Snake Bite.ppt


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Snake Bite

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  • Deep vein thrombosis (DVT) and acute pulmonary embolism (PE) are two manifestations of the same disorder, venous thromboembolism.
  • Cold blooded animals take the temp. of there surrounding.
  • Cold blooded animals take the temp. of there surrounding.
  • Snake Bite.ppt

    1. 1. ENVENOMATION SNAKE BITE Vikas Kesarwani MD A/Professor Consultant, Pulmonary & Critical care medicine, HIHT University, Dehradun.
    2. 2. Epidemiology <ul><li>India estimates: 200,000 Snake bites and 15-20,000 deaths per year </li></ul><ul><li>Males:Female::2:1. </li></ul><ul><li>Majority of the bites being on the lower extremities. </li></ul>
    3. 4. Epidemiology <ul><li>India estimates: 200,000 Snake bites and 15-20,000 deaths per year </li></ul><ul><li>Males:Female::2:1. </li></ul><ul><li>Majority of the bites being on the lower extremities. </li></ul><ul><li>50% of bites by venomous snakes are dry bites . that result in negligible envenomation. </li></ul>
    4. 5. Snakes : Introduction <ul><li>Anatomy: </li></ul>
    5. 7. Snakes: Introduction <ul><li>Cold Blooded : No efficient thermoregulatory mechanism.(no sweat glands) </li></ul><ul><li>Venom has digestive enzymes which starts working even before the prey is swallowed </li></ul><ul><li>They Do not chew but swallow their prey completely. </li></ul>
    6. 9. India: Poisonous snakes In India, >200 species of snakes. Only 52 are poisonous. Krait and russell’s viper is much more toxic than that of cobra Sea Snakes Russell’s Vipers., Saw scaled Vipers., Pit Vipers. Cobra, Kraits Myotoxic Hydrophidae Hemotoxic Viperidae (Vipers) Neurotoxic Elapidae
    7. 10. Krait Cobra Pit Viper Rusell’s viper
    8. 11. Snake Venom <ul><li>Combination of Enzymes & Non-Enzymatic polypeptides. </li></ul><ul><li>-Acidic </li></ul><ul><li>-Sp Gravity: 1.030-1.070 </li></ul><ul><li>-On drying  Fine needle like crystals. </li></ul><ul><li>-Water Soluble. </li></ul><ul><li>- Lethal Dose : Cobra -0.12gm, Krait 0.06gm- Russell’s V -0.15gm </li></ul>
    9. 12. DIAGNOSIS OF SNAKE BITE <ul><li>FANG MARKS: classically, two puncture wounds seperated by a distance varying from 8mm to 4cm, depending on the species involved. </li></ul><ul><li>However a side swipe may produce only a single puncture,while multiple bites could result in numerous fang marks. </li></ul>
    10. 13. Effects of envenomation <ul><li>Local effects </li></ul><ul><li>Systemic effects: - Neurotoxic. - Haemotoxic. - Cardiotoxic. </li></ul>Max. with Viper bite , least with Krait bite. Hence krait bite can sometimse go unnoticed .
