Snake bite and its management by first aid and antivenom

about snake bite ,venom,types of venom,first aid,antivenom,and management ,epidemiology ,dosage and route of antivenom administration , anaphylactic reaction due to antivenom , general symptoms of snake bite,immobilization process , formation of antivenom

1. Snake bite

2. Objectives Introduction Epidemiology Venom Component of venom Difference between poisonous and non poisonous snake Classification of venom Management

3. Snake A long limbless reptile which has no eyelids ,a short tail, and jaws that are capable of considerable extension .

4. Introduction Snake bite are punctured wounds caused by the fangs of snakes where it release it’s venom . • 3500 Species found globally 500 species are poisonous • In Nepal 77 species known, 22 of these are poisonous. Studies in Nepal have identified 4 species of snake responsible for fatal bites. They are indian cobra( naja naja ),common krait( bungaris caeruleus ), Russell’s viper(viper ressellii ) and greenpit viper

5. cobra Greenpit viper Common krait Russells viper

6. Epidemiology There are at least 40,000 cases of snakebite every year in Nepal,with some fatalities in terai alone. Death rate has come down from 18.7% 20 years ago to 6.62% . India has the highest number of deaths due to snake bites in the world with 35,000–50,000 people dying per year according to World Health Organization (WHO) direst estimates. South Asia has the highest incidence and mortality rates of snake bite in the world.

7. Venom A poisonous substance secreted by animals such as snakes,spiders ,and scorpions and typically injected into prey by biting or stinging. Freshly secreted venom is transparent and pale. On storing and on exposure to light it becomes yellowish and opaque

8. Component of venom Contains 20 different constituents mainly proteins including enzymes and polypeptide toxins. Procoagulants Other cytolytic or necrolytic toxins

9. Difference between poisonous and non poisonous snake S.N Poisonous snake Non-poisonous snake 1 Fangs are hollow like hypodermic needle Fangs are short and solid 2 Belly scales are large and cover entire breadth Belly scales are like those on back and don’t cover the entire breadth 3 Teeth are two long fangs Teeth are several and small

10. Classification of venom 1. Haematotoxic venom 2. Neurotoxic venom 3. Myotoxic venom 4. Cytotoxic venom (NOTE- Most snakes have both type of venoms but one is dominant to the other.)

11. 1.Haematotoxic venom Affect blood and circulation . The prey dies from cardiovascular failure and bleeding. Sign and symptoms Vomiting Numbness , confusion Intense pain Bruising , bleeding Rapid pulse

12. 2.Neurotoxic venom Affects the nervous system and brain. Signs and symptoms Ptosis Respiratory paralysis Double vision,dilated pupil Sweating,vomiting Excessive salivation Muscle paralysis It takes about 10 min for the venom to affect nervous system Neurotoxic symptom usually resolve in 2-3 days

13. 3.Myotoxic venom Affect muscle tissue Sign and symptoms Most important symptom are rhabdomyolysis(rapid breakdown of skeletal muscle tissue)and paralysis Disable muscle contraction Pain in legs ,hips and shoulders,with paralysis and damage to kidney

14. 4.Cytotoxic venom Destroy cells Sign and symptoms Bleeding , Blistering and discolouration Painful and progressive swelling Examples of venom Sea MY HEAVY NECK Myotoxic -Sea Snake Hematotoxic – Viper ( Viperidae ) Neurotoxic- Cobra, Krait ( Elapidae ) cytotoxic –puff adder

15. Management First aid treatment and transport to hospital Rapid clinical assessment and resuscitation Antivenom treatment Treatment of bitten part Prevention

16. 1.First aid Reassurance The victim may be frightened and anxious . Reassure victim on that it is a treatable condition . The confirmation can be done by presence of teeth prints . Remove tight clothes,rings etc from bitten limb . b. Immobilization Immobilize the bitten limb with a splint or sling . Any cloth or bandage may be used for this. Any form of movement cause musle contraction that will increase absorption and spread of venom by squeezing vein . Keep the affected limb as low level as possible . Regularly check circulation in fingers or toes. c. Rapid transport

17. First aid if venom enter in eye Irrigating the eye with water or if possible normal saline A single application of local anesthetic eye drops helps to overcome tightly closed eyelids and facilitates irrigation Antivenom treatment is not indicated

18. First aid of bite to trunk If possible apply firm pressure over the bitten area. Donot restrict chest movement and keep patient still First aid of bite in neck There is no first aid keep patient still and take to hospital

19. Do’s Immobilize the limb Get to hospital immediately . traditional remedies have no proven benefit in treating it Tell the doctor if any systemic symptom that manifest on the way to hospital

