Snake bites are a major public health issue, with an estimated 5 million bites annually resulting in over 100,000 deaths. Sri Lanka has a particularly high rate, with 800 deaths annually from bites mainly by three venomous snakes. Snake venom contains various toxins that can cause local and systemic effects from bleeding and clotting disorders to neurotoxicity and kidney damage depending on the snake type. Symptoms of envenoming may include pain and swelling at the bite site, nausea, vomiting and visual changes. Prompt first aid and antivenom treatment can prevent death and complications from snake bites.
2. It is estimated that there are about 5 million snake bites every year, of
those it’s estimated around 2.4 million are envenoming
These snake bites cause around 94 000 to 125 000 deaths annually with an
additional 400 000 amputations and other consequences -infection,
tetanus, scarring, contractures, and psychological sequelae
Most snake bites are caused by non-venomous snakes
Of the roughly 3000 known species of snake found worldwide, only 15%
are considered dangerous to humans
Snakes are found on every continent except Antarctica
3. In Sri Lanka there are about 65 000 snake bites annually
More people die of snake bite in Sri Lanka than in any other
comparable area in the world
An average of 800 people are killed by snakes every year on the
656,120Km² (25,332miles²) island - equivalent to one person every
82Km² (32 miles²) annually
Over 95% of the fatalities are caused by the common krait (Bungarus
caeruleus), the Sri Lankan cobra (Naja n. naja) and Russel's pit viper
(Vipera russelli pulchella)
4. Snake Venom :
Snake venom is made up of more than 20 different compounds, mostly
proteins and polypeptides
Procoagulant enzymes (activate coagulation cascade)
Phospholipase A2 (myotoxic, neurotoxic, cardio toxic – cause hemolysis,
increase vascular permeability)
Proteases (tissue necrosis)
Polypeptide toxins (disrupt neuromuscular transmission)
Lethal dose of venom of certain snakes :
Cobra-0.12gm, Krait-0.06gm- Russell’s V-0.15gm
12. Puncture mark or scratches on suspected bite area. At times marks could not
be visible
Bleeding at bite site, unusual pain around the bitten area and limb, swelling
Nausea, headache, vomiting , stomach ache, difficulty in swallowing or
drinking
Double or blurred vision
Drooping eyelids
Difficulty in talking.
Bleeding in gums.
Dark or brownish urine bloody urine.
Giddyness
The following are few of the most common symptoms of envenomation due
to a snake bite. Symptoms may occur soon after the bite or take hours to
appear.
A minimum of twenty-four hour observation of the patient is suggested.
13. These images of actual bite marks
by venomous snakes show that
marks may or may not be clearly
visible.
Bite marks dependent on the type
and size of snake in question.
Common locations of snake bites
14. Drooping eyelids
Change in color of tissue around the bite area
Swelling in the limb
Blisters in the bite
area
Signs and symptoms of a venomous snake
bite
21. Attempt to retard systemic absorption of venom
Preserve life and prevent complications before the patient can receive
medical care
Control distressing or dangerous early symptoms of envenoming
Arrange the transport of the patient to a place where they can receive
medical care
22.
23. Anti-venom is the only specific antidote to snake venom
A most important decision in the management of a snake bite victim is whether or not to
administer anti-venom
Indications for anti-venom. Anti-venom treatment is recommended if and when a patient with
proven or suspected snakebite develops one or more of the following signs
1. Systemic envenoming
2. Haemostatic abnormalities : spontaneous systemic bleeding,
coagulopathy(20WBCT,prothrombin time) thrombocytopenia(less than 100*109 per litre)
3. Neurotoxic signs (ptosis, external opthalmoplegia, paralysis)
4. Cardiovascular abnormalities (hypotension, shock, cardiac arrhythmia)
In Sri lanka given to all patients with systemic envenomation except in hump nosed viper bite
and sea snake bite
If the snake is identified as nonvenomous patient can be discharged after a booster dose of
tetanous toxoid.
24. Anti-venom administration must be temporarily suspended
Epinephrine(0.1%solution,1 in 1000,1mg/ml)is the effective treatment
for early anaphylactic and pyrogenic anti-venom reactions
All patients should be watched carefully for 2 hours after the
completion of anti-venom administration and should be treated with
epinephrine/adrenaline at the fist sign of a reaction
25. Q.a farmer presents with a history of snake bite but could not identify or
kill the snake. His foot is swollen and painfull and bite site is necrotic. b/l
partial ptosis. uop is normal. rft normal. 20 min wbct normal. what is the
most likely snake
1. Russell’s viper
2. Cobra
3. Hump nose viper
4. Sea snake
5. Saw scale viper
These are the main snakes seen in sri lanka.
In the emergency department doctors use this classification of symptoms to identify the type of the snake involved.