Snakes and snake bites


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Snakes and snake bites

  2. 2. SNAKE BITE Irfan Ahmed
  4. 4. • At least 750,000 species • Three times number of all other animal species combined • Scorpions, spiders, ticks, Insects etc. ARTHROPODS
  5. 5. SNAKES  A world free of snakes • Nearly a quarter of us would go hungry • Are important elements in the food chain to control the rodent population- Which destroy all major crops The bottom line is we need snakes to survive
  6. 6. • Snakes belong to the order of animals called reptiles • This group also include crocodiles, lizards, and turtles • Snakes maintain a fairly steady body temperature by their behavior • Raise their temperature by lying in the sun or lower it by crawling into the shade SNAKES
  7. 7. • Snakes have a long, legless, flexible body that is covered with dry scales • Snake's eyes are covered by clear scales rather than movable eyelids; therefore, their eyes are always open SNAKES
  8. 8. • They repeatedly flick out their narrow, forked tongue, using it to bring odors to a special sense organ in the mouth SNAKES
  9. 9. SNAKES – EVOLUTION • Early snakes killed their prey using surprise attacks and by suffocating them to death • Snakes evolved a venom as new weapon about 60 million years ago
  10. 10. • 3000 species of snakes in the world • 375 are venomous (10 to 15 %) SNAKES
  11. 11. WORLD DISTRIBUTION OF SNAKES • Occur practically all over the world, apart from places like Greenland, Iceland, and Antarctica • Most snakes are found in tropical regions
  12. 12. SNAKES – HABITAT • Long grass • Shrubs & hedges • Holes & burrows • Shady places like under pre- fabricated construction • Garbage pits
  13. 13. SNAKES – COLD BLOODED • Do not have the ability of generating adequate amounts of heat in order to keep their body temperature at a constant level • Dependent on the heat from their surroundings and the sun to control the temperature of their body • Most snake species are found in the humid and warm climes of tropical regions
  14. 14. SNAKES – SIZE • Anaconda can grow up to 38 feet in length • Brahminy blind snake is just 2 inches long, making it the smallest snake
  15. 15. SNAKES – SENSE OF HEARING • No external ears • Probably deaf to most sounds • Hear by sensing vibrations with their belly scales and lower jaw
  16. 16. SNAKES – SENSE OF SMELL • Snakes use their forked tongue to smell • Tongue gathers airborne particles
  17. 17. SNAKES – COLOUR • Dull to brilliant with striking patterns • Dull for camouflage • Brightly coloured are usually poisonous • Use bright colours to warn predators • Some non-poisonous snakes mimic the patterns and bright colors of poisonous snakes to fool predators
  18. 18. SNAKES – METABOLISM • Slow rate of metabolism • King Cobra can go for months without food
  19. 19. SNAKES – MOLTING • We shed small quantities of old skin continuously • Snakes shed their old skins in a continuous sheet (a process called ecdysis)
  20. 20. SNAKES – MOLTING • Interval between sheds depends on age, growth rate, environmental factors • Young shed more frequently • Adult snakes shed less often
  21. 21. SNAKES – CRAWLING • The type of movement used depends largely on the terrain  Concertina  Serpentine  Side – winding  Rectilinear
  22. 22. SNAKES – VENOM • Venom is the toxic saliva produced by the parotid salivary glands of the poisonous snakes
  23. 23. • Snake venom is highly modified saliva, and is produced by modified saliva glands • Proteinaceous nature of snake venom was established by Napoleon Bonaparte's brother, Lucien in 1843 SNAKES – VENOM
  24. 24. • Proteins constitute the major portion of venom's dry weight–90% or more • Snake venom is a cocktail of hundreds, sometimes thousands, of different proteins and enzymes • Many of these proteins are harmless but a percentage of them are toxins • The makeup of these toxins varies widely from species to species • This complexity accounts for the widely differing effects of snakebite SNAKES – VENOM