20. Don’t Interfere with bitten area Suck by mouth Apply chemicals Use tourniquets Cooling agents on bitten area Make incision Walking Give anything to eat

21. 2.Rapid clinical assessment and resuscitation It is a medical emergency. Therefore a quick clinical assessment should be done to decide if patient needs immediate resuscitation or antivenom therapy . Rapid clinical assessment and resuscitation using ABCDE( airway , breathing, circulation,disability of nervous system , exposure and environmental control ) approach should be initiated . Airway obstruction or respiratory failure caused by neurotoxic envenoming requires immediate airway support In case of russells viper bite,shock may occur because of hemorrhage due to incoagulable blood , fluid shift into bitten limb,myocardial depression . This patient must be treated promptly with rapid infusion of normal saline and antivenom started as soon as possible .

22. 3. Antivenom treatment It is only effective treatment for snake bite envenoming . It is prepared from animals plasma ( most often horses , but also donkey or sheep ) after hyper immunized against venom of snakes The currently available antivenom in Nepal is imported from india and is polyvalent( hyperimmunized against venom of several snake species) available in lypophilized powder form . Each vial is reconstituted with 10ml of sterile water for IV administration. It is effective against 4 common species of snakes found in india ; Russells viper ( Daboia russelii ), common cobr ( naja naja ) ,common krait ( bungarus caeruleus ) and saw scaled viper ( echis carinatus ). Saw scaled is not yet reported from Nepal .

23. Indication for administering antivenom Administration of antivenom carries risk of anaphylactic reaction and should not therefore be used unnecessarily Evidence of neurotoxicity Evidence of coagulopathy which is detected by bleeding Evidence of cardiovascular collapse eg . Shock and hypotension

24. Route of administration and dosage of antivenom Adult Reconstituted antivenom is diluted in 5-10 ml/kg body weight (approx. 250-500 ml) of isotonic saline or glucose and administered as infusion @2ml/min. Children Reconstituted antivenom is diluted in 3-5 ml/kg body weight of isotonic saline or dextrose water and administered as infusion @2ml/min Reconstituted antivenom is administerd by slow iv @2ml/min however,this route is not practiced commonly Iv infusion Iv injection

25. Neurotoxic envenoming Initial dose 10 vials (100) ml is further diluted or mixed with dextrose water or saline(100 ml to 400 ml) . Then it is administered with iv infusion at rate of 2ml/min (@60-70 drops /min). Repetition of antivenom dose If neurological signs deteriorates an iv push of 5 vials of antivenom (50ml) reconstituted antivenom should administer @2ml/min Note : donot repeat if neurological sign persist.repeat only if deteriorate Cont …

26. Hematotoxic envenoming Initial dose Same as for neurotoxic envenoming Repetition of dose Persistence of blood incoagulability after every 6 hr of antivenom dose . Repeat coagulation test if it comes abnormal repeat 5 vials of antivenom (50 ml reconstituted antivenom ) iv push@2ml/min Cont …

27. Observation and monitoring Patient receiving antivenom requires continuous observation and frequent monitoring of vital signs . The anaphylaxis reaction may be life threatening so adrenaline(s/c) must be kept ready . 3 types of antivenom reaction can occur ,early anaphylactic reaction (EAR) , pyrogenic reaction and late reaction .

28. Detection of early EAR and PR (pyrogenic reaction It usually occurs within 3hours after initiation of antivenom administration. Following are associated features : Itching,urticaria,swollen lips or tongue Respiratory symptoms:dry cough,wheezing,stridor,hoarse voice Nausea,vomiting,diarrhea Airway obstruction,fever Tachypnea,shock Urticaria

29. 4.Treatment of bitten part Elevation of limb with rest Simple washing with antiseptic solution like chlorhexidine , povidone iodine etc In case of local necrosis and gangrene surgical debriment should done Snakebites are considered tetanus prone wounds . so,tetanus toxoid IM injection should given . If patients presents with coagulopathy , it should postponed until after resolution of coagulopathy .

30. 5.Prevention It is a seasonal events . It occurs when snake comes out of hibernation and after rain . Following preventive measures should be taken : Keep household clean by cutting grasses,bushes building materials etc from near and around house . Close door ,windows properly so that snake cannot enter house. Try to avoid sleeping on floor . If it is unavoidable ,then mosquito net should be used and tucked well. Use light when you walk outside the house at night . Use high shoes or boots while walking in paddy field . Never insert hands into long grasses,holes etc Shoes and clothes should be check before wearing .

31. Reference National guideline for snakebite management in Nepal K park 24 th edition

32. Thank you