Hopes everybody will be able to understand the signs and symptoms of snake bite and can know which are the most common poisonous snakes in India. This is for everybody not only medicos.

1. Management of Snake Bite Victims
Dr. Smrutiranjan Patanaik
Hopes everyone finds it helpful ….. Just a quick review

2. Epidemiology
• India estimates in the region of 200,000 bites and 15-
20,000 snake bite deaths per year
• Originally made in the last century, are still quoted. No
reliable national statistics are available.
• Males are bitten almost twice as often as females
• Majority of the bites being on the lower extremities.
• 50% of bites by venomous snakes are dry bites. that
result in negligible envenomation.

3. Favorite Four Snakes Which Can Bite U
• In India, more than 200 species of snakes but only 52
are poisonous.
Majority of bites
• Saw-scaled viper (Echis carinatus) Nearly 70-80%
Hemotoxin
• Russell’s viper (Daboia russelii) Vasculotoxin
• Common krait (Bungarus caeruleus)
Neurotoxic
• Indian cobra (Naja naja)
1 2 3 4

4. Species: Signs and Symptoms
Signs/Symptoms Russell’s
Cobra Krait Saw Scaled Other
and Potential Viper
Viper Vipers
Treatments
Local pain/ Tissue
Damage
Yes No Yes Yes Yes
Ptosis/Neurotoxicity Yes Yes Yes! NO No
Coagulation No No Yes Yes Yes
Renal Problems No No Yes NO Yes
Neostigmine &
Atropine Yes No? No? NO No

5. Syndromic approach
• No local signs with Neuro-toxicity- Krait
• With or with out local signs and Neuro-toxicity-Cobra
• With or with out Neurotoxicity and local signs and
hemotoxicity-Rusell’s Viper
• Local signs with hemotoxicity-Saw Scaled Viper

6. Snake bite
Majority is by non-venomous snakes
Venomous snakes
About 50% of bites are dry i.e
poison is not present
Anti snake venom
ASV -severe adverse reactions, Costly, Limited supply.
Used- benefits of ASV treatment is considered to exceed
the risks.

7. HEMOTOXICITY
NEUROTOXICITY • Starts late hence most of them
• Starts early- many die before reach hospitals
they reach hospitals • Many organ involvement hence
• Many reverse very well with supportive to buy time for organs
ASV if started early to recover.
• Less number of cases • More number of cases
70-80%
20-30%

8. Case scenario…….
• 34 yr old male shifted from rural health center with H/O
snake bite 6 hrs back has ptosis, respiratory distress, RR
35/mt, BP 120/60, oral secretions present, absent gag
and cough reflex shifted to ICU for teritary care.
• On ASV 100ml stat, & 50ml in NS over 6 hrs
• Oxygen 3l/mt
Patient is comfortable, vitals
stable
Patient received No ptosis, distress
in casualty
Patient is dead –what do you
think went wrong ?

9. Patient is dead –what do you think went wrong ?
• What could have been done better ?
• Bulbar signs-probably aspirated and died
• Endotracheal intubation can be placed on T-piece
Ambuing or Transport Ventilator
• Anticholinesterases
• Neostigmine with atropine

10. Components of Snake Venom

11. Krait- Pre-synaptic action
Beta-bungarotoxin- Phospholipases
A2
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
Paralysis lasts several weeks and frequently requires prolonged
MV. Recovery is dependent upon regeneration of the terminal
axon.

12. Cobra –post-synaptic
 alpha-neurotoxins
“Curare-mimetic toxins’’
Bind specifically to
acetylcholine
receptors, preventing the
interaction between acetylcholine
and receptors on postsynaptic
membrane.
Prevents the opening of the
sodium channel associated with
the acetylcholine receptor and
results in neuromuscular
blockade.
 ASV -rapid reversal of paralysis.
 Dissociation of the toxin-
Anticholinesterases reverse the receptor complex, which leads to
neuromuscular blockade a reversal of Paralysis

13. Snake Envenomation Signs in Indian Hospitals
Ptosis
Ophthalmoplegia
RS
involvement

14. Neurotoxic Venom - Examination
•Ask the patient to look up and observe whether the
upper lids retract fully.
•Test eye movements for evidence of early external
ophthalmoplegia .
•Check the size and reaction of the pupils.
•Krait can cause fixed, dilated non reactive pupils
simulating brain stem death – however, it can recover
fully
•Ask the patient to open their mouth wide and
protrude their tongue; early restriction often paralysis
of pterygoid muscles.
• The muscles flexing the neck may be
paralysed, giving the “broken neck sign

15. Bulbar paralysis
• Can the patient swallow or are secretions accumulating
in the pharynx- an early sign of bulbar paralysis?
• Ask the patient to take deep breaths in and out.
―Paradoxical respiration‖.
• Objective measurement of ventilatory capacity is very
useful. Use a peak flow metre, spirometer (FEV1 and
FVC)
• Ask the patient to blow into the tube of a
sphygmomanometer to record the maximum expiratory
pressure (mmHg).

