Snake bite

1. Snake bite Dr S.Parthasarathy MD., DA., DNB. PhD., FICA., IDRA. Diploma in software based statistics. Associate editor – IJA

2. Number of deaths • India has the highest number of deaths due to snake bites in the world with 35,000–50,000 people dying per year—statistics !! ?? • Pakistan – 8200 deaths • Nepal – 1000 • Sri Lanka - ?? 15000 • 10 – 20 % case fatality

3. Critical points • Mean age – 30 years • Male : female 2:1 • Farmers – most affected • Rains and floods – more • Bites – nocturnal – krait , diurnal – cobras • bite-to-treatment delay varies greatly, ranging from 30 minutes to 15 days.- six hours is common.. • 50 % used harmful first aid measures • Lower limbs in day bites – face in night bites

4. Innumerable types • Elapidae • ----- rat snakes look like but not venomous • Viperidae • -- wolf snakes look like – not venomous • Can you make ASV ??

5. Cobras Krait Viper

6. Belief – 100 % venomous • Not so – non venomous and dry bites by venomous snakes more common • 60 % in India

7. Viperidae ( viriyan) • Local pain and tissue damage, characterised by swelling, blistering, bleeding, and necrosis at the bite site, sometimes extending to the whole limb… • Coagulopathy and platelet dysfunction • Haemorrhages including ICH • persistent bleeding from fang marks, wounds, or gums Procoagulases Metalloproteinases

8. Viper bites

9. Viper bites

10. Can also cause !! • In addition, Russell’s viper can cause acute renal failure and neurotoxicity, as has been shown in several studies conducted in south India and Sri Lanka--- • bites by kraits or sea snakes do not usually cause signs of local envenoming and can be virtually painless

11. Cobra and nerves • Cobra venom contains mainly postsynaptic neurotoxins, which bind and block acetylcholine receptors of the neuromuscular junction, while krait venom in addition contains presynaptic toxins--- • Ptosis and the sleeping story of villagers

12. Neurotoxins • Sweating and salivation increase • Difficult swallowing • Speech difficulty • Weakness of knees • Slow progressive diaphragm failure and death • May take 30 minutes for diaphragm to paralyse • Krait bites – slow paralyses

13. Some bites may confuse • Myotoxic • Rhabdomyolysis and renal failure • Snakes do not exhaust their store of venom, even after several strikes, and they are no less venomous after eating their prey.

14. What is the common early symptom of systemic envenoming?? • vomiting • Manson Bahr tropical disease !!

15. First AID !! • The bite victim should be reassured, the bitten limb immobilized with a makeshift splint or sling, and the patient transported. • Walking is contraindicated, because muscular contractions promote venom absorption • Danger ?? Incisions big and tight tourniquet are followed !!

16. “Do it R.I.G.H.T.” • R = Reassure • I = Immobilise • GH = Go to Hospital • T = Tell the doctor about history

17. Now what is wrong • Sucking • Shock • Extreme cold • Herbs • Water wash with soap – detergent vasdilates • Catch the snake • Incisions

18. What does traditional treatment say ?? Constricting bands or tourniquets may cause pain, swelling and congestion that suggest local envenoming. Ingested herbal remedies may cause vomiting. Instillation of irritant plant juices into the eyes may cause conjunctivitis. Forcible insufflation of oils into the respiratory tract may lead to aspiration pneumonia, bronchospasm, ruptured ear drums and pneumothorax. Incisions, cauterization, immersion in scalding liquid and heating over a fire can result in devastating injuries.

19. Clinical diagnosis • Fang marks – identification ? • Snake dead are brought – misidentification – problem • Tourniquet or venom – which has caused necrosis ?? • Non venomous snakes can also cause cellulitis

20. Syndromes Local envenoming (swelling etc.) with bleeding/clotting disturbances = Viperidae Local envenoming (swelling etc.) with bleeding/clotting disturbances, shock or acute kidney injury = Russell’s viper Local envenoming (swelling etc.) with paralysis = cobra or king cobra Paralysis with dark brown urine and acute kidney injury: Krait or sea snakes or viper

21. Tricky sometimes !! Loin (low back) pain and tenderness in a case of snake bite signifies ?? Renal ischemia

22. 20-minute whole blood clotting test (20WBCT) Place 2 ml of freshly sampled venous blood in a small, new or heat cleaned, dry, glass vessel. Leave undisturbed for 20 minutes at ambient temperature. Tip the vessel once. If the blood is still liquid (unclotted) and runs out, - yes envenomation – go ahead with ASV – safety 10 minutes extra

23. Tip it !! Don’t shake !!

24. Danger of twenty minutes test • If the vessel used for the test is not made of ordinary glass, or if it has been cleaned with detergent, its wall may not stimulate clotting of the blood sample (surface activation of factor XI – Hageman factor) and test will be invalid

