1) Snake bites are a major public health issue in India, with an estimated 200,000 bites and 15,000-20,000 deaths annually. The "Big Four" venomous snakes that cause the majority of bites are the saw-scaled viper, Russell's viper, common krait, and Indian cobra. 2) Symptoms of snake envenomation depend on the species, with cobras and kraits causing neurotoxicity and vipers causing hemotoxicity. Examination focuses on neurological status, local wound, bleeding, and kidney function. 3) Treatment involves snake antivenom (ASV), supportive care, and management of specific toxicities. ASV is administered

1. Dr. T.R.Chandrashekar
Intensivist
Institute of Gastrointestinal diseases and Liver Transplant
(IGOT), Bangalore.
Management of Snake Bite Victims in ICU

2. How to prevent snake bites?
 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

3. 1
QRG Snakebite Version 4 Final December 22, 2015
STANDARD TREATMENT
GUIDELINES
Management of Snake Bite
Quick Reference Guide
January 2016
Ministry of Health & Family Welfare
Government of India

4. 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Originally made in the last century, are still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.

5. FAB FOUR
 In India, more than 200 species of snakes but only 52
are poisonous.
 Saw-scaled viper (Echis carinatus)
 Russell’s viper (Daboia russelii)
 Common krait (Bungarus caeruleus)
 Indian cobra (Naja naja)
Majority of bites
Nearly 70-80%
Hemotoxin
Vasculotoxin
Neurotoxic
1 2 43

6. Species: Medical Implications
Signs/Symptoms
and Potential
Treatments
Cobra Krait
Russell’s
Viper Saw Scaled
Viper
Other
Vipers
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

7. Syndromic approach
 No local signs with Neuro-toxicity- Krait
 With or with out local signs and Neuo-toxicity-Cobra
 local signs and hemotoxicity and Renal damage and + or
– Neurotoxicity -Rusell’s Viper
 Local signs with hemotoxicity-Saw Scaled Viper

8. Snake bite
Venomous snakes
Anti snake venom
Majority is by non-venomous snakes
●
ASV -severe adverse reactions, Costly, Limited supply.
●
Benefits of ASV treatment is considered to exceed
●
the risks.
●
About 50% of bites
are dry

9. Mechanism of Toxicity of Venom
– Proteolytic Enzymes: digestive properties
– Enzymes :Endopeptidaes, Factor X, Prothrombin
activating enzyme
– Phospholipases: degrade lipids
– Hyaluronidases: speed venom spread through the body
Cobra- Post synaptic action
Curare-mimetic toxins
ASV –rapid reversal
Anticholinesterases reverse
the neuromuscular blockade
Krait- Presynaptic action-Inhibits release of Ach
Antivenoms & anticholinesterases have no effect
Paralysis lasts several weeks and frequently
requires prolonged MV. Recovery is dependent
upon regeneration of the terminal axon
Hemo-toxicity
Neuro-toxicity

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

11. ASV is the main stay in snake
bite management
Supportive care
MV
Shock management- Fluids, vasopressors
Correction of coagulopathy- PRBC, FFP, Platelets, CRYO
Antibiotics
Renal management- forced alkaline diuresis, HD

12. Pre- Hospital Management
•
The first aid being currently recommended is based around the
mnemonic: “Do it R.I.G.H.T.”
• R. =
– Reassure the patient. 70% of all snakebites are from non-venomous species.
Only 50% of bites by venomous species actually envenomate the patient
• I =
– Immobilise in the same way as a fractured limb. Use bandages or cloth to
hold the splints, not to block the blood supply or apply pressure. Do not
apply any compression in the form of tight ligatures, they can be
dangerous!
• G. H. =
– Get to Hospital Immediately. Traditional remedies have NO PROVEN
benefit in treating snakebite.
• T=
– Tell the doctor of any systemic symptoms such as ptosis that manifest on the
way to hospital.