16. Local examination
• During the initial evaluation, the bite site
should be examined for signs of local
envenomation
(edema, petechiae, bullae, oozing from the
wound, etc) and for the extent of swelling.
• The bite site and at least two other, more
proximal, locations should be marked and the
circumference of the bitten limb should be
measured every 15 min thereafter, until the
swelling is no longer progressing.

17. Treatment
• Anti Snake Venom
• Polyvalent /Monovalent
• Dose-large vs small
• Timing
• Repeat dose
• Hypersensitivity
• Anticholinesterases- Tensilon test
• Mechanical ventilation

18. Anti Snake Venom (ASV)
• The decision to treat a snake bite with antivenin is
largely based on clinical parameters.
• Trying to capture, kill, or transport a snake for
identification purposes seems of little value and
possibly dangerous
ASV is polyvalent
Syndromic approach helps in
examination and investigations and
outcome predictions

19. Skin testing for ASV
• Skin/conjunctival hypersensitivity testing does not
reliably predict early or late antivenom reactions
and is not recommended.

20. What is ASV?
• Antivenom 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 immunised
with the venoms of one or more species of snake.
• Monovalent or monospecific antivenom neutralises the
venom
• of only one species of snake
• Polyvalent or polyspecific antivenom neutralises the
venoms of several different species of snakes
• The ASV that is available in India is a polyvalent type
which is active against the commonly found snakes in
India including the Favourite Four.

21. Indications for ASV
• Neurotoxicity
• ARF
• Bleeding/coagulopathy
• Myoglobinuria/haemoglobinuria
• Cardiac toxicity
• 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

22. Timing of ASV
• There is no consensus as to the outer limit of time of
administration of antivenom. Best effects are observed
within four hours of bite .
• It has been noted to be effective in symptomatic patients
even when administered up to 48 hours after bite.
• Reports suggest that antivenom is efficacious even 6-7
days after the bite from vipers
• When there are signs of local envenoming, without
systemic envenoming, antivenom will be effective only if
it can be given within the first few hours after the bite

23. Dose
5 vials(50ml)
5-10 vials
(50-100ml)
10-20 vials
(100-200ml)

24. Repeat dose
• Signs of systemic envenoming may recur within 24-48 hrs
• Criteria for repeating the initial dose of antivenom
• Persistence or recurrence of blood incoagulability after 1-2 hr
• Deteriorating neurotoxic or cardiovascular signs after 1-2 hr
Causes
• Continuing absorption- due to improved blood supply
following correction of shock, hypovolemia etc,
• After elimination of antivenom
• A redistribution of venom from the tissues into the vascular
space.

25. Observation of the response to
Antivenom
Cobra bites-Post synaptic
May begin to improve as early as 30 minutes
after anti-venom, but usually take several hours.
Krait and sea snakes- Pre synaptic
Depends on the timing of ASV
administration
If delayed may not produce any action or
Minimal delayed action

26. Antivenom reactions
• Complement activation by IgG aggregates or residual
Fc fragments or direct stimulation of mast cells or
basophils by antivenom protein are more likely
mechanisms for these reactions.
• 20%, of patients, usually more than develop a reaction
Types
1. Early anaphylactic reactions- within 10-180 min
2. Pyrogenic (endotoxin) reactions- develop 1-2 hours
3. Late (serum sickness type) reactions- develop 1-12
(mean 7) days.
Fatal reactions have probably been under-reported as
death after snake bite is usually attributed to the venom.

27. Antivenom reactions
• 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
• There is increasing evidence for anti H2 antihistamines-
Ranitidine – adults 50 mg, children 1 mg/kg.
• Pyrogenic reactions require- antipyretics.
• In case of circulatory collapse- start fluids, inotropes
along with IV adrenaline

28. Trial of anticholinesterase
Anticholinesterase (“Tensilon”/Edrophonium) test
• Record baseline parameters
• Give atropine IV
• Give anticholinesterase drug edrophonium chloride (adults 10 mg, children
0.25 mg/kg body weight) given intravenously over 3 or 4 minutes
Neostigmine 25µg/kr/hr
Neostigmine 0.5 mg / 6 hr
Dose of
IV atropine 0.5 mg / 12 hr
Neostigmine
Observe
Negative response
Positive response Tearing, salivation,
Improvement in
ptosis, Respiratory muscle
distress, better fasciculation, abdom
cough inal cramp,
effort, decrease in bronchospasm, brad
RR ycardia, cardiac
Atropine IV
Neostigmine arrest

29. Mechanical ventilation
• If patient has respiratory distress or bulbar paralysis-
intubate and ventilate.
• If delayed can cause aspiration or hypoxia and cardiac
arrest.
• Even if the facility for MV is not available
Ambuing can save the day.
• This helps even during transport.
• MV is not complicated is like ventilating a patient with
curare over-dosage

30. ASV and children (Biggest Myth among
doctors)
• Dose of antivenom
• Snakes inject the same dose of venom into children and
adults.
• Children must therefore be given exactly the same dose
of antivenom as adults.