  25. 25. SNAKES – VENOM • Composition  Fibrinolysins  Proteolysins  Neurotoxins  Cholinestarses  Haemolysins  Thromboplastin  Agglutinins  Cardiotoxins  Hyaluronidase
  28. 28. • Venoms are rich in hydrolithic enzymes, a complex mix of polypeptides, nucleases, peptidases, etc ., which help digest the snake's prey • Some of them also enhance or contribute to the toxic effect of the venom SNAKES – VENOM
  29. 29. • Hemotoxin (blood toxin)  Hemotoxic venom attacks the circulatory system and muscle tissue causing excessive scarring, gangrene, and sometimes leads to amputation of the affected area  This venom basically destroys tissue and blood cells  In addition to killing the prey, part of the function of a hemotoxic venom for some animals is to aid digestion  The venom breaks down protein in the region of the bite, making prey easier to digest.ex : Vipers SNAKES – VENOM
  30. 30. SNAKES – VENOM • Vasculotoxic poison  Enzymatic destruction of cell membranes and coagulation disorders  Result in  Destruction of endothelial cells of blood vessels  Lyses of RBCs  Failure of blood clotting
  31. 31. • Neurotoxin (nerve toxin)  Neurotoxic venom attacks the victim's central nervous system and usually result in heart failure and/or breathing difficulties or even total respiratory paralysis. eg: Cobras, Kraits, Coral Snakes SNAKES – VENOM
  32. 32. SNAKES – VENOM • Neuro Toxin  Acts on motor nerve  Similar manner to tubocurarine poison  Compete with acetylcholine at nicotinic receptors  Render acetylcholine inactive  Leading to muscular weakness
  33. 33. SNAKES – VENOM• Krait- Pre-synaptic action  Beta-bungarotoxin- Phospholipases A2  Inhibiting the release of acetylcholine from the presynaptic membrane  Presynaptic nerve terminals exhibited signs of irreversible physical damage and are devoid of synaptic vesicles  Antivenoms & anticholinesterases have no effect  Paralysis lasts several weeks and frequently requires prolonged MV. Recovery is dependent upon regeneration of the terminal axon
  34. 34. SNAKES – VENOM • Krait- Pre-synaptic action 1) Inhibiting the release of acetylcholine from the presynaptic membrane 2) Presynaptic nerve terminals exhibited signs of irreversible physical damage and are devoid of synaptic vesicles 3) Antivenoms & anticholinesterases have no effect
  35. 35. SNAKES – VENOM • Myotoxic poison  Muscular pains  Myoglobinuria  Respiratory failure due to muscular weakness
  36. 36. CLASSIFICATION OF SNAKES Five families
  37. 37. CLOBRIDAE • Most numerous snake family • Two third of all snakes in the world • Majority are non-poisonous • Examples — Corn snakes — Rat snakes
  38. 38. • Largest (size) snakes in the world • Non-poisonous (Use their strength to constrict and kill prey) • Three largest snakes — African rock python — Reticulated python — Anaconda BOIDAE
  39. 39. VIPERIDAE• Poisonous (Haemotoxic - Affects blood) • Body characteristics — Typical triangle shaped head — Folding fangs — Head covered with small scales and nostrils are placed vertically • Examples ─ Copperheads, cottonmouths and rattlesnakes
  40. 40. ELAPSIDAE • Poisonous (Neurotoxic - Affects nerves) • Body characteristics — Hollow fixed fangs in the jaw below or in front of the eyes — Do not have the triangle shaped head — Head covered with large scales — Lateral Nostrils • Examples — Cobras, mambas, kraits and the coral snake
  41. 41. • 18 feet • Head as large as man’s hand • Hood • Six feet tall
  42. 42. HYDROPHIIDAE • Sea snakes • Majority are poisonous (Neurotoxic – Affects nerves) • Examples — Banded sea snake — Yellow bellied sea snake
  45. 45. Scale arrangement Single row Double row COMPARISON OF POISONOUS & NON- POISONOUS SNAKES
  47. 47. WATER SNAKES
  48. 48. WATER SNAKES • If just the head is showing, it is probably a harmless water snake • Almost all venomous snakes swim with their lungs inflated, leaving the majority of their bodies afloat
