sea snake antivenom, 1 vial

SPIDERS

Sources

http://arnhemlandpestcontrol.com.au/spiders/spiders.htm

Common spiders in the Darwin area, Chin, july 2014

Rural EM skills training syllabus, ACRRM

Red back

Mechanism

Venom depletes neurotransmitters at

Neuromuscular junction -> patchy paralysis

Adrenergic nerve ending -> autonomic dysfunction

Can cause serious illness / death.

No fatalities since antivenom 1956, but painful.

Symptoms

Immediate pain and local swelling, sweating

20 min: swelling lymph nodes, abdo pain, tachycardia,

60 min: headache, N and V, fever, insomnia, restlessness

Occasionally: severe hypertension, paralysis, convulsions, skin rashes, tongue swelling, jaw rigidity, migratory arthralgia

Treatment

Monitoring and neuro obs

Do not apply pressure bandage, increases pain

Apply ice

Morphine

Benzodiazepine for muscle spasms or extreme anxiety

Antivenom for syst symptoms or severe pain: 2 vials / 500 IE im (adults and kids) and monitor for 4 h after administration. Can be given days / weeks after bite.

Tetanus status check +/- ADT

Northern mouse

No fatalities but painful bite, can cause headache and N, treat with funnel-web antivenom

Huntsman

Local symptoms, sometimes inflammation, headache, V and irreg. pulse

Orb

Occasional N and dizziness

Wolf

Local symptoms, less commonly ulceration, sometimes with N and V

STINGERS

Sources

RDH guideline

Resus.com.au

Pictures from the web

Rural EM skills training syllabus, ACRRM

CARPA standard treatment manual

eTG

Box jellyfish

Box Jellyfish

= Chironex fleckeri

About 40 ED visits RDH every wet season = october-may

Bell 20 cm, up to fifteen tentacles on each corner, up to 3 mtrs long, up to 5000 nematocysts on each tentacle

Venom:

Neurotoxins

Cardiotoxins

Dermatonecrotic toxins

Symptoms

Intense pain and tentacle marks

Irrational behaviour

Arrhythmias

In severe envenomation systemic effects WITH CARDIORESPIRATORY ARREST within minutes

Fatalities rare. Last 11 deaths in children

Appearance

Investigations

ECG – ventricular ectopy or arrhytmias?

Cardiac monitoring

Sticky tape test to send to Bart Currie, identifying species

Tx non-systemic ABCDE

Vinegar to inactivate undischarged nematocysts

Remove tentacles

Apply ice

Analgesia - Morphine

Antivenom 1 ampule if pain not controlled iv or im

No pressure bandage, increases pain

Treat as burn. Tetanus status check +/- ADT

d/c home with advise, RDH guideline

Tx if systemic

Resuscitation and supportive therapy

Incl 2 iv lines and high flow O2

Antivenom 1 ampule 1: 10 diluted in NS, in 5 min iv, up to 3 ampules

Or 3 ampules im at different sites

Repeat if no response, up to 6 ampules

Tx (imp) cardiac arrest

Resuscitation

6 ampules antivenom

20 mmol = 2 ampules MgSO4 iv

Continue CPR until all 6 ampules given

Irukandji

Irukandji

= Carukia Barnesi

25 cms across, 1 tentacle from each corner

Usually october to april

Symptoms

Severe lower back, chest and abdo pain

On and off muscle cramps

V, restlessness, anxiety, sweating, piloerection

Tachycardia, hypertension, heart failure, pulmonary edema

Tx

RDH

Blue ringed octopus

Can penetrate wetsuit. Enough venom to kill 26 adults

Saliva potent fast acting paralytic neurotoxin

Small painless bite

Perioral paraesthesia, then N/V and rapid onset flaccid paralysis in 5-30 min

In severe cases respiratory and cardiac arrest

Irrigate wound, suction, PBI, supportive care

Tetanus status check +/- ADT

Stonefish

Pain, swelling, weakness limb.

Tx 40-45 degrees water

Local Lignocaine, opioids, nerve block

Antivenom 1 vial

No pressure bandage

Tetanus status check +/- ADT

Catfish

Same as stonefish

No antivenom

X-ray, piece of barb often breaks off into wound

Stingray

Stingray barb injury:

Pain, bleeding wound, then pale / bluish-white wound

Significant local trauma, damage to underlying structures (heart / lung if chest wall puncture)

Rarely systemic symptoms

Pain relieve same as other fish

Xray. May need surgery to remove pieces

Don’t let it be