    11. 14. Clinical features: VENOMOUS SNAKE BITES <ul><li>ELAPID BITE (Krait,Cobra) </li></ul><ul><li>Local features : </li></ul><ul><li>indistinct fang marks , </li></ul><ul><li>burning pain, </li></ul><ul><li>swelling and discolouration, </li></ul><ul><li>serosanguinous discharge </li></ul>
    12. 15. Systemic features <ul><li>ELAPID BITE (Krait,Cobra): Neurotoxicity </li></ul><ul><li>pre-paralytic stage : emesis, </li></ul><ul><li>headache, </li></ul><ul><li>LOC. </li></ul><ul><li>paralytic stage : ptosis, </li></ul><ul><li>ophthalmoplegia </li></ul><ul><li>drowsiness, </li></ul><ul><li>dysarthria, </li></ul><ul><li>dysphagia, </li></ul><ul><li>convulsions, </li></ul><ul><li>bulbar paralysis, </li></ul><ul><li>resp failure . </li></ul>
    13. 16. <ul><li>Cardiac Depression </li></ul><ul><li>Cardiogenic/Vasogenic Shock </li></ul><ul><li>Systolic cardiac arrest. </li></ul>COBRA envenomation Cardiotoxicity
    14. 17. VIPERID BITE ( Viper ) <ul><li>Local features: </li></ul><ul><li>rapid swelling , </li></ul><ul><li>discolouration , </li></ul><ul><li>blister formation, </li></ul><ul><li>bleeding from bite site, </li></ul><ul><li>severe pain </li></ul>
    15. 18. <ul><li>Systemic features( Haemotoxic )- </li></ul><ul><li>Generalised bleeding manifestations. </li></ul><ul><li>epistaxis, </li></ul><ul><li>hemoptysis, </li></ul><ul><li>bleeding gums </li></ul><ul><li>hemauria </li></ul><ul><li>purpuric spots </li></ul><ul><li>Renal failure </li></ul>VIPERID BITE ( Viper )
    16. 19. HYDROPHID BITE ( sea snake ) Myotoxic <ul><li>Local features : minimal swelling and pain </li></ul><ul><li>Systemic features : Myalgia, Muscle stiffness, Myoglobinuria , renal tubular necrosis. </li></ul>
    17. 20. Management <ul><li>Local </li></ul><ul><li>Specific </li></ul><ul><li>Supportive </li></ul>
    18. 21. Management: Local <ul><li>Tourniquet : Between wound & heart, Pressure adequate to occlude lymphatics only , Released for few seconds every 10 minutes. </li></ul><ul><li>Immobilize affected limb. Elastocrepe bandage may be applied (except viper bites with lots of local reaction.) </li></ul><ul><li>Clean with Normal Saline. if bite <1hr old: Short skin incision and suction </li></ul>
    19. 22. Management: local reactions <ul><li>BULLAE - LEFT INTACT </li></ul><ul><li>NECROSIS - DEBRIDEMENT </li></ul><ul><li>COMPARTMENT SYNDROME - FASCIOTOMY </li></ul>
    20. 23. Specific Management <ul><li>Anti Snake Venom (ASV) - Timing - Dose - Repeat dose - Hypersensitivity </li></ul><ul><li>Mechanical ventilation </li></ul>
    21. 24. What is ASV? <ul><li>Antivenom is immunoglobulin purified from the serum or plasma of a horse or sheep that has been immunised with the venoms of one or more species of snake . </li></ul><ul><li>ASV IN INDIA: Polyvalent </li></ul><ul><li>COBRA </li></ul><ul><li>KRAIT </li></ul><ul><li>RUSSEL’S VIPER </li></ul><ul><li>SAW SCALED VIPER </li></ul><ul><li>Potency; 1 ml ASV neutralizes: 0.6mg Cobra , 0.45mg Krait , 0.6mg Rusell’s V , 0.45mg Saw scaled Viper . - Lethal Dose : Cobra -0.12gm, Krait 0.06gm- Russell’s V -0.15gm </li></ul>
    22. 25. <ul><li>Trying to capture, kill, or transport a snake for identification purposes seems of little value and possibly dangerous </li></ul>
    23. 26. ASV Indication: Systemic manifestaiton <ul><li>NEUROTOXICITY </li></ul><ul><li>HAEMOTOXICITY </li></ul><ul><li>NEPHROTOXICITY </li></ul><ul><li>CARDIOTOXICITY </li></ul><ul><li>RHABDOMYOLYSIS </li></ul><ul><li>REPEATED VOMITING </li></ul><ul><li>Others: -Local swelling involving more than half of the bitten limb. - Rapid extension of swelling. -Development of an enlarged tender lymph node draining the bitten limb </li></ul>