  49. 49. Characteristic Poisonous Nonpoisonous Shape of head Triangular Round Pit (+) (-) Pupils Elliptical Round Bite marks Fang marks 2 rows of teeth Caudal plates Single row Double row Color body Red ring next to yellow Alternating color Swim in water Most of the body afloat Often only head showing POISONOUS / NON POISONOUS SNAKES
  50. 50. POISONOUS SNAKES IN PAKISTAN • Rat Snake (Ptyas mucosus) Local Name: - Dhaman • Indian Python (Python molurus) Local Name: - Azdaha • Indian Cobra (Naja naja) Local Name: - Cobra • Leaf-nosed Viper ( Eristocophis macmahoni) Local Name: - Cobra
  51. 51. RISK TO HUMANS • Species and size of the snake • Venom injected • Localization of the bites • Weight & general health of the victim • Sensitivity to the venom • The availability of health facility
  52. 52. SIGNS AND SYMPTOMS • Local effects  Fang mark at the site of injection  Intense local pain  Swelling  Oozing out of haemolyzed blood  Blisters may appear
  53. 53. SIGNS AND SYMPTOMS• General effects  Haemoglobinuria  Petechial haemorrhages  Bleeding from gums, mucus membranes such as rectum and body orifices  Haemoptysis  Cold, clammy skin  Death due to circulatory failure
  54. 54. SIGNS AND SYMPTOMS • Myotoxic  At the site of bite no pain and swelling  Muscle weakness  Ptosis develops  Generalized muscle paralysis  Urine is brown in colour  Respiratory muscle weakness leads to death  Hyperkalemia may result in cardiac failure
  55. 55. SIGNS AND SYMPTOMS • Neurotoxic  Lethargy , giddiness , muscular weakness and spreading paralysis  Increased salivation and vomiting  Ptosis and paralysis of extra ocular muscles  Breathing becomes slow and laboured  Patient remains conscious but unable to speak  Finally respiratory paralysis consequently death
  56. 56. WHAT TO DO On seeing the Snake • Remain calm and cautious • Get out of the way • Call for help • Use stick to kill the snake by keeping a safe distance and striking the head
  57. 57. If you are the Victim • Be calm • Try not to move the effected part much • Call for help • Move away from snake • Prevent further bite • Nearest health facility WHAT TO DO
  58. 58. If you are the helper of the Victim • Remain calm • Reassure the victim • Call for help • Move the patient to safety • Evacuate the patient to the nearest health facility • Try to kill the snake with the help of others WHAT TO DO
  59. 59. • There are two important aspects of snakebite treatment, one is the first-aid and then the treatment (antivenom serum) TREATMENT – SNAKE BITE
  60. 60. FIRST AID •Reassure •Evacuate •Splintage •Tourniquet
  61. 61. TREATMENT • Allaying anxiety and fright • Prevention of spread of venom • Shifting the victim to medical aid center • Use of antivenin
  62. 62. TREATMENT • Allaying anxiety and Fright  To prevent the shock due to fright it is desirable to reassure the victim by clarifying that  All snakes are not poisonous  Even poisonous snakes are not fully charged with poison all the time  Even a snake with fully charged with poison does not always inject it’s lethal dose
  63. 63. TREATMENT • Prevention of spread of Venom  Immobilization  Application of tourniquet  Cleaning the wound  Local emetine injection  Incision and suction at the site
  64. 64. TREATMENT • Prevention of spread of Venom  Immobilization  Application of tourniquet  Cleaning the wound  Local emetine injection  Incision and suction at the site
  65. 65. TREATMENT • Wash the bitten surface with plain water without rubbing • Polyvalent anti-venom should be given • Antibiotic & Tetanus prophylaxis
  66. 66. TREATMENT • Anti – Venom  Types  Specific antivenin  Polyvalent antivenin  Strength of polyvalent antivenin is  1ml will neutralize 0.6mg of dried cobra venom, 0.45mg of dried krait venom, 0.6mg of dried russel’s viper venom and 0.45mg of dried saw-scaled viper venom
