Snake bite


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


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.


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

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


 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


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)


Creatine Kinase (CK)

Urea, electrolytes and creatinine

Lactate Dehydrogenase (LDH)



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
Raised white cell count
Raised APTT or CK > 1000U/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


  • 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 bites are a time critical presentation
  • Rapidly complete initial physical examination and laboratory tests.


  • Geographical area where the patient was bitten may aid in determining the type of snake
  • Appearance of snake (note: this is often unreliable)
  • Time of snake bite, site of bite, number of bites
  • Use of pressure immobilisation bandage and other first aid treatment prior to hospital arrival.



  • Observations (vital signs, neurological observations and neurovascular observations of the bandaged limb)
  • Mental status
  • Bite site – anatomical location, appearance
  • Lymphadenopathy
  • Evidence of bleeding
  • Cardiovascular, respiratory and neurological examinations.

Signs of envenomation

Systemic signs1

  • Neurological: headache, photophobia, irritability, confusion, seizures
  • Cardiovascular: hypotension, collapse
  • Respiratory: respiratory failure (due to muscle paralysis)
  • Gastrointestinal tract: nausea, vomiting, abdominal pain
  • Other: mild fever.

Tissue specific signs1

Toxin type

Toxin effects

Clinical Signs

Laboratory Tests


  • 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



  • 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
  • U&E
  • Urine positive for blood (myoglobin)


  • 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)
  • Coagulation profile
  • Fibrinogen
  • Fibrin degredation products
  • FBP


Clinical and laboratory features of snake bites1


Neurological – Paralysis 



Brown Snakes:

Western Brown Snake (Gwarder)


Always present



  • Renal failure uncommon
  • Microangiopathic haemolytic anaemia
  • Thrombocytopaenia

Black Snakes:

King Brown (Mulga)


(raised APTT but normal  fibrinogen)


Develops over hours to days

  • Renal failure can occur
  • Significant local bite site pain

Tiger Snake

Always present

Slow onset over hours

Slow onset over hours

  • Renal failure can occur
  • Microangiopathic haemolytic anaemia
  • Thrombocytopaenia

Death Adder


Slow onset over hours


  • Local bite site pain is common

 Sea Snakes


Rapid onset

Develops over minutes to hours

  • Renal failure can occur


Blood tests

  • Coagulation profile – INR, APTT, Fibrinogen
  • Fibrinogen
  • D-dimer, fibrin degredation products
  • FBC
  • Creatinine kinase (CK)
  • Urea, electrolytes, creatinine (UEC)
  • Urine microscopy – red blood cells, myoglobin.


First Aid
  • Reassure the patient
  • Keep the patient still (bring transport to them)
  • Immediately apply a pressure immobilisation (compression) bandage, then splint the limb
  • Seek medical attention urgently.
  • 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
  • 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.
  • Pressure immobilisation bandage removed if all tests are normal and patient remains asymptomatic. If there is clinical or biochemical evidence of envenomation, give antivenom as below.


Administration of Antivenom1

  • Refer to Toxicology and Toxinology – Therapeutic Guidelines or consult WA Poisons Information on 13 11 26.
  • Type of antivenom used depends on the geographical site, clinical features and laboratory tests.
  • Monovalent is always preferred to polyvalent as it is safer (fewer side effects), cheaper and specific.
  • 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 ampoule in sodium chloride 0.9% 10mL/kg to a maximum of 500mL.1
  • Administer via intravenous infusion over 30 minutes.
  • Repeat bloods 6 and 12 hours after antivenom, then every 12 hours until normalised.
  • Note: Dose is NOT calculated by patient weight, it is the same for all children.

Further management

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.

Adjuvant therapy

Blood products

  • Use of blood products is controversial – they should be reserved for life threatening haemorrhage and only given after consultation with WA Poisons Information on 13 11 26.

Tetanus prophylaxis


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
  • Prevention: oral steroids (Prednisolone) 1mg/kg/day for 5 days is recommended for patients who received high doses of antivenom, either as a single dose of polyvalent antivenom or multiple doses of monovalent antivenom
  • Treatment: For moderate to severe cases of serum sickness, use: prednisolone 1 mg/kg (up to 50 mg) orally, daily for up to 5 days.1

Admission criteria

  • Patients are monitored in hospital with serial clinical examination and laboratory tests at 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.

Discharge criteria

  • Patients can be discharged at 12 hours post bite if there is no clinical or biochemical evidence of envenomation.
  • Do not discharge at night.


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


  • 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.


  1. Murray L, Little M, Pascu O and Hoggett K. Toxicology Handbook. 3rd Edition. Chatswood, NSW: Elsevier Australia; 2015. Available from: Toxicology Handbook - ClinicalKey (
  2. First-aid management of bites and stings. Western Australian Poisons Information Centre. October 2021. Cited 22 December 2021. Available from: 6674063A8BF94460A7EE9B5B417338EC.ashx (
  3. Snake bite. Therapeutic Guidelines Published March 2021. Cited: 12 January 2022. Available from: Topic | Therapeutic Guidelines (
  4. Fleisher, Gary R. Ludwig, Stephen. Textbook of Pediatric Emergency Medicine, 7th Edition. 2015

Endorsed by: CAHS DTC  Date:  Mar 2022

 Review date:   Feb 2025

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