Thursday, March 17, 2011

First Aid Treatment Of Snake Bite

Out of 3500 species of snakes only 250 are poisonous.The viper(except America) and Cobra (except Europe) are found in all parts of world including India.All sea snakes are poisonous.A brief description of these three types of medically important,poisonous snakes is as follows:
1.Cobras: They belong to the family of Elapidae.They are terrestrial snakes having short fangs.Their venom is neurotoxic.
2.Vipers:They belong to the viperidate family.These snakes have long erectile fangs.The vipers can be of two types.The true vipers,such as Russell's viper and carpet vipers belonging to the sub-family of Viperinae and Pit vipers such as rattle snakes belonging to the sub-family of cortalidate.Their venom is vasculotoxic.
3.Sea snakes:They belong to Hydrophidae family,having characteristic flattened tail and short fangs.The venom of sea snakes is myotoxic.
Clinical features of snake bite:
In poisoning due to the cobra snake the patients feel sleepy,weakness of legs gradually develops into paralysis of legs.There is excessive salivation and vomiting.Due to paralysis of tongue and pharynx,there is difficulty in swallowing and speech,coma sets in and finally respiration ceases and heart stops.
           In the viper poisoning the bite area is swollen and painful.There can be pain abdomen,vomiting,dilatation of pupil and often complete loss of consciousness.Body temperature is raised.There can occur haemorrhages from the gum,rectum or site of bite.The whole body becomes edematous.Death occurs due to shock and haemorrhage.In sea snake bite,the early signs and symptoms are similar to cobra bite.Other signs include myalgia,myoglobinuria,paralysis of limbs and cessation of respiration.
First aid treatment of snake bite:
The first aid treatment of snake bite is as follows:
i)Assure the patient;
ii)Apply firm pressure over the bitten area to delay absorption of poison;
iii)Apply a broad firm bandage around the limb and on the bitten area.As much of the limb should be bandaged as is possible.The bandage should be tight enough to occlude the superficial veins and lymphatic channels but not the arteries or deep veins.Alternatively a ligature can be applied above the site of bite which should be loosened for 90 seconds after every 10 minutes.If bite is on an area other than the limbs,apply firm pressure over the site of the bite;
iv)Immobilise the limb to minimise the spread of venom;
v)Make a cross incision 1 cm long and 0.5 cm deep over each bite mark.Drainage of blood and lymph should be done from each cut by using a glass and a rubber suction bulb for at least one hour;
vi)Clean the wound with sterile saline or water and cover it with a sterile dressing;
  The patient should be shifted to a hospital as early as possible,where antisnake venom serum 20 ml is given intravenously immediately after sensitivity test.Further doses are repeated every six hours till symptoms disappear.

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