SNAKE BITE M.pptx FOR UTTARIKA SIR SO ASCCEPT THIS

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1. Snake bite management Uttarika Budhathoki T/SUB Nepalgunj

2. Snake bite Potentially life- threatening disease caused by toxins in the bite of a venomous snake. by having venom sprayed into the eyes by some species. Occupational hazard affecting farmers, plantation workers, herders and fishermen. Neglected tropical disease.

3. Epidemiology Out of more than 3000 species of snakes in the world, some 600 are venomous and over 200 are considered to be medically important. According to the World Health Organization, more than 5 million snakebites occur worldwide each year approximately 2.5 million envenomations and 81,000 to 138,000 deaths

4. In Nepal, WHO estimates that 20,000 people are bitten by snakes each year, resulting in over 1000 deaths So far, 89 snake species have been recorded in Nepal . Among this great diversity of snakes, we know with certainty of 17 species of snake that are found in Nepal.

5. Not all bites by venomous snakes are accompanied by the injection of venom. Approximately 20% of pit viper bites and higher percentages of other snakebites (up to 75% for sea snakes) are “dry” bites ; i.e., no venom is released. Significant envenomation probably occurs in ~50% of all venomous snakebites.

6. Venoms Complex chemical mixture of enzymes, polypeptides, non- enzymatic proteins, nucleotides, and other substances Neurotoxins- Phospholipase A2 (PLA2) toxins (mostly beta- neurotoxins). Postsynaptic neurotoxins (alpha- neurotoxins). Hematotoxins- factor V activators, factor X activators, prothrombin activators, and thrombin- like enzymes or fibrinogenase. Cytotoxins- phosphodiesterases, hyaluronidases, peptidases, metalloproteinases etc.

7. ASK Where were you bitten? What were you doing/ when were you bitten? Did anyone take the picture? What did it look like? How the bite occurred and whether there was more than one bite? Any signs or symptoms and the timing of onset? Initial treatment and first aid that was provided, including timing of first aid

8. Local effects Bite marks : Single puncture, dual puncture or marks of multiple tooth marks, only scratch mark. Krait bite may leave no mark at all. Site : arm or lower limb , may occur in trunk or other parts also.

9. Local effects Cobra Swelling and local pain with or without erythema or discoloration at the bite site. Blistering, bullae formation and local necrosis are also common. If it is infected, there may be abscess formation. Krait Usually do not cause signs of local envenoming and can be virtually painless. Viper Swelling, blistering, bleeding, and necrosis at the bite site, sometimes extending to the whole limb. Persistent bleeding from fang marks, wounds or any injured parts of the body. Swelling or tenderness of regional lymph node.

10. Systemic manifestations General manifestations Nausea, Vomiting Pain abdomen Malaise Weakness Drowsiness Prostration Anxiety Excessive salivation, etc.

11. Systemic manifestations Hematotoxic Bleeding may from venipuncture site, gums, Epistaxis Hemoptysis Melena, rectal bleeding Hematuria, bleeding from vagina Subconjunctival hemorrhage Petechiae, purpura, ecchymosis Neurotoxic Ptosis Ophthalmoplegia Pupillary dilatation- often non- responsive to light Inability (or limitation) to open mouth Numbness around lips and mouths Neurotoxic Tongue extrusion- inability to protrude the tongue beyond incisors teeth. Inability to swallow Broken neck sign Skeletal muscle weakness. Loss of gag reflex Paradoxical breathing Respiratory failure

12. LONG TERM COMPLICATIONS ( SEQUELAE ) Chronic ulceration, infection, osteomyelitis or arthritis Physical disability Chronic kidney disease due to bilateral renal cortical necrosis Chronic pan- hypopituitarism may occur in Russell’s viper envenoming Sequelae of intracranial bleeding in hematotoxic envenoming Delayed psychological morbidity like depression and anxiety, impaired functioning, post- traumatic stress disorder

13. Diagnosis No investigations available that can help diagnose the neurotoxic manifestations Neurotoxic

14. Diagnosis Hematotoxic 20- minute whole blood clotting test (20WBCT) Bleeding time (BT) and clotting time (CT) Prothrombin time and International normalization ratio (INR) FDP, fibrinogen, d- dimer Kidney function test and liver function test Complete blood count, blood group Urine for RBCs or myoglobin Creatine kinase

15. 20 WBCT Place 3 ml of freshly sampled venous blood in a small, new, dry, glass tube. Leave the tube standing undisturbed for 20 minutes at ambient temperature. A positive 20WBCT is a reasonable indication for antivenom administration, but a negative 20WBCT does not mean that antivenom should be withheld, especially if other clinical findings of coagulopathy (eg, blood oozing at puncture sites, bleeding gums, or epistaxis) are present.

