snake bite management for medical students prepared from MHFW India Snake bite national guidelines 2017 and Davidson textbook of medicine 2018 Ed.

1. 9th TermLecture25Aug2021
Col Bharat Malhotra
Senior Advisor (Medicine)

2. World: 2000 species
India:
300 species
Venomous 52 species
5,00,000 bites
30% venomous
20% visit hospital
50,000 deaths/year
No reliable national
statistics
Trends in snakebite deaths in India from 2000 to 2019 in a nationally
representative mortality study eLife 2020;9:e54076

3. In India, 300 species of snakes;
only 52 are poisonous.
Saw-scaled viper (Echis carinatus)
Russell’s viper (Daboia russelii)
Common krait (Bungarus caeruleus)
Indian cobra (Naja naja)
Neurotoxic
20-30%
1 2 4
3
Majority of bites 70-80%
Hemotoxin / Vasculotoxin
ANNUAL REQ
10 MILLION VIALS OF ASV
Regional Office for South-East Asia, World Health Organization. (2016). Guidelines for the management of snakebites, 2nd
edition. WHO Regional Office for South-East Asia
VIPERIDAE
ELAPIDS
HYDROPHINAE

4. Hump-nosed viper bite: an important but under-recognized cause of systemic envenoming
J Venom Anim Toxins Incl Trop Dis. 2014; 20: 24

5. The greater black krait (Bungarus niger), a newly recognized cause of neuro-myotoxic snake bite
envenoming. Brain. 2010 Nov;133(11):3181-93

6. Indian
Green Pit Viper
SIND KRAIT Coral Snakes
Asian Sand Viper
( )
(Bungarus sindanus walli )
South India Thar Dessert
Western Ghats
Thar Dessert

7. Indian Rat Snake
KEEL BACK
Indian Rock Python
Snake bite
Majority (70%) is by non-venomous snakes
Venomous snakes
30% bites by poisonous snakes
50% Dry Bites

8. • Species of snake,
• Amount of venom injected,
• Venom concentration
• Season of the bite,
• Whether snake is fed or unfed,
• Site of bite,
• Area covered or uncovered,
• Dry or incomplete bite,
• Multiple bites,
• Venom injection in vessel,
• Time elapsed between the bite and administration of ASV

9. How to identify snake ?

10. Indian Cobra
Russell Viper
Saw Scaled Viper
Common Krait
SCALES IN
DORSUM
SHIELDS
TRIANGULAR HEAD
SMALL SCALES
POINTED
TAIL
BITE MARKS
HEAD
Decapitate head
can strike- Don’t touch

11. Variations in venom
composition within species
Pre-synaptic
neurotoxins (krait)
Post-synaptic
neurotoxins (Cobra)
Phospholipases A2. Cytolytic or necrotic
Cytotoxins – Muscles, Endothelium
Neurotoxins system Vasculotoxic/ Hemostasis Toxins

12. What is syndromic approach ?
Clinical Symptoms and signs
Desired when snake is unidentified

13. Species: Overlapping syndrome
Signs/Symptoms
and Potential
Treatments
Cobra Krait
Russell’s
Viper Saw Scaled
Viper
Other
Vipers
Local pain/ Local
Tissue Damage
Yes No Yes Yes Yes
Neuroparalytic/
neurotoxic
Yes Yes No No No
Vasculotoxic/
hemotoxic
No No Yes Yes Yes
Myotoxic
KRAIT- Painless(No local signs), Neuroparalytic, Severe abdominal pain & vomiting
Cobra- local pain, Neuroparalytic
Russell Viper, Saw scaled viper- Local pain, Vasculotoxic/hemotoxic, renal failure
Flat tailed Sea snakes

14. 5D 2P
ABC
SPO2
Dysrhythmias
Shock, Collapse
Level of
consciousness
Cranial Nerves
Pupils
Paralysis
Respiratory paralysis
Conjunctiva
Gums
Orifice – bleed
Coagulopathy
AKI, Intra-Abdomen
Muscle
LN, Ecchymosis,
Necrosis, Bullae

15. NEUROTOXICITY
Starts early- many die
before they reach
hospitals
Many reverse
ASV (early)
HEMOTOXICITY
Starts late hence most of
them reach hospitals
Many organ involvement
Mostly supportive + ASV
70-80%
20-30%
Overlap:
Neuro hemat

16. Case based – clinical situations
when to give ASV

17. Snake bite on Rt Leg 24h
No neurological deficit
No bleed / coagulopathy
Local swelling
With discolouration
Inguinal Lymph node +
ASV 10 vials
Inj TT
Inj Augumentin
Oral paracetamol
Recovered
1