13. ASV in INDIA
 Polyvalent active on FAB four
 Liquid (1 yr shelf life requires cold chain)
 Lyophilized form (5 yr shelf life at room temp)
Average potency of the ASV available is such that
1 ml will neutralize
0.6mg cobra,
0.45mg krait,
0.6mg Russel’s viper
0.45mg saw scaled viper venom
ASV’s only role is to neutralize
unbound free flowing venom

14. ASV
Indications
Dose / Repeat dose
 Neurotoxicity
 Haemotoxicity
 Local toxicity
 Renal damage
Anaphylaxis management
Test dose
12 Oct 2015
n for clotting is prolonged and the blood
be liquid at 20 minutes.) This is a useful
st to diagnose hemotoxic envenomation.
bin
ount
bin Time, APTT
xamination for RBC, Hemoglobin,
n
eatinine, Urea, Electrolytes (Potassium)
The advantage
of the lyophilized form
is that it does not
require refrigeration.
However, it is more
expensive than the
liquid preparation.

15. ASV available in India
• Polyvalent Snake Antivenom I.P
4 Antivenoms effective against the Big 4, mixed together
• Manufacturers:
1.VINS Bioproducts Ltd, AP
2.Serum Institute of India Ltd, Pune
3.Haffkine Institute, Mumbai
4.Bharat Serums of India, Mumbai

16. Polyvalent ASV
No need to waste time or
effort at identifying the
exact nature of venomous
snake
Less expensive
Easy distribution to all
parts of the country
• Decreased efficacy (?)
• Increased incidence of
allergic reactions
Advantages Disadvantages

17. Skin testing for ASV
 Not reliably to predict early or late antivenom reactions
and is not recommended.
Intradermal allergy testing
IgE mediated reaction Complement mediated
ASV reactions
Waste of precious time

18. ASV administration
24
1 0 v ia ls o f A V S d is s o lv e d
in 1 0 0 m l o f d is t ille d
w a t e r a n d a d d e d t o
4 0 0 m l o f n o r m a l s a lin e
A S V in
s y r in g e
A d m in is t e r 1 0 v ia ls o f A S V in f ir s t h o u r.
M a in t a in s lo w d r ip fo r 2 4 h o u r s
M e n t io n d a t e a n d
t im e o f s t a r t in g
in f u s io n
Figure 8. ASV infusion and dosage schedule Each vial of AVS be dissolved in 10 ml
One ampoule of lyophilized ASV is reconstituted with
10 ml of sterile water for injection.
This can then be administered in two ways
IV push: at a rate not more than 2 ml/min
or
Infusion: ASV diluted in 250-500 ml of saline or 5%
dextrose and infused over about 1 hour
Prophylactic adrenaline must be
given subcutaneously along with ASV
(0.25 mg of 1:1000 adrenaline).

19. Timing of ASV
 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.
 Victims who arrive several days have acute renal failure.
 The key determining factor to administer ASV is there are
any signs of current venom activity
 Venom can only be neutralised if it is unattached! Perform a
20WBCT and determine if any coagulopathy is present.
 If coagulopathy is present, administer ASV.
 If no coagulopathy is evident treat any renal failure by
reference to a nephrologist and dialysis.

20. 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.

21. 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
5-day course of oral antihistamine/ Prednisolone.
Chlorpheniramine: 2 mg six hourly
Prednisolone: 5 mg six hourly
Serum
sickness

22. Snake bite
Neurotoxic
Examination
ASV dosing + MV?
Repeat ASV dosing
Hemotoxin
Examination
ASV dosing +
coagulopathy correction
Repeat ASV dosing
AKI management
Local toxicity
Examination
ASV+Management

23. Evaluation of Snake bite
Neurological
Local site
Bleeding
Kidney

24. Local examination

25. Examination of the bitten Limb
 Fang marks
 The extent of swelling
 Palpate lymph nodes draining the
limb
 Limb girth
 Bleeding/necrosis
15
Progressive painful swelling is indicative of local venom toxicity. It is prominent in
Russel’s viper bite, Saw scaled viper bite and Cobra bite. This is associated with
• Local necrosis which often has a rancid smell. Limb is swollen and the skin is taut
and shiny. Blistering with reddish black fluid at and around the bite site. Skip
lesions around main lesion are also seen. (Figure 5).
• Ecchymoses due to venom action destroying blood vessel wall.
• Significant painful swelling potentially involving the whole limb and
extending onto the trunk.
• Compartment syndrome will present invariably.
• Regional tender enlarged lymphadenopathy.