16. SYNDROME FEATURES SYNDROME 1 Local swelling or other features of local envenoming with paralysis with NO features of bleeding or clotting disturbances. COBRA or KING COBRA SYNDROME 2 Nocturnal bite while sleeping on ground and paralysis with NO/or minimal local sign of envenoming. KRAIT SYNDROME 3 Neurotoxicity with dark brown urine, severe muscle pain, without local swelling, bleeding or clotting disturbances and with or without renal failure. Bitten on land while sleeping indoors. KRAIT (B. niger) SYNDROME 4 Marked swelling (sometime with blisters and necrosis) with incoagulable blood and /or spontaneous systemic bleeding. RUSSELL’S VIPER (Daboia russelii) SYNDROME 5 Marked swelling on bitten limb/part often with blisters (sometime with severe pain) without bleeding or clotting disturbances. PITVIPERS (Ovophis monticola, Trimeresurus sp.: T. albolabris, and T. popeiorum).

17. TREATMENT OF SNAKEBITE ENVENOMING First aid treatment and transport to the hospital Rapid clinical assessment and resuscitation Antivenom treatment Supportive/ancillary treatment Treatment of the bitten part

18. Recommended first aid treatment REASSURANCE Most are nonvenomous snakes. Many are dry bites. Treatable condition. IMMOBILIZAT ION With a splint or sling. Pressure immobilization in case of purely neurotoxic snake bite Pressure pad immobilization Remove rings, jewelries, tight fittings and clothing RAPID TRANSPORT To decrease the delay in accessing the emergency care and reduce mortility

19. CAUTION Tight arterial tourniquet must never be recommended Delay the release of tight tourniquets if patient has already applied this popular method of first- aid These practices must be discouraged Cutting and sucking of bite site. Application of snake stone (Jharmauro). Application of electric current. Application of various chemicals, cow dung etc

20. Rapid clinical assessment and resuscitation Airway Breathing Circulation Disability of the nervous system Exposure and environmental control

21. Antivenom treatment Phisalix and Bertrand and Calmette simultaneously, but independently, presented their observations in the year 1894 on the antitoxic properties of the serum of rabbits and guinea- pigs immunized against cobra and viper venoms, respectively. The first horse-derived antivenom sera that he prepared were already in clinical use in 1895 by Haffkine in India and by Lépinay in Viet Nam. The latter reported the first successful use of antivenin serum therapy in patients in 1896 .

22. Antivenom in Nepal Imported from India and is polyvalent. Effective against the four common species of snakes; Russell's Viper (Daboia russelii), Common Cobra (Naja naja), Common Krait (Bungarus caeruleus) and Saw Scaled Viper (Echis carinatus).

23. Indications for administering antivenom Evidence of Neurotoxicity Ptosis, ophthalmoplegia, broken neck sign, respiratory difficulty, etc. Evidence of Coagulopathy Evidence of coagulopathy primarily detected by 20 WBCT or visible spontaneous systemic bleeding, bleeding gums, etc., including myoglobinuria and hemoglobinuria, deranged PT/INR, etc Rapid extension of local swelling (more than half of limb) which is not due to tight tourniquet application. Evidence of Cardiovascular Collapse Shock and hypotension (in case of Russell’s viper bite). Evidence Of Acute Kidney Injury AKI is an indication for antivenom therapy.

24. Contradications No absolute contraindication to antivenom treatment, But patients who have reacted to horse (equine) or sheep (ovine) serum in the past (for example after treatment with equine anti- tetanus serum , equine anti- rabies serum or equine or bovine antivenom ) and those with a strong history of atopic diseases (especially severe asthma ) are at high risk of severe reactions and Should therefore be given antivenom only if they have signs of systemic envenoming.

25. How long after the bite can antivenom be expected to be effective? Antivenom treatment should be given as soon as it is indicated . It may reverse systemic envenoming even when this has persisted for several days or, in the case of haemostatic abnormalities, for two or more weeks .

