Snake bite

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full CAHS clinical disclaimer

Aim

To guide staff with the assessment and management of snake bite.

This is a general approach to snake bite – for specific management details, please contact Poisons Information on 13 11 26 or refer to the Toxicology and Toxinology – Therapeutic Guidelines.

Background¹

• Envenomation is rare but can be lethal. Treat all suspected snake bites as envenomed until proven otherwise.
• Apply a pressure immobilisation bandage for suspected snake bites that present to the Emergency Department if one is not already insitu.

Risk

Failure to follow this guideline may lead to significant envenomation of a child bitten by a snake.

General¹

• Snakes that can be found in Western Australia include black snakes (Mulga or King Brown), brown snakes (Dugite, Western Brown), Death Adders, Tiger Snakes, Taipans and sea snakes.
• Around Perth, brown snakes are found everywhere, Death Adders in the hills, brown snakes in sand and Tiger Snakes in waterways.

Snake bite quick reference guide
All patients are treated as if they are potentially envenomated until proven otherwise. This takes over 12 hours to evaluate. Determination of snake type is dependent upon the geographical location, physical signs and laboratory findings.
First aid Ensure pressure bandage with immobilisation (PBI) is applied.	Transport to a hospital with: Doctor who can manage the snake bite Laboratory who can operate within 24 hours Antivenom available
Resuscitation - if collapse, seizure, major haemorrhage or cardiac arrest Manage as per the ED Guideline: Serious illness Call WA Poisons Information Centre on 13 11 26, and prepare for antivenom administration
Assessment	Signs and symptoms of envenomation
Time of bite Geographical location – near fresh water? Location of bite on the person/ number of bites Time PBI applied Signs and symptoms of envenomation	Systemic – nausea, vomiting, diarrhoea, abdominal pain, headache Hypotension Bleeding – IV site, mucosal Descending flaccid paralysis – early signs are ptosis, diplopia, blurred vision, difficulty swallowing and altered voice. Then respiratory muscle (assess Peak Expiratory Flow Rate (PEFR) in older child) and limb weakness. Muscle tenderness and pain Bite site pain
Laboratory investigations (don't use point of care testing)
Full blood picture Coagulation profile including: Activated Partial Prothrombin Time (APTT) International Normalised Ratio (INR) D-Dimer Creatine Kinase (CK) Urea, electrolytes and creatinine Lactate Dehydrogenase (LDH)	Urinalysis ECG Snake Venom Detection kit (SVDK) – only at the request of the Toxicologist where evidence of envenomation exists. Bite site swab preferred over urine sample.
If asymptomatic and normal initial investigations, remove PBI Repeat examination and bloods 1 hour post removal of PBI and then 6 and 12 hours post bite.
If at any stage INR > 1.3, or the patient has paralysis	If at any stage Symptoms other than paralysis OR Raised WBC or Raised LDH or Low Plts OR Raised APTT or Low Fibrinogen or DDimer >2.5 mg/L OR Rising Creatinine or CK > 1000 U/L	If all laboratory results and examinations are normal at 12 hours
Call WA Poisons Information Centre: 13 11 26 and prepare for antivenom administration Move patient to resuscitation area to manage potential anaphylaxis Give monovalent antivenom (as guided by Poisons Information Centre) Dilute 1 ampoule in 10mL/kg of sodium chloride 0.9% and administer via IV infusion over 30 minutes Remove PBI halfway through the antivenom administration Discuss with WA Poisons Information Centre: 13 11 26 regarding post antivenom care and repeat bloods	Discuss with WA Poisons Information Centre: 13 11 26 Consider antivenom	Discharge during daylight hours

 

Assessment

• Snake bites are a time critical presentation
• Complete a full set of observations and record on the Observation and Response Tool, Clinical Comments Chart and the Neurovascular Observations Chart.
• Rapidly complete initial physical examination and laboratory tests.

History

• Circumstances
• Confirmed or suspected.
• Geographical area where bite occurred.
• Appearance of snake (Unreliable).
• Time, site, number of bites.
• First aid and use of pressure bandage immobilisation prior to hospital arrival.
• Symptoms
• Systemic: Nausea, vomiting, abdominal pain, diarrhoea, mild fever.
• Localised: Diaphoresis, local pain/swelling/enlarged lymph nodes.
• Haematological: Bruising, Bleeding from site/mucus membranes, Haematuria.
• Neurological: Headache, visual changes, slurring of speech, muscular weakness or aches, respiratory distress, reduced consciousness.