26. Local toxicity
• Local effects:
–This is related to the digestive function of the venom
and causes local tissue necrosis.
–It is maximal with a viper bite and least with krait
– (so much so that the bite may go unnoticed and symptoms
which follow may not be attributed to snake bite).
Limbs are marked and
circumference measured
every 1 hour to assess the
edema progression
NO ASV around the bite site

27. ASV for local toxicity
 Severe Local Envenomation: is another indication for ASV.
 Suspect severe local envenomation if there is
 Rapidly expanding painful swelling with tender
lympadenopathy
 Local swelling involving more than half of the bitten limb
 Rapid extension of swelling across a joint over one to two
hours following a bite to the hands or feet.
 Compartment syndrome +or- Surgery
8 to 10 vials in 250-500 ml of saline or 5% dextrose and infused
over about 1 hour

28. F a s c i o t o m y

29. 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
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)
Early treatment with antivenom remains the best
way of preventing irreversible muscle damage

30. Neurotoxicity
 Neuroparalytic symptoms within 30 min– 6 hours –Cobra 6
– 24 hours for Krait.
 These symptoms can be remembered as 5 Ds and 2 Ps.
 5 Ds – dyspnea, dysphonia, dysarthria, diplopia,
dysphagia
 2 Ps – ptosis, paralysis
 Diminished or absent deep tendon reflexes and head lag.
 Additional features like stridor, ataxia may also be seen

31. Neurotoxic envenoming-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
• The muscles flexing the neck may be paralysed, giving
the “broken neck sign
12
– In chronological order of appearance of symptoms – furrowing of forehead,
Ptosis (drooping of eyelids) occurs first (Figure 3), followed by Diplopia
(double vision), then Dysarthria (speech difficulty), then Dysphonia (pitch of
voice becomes less) followed by Dyspnoea (breathlessness) and Dysphagia
(Inability to swallow) occurs. All these symptoms are related to 3rd
, 4th
, 6th
and lower cranial nerve paralysis. Finally, paralysis of intercostal and skeletal
muscles occurs in descending manner.
– Other signs of impending respiratory failure are diminished or absent deep
tendon reflexes and head lag.
– Additional features like stridor, ataxia may also be seen.
– Associated hypertension and tachycardia may be present due to hypoxia.
Figure 3. Ptosis with neuroparalytic snakebite
– To identify impending respiratory failure bedside lung function test in adults

32. Bulbar paralysis
 Can the patient swallow or are secretions accumulating
in the pharynx- an early sign of bulbar paralysis?
Bulbar paralysis leads to aspiration- intubation may be
Bed side tests of impending respiratory failure
 Single breath count – number of digits counted in one
exhalation - >30 normal
 Breath holding time – breath held in inspiration – normal
> 45 sec
 Ability to complete one sentence in one breath.
required + MV

33. 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
Observe
Improvement in
ptosis, Respiratory
distress, better cough
effort, decrease in
RR
Tearing, salivation,
muscle fasciculation,
abdominal cramp,
bronchospasm,
bradycardia, cardiac
arrest
Neostigmine
Positive response
Atropine IV
Negative response
Dose of
Neostigmine
Neostigmine 25µg/kr/hr
Neostigmine 0.5 mg / 6 hr
IV atropine 0.5 mg / 12 hr

34. Management of neurotoxicity
ASV
8 to 10 vials – in 500ml infused in one hour
If there is worsening of neurological deficits or
persistence of weakness after 1- 2 hours, repeat 10 vials
No more ASV after that
MV- respiratory failure + or Bulbar paralysis+
Simple if uncomplicated by aspiration or VAP

