Snake & Snake bites

Snake Bite and its Management

1. snake & snake Bites Presented by: Anish Dhakal (Aryan) MBBs, pahs

2. snakes Poisonous : Cobra, Russell viper, saw scaled viper, pit viper and Krait Non poisonous : Rat snake , vine snake, sand boa and mud snake

3. Snake bites Around 30-40 thousand death per year More prevalent in rural than urban areas, commonly seen in summers, mostly at night Most of the bites in tropical countries: lower extremities since non-tropical countries: on fingers and hands due to deliberate handling of snakes

4. Poison apparatus 4 Glands Ducts Fangs Hollow hypodermic needle Grooved (cobra, krait) Tubular (vipers)

5. Snake venom Poisonous secretion (saliva) Faint transparent yellow and viscous , when fresh Proteinous in nature, which are glycopolypeptides that are enzymatic in action Contents: 5

6. Types and differences

7. Fatal dose and period Fatal periods: Cobra: 30 mins to 24 hour Viper: 1 to 4 days Death may occur immediately from shock due to fright.

8. Identification of snakes 8

9. Venomous snakebite ( ophitoxaemia / envenomation) Incidence: Usually accidental. Rarely, homicidal or suicidal Entry: Inoculation Spitting Degree of toxicity Toxic principle in venom Quantity Types of fang Channeled ( viperine ): complete transfer Grooved (elapid): less transfer

10. Signs and symptoms Most common symptom is fear - semi consciousness, cold clammy skin, hypotension, rapid breathing Shock Local signs: fang marks, pain, bleeding, inflammation

11. Neurotoxic Local action: Severe burning at bite site, rapid edema and inflammatory changes followed by oozing of serum Systemic action: Within 15-30 minutes or 2 hours of bite Neurotoxic effect: giddiness, weakness, lethargy, etc.

12. Hemotoxic Local actions: Severe pain at bite site followed by swelling, ecchymosis, cellulitis and severe hemorrhage Systemic action: Due to hemolytic effect If the patient survives, suppuration, sloughing with infection at the bite site, hemorrhage from mucosa of rectum, other natural orifice, etc. Gangrene of the parts involved

13. Myotoxic Local action: Minimal swelling and pain Systemic action: Myalagia , muscle stiffness, myoglobinuria , renal tubular necrosis

14. Signs and symptoms -Cobra One or two puncture marks Local symptoms start within 6–8 minutes (min ) Reddish wheal at site of bite, tender bite site Early symptoms: vomiting, heaviness of eyelids, blurring of vision, parasthesia around mouth, hypersalivation Soft tissue swelling (progressive) Alteration of mental status Ptosis Progressive paralysis Chest pain and tightness 16

15. Signs and symptoms -Krait Similar to cobra, but less rapid Abdominal pain, ptosis, dysarthria, dysphagia, chest pain, respiratory paralysis and death may occur. No nausea and froth, but drowsiness is more. Common krait hunt nocturnally and are quick to bite people sleeping on the floor Often without waking their victims since the venom is painless. Victims w ake up later, paralyzed or die in their sleep. 17

16. Signs and symptoms -Viper One or two fang marks More local reaction is seen along with pain and oozing . Serous and serosanginous blisters sometimes appear Progressive tissue swelling Extensive local necrosis leading to gangrene Bilateral parotid swelling (viper head), conjunctival edema and subconjunctival hemorrhage Bleeding from bite site and rectum, Petechial hemorrhages, epistaxis, gum bleeding, hemoptysis , hemetemesis , hematuria, Death: d/t circulatory failure and hemorrhagic complications 18

17. Signs and symptoms -Sea snake Painless bite, minimal or no local swelling Headache, sweating, thirst Generalized rhabdomyolysis Myoglobinuria may be seen within 3 hours after the bite

18. Snake venom ophthalmia If the spat venom enters the eyes - - immediate and intense burning - stinging pain - profuse watering of eyes - production of whitish discharge - congested conjunctiva - swollen eyelids

19. Diagnosis History time elapsed since the bite is important to determine if the process is confined locally or if systemic signs have developed. Description of the snake to determine its species. Examination (including neurologic examination) Urinary venom may be detected even after treatment with anti-venom Radioimmunoassay: most sensitive and specific Enzyme immunoassay ELISA 20 min whole blood clotting test (WBCT) A normal 20 WBCT and clot lysis would exclude viperidae species .