Examination and signs of envenomation

General

• Complete a full Cardiac, Respiratory, Abdominal and Neurological examination. Do not remove PBI during examination, instead cut a window at the bite site.
• Cardiovascular: Hypotension, Collapse
• Respiratory: Respiratory Failure secondary to Muscle Paralysis
• Neurological: Photophobia, Confusion, Irritability, Weakness, CN abnormalities
• Haematological: Evidence of Bleeding or Bruising.

Tissue specific signs¹

Toxin type	Toxin effects	Clinical Signs	Laboratory Tests
Neurotoxins	Act on the neuromuscular junction of the skeletal muscle, causing progressive paralysis Can be pre-synaptic or post-synaptic Order of progression tends to be cranial nerve palsies → skeletal muscles → respiratory muscles	Ptosis, partial ophthalmoplegia with diplopia Dysarthria, difficulty swallowing, drooling Loss of facial expression Limb weakness
Myotoxins	Bind to muscle fibres causing destruction of muscle cells with release of myoglobin Causes muscle weakness, pain on movement Leads to secondary acute tubular necrosis and renal failure	Pain on contracting muscles against resistance Muscle weakness	CK Urea and Electrolytes (U&E) Urine positive for blood (myoglobin)
Haemotoxins	Procoagulants – cause a consumptive coagulopathy (consumption of fibrinogen, and increased fibrin degradation products (FDP), disseminated intravascular coagulation, bleeding tendency Anticoagulants – cause an anticoagulative coagulopathy without generation of FDP	Persistent ooze from the bite site or venepuncture sites Signs of cerebral irritation (intracranial haemorrhage)	FBC and Film Coagulation profile Fibrinogen D Dimer Fibrin degradation products

 

Toxidromes of snake bites¹

	Coagulopathy	Neurological – Paralysis	Rhabdomyolysis	Other
Brown Snakes: Western Brown Snake (Gwarder) Dugite	Always present	Rare	No	Renal failure uncommon Microangiopathic haemolytic anaemia Thrombocytopaenia
Black Snakes: King Brown (Mulga)	Mild (raised APTT but normal  fibrinogen)	No	Develops over hours to days	Renal failure can occur Significant local bite site pain
Tiger Snake	Always present	Slow onset over hours (pre-synaptic)	Slow onset over hours	Renal failure can occur Microangiopathic haemolytic anaemia Thrombocytopaenia
Death Adder	No	Slow onset over hours (post-synaptic)	No	Local bite site pain is common
Sea Snakes	No	Rapid onset (pre-synaptic)	Develops over minutes to hours	Renal failure can occur

Investigations

Blood tests

• Coagulation profile – INR, APTT, Fibrinogen
• D-dimer, fibrin degradation products
• FBC and Film
• Creatinine kinase (CK)
• Urea, electrolytes, creatinine (UEC)
• LDH

Other tests

• ECG
• Urinalysis; looking for Myoglobinuria identified as positive blood on dipstick

Management²

First Aid

Do Reassure the patient Keep the patient still (bring transport to them), do not permit walking Remove jewellery and clothing of affected limb Immediately apply a pressure immobilisation (compression) bandage, then splint the limb Seek medical attention urgently.

Don't Wash the wound Incise the wound Suck the wound Use the tourniquet

Pressure Immobilisation Bandage To delay the lymphatic spread of toxin from the bite site by compressing the lymphatic vessels at, and proximal to the bite site Immobilise the limb to prevent “muscle pump” effect Animal studies show little movement of venom centrally if the limb is still Avoid further activity – keep the patient still Technique Apply a broad elasticated compression bandage (or crepe if unavailable) over the bite and extend it (or a 2nd bandage) as proximal as possible. Apply the same amount of pressure as one would for a sprained ankle Do not occlude the circulation Splint the limb once pressure bandage applied The pressure immobilisation bandage should not be removed until: the patient has been fully assessed in hospital and there is no evidence (clinical or initial laboratory tests) of envenomation or if envenomed – antivenom has been administered.

Initial management

• The patient must be transferred to a hospital that has a doctor able to manage snake bite, a 24-hour laboratory and adequate antivenom stocks for further management.
• Insert 2 IV lines and take initial blood tests (see above).
• Determine whether to follow Envenomation pathway or Observation pathway depending on symptoms, clinical assessment, laboratory result and discussion with ToxicologyOnly remove pressure immobilisation bandage once asymptomatic, normal investigations and discussed with Toxicology OR antivenom administered.