35. Blood tests
QRG Snakebite Version 4 Final December 22, 2
Figure 7. 20 minute whole blood clotting test (20 WBCT).
– If clotted, the test should be carried out every 1 h from admissio
hours and then 6 hourly for 24 hours. In case test is non-clottin
hour after administration of loading dose of ASV. In case of
envenomationrepeat clottingtest after 6 hours.
Other investigationsthat mayassist in the management of snake bite at
levelsof healthcare
4.4.2 – Other Labtestsat Primaryhealth centre
– Peak flow meter in patients (adolescents and adults) presenting w
neuroparalytic syndrome.
– If Peak flow meter is not available in PHC then assess respiratory f
using bedside tests - single breath count, breath holding time and
complete one sentence in one health as described earlier.
– Urine examination for albumin and blood by dipstick.
4.4.3 Otherslab test at District Hospital
20 minute whole blood
clotting time:
2-3 ml of blood should be
withdrawn in a dried glass test tube
and left undisturbed for 20
minutes.
At the end of 20 minutes the tube
is slightly tilted to look for clot
formation. Normally, the blood is
fully clotted by this time but in
hemotoxic snake poisoning, the
time taken for clotting is prolonged
and the blood may still be liquid at
20 minutes.
CBC
BUN
SC
Coagulation profile; PT, aPTT, INR,
Fibrinogen, Platelet count
Urine examination
Not clotted consumption coagulopathy → ASV required
Clotted: ASV not necessary (at this stage)
Done every 30 minutes from admission for 3 hours and then hourly after that.
If incoagulable blood is there, 6 hourly cycle will then be adopted to test for the
requirement for repeat doses of ASV

36. ASV dosing- Haemotoxicity
ASV
8 to 10 vials – in 500ml infused in one hour
19
venom-inducedconsumptioncoagulopathy (Figure7).
– If blood clot is formed and signs and symptoms of neurotoxic envenomation
present,classifyasneurotoxicenvenomation.
– If there is any doubt, repeat the test in duplicate, including a “control”
(bloodfromahealthyperson).
– Caution:If the test tube used for the test is not made of ordinary glass, or if
it has been used before and cleaned with detergent, its wall may not
stimulate clotting of the blood sample in the usual way and test will be
invalid).
– Counsel patient and relatives in the beginning that, 20WBCT may be
repeatedseveral timesbeforegivinganymedication.
Figure7.20minutewholebloodclottingtest(20WBCT).
– If clotted, the test should be carried out every 1 h from admission for three
hours and then 6 hourly for 24 hours. In case test is non-clotting, repeat 6
hour after administration of loading dose of ASV. In case of neurotoxic
envenomationrepeatclottingtest after6hours.
Otherinvestigationsthatmayassist inthemanagementofsnakebiteatvarious
levelsofhealthcare
4.4.2–OtherLabtestsat Primaryhealthcentre
– Peakflowmeterinpatients(adolescentsandadults)presentingwith
neuroparalyticsyndrome.
– IfPeakflowmeterisnotavailableinPHCthenassessrespiratoryfunction
usingbedsidetests- singlebreathcount,breathholdingtimeandability to
or if there is
clinical bleeding
1-2 hours after the
dose,
Not clotted
Repeat -8 to 10 vials – in 500ml infused in one hour
As many as five doses of 10 vials each have been
given, if bleeding persists

37. ASV in AKI
 AKI- ASV may not work,
 Shock management-Fluids, vasopressors and blood and
blood products for coagulation correction is required
 Forced alkaline diuresis may be beneficial.
 Hemodialysis may be required in a small %
 Majority make complete recovery in a few weeks time
 Some may land up in CKD

38. 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
 Supportive care- MV, shock management , correction of
coagulopathy, wound management, antibiotics are
important for good outcome
 Children should be given adult dose
 Pregnant women also require regular dosing

39. T h a n k y o u
s h i n g y o u a l l a w o n d e r f u l 2 0