20. Management

21. principle To reduce the anxiety and fear Prevention of the spread of venom (first aid measures) Anti-venom treatment General measures

22. First aid Reassurance of the victim Do not tamper bite wound Clean the wound with soap and water , or iodine Apply firm pressure over the area (delay absorption of venom) Pressure immobilization Immobilize the limb Avoid local incision, suction (bleeding and nerve injury) and cryotherapy Avoid tourniquets Make the patient lie on one side in recovery position Transport to medical facility immediately

23. Pressure immobilization Recommended for bites by neurotoxic elapid snakes, including sea snakes Should NOT be used for viper bites because of the danger of increasing the local effects of the necrotic venom. Broad firm bandage (Sutherland wrap) applied around limb; pressure of 50-70 mm Hg maintained, enough to occlude superficial venous and lymphatic return

24. At hospital Primary survey Release of a tight tourniquet or compression bandage may result in the dramatic development of severe systemic envenoming Ideally, compression bandages should not be released until the patient is in hospital, resuscitation facilities are available and anti-venom treatment has been started

25. Anti-venom treatment Two types: Monovalent/ monospecific anti-snake venom specific antibody to neutralize that venom Polyvalent/ polyspecific anti-snake venom (PAV) Neutralizes venoms of several species; effective against common poisonous snakes Useful when given within 4 hours of bite Each vial neutralize about 6-8 mg of venom Half life: about 90 hours Patients should be observed for at least 1 hour after starting antivenom

26. Anti-venom treatment Administration IV 5ml/minute, or dilute in isotonic fluid, infused over 30 to 60 minutes Minimal symptoms: local swelling without systemic reactions, 5 vials Moderate symptoms: progressing beyond bite site with systemic reaction, 10 vials Severe symptoms: marked local reactions, severe symptoms, 10 to 15 vials Children require the same dose as in adults

27. Anti-venom reactions Early reactions ( Anaphylactic): itching, urticaria , glottic edema, wheezing, cough,palpitation , nausea, vomiting Adrenaline (0.5 to 1 ml of 0.1% solution, SC; children: 0.01 mg/kg), antihistamines Pyrogenic reactions: In 1-2 hours; chills, shivering, sweating, vomiting, etc. Hypothermia blanket, sponging and antipyretic drugs Late reactions: About 7 days after treatment Antihistamines Steroids in more severe cases

28. Supportive treatment Antibiotics: if wound infection Tetanus injection Paracetamol for pain If clotting abnormalities, Heparin Ventilatory support for respiratory failure Surgical debridement of blebs, vesicles and superficial necrosis 31

29. Postmortem finding Clothing may show amber-colored fluid which becomes yellowish on drying Venom over skin: present as yellow crystals Venomous : Two or occasionally one fang marks with marks of smaller teeth Non-poisonous snakes: leave a set of semicircular teeth marks Bite marks 1-1.5 cm deep in colubrine 2.5 cm deep in viperine bites.

30. Postmortem finding Cobra/Krait bite: bite site contains fluid and hemolysed blood causing staining of vessels Viper bite: discoloration, swelling and cellulitis around the mark and hemorrhage Hemorrhage into bowel and lungs Purpuric spots on pericardium Inflamed kidneys with tubular necrosis, interstitial nephritis, congestion, subcapsular pinpoint hemorrhage Regional lymph nodes: swollen and hemorrhagic

31. Medico-legal aspects Poisoning is mostly accidental Occasionally, murder by throwing a poisonous snake on to someone Very rarely used for suicide Cattle poisoning

32. References The Essentials of Forensic Medicine and Toxicology, Reddy, 34 th edition Textbook of Forensic Medicine and Toxicology, Rao, 2 nd edition Review of Forensic Medicine and Toxicology, Biswas 3 r d edition

33. Thank you 36