 |
|
|
![Naja siamensis ( Thai Spitting Cobra ) [ Original photo copyright © Dr Wolfgang Wuster ]](images/snakes/SNP00451.jpg)
|
|
Family: Elapidae
|
|
Subfamily: Elapinae
|
|
Genus: Naja
|
|
Species: siamensis
|
Common Names
Thai Spitting Cobra , Isan Spitting Cobra , Indo-Chinese Spitting Cobra
|
Local Names
Ngu Hao Phon Phit
|
Region
Southeast Asia
|
Countries
Cambodia, Laos, Thailand, Vietnam
|
|
|
|
|
|
Taxonomy and Biology
|
|
Adult Length: 0.90 m
|
General Shape
Medium in length, heavy bodied snake with long cervical ribs capable of expansion to form a hood when threatened. Body is compressed dorsoventrally and sub-cylindrical posteriorly. Can grow to a maximum of about 1.60 metres. Head is elliptical, depressed and slightly distinct from neck with a short, rounded snout and large nostrils. Eyes are medium in size with round pupils. Dorsal scales are smooth and strongly oblique.
|
Habitat
Found mainly in lowlands and foothills in a variety of habitats.
|
Habits
Terrestrial and mainly diurnal snake. Readily spits its venom in defense.
|
Prey
Feeds mainly on rodents, frogs and snakes.
|
|
|
|
Venom
|
General: Venom Neurotoxins
Postsynaptic neurotoxins
|
General: Venom Myotoxins
Probably not present
|
General: Venom Procoagulants
Probably not present
|
General: Venom Anticoagulants
Probably not present
|
General: Venom Haemorrhagins
Probably not present
|
General: Venom Nephrotoxins
Probably not present
|
General: Venom Cardiotoxins
Possibly present
|
General: Venom Necrotoxins
Present but not defined
|
General: Venom Other
Not present or not significant
|
|
|
|
Clinical Effects
|
General: Dangerousness
Severe envenoming possible, potentially lethal
|
|
General: Rate of Envenoming: Unknown but likely to be high
|
|
General: Untreated Lethality Rate: Unknown but lethal potential cannot be excluded
|
General: Local Effects
Marked local effects; pain, severe swelling, bruising, blistering, necrosis
|
General: Local Necrosis
Common, moderate to severe
|
General: General Systemic Effects
Variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or convulsions
|
General: Neurotoxic Paralysis
May cause moderate to severe flaccid paralysis
|
General: Myotoxicity
Does not occur, based on current clinical evidence
|
General: Coagulopathy & Haemorrhages
Does not occur, based on current clinical evidence
|
General: Renal Damage
Rare, usually secondary effect
|
General: Cardiotoxicity
Rare, usually secondary
|
General: Other
These snakes can spit their venom, causing venom spit ophthalmia.
|
|
|
|
First Aid
|
|
Description: First aid for bites by Elapid snakes which are likely to cause significant local damage at the bite site as their major clinical effect (see listing in Comments section). This includes venom spat into eyes by spitting cobras.
|
Details
Section 1: General first aid (for first aid of venom spit ophthalmia (venom in eyes) see Section 2 below).
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.
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. The bitten limb should be immobilised as effectively as possible using an extemporised splint or sling; if available, crepe bandaging of the splinted limb is an effective form of immobilisation.
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.
Section 2: First aid for venom spit ophthalmia.
1. Venom coming into contact with eyes can cause intense conjunctivitis with a risk of corneal erosions, complicated by secondary infection, anterior uveitis and even permanent blindness. All this can occur following venom spat into the eyes from a spitting cobra.
2. Irrigate the eye or other affected mucous membrane as soon as possible using large volumes of water or any other available bland fluid. Never use chemical solutions or petroleum products such as petrol or kerosene. Milk is soothing and can be used, or in an emergency beer or urine are possibilities. Keep irrigating the eyes, hold them under a slowly running tap for a several minutes, while opening the eyelids and rotating the eyeball. The eye will be very painful, so patience, tact and reassurance are needed.
3. The eye should be bandaged using a pad over the eye and dark glasses worn.
4. Don''t let the victim rub the eye.
5. Seek urgent medical attention
|
|
|
|
Treatment
|
Treatment Summary
Bites can cause both local tissue injury and systemic effects, principally flaccid paralysis. Treatment is therefore twofold; good wound care and control of secondary infection, plus watch for flaccid paralysis. If severe paralysis present, with respiratory failure, requires intubation & ventilation. Specific antivenoms available, which should be given at first sign of developing paralysis.
|
Key Diagnostic Features
Local pain, swelling, blistering, necrosis ± flaccid 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.
|
|
|
|
