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Pseudonaja nuchalis
General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid , Antivenoms
Pseudonaja nuchalis  ( Western Brown Snake )  [ Original photo copyright © Dr Julian White ]
Family: Elapidae
Subfamily: Elapinae
Genus: Pseudonaja
Species: nuchalis
Common Names
Western Brown Snake , Gwardar
Region
Australia
Countries
Australia
 
Taxonomy and Biology
Adult Length: 1.30 m
General Shape
Large in length, slender bodied snake with a medium to moderately short length tail. Can grow to a maximum of about 2.06 metres. Head is moderately small and short and indistinct from neck with a prominent canthus rostralis. Snout is somewhat chisel shaped when viewed from above. Dorsal scales are smooth.
Habitat
Diverse range of habitats from tropical and temperate sclerophyll forests and woodlands to the arid spinifex covered dunes, stony plains and ranges of the inland deserts. Also found in urban and semi-urban areas.
Habits
Diurnal and terrestrial snake with nocturnal tendencies in hotter weather. A swift moving snake with a nervous but mild disposition. Generally speaking it is reluctant to bite. If approached or confronted it will flee for the nearest cover. If cornered and provoked it will strike rapidly and attempt to escape. Takes shelter mostly in abandoned animal burrows, deep soil cracks ( particularly at the base of trees or large exposed tree root systems ) under logs or large flat rocks.
Prey
Feeds mainly on lizards ( particularly skinks, agamids and geckos ) and small mammals ( particularly mice ) but will eat small birds and other snakes.
Species Map
Small (Approx 20k) version
 
Venom
Average Venom Qty
18 mg ( dry weight of milked venom ), Meier and White (1995) ( Ref : R000001 ).

Eyre Peninsula, SA : 19.4 ( 9.4 to 32.3, n = 4 ) mg ( dry weight of milked venom ), Williams et al (1994) ( Ref : R000749 ).

Whyalla, SA : 15.01 ± 5.25 ( n = 4 snakes, 142 milkings ) mg ( dry weight of milked venom ), Masci et al (1998) ( Ref : R000989 ).
Preferred LD50 Estimate
0.473 mg / kg sc ( mice ), Meier and White (1995) ( Ref : R000001 )
General: Venom Neurotoxins
Pre- & Post-synaptic neurotoxins
General: Venom Myotoxins
Not present
General: Venom Procoagulants
Prothrombin convertors
General: Venom Anticoagulants
Not present
General: Venom Haemorrhagins
Not present
General: Venom Nephrotoxins
Possibly present
General: Venom Cardiotoxins
Not present
General: Venom Necrotoxins
Not present
General: Venom Other
Not present or not significant
 
Clinical Effects
General: Dangerousness
Severe envenoming likely, high lethality potential
General: Rate of Envenoming: 20-40%
General: Untreated Lethality Rate: 10-20%
General: Local Effects
None or minimal
General: Local Necrosis
Not likely to occur
General: General Systemic Effects
Variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or convulsions. Early cardiac arrest possible and potentially lethal unless immediate effective resuscitation given.
General: Neurotoxic Paralysis
Rarely reported, usually minor
General: Myotoxicity
Not likely to occur
General: Coagulopathy & Haemorrhages
Very common, coagulopathy is major clinical effect
General: Renal Damage
Recognised complication, usually secondary to coagulopathy
General: Cardiotoxicity
Uncommon, secondary to procoagulant-induced temporary thrombosis in coronary vessels
General: Other
Not likely to occur
 