31. Pregnancy and snake bite
• Pregnant patient is treated the same manner as the
nonpregnant patient. Spontaneous
abortion, bleeding, fetal death & malformations are
common.
• Lactating mothers can continue lactating
• Fetal demise is difficult to predict because of associated
symptoms, such as coagulopathy or hypotension, and
complications of treatment including anaphylaxis.
• Generally speaking, the severity of the mother's clinical
course seems to be the best indicator of the fetal
survival.

32. Treatment issues in non Neurotoxic
respiratory paralysis
• Aspiration can complicate Mechanical Ventilation.
• Respiratory paralysis due to Shock, ARF, Sepsis, etc..
MV is instituted to buy time till the organs recover
Treatment is directed towards the cause
ASV
Antibiotics
Source control-Fasciotomies ?
Dialysis
Inotropes
Blood and blood products

33. • A 25 yr old male with snake bite has signs of
compartment syndrome and the pressure is 60 mmHg is
undergoing surgery has a Hb of 6 gm%, is hypotensive
100/60, on noradrenalin, acidotic,coagulation profile is
normal
• Blood is started
• After 15 mts of surgical time patient develops
• Dark colored urine Treatment
• Bp drops to 80/60 Fluids, Mannitol,
Alkalinize the urine,
• What are the possibilities ? Manage electrolytes
Fasciotomy
RRT
Rhabdomyolysis
Mismatched Blood transfusion

34. Krait
• Bites by krait, coral snake, and some cobras are
associated with minimal local changes;
• However, bite by the Indian cobra (Naja naja)
results in tender local swelling, blistering, and
necrosis. Local necrosis causes a picture of wet
gangrene with a characteristic putrid smell due to
the direct cytolytic action of the venom.
• Skip lesions are typical findings

35. Viper
• Viper bite is primarily vasculotoxic. It causes
rapidly developing swelling of the bitten part.
• Local necrosis is mainly ischemic as thrombosis
blocks the local blood vessels and causes a dry
gangrene

36. Clinical features of a compartmental syndrome
• Disproportionately severe pain
• Weakness of intracompartmental muscles
• Pain on passive stretching of intracompartmental muscles
• Hypoaesthesia of areas of skin supplied by nerves running through the
compartment
• Obvious tenseness of the compartment on palpation
Early treatment with antivenom remains the best
way of preventing irreversible muscle damage
Criteria for fasciotomy in snake-bitten limbs
Haemostatic abnormalities have been corrected (antivenom, with or
without clotting factors)
• Clinical evidence of an intracompartmental syndrome
• Intracompartmental pressure >40 mmHg (in adults)

37. Fasciotomy
• Fasciotomy should not be carried out in snake
bite patients unless or until haemostatic
abnormalities have been corrected.
• Clinical features of an intracompartmental
syndrome are present and a high
intracompartmental pressure has been confirmed
by direct measurement

38. High-Dose Anti-Snake Venom Versus Low-Dose Anti-
Snake Venom in The Treatment of Poisonous Snake
Bites — A Critical Study
• Results :
• In the low-dose group
• Mortality rate of 10%, 18% required dialysis and 6%
required ventilatory support. LOS 8.42 days
• In the high-dose group
• Mortality rate of 14%, 26% required dialysis 6% required
ventilatory support.LOS 9.02 days
• Conclusion : While there was no additional advantage in
following a high-dose regime for snake bite cases, there
was considerable financial gain by following the low-
dose regime,
• Most of the parameters showed a beneficial trend for
the low-dose group though the differences were not
statistically significant

39. High vs low ASV
• Repeated high doses of ASV to restore the clotting time
to normal within the shortest time, do not seem to be
necessary to reduce the ultimate morbidity and
mortality.
• A smaller dose sufficient to make the clotting time graph
take a downward trend is sufficient.
• The body’s detoxifying system will bring down the clotting
time eventually though it may take a slightly longer time.
• This delay does not seem to affect the morbidity and
mortality as shown by the results of some trial.

40. Summary
• Snake bites may be by an non venomous snake or a dry
bite
• Not all snake bites require ASV
• ASV is the main stay in the treatment of snake bites
• ASV must be initiated if indicated at the earliest
• Respiratory paralysis 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.