  67. 67. TREATMENT • Neutralize Toxin at Tissue Level  Neostigmine and atropine administration in elapid snakebite  Heparin and fibrinogen in viper snakebite • Contraindications  Morphine and alcohol as these depresses respiratory center
  68. 68. TREATMENT • General measures  Artificial respiration  Blood Transfusion  Steroids  Antihistamines  Antibiotics  Stimulants are helpful in paralytic cases  Aspirin short acting barbiturates
  69. 69. TREATMENT • Anti – Snake Venom (ASV)  Anti–venom is immunoglobulin (usually the enzyme refined F(ab)2 fragment of IgG) purified from the serum or plasma of a horse or sheep that has been immunized with the venoms of one or more species of snake
  70. 70. TREATMENT 5 vials(50ml) 5-10 vials (50- 100ml) 10-20 vials (100-200ml)
  71. 71. TREATMENT • Repeat dose of Anti – Snake Venom (ASV)  Continuing absorption- due to improved blood supply following correction of shock, hypovolaemia etc,  After elimination of antivenom  A redistribution of venom from the tissues into the vascular space
  72. 72. TREATMENT • At the earliest sign of a reaction  Antivenom administration must be temporarily suspended  Adrenaline-0.1% solution, 1 in 1,000, 1 mg/ml is the effective treatment for early anaphylactic reactions  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  Increasing evidence for anti H2 antihistamines-Ranitidine – adults 50 mg, children 1 mg/kg  Start fluids, inotropes along with IV adrenaline for circulatory collapse- 5-day course of oral antihistamine/ Prednisolone. Chlorpheniramine: 2 mg six hourly Prednisolone: 5 mg six hourly Serum sickness
  73. 73. DON'TS• Tight tourniquets (Tight band / rope) • Incisions at the site of snake • Local suction • Application of herbal medicines, cow dung, seeds, saliva etc • Unnecessary delaying
  74. 74. • Always remain cautious, snakes may silently harbour anywhere • Ankle boots be used, with trousers tucked in the socks • Boots should be shaken before use • Remove bushes, shrubs etc lying close to the buildings • Alter all sites that provide cool, damp, dark habitat • A stick and torch, be used at night PREVENTION OF SNAKE BITES
  75. 75. PREVENTION OF SNAKE BITES • Never reach in to holes or crevices • Bedding & clothing should be thoroughly shaken • Mosquito nets • Two feet deep and two feet wide trench with vertical sides • The trench or the sleeping platform should be thoroughly inspected • Watch your step; very few snakes bite unprovoked
  77. 77. • Black Mamba  Most deadly snake  Located in Africa and is colored dark olive or a dark brown color with black spotting along its back  Longest fangs  Delivers quick multiple bites and flees  Venom is a cardio toxin and a fully grown Black Mamba can deliver 100mg to 120mg.  A lethal dose of a cardio toxin to a human is 10mg to 15mg WORLD DEADLIEST SNAKES
  78. 78. Black Mamba
  79. 79. • Common Krait  Located mostly in Southeast Asia  Normally black with yellow bands around it  Can go either on land or water  Affects the nerves and produces a nerve paralysis.  Fangs are not very long so has to chew on it’s pray to induce the venom into the blood stream WORLD DEADLIEST SNAKES
  80. 80. Common Krait
  81. 81. • Russell’s Viper  Located in South Asia  Light brown with three rows of black or brown spots bordered by yellow or white around  Responsible for the most fatalities  Highly irritable, coils up before strike  Damage to the blood cells and tissue WORLD DEADLIEST SNAKES
  82. 82. Russell’s Viper
  83. 83. • Taipan  Located in Australia  Pale creamy color on the head  Light brown, dark brown, copper, or olive  Usually stay away from humans  Defend itself WORLD DEADLIEST SNAKES
  84. 84. Taipan
  85. 85. • Cobra  Located in South Asia  Hood that pops up behind  Symbol on the back, looks like eyes  Either spit venom or bite  Spiting venom isn’t deadly  Severe pain and damage to eyes WORLD DEADLIEST SNAKES
  86. 86. Cobra
  87. 87. A Q&Q u e s t i o n s A n s w e r s