18. Snake bite – 10 days prior
Treated with ASV at time of bite
No neurological deficit
No bleed / coagulopathy
Gangrene
With pus
ASV - not required later
Wound Debridement
IV (Augumentin + Clindamycin)
Supportive care
2

19. Snake bite on Rt Leg - 9 hrs
No neurological deficit
No bleed
PT
T 12 Sec
C 58 Sec
INR 5.4
ASV 10 vials
Repeat 5 vials 6h later
Supportive care
PT normalized
3

20. Snake bite on lt Leg 2 hrs
Breathing difficulty – 15 mins
Pulse 110/min, BP 110/70 mm/Hg
Labored breathing 10-12 /min
Ptosis, Non communicative
No bleeding manifestations
20 min clot time normal , PT INR WNL
2 bite marks visible on leg
4
Ventilatory support – 24h
Supportive care
ASV 10 vials  repeated
Total Dose 40 ml ASV

21. Difficulty in eating and swallowing- 1 day
Tachycardia , Single breath count 30  14
5
Look to Right Look to Left

22. Inj ASV (Antisnake Venom)
10 vials in 500ml N/S
over 1 h stat  repeated ASV thereafter 2hly
Anaphylactic Tray
Ventilator
Stand by
Inj Neostigmine +
Inj Atropine
Inj Magnex
IV Fluids

23. Marked Improvement
Total Dose 40 ml ASV

24. What is the mode of Neurotoxicity
in Krait Bite & Cobra Bite?

25. Krait- Pre-synaptic action
Damage to presynaptic vesicles
Paralysis lasts longer
Cobra–post-synaptic
Damage to post synaptic Ach
receptors
Paralysis lasts shorter

26. Ptosis
RS
involvement
N Sharma, S Chauhan, S Faruqi, P Bhat, S Varma, Snake envenomation in a north Indian hospital.
Emerg Med J 2005;22:118–120
Ophthalmoplegia
Ptosis
Absent Gag reflex
Dysphagia
KRAIT
Fixed
dilated pupil
KRAIT
No local
Abdominal Pain
& Vomiting
Descending
neuroparalytic
Unexplained
respiratory
distress

27. Early sign
Bulbar Palsy
Difficulty in swallowing,
speaking
Pooling of Secretions -
pharynx
Early sign
Respi Failure
Single breath count N>30
Breath Holding time N>45
Ability to complete one
sentence in 1 breath
Paradoxical Respiration
Head Lag
Ptosis
Bilateral
dilated pupils –
don’t mistake it
for brain dead

28. Neostigmine
KRAIT
NO EFFECT
COBRA
USEFUL
Atropine 0.6 mg followed by
Neostigmine 0.5 mg
30 min interval x 5 doses
YE
S
NO

29. Local, Vasculotoxic & Hematological
problems in viper Bite.

32. 10 ml freshly venous blood
New Dry Glass Tube
Undisturbed for 20 minutes
Tip the vessel once
NEEDS ASV
Hypo fibrinogenaemia

33. PTTK PT
Serum Fibrinogen
FDP

34. • Neuroparalytic  respiratory failure
• Coagulopathy & Bleeding diathesis
• Intra abdominal bleed / Intracranial bleed
• DIC
• Hypotension  Shock  Refractory shock
• Systemic Capillary Leak syndrome
• Acute Kidney Injury
• Cardiotoxicity
• Long term sequele: Pituitary insufficiency with Russell’s
viper

35. Management

36. Treatment
• First AID
Periphery
• First AID
• ASV (if indicated) (After consultation)
Dispensary
• ASV ( if indicated)
• Specialized care
Hospital

37. Reassure (70% NV/dry bite)
Clean - Betadine
Remove constricting
clothing / jewellery
Avoid any interference
Immobilize splint limb
Pain control
Paracetamol
Shift Patient-
(under supervision)
Even a severed head can bite!
Reassure (70% NV/ dry bite)
Clean - Betadine
Remove constricting clothing /
jewellery
Immobilize splint limb
Nil Orally
IV Fluids
Inj TT
Antibiotic – skin breached
Pain control Paracetamol
Look for Fang marks
Sign of Envenomization
ASV – after consult

38. Don’t do INCISION & SUCTION
Don’t do TIGHT VENOUS/ ARTERIAL TORNIQUET
No!
Local incision
Punctures
Tattooing
Suck venom from wound
Tying tight torniquets
Electric current/cautery
Chemicals tropically
Apply Herbs
Ice packs
Herbal treatments
Do not attempt to kill or catch
the snake as this may be dangerous.