25. Toxins affect at ? Multiple levels of coagulation pathway • Hence • prothrombin time ,apTT cannot be standardized • Can be prolonged-- but can we form guidelines ?? • Some studies titrate ASV with TEG

26. Broken neck sign Looking for the broken neck sign, which is caused by paralysis of the neck flexor muscles thrombocytopenia, Venom injected to the vessel – platelet may be less than 10000 – early Haemoglobin abnormalities, PCV, Peripheral smear

27. Latest !! • PCR amplification and sequencing of snake DNA obtained from bite-site swabs has recently been used to identify biting snakes in an animal model and in clinical cases from Bangladesh and Nepal • Late envenomation – can come after 6 hours

28. Management • Inj. TT • Antivenom !! • Antibiotics ?

29. Common antivenom preparation • Antivenoms are produced by fractionation of plasma obtained from immunized animals, usually horses • N. naja, B. caeruleus, D. russelii, and E. carinatus. • For others ?? • Manufacture - State of Tamilnadu • Can it be useful in srilanka ??

30. How to administer ASV and how often ? The recommended initial dose of ASV is 8-10 vials administered over 1 hour. Liquid or Lyophilised ASV are equally effective and the choice should be determined by the robustness of the cold chain. -- Mode of administration is IV only Repeat doses for haemotoxic - based on 6 hour rule Repeat doses for neurotoxic is based on the 1-2 hour rule. The maximum recommended dose for haemotoxic bites in 20 vials of ASV The maximum recommended dose for neurotoxic bites is 30 vials of ASV

31. As such – these guidelines exactly true and practicable in a scenario of innumerable species ??? Same ASV – vial Manufactured today – may be 100% same with manufactured tomorrow ?? One vial of antivenom of Indian production costs around US$8–10, which is equivalent to several days of salary for poor farmers. Thus, many cannot afford to purchase the average 10–15 vials needed to reverse envenoming

32. ASV vials usage ?? • Children need the same ASV dose • Snakes inject the same venom • Some use inj, avil and hydrocortsione • Do we need test doses ? • Intra cranial bleeds and going for evacuation – go ahead with initial 25 vials • Over a period of one hour

33. Dangers of ASV • Itching, fever, shaking chills, nausea, vomiting, diarrhoea, abdominal cramps, tachycardia, hypotension, bronchospasm and angio-oedema. • Discontinue administer adrenaline dose titrated 0.5 mg IM ---- • Once the patient has recovered, the ASV can be restarted slowly for 10-15 minutes, keeping the patient under close observation. Then the normal drip rate should be resumed

34. Maximum 20 vials of ASV in neurotoxic and 30 vials in hemotoxic • Go ahead with ventilation • Or FFP • 50 + vial regimens in INDIA ?? • ASV acts for 90 hours – need not repeat

35. Neostigmine Test • 2 mg neostigmine IM with 0.6 mg atropine • Observe for 1 hour • Single breath count, mouth opening • Inter incisor distance • If the victim responds to the neostigmine test then continue • with 0.5mg of neostigmine IM half hourly plus 0.6mg of atropine IV over an 8 hour period by continuous infusion. • We give combined infusions

36. Drugs not to be used in viper bites : • Heparin and Botropase

37. Complications • Hypotension • Hemorhage • Vasodilation • Cardiac depression • Sepsis • Pituitary adrenal insufficiency • Treat the cause

38. Monitor !! • USG guided absolutely atraumatic central vein cannulation • Sometimes a low dose dopamine may help • Beware of repeated venepuncture to take biochemistry • No arterial puncture in bleeding patients • Healthy patients – urine output is good enough

39. Surgical • Fasciotomy – role is limited • Think in terms of compartment syndrome • Strykers compartment pressure monitoring • Removal of dead necrotic material after stabilising !! • Nothing before coagulation stabilises • Even ASV decreases edema and the need for fasciotomy

40. Other complications • Persistent bleeding • Renal failure • Cardiac complications • Stiffness

41. Cobra spit ophthalmia • First aid consists of irrigating the affected eyes and other mucous membranes with liberal quantities of water or any other available bland liquid. • Instillation of 0.5% adrenaline drops relieves pain and inflammation. • Local ASV – NO

42. Titbits • Bites by small snakes should not be ignored or dismissed. They should be taken just as seriously as bites by large snakes of the same species. • Local administration of ASV near or on to the bite site should not be done.

43. Spiritual touch ??

44. Summary • Incidence • Types • Envenomation – clinical picture • WBCT • ASV doses, dos and donts • Neostigmine test • Fasciotomy • Complications • Rehabilitation

45. Thank you all