26. Route of administration Each vial is diluted with 10 ml. of sterile water as supplied with the antivenom.

27. Randomized, controlled, double- blind trial in Nepal (Damak & Charali snakebite treatment centres and Bharatpur Hospital) To compare the efficacy of a ten vials initial dose versus a two vials initial dose of Polyvalent Anti- Snake Venom Serum in the treatment of snake bite Result : Similar efficacy and safety of low vs high initial dose regimen of anti- venom in patients with neurotoxic envenoming in Nepal .Recovery is faster with high initial dose

28. Response to treatment General symptoms may disappear vary quickly. Spontaneous systemic bleeding usually stops within 15- 30 min. Blood pressure may increase within 30-60 min. Neurotoxicity may improve as early as 30 min. Blood coagulability is usually restored in 3-9 hrs.

29. Reasons for failure to respond to antivenom Excessive delay in administration of antivenom Patient with established respiratory failure. If antivenom administered does not contain neutralizing antibodies against the venom of biting species. Insufficient dose of antivenom. Inactive or poor quality antivenom.

30. Prophylactic adrenaline Prophylactic adrenaline should be routinely used before initiation of anti- venom treatment to prevent anti- venom reaction except in older patients with evidence or suspicion of underlying ischemic heart disease or cerebrovascular disease.

31. Antivenom reactions within 3 hours of antivenom initiation. itching, urticaria, fever, angio- edema, dyspnea, laryngeal edema, hypotension etc. . Early anaphylactic reactions Usually develops 1- 2 hrs. after treatment initiation. Chills, rigors, fever, fall of blood pressure, febrile convulsion may develop in children. Pyrogenic reaction May develop 1- 12 (mean 7) days after treatment. Fever, itching, recurrent urticaria, arthralgia, myalgia, lymphadenopathy, proteinuria etc. Late reaction (serum sickness type)

32. Treatment of Early Anaphylaxis Reaction/Anaphylaxis INTERRUPT antivenom IM adrenaline IV chlorpheniramine IV fluids Oxygen IV hydrocortisone Nebulized salbutamol

33. IF ANTIVENOM HAS TO BE RESTARTED Consider transfer to ICU. Continue IV hydrocortisone. IV adrenaline infusion will be required and should be started before giving antivenom. Stop infusion 30 minutes after resolution of all symptoms and signs.

34. Treatment Pyrogenic reaction Do not interrupt antivenom unless hypotension is present. Give injection paracetamol. Treat hypotension with rapid infusion of normal saline. Serum sickness Anti- histaminic Pheniramine maleate If no response to antihistaminic Prednisolone

35. SUPPORTIVE/ANCILLARY TREATMENT Fluid resuscitation Oxygen Intubation and ventilation Dialysis Fasciotomies

36. When antivenom is not available or not effective Neostigmine: 0.5 mg SC/IV/IM (0.02mg/kg). Repeat 4 hourly until neurotoxicity improves (maximum 10 mg/24hrs)/ Edrophonium Atropine: 0.6mg IV / Glycopyrolate FFP and cryoprecipitate or whole blood

37. TREATMENT OF THE BITTEN PART Elevation of limb with rest. Simple washing with antiseptic solution like chlorhexidine, povidone iodine etc. Broad-spectrum antibiotic if features of infection. In case of local necrosis and gangrene: Surgical debridement. Tetanus toxoid IM injection should be given. If patient presents with coagulopathy, it should be postponed until after resolution of coagulopathy.

38. PREVENTION OF SNAKEBITE Community based education. Keep household clean by cutting grasses, bushes, and plants, remove heaps of rubbish, building materials etc. from near and around house. Bamboo, wood piles should be removed from household so that snake cannot hide. Close door, windows properly. Try to avoid sleeping on floor . If it is unavoidable, then mosquito net should be used and tucked well under the mattress or sleeping mat. It not only prevents from krait bite but also from mosquito bite. Keep your granary away from the house, it may attract rodents that snakes will hunt

39. PREVENTION OF SNAKEBITE Use high shoes or boots while walking in paddy field, bushes, long grasses. In dark, use light or strike the path using stick. Never play with snakes, or irritate them even if they are dead. Never provoke them, they usually do not bite if not irritated or provoked. Never insert hands into long grasses, tree holes or mud holes. Take care while pulling straw. Shoes and cloths should be check before wearing , in an area where snakes are abundant.