Snake bites

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1. Signs and management done by U dawattage G eewan K amal 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 Introduction

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, Krait0.06gm- Russell’s V-0.15gm

5. Highly venomous Russell’s viper Hump-nosed viper Saw scaled viper Sea snake Cobra Common krait Ceylon krait Snakes of Sri Lanka

6. Russell’s viper Hump nosed viper

7. Sea snake Cobra

8. Ceylon krait

9. Moderately venomous Cat snake Green-pit viper

10. Non-venomous snakes Rat snake Wolf snake

11. Signs and Symptoms

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 Common envenomation signs and symptoms 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

15. Diagnosis Between Different Species Using Symptoms

16. Fang marks Local pain Local bleeding Bruising Lymphadenitis Inflammation (swelling, redness, heat) Blistering Local infection Necrosis Local

17. Cardiovascular signs and symptoms Bleeding and clotting disorders Neurotoxicity Rhabdomyolysis with myoglobinuria Renal Systemic – Specific signs

18. Nausea Vomiting Malaise Abdominal pain Weakness Drowsiness Systemic – Non specific signs

19. Snake type Local reaction clotting Neurological Renal Russell’s viper + + + + Hump nosed viper + + + Saw scaled viper + + Cobra ++ + Krait + Sea snake +

20. 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 A ims of first aid

21. 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 Systemic envenoming Haemostatic abnormalities : spontaneous systemic bleeding, coagulopathy(20WBCT,prothrombin time) thrombocytopenia(less than 100*109 per litre ) Neurotoxic signs (ptosis, external opthalmoplegia , paralysis) Cardiovascular abnormalities (hypotension, shock, cardiac arrhythmia) In S ri 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. AVS

22. At the earliest sign of a reaction 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

23. 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 Russell’s viper Cobra Hump nose viper Sea snake Saw scale viper