the top end. envenomations royal darwin hospital rmo education 29.09.2015 laura k. reg ed
TRANSCRIPT
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