Snakebite

Snake bite ppt

1. SNAKE BITE
Ophitoxaemia
(Venomous
snakebite)

2. Introduction
In the world
3000 species, 500 poisonous
In India
216 species, 52 poisonous(There
are 4 major poisonous landsnakes)
Annual mortality in India
5.6 to 12.6 per 100000

3. Venomous Snakes in India
Elapidae
Cobra
Common Krait
Viperidae
Russell’s viper
Saw-scaled viper
Crotalidae
Pit viper
Hydrophidae
Sea snakes

4. Recognition of Poisonous snakes
1.Fangs

5. •Short Anterior Fangs
•Elapidae
• Hydrophidae

7. 2. Head

8. Vipers ElapidsVipers Elapids

9. 3. Pupils

10. 4. Belly scales

11. 5. Body design
Cobra

12. Russell’s viper

13. Pit Vipers
The loreal pit is characteristic of the pit vipers (Family Crotalidae)

14. Krait

15. Banded Krait

17. Snake Venom
Common components
Procoagulant enzymes
Haemolytic toxins
Cytolytic / necrotic toxins
Myolytic toxin
Pre-synaptic neurotoxin
Post-synaptic neurotoxin

18. Snake venoms
CobraKraitViper Sea
snakeR

SS
Local effect ++ - +++ -
Vasculotoxic - - +++ -
Neurotoxic ++++++ - ++
Cardiotoxic ++ ++ - +
Myotoxic - - - +++
Dose/bite (mg)200 2215
0
4.6
Fatal dose (mg)120 6015
0
80

19. Clinical Features
Dry bites
20% pit viper and 43% cobra bites
Local features
Fang marks
Pain
Swelling
Blistering & necrosis
Lymphangitis, lymphadenopathy
Venom ophthalmia
Secondary infection

20. FANG MARKS IDENTIFICATION

21. Local effects of pit-viper bite

22. LOCAL EFFECTS OF SNAKE BITE

26. Local effects of a viper bite

28. General features
Flushing
Sweating
Breathlessness, palpitation
Tightness in chest
Nausea, vomiting (in all severe envenoming)
Acroparaesthesiae
Hyper salivation, blurring of vision (cobra)
Abdominal colic, diarrhoea, collapse ( krait)

29. Systemic Features – Elapid / Krait bite
Neurotoxicity
• Onset as early as 15 min with ptosis &
external ophthalmoplegia
• Rapid descending paralysis
• Life-threatening respiratory paralysis
• Effects completely reversible with antivenin /
anticholinesterases
• Spontaneously wears off in 1 – 7 days
Cardiotoxicity
• Direct myocardial toxicity

30. Systemic Features – Viper bite
Clotting defect & haemolysis
• Persistent bleeding from puncture sites
•Nephrotoxicity
Commonest with Russell’s viper
Cause - hypovolemia & ischaemia

31. Systemic Features – Sea snake bite
Myotoxicity
• Pain & tenderness in muscles develop 0.5
to 3.5 hours after bite
• Trismus common
• Rhabdomyolysis
Nephrotoxicity
Neurotoxicity
Generalized flaccid paralysis
Cardiotoxicity

32. UNUSUAL AND RARE MANIFESTATIONS OF
OPHITOXAEMIA
Delayed manifestations
•Bleeding as late as 4-6 days after the bite
• local blebs =venom depot

33. Long term effects of snake bite
•swelling and oedema resolve within 2 to 3
weeks.may persist up to 3 months
•Necrosis , gangrene

34. Recurrent manifestations
•Signs of systemic envenomation may recur hours or
even days after initially good response to antivenom.
•
•Daily evaluation of patients for at least 3-4 days

35. Management
First aid
• Reassure
• Immobilize
• Move to hospital as soon as possible
• Tourniquet / pressure immobilization
in severe elapid envenoming
(to delay onset of respiratory paralysis)
remove only after 1
st
dose of antivenin
• Treat shock with colloids
• Maintain patent airway

36. Pressure immobilization

38. Evaluation in hospital
• Look for fang marks
• Monitor vitals, local swelling &
muscle weakness hourly
• Look for bleeding
• Platelet count q 12 h
• 20 min WBCT , PT, FDP q 6h
• Serum electrolytes q 6 h
• LFT, RFT, CPK, ECG daily
• Monitor urine output, myoglobinuria

39. Evenomation grading
•Mild envenomation
•Moderate envenomation
•Severe envenomation

40. Antivenin therapy
To give or not to give?
Benefits >>risks
Indications
• Local
Local swelling > half limb
Severe local blistering / bruising / necrosis
• Systemic
Bleeding / shock / cardiotoxicity/
Neurotoxicity / impaired consciousness
Generalized rhabdomyolysis

41. Antivenin
Lyophilized, polyvalent equine anti - serum
Effective against cobra, common krait, Russell’s
viper & saw-scaled viper
Dilute in 5ml / kg BW of NS / 5% D
Give slow i/v over 1 – 2 h
Dose
For viper bite
local swelling, no systemic signs 50ml
mild systemic signs 50 – 100 ml
severe poisoning 150 – 200ml
For cobra bite 100 – 200ml

42. Response to antivenin
• Rapid & dramatic
• Neurotoxic signs may improve within 30 min
spontaneous bleeding stops in 15 – 30 min
• Repeat antivenin q 6 h till progression of
paralysis stops / clotting profile normalizes

43. Avoid
Arterial tourniquet
Incision and suction
Electric shock
Cryotherapy
Local heat
Corticosteroids, EDTA, Heparin

44. Thank you