39. Special danger of rapidly developing paralytic envenoming
after elapid bite - prompted above use
OXFORD 2020 DAVIDSON 2018– TEXT BOOK OF MEDICINE – AVOID TERM TORNIQUET

40. Profound hypotension and shock
Respiratory failure
Bleeding diatheses
Hyperkalemia - Rhabdomyolysis
Sudden deterioration – Tourniquet release
Respiratory
Failure
& Shock

41. Secure IV line – Normal saline
Admit (observe 24-48h), First aid
Supportive measures
Observe for signs of envenomization
Administer ASV as soon as there is evidence of
envenomization- Local & Systemic.
Observe for misleading clinical features (due to First Aid/ Anxiety)
Manage complications

43. Powder Vial
• 25 C
• 5 yrs
Liquid Vial
• 4-8 C
• 2-3 Years
Immunoglobulin Polyvalent

44. Local swelling more than
half of the limb
(inflammation).
Rapid extension of
swelling (beyond the wrist or
ankle within a few hours)
Lymphangitis
Enlarged tender lymph
node draining the bitten limb.
Blister or bullae.
Necrosis of part of limb

45. General
Local – tissue damage
Neurological
Haematological
Derranged Lab
Acute Kidney Injury
(Early)

46. Emergency treatment of a snake bite: Pearls from literature. J Emerg Trauma Shock. 2008
No ASV for Sea snakebite, confirmed Green Pit snakebite even if with signs of
envenomation as available ASV do not contain antibodies against them.

47. Test Dose?
Has no predictive value
Not IgE mediated, but complement – activated
& direct stimulation mast cells
Premedicate
Inj Avil, Inj Hydrocortisone ( high risk cases only)
Load & keep Inj Adrenaline 1:1000 0.5 ml
Prophylactic S/C Inj Adrenaline 1:1000 0.25ml selected cases
Dose
ASV – For Envenomization
loading dose 10 vials IV (100 ml)
over 1 hour
Monitor
Physician at bed side
[5min x 30min then 15 mins for 2 h]
ANAPHYLAXIS
PYROGENIC
REACTIONS
LATE SERUM
SICKNESS
REACTION
WATCH
Yes
NO

48. Preparation:
Put 10 ml N/S in each freeze-dried vial
Swirl well so it mixes properly.
Avoid shaking so that foam doesn’t occur.
Add all 10 vials (100 ml) to N/S bottle
10 vials in
30 mins-1 h

50. Early Anaphylaxis (10-180 mins of Rx)
Pyrogenic Reactions ( 1-2 h after Rx)
Late serum sickness reactions (1-12 days after Rx)
Any new sign or symptom after starting the
ASV in drip should be suspected as a
reaction to ASV
Stop ASV temporarily  Adrenaline  Desensitization procedure to treat with ASV

51. Envenoming signs may recur within 24-48 hrs
NEUROPARALYTIC: 10 vials infusion over 30min -1h
followed by 10 vials after 1-2h if no improvement.
VASCULOTOXIC: 10 vials infusion over 30min -1h
followed by 2 to 6 vials every 6 hourly till clotting time
normalize or for 3 days.
Neurological Signs Vasculotoxic Signs

52. High or Low- A Trial of Low Dose Anti Snake Venom in the Treatment of Poisonous Snakebites
J Assoc Physicians India. 2013 Jun;61(6):387-9, 396
54 Snake Bite patients – Bangalore Hospital:
MILD
• 60%
• 4-7 vials
MOD
• 13%
• 8-11 vials
SEVERE
• 27%
• 12 or
more vials
Average dose only
6.70 ± 3.24 vials

53. Spontaneous
bleeding stops Coagulability restored
Neurotoxic envenoming
If 30 vials of ASV have been administered reconsider whether continued
administration of ASV is serving any purpose, particularly in the absence of
proven systemic bleeding. Correct coagulation abnormalities.

55. Saw scaled Viper, Russel Viper
Airway
Mechanical Ventilator
Atropine + Neostigmine
in cobra bite only
FFP , Cryoprecipitate
Platelet Concentrate
Fresh Whole Blood
Krait, Cobra
Rx hypotension -- IV fluids
Rx Oliguria / AKI -- Dialysis
Rx Infection -- Antibiotic
Supportive care, Tetanus prophylaxis
Treatment of Bitten part
Reassurance , Analgesia if required

56. Disposition (Dry bite)
* Viper Bite
12h later repeat PT INR
* Neurotoxic snake
Observation period 12-24hr.
Neurotoxicity can be delayed

57. 24 hours
if no sign/ symptoms of envenomization
48 hours
After ASV is given
Return to emergency if recurrence of worsening
Watch for serum sickness till 10 days
Local bite – Limb rehabilitation

58. ANY
Questions
?