Management if Envenomation Unlikely ⁴

• Patients are monitored in hospital with serial clinical examination and laboratory tests at 1 hour post pressure immobilisation bandage removal, and at 6 hours and 12 hours post bite.
• If evidence of envenomation occurs at any time, administer the appropriate antivenom.
  Patients can be discharged at 12 hours post bite if there is no clinical or biochemical evidence of envenomation. Do NOT discharge at night.

Management if Envenomation Likely⁴

• Do not remove pressure immobilisation bandage until at least half of the Antivenom administered.
• Patients are monitored in hospital with serial clinical examination and laboratory tests 6 hours, 12 hours and then every subsequent 24 hours until asymptomatic and investigations normalised following antivenom administration.

Administration of Antivenom¹

• Refer to Toxicology and Toxinology – Therapeutic Guidelines or consult WA Poisons Information on 13 11 26.
• Antivenom at PCH is stored in the High Dependency Unit – Refer to Formulary One for imprest locations.
  • Further stockholdings can be found on the Statewide Toxicology Medicines List.
• Type of antivenom used depends on the geographical site, clinical features and laboratory tests.
• Monovalent is always preferred to polyvalent as it is safer and less expensive.
• Consult the WA Poisons Information on 13 11 26 for guidance on the choice of anti-venom and need for repeat doses.
• Dilute the contents of 1 antivenom vial in sodium chloride 0.9% 10 mL/kg to a maximum of 500 mL.^1,3
• Note: Dose is NOT calculated by patient weight, it is the same for all children.
• Administer via intravenous infusion over 30 minutes, start slowly and increase rate. 

Side effects of antivenom

• Usually mild reactions – erythema or urticaria
• Anaphylaxis (incidence: 1% for monovalent, 5% for polyvalent).

Management of antivenom reactions

• Stop the antivenom infusion temporarily
• High flow oxygen
• If true anaphylaxis has occurred: refer to ED guideline: Anaphylaxis
• Recommence antivenom infusion as soon as clinically possible at a slower rate. 

Complications

Serum sickness³

• Warn all patients who have received antivenom about the possibility of delayed serum sickness and the need to seek urgent medical attention should this occur.
• May occur up to 21 days after antivenom administration, and is characterised by fever, rash, generalised lymphadenopathy, aching joints and sometimes renal impairment.
• Treatment: For moderate to severe cases of serum sickness, use: prednisolone 0.5 mg/kg (up to 25 mg) orally, daily for up to 7 days.

 

Further management

• Use of blood products is controversial – they should be reserved for life threatening haemorrhage and only given after consultation with Poisons Information on 13 11 26
• Monitor for signs of Renal Failure; more likely to be caused by thrombotic microangiopathy rather than rhabdomyolysis.
• Assess tetanus status once coagulation normalised. Refer to Tetanus prone wounds 

Nursing

• If any systemic and/or tissue specific signs of envenomation become evident, document and report immediately to the medical team.

Observations

• Baseline observations include heart rate, respiratory rate, oxygen saturation, temperature, blood pressure, pain score, neurological observations and neurovascular observations (of the bandaged limb). Record on the Observation and Response Tool, Clinical Comments Chart and the Neurovascular Observations Chart.
• Minimum of hourly observations should be recorded whilst in the emergency department.
• Any significant changes should be reported immediately to the medical team.
• A baseline electrocardiogram (ECG) should be performed on arrival.

References

1. Armstrong J.. Toxicology Handbook. 4thd Edition. Chatswood, NSW: Elsevier Australia; 2022. Available from: Toxicology Handbook - ClinicalKey (health.wa.gov.au)
2. First-aid management of bites and stings. Western Australian Poisons Information Centre. October 2021. Cited 06 May 2025. Available from: 6674063A8BF94460A7EE9B5B417338EC.ashx (health.wa.gov.au)
3. Australian Injectable Drugs. Handbook, 9th Edition. Cited 8 May 2025. Available from: AIDH - ANTIVENOM, SNAKE
4. Snake bite. Therapeutic Guidelines Published March 2021. Cited: 06 May 2025. Available from: Topic | Therapeutic Guidelines (health.wa.gov.au)
5. Fleisher, Gary R. Ludwig, Stephen. Textbook of Pediatric Emergency Medicine, 7th Edition. 2015
6. ANZCOR Guideline; Guideline 9.4.1 – First Aid Management of Australian Snake Bite. Accessed 06 May 2025.
7. Australian Medicines Handbook. Antivenoms in snakebite - Australian Medicines Handbook. Accessed 06 May 2025.

 

Endorsed by:	CAHS DTC	Date:	Jan 2026
		Review date:	Jan 2029

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