First Aid
Description: First aid for bites by Elapid snakes which do not cause significant injury at the bite site (see Comments for partial listing), but which may have the potential to cause significant general (systemic) effects, such as paralysis, muscle damage, or bleeding.
Details
1. After ensuring the patient and onlookers have moved out of range of further strikes by the snake, the bitten person should be reassured and persuaded to lie down and remain still. Many will be terrified, fearing sudden death and, in this mood, they may behave irrationally or even hysterically. The basis for reassurance is the fact that many venomous bites do not result in envenoming, the relatively slow progression to severe envenoming (hours following elapid bites, days following viper bites) and the effectiveness of modern medical treatment.
2. The bite wound should not be tampered with in any way. Wiping it once with a damp cloth to remove surface venom is unlikely to do much harm (or good) but the wound must not be massaged. For Australian snakes only, do not wash or clean the wound in any way, as this may interfere with later venom detection once in a hospital.
3. All rings or other jewellery on the bitten limb, especially on fingers, should be removed, as they may act as tourniquets if oedema develops.
4. If the bite is on a limb, a broad bandage (even torn strips of clothing or pantyhose) should be applied over the bitten area at moderate pressure (as for a sprain; not so tight circulation is impaired), then extended to cover as much of the bitten limb as possible, including fingers or toes, going over the top of clothing rather than risking excessive limb movement by removing clothing. The bitten limb should then be immobilised as effectively as possible using an extemporised splint or sling.
5. If there is any impairment of vital functions, such as problems with respiration, airway, circulation, heart function, these must be supported as a priority. In particular, for bites causing flaccid paralysis, including respiratory paralysis, both airway and respiration may be impaired, requiring urgent and prolonged treatment, which may include the mouth to mask (mouth to mouth) technique of expired air transfer. Seek urgent medical attention.
6. Do not use Tourniquets, cut, suck or scarify the wound or apply chemicals or electric shock.
7. Avoid peroral intake, absolutely no alcohol. No sedatives outside hospital. If there will be considerable delay before reaching medical aid, measured in several hours to days, then give clear fluids by mouth to prevent dehydration.
8. If the offending snake has been killed it should be brought with the patient for identification (only relevant in areas where there are more than one naturally occurring venomous snake species), but be careful to avoid touching the head, as even a dead snake can envenom. No attempt should be made to pursue the snake into the undergrowth as this will risk further bites.
9. The snakebite victim should be transported as quickly and as passively as possible to the nearest place where they can be seen by a medically-trained person (health station, dispensary, clinic or hospital). The bitten limb must not be exercised as muscular contraction will promote systemic absorption of venom. If no motor vehicle or boat is available, the patient can be carried on a stretcher or hurdle, on the pillion or crossbar of a bicycle or on someone's back.
10. Most traditional, and many of the more recently fashionable, first aid measures are useless and potentially dangerous. These include local cauterization, incision, excision, amputation, suction by mouth, vacuum pump or syringe, combined incision and suction ("venom-ex" apparatus), injection or instillation of compounds such as potassium permanganate, phenol (carbolic soap) and trypsin, application of electric shocks or ice (cryotherapy), use of traditional herbal, folk and other remedies including the ingestion of emetic plant products and parts of the snake, multiple incisions, tattooing and so on.
 
Treatment
Treatment Summary
While most brown snake bites will prove minor, rapid lethal envenoming can occur, thus all cases must be assessed urgently. If there is systemic envenoming (coagulopathy or renal damage, rarely paralysis) give antivenom (number of vials required is reducing following ongoing clinical research).
Key Diagnostic Features
Minimal local reaction + defibrination coagulopathy ± renal damage, occasionally microangiopathic haemolytic anaemia, rarely paralysis
General Approach to Management
All cases should be treated as urgent & potentially lethal. Rapid assessment & commencement of treatment including appropriate antivenom (if indicated & available) is mandatory. Admit all cases.
Antivenom Therapy
Antivenom is the key treatment for systemic envenoming. Multiple doses may be required.
Antivenoms
1. Antivenom Code: SAuCSL11
Antivenom Name: Brown Snake Antivenom
Manufacturer: CSL Limited
Phone: ++61-3-9389-1911
Toll free: 1800 642 865
Address: 45 Poplar Road
Parkville
Victoria 3052
Country: Australia
2. Antivenom Code: SAuCSL12
Antivenom Name: Polyvalent Snake Antivenom ( Australia - New Guinea )
Manufacturer: CSL Limited
Phone: ++61-3-9389-1911
Toll free: 1800 642 865
Address: 45 Poplar Road
Parkville
Victoria 3052
Country: Australia
Pseudonaja nuchalis ( Western Brown Snake ) [ Original photo copyright © Dr Julian White ]
Larger version
 
Pseudonaja nuchalis ( Western Brown Snake ) [ Original photo copyright © Dr Julian White ]
Larger version
 
Pseudonaja nuchalis ( Western Brown Snake ) [ Original photo copyright © Dr Julian White ]
Larger version
 
Pseudonaja nuchalis ( Western Brown Snake ) [ Original photo copyright © Dr Julian White ]
Larger version
 
Pseudonaja nuchalis ( Western Brown Snake ) [ Original photo copyright © Dr Julian White ]
Larger version
 
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