    24. 27. Timing of ASV <ul><li>Best effects are observed within four hours of bite . </li></ul><ul><li>Effective in symptomatic patients even 48 hours after bite . </li></ul><ul><li>Efficacious even 6-7 days after the bite from vipers. </li></ul>
    25. 28. Dose 5 vials(50ml) 5-10 vials (50-100ml) 10-20 vials (100-200ml)
    26. 29. Repeat dose <ul><li>Criteria for repeating the initial dose of antivenom </li></ul><ul><li>Persistence or recurrence of blood incoagulability after 1-2 hr </li></ul><ul><li>Deteriorating neurotoxic or cardiovascular signs after 1-2 hr </li></ul><ul><li>Continuing absorption- due to improved blood supply following correction of shock, hypovolaemia etc  A redistribution of venom from the tissues into the vascular space. </li></ul>
    27. 30. Antivenom reactions <ul><li>20% of patients, usually develop a reaction </li></ul><ul><li>Types: </li></ul><ul><li>Early anaphylactic reactions- within 10-180 min </li></ul><ul><li>Pyrogenic (endotoxin) reactions- develop 1-2 hours </li></ul><ul><li>Late ( serum sickness type) reactions- develop 1-12 (mean 7) days. </li></ul><ul><li>Fatal reactions have probably been under-reported, as death after snake bite is usually attributed to the venom . </li></ul>
    28. 31. Antivenom reactions: What to do ? <ul><li>At the earliest sign of a reaction: </li></ul><ul><li>Antivenom administration must be temporarily suspended </li></ul><ul><li>Adrenaline-0.1% solution, 1 in 1,000, 1 mg/ml is the effective treatment for early anaphylactic reactions. </li></ul><ul><li>IV hydrocortisone (adults 100 mg, children 2 mg/kg body weight). The corticosteroid is unlikely to act for several hours, but may prevent recurrent anaphylaxis </li></ul><ul><li>Anti H2 antihistamines-Ranitidine – adults 50 mg, children 1 mg/kg. </li></ul><ul><li>In case of circulatory collapse- start fluids, inotropes along with IV adrenaline </li></ul>
    29. 32. Skin testing for ASV <ul><li>Skin/conjunctival hypersensitivity testing does not reliably predict early or late antivenom reactions and is not recommended. </li></ul>
    30. 33. ASV and children <ul><li>? Dose of antivenom </li></ul><ul><li>Snakes inject the same dose of venom into children and adults. </li></ul><ul><li>Children must therefore be given exactly the same dose of antivenom as adults. </li></ul>
    31. 34. Mechanical ventilation <ul><li>If patient has respiratory distress or bulbar paralysis- intubate and ventilate. </li></ul><ul><li>If delayed can cause aspiration or hypoxia and cardiac arrest. </li></ul><ul><li>Even if the facility for MV is not available </li></ul><ul><li>Ambuing can save the day. </li></ul><ul><li>This helps even during transport. </li></ul>
    32. 35. SUPPORTIVE CARE <ul><li>ANTIBIOTICS </li></ul><ul><li>METHYL PREDNISOLONE </li></ul><ul><li>FFP,FRESH BLOOD </li></ul><ul><li>PREVENTION AND Rx OF HYPOTENSION </li></ul>
    33. 36. Summary <ul><li>Snake bites may be by a non-venomous snake or a dry bite. Not all snake bites require ASV. </li></ul><ul><li>ASV is the main stay in the treatment of snake bites. </li></ul><ul><li>ASV must be initiated if indicated at the earliest </li></ul><ul><li>Respiratory failure can be because of different reasons-Neurotoxicity, shock, sepsis, ARF… MV may be main stay of treatment or just supportive depending on the cause of failure. </li></ul>
    34. 39. HAEMOTOXIC ENVONOMATION <ul><li>MILD CT < 30 MINS </li></ul><ul><li>CLOT SIZE = 50% blood col </li></ul><ul><li>initial dose = 5 vials </li></ul><ul><li>MODERATE CT > 30 MINS </li></ul><ul><li>CLOTS ONLY SPECKLES </li></ul><ul><li>intial dose = 10 vials </li></ul><ul><li>SEVERE INCOAGULABLE </li></ul><ul><li>initial dose = 15 vials </li></ul>