1. SNAKE BITE

2. SNAKE BITE - Facts It is a major medical concern.
In India, every one minute one person is bitten by a snake.
Every two hours one person dies.
In India, over four lakhs persons bitten by snakes every year.
Envenomation in 82,000.
Death occurs in 11,000.

3. SNAKE BITE – Facts contd…
Many death occurs before the victim reaches the hospital.
Most of the victims are young and the only bread winner.

4. SNAKE BITE – Facts contd…
All snakebite patients do not develop clinical symptoms and signs of envenomation reactions because snakes sometimes bite without injecting venom or inject too little venom to cause damage.
Site of action of venom varies from one snake to another.
Complications due to snake bite may also vary from individual to individual.
The status of poisoning cannot be judged by the bite mark
reaction to envenomation, size or the type of snake.
However, one has to observe for signs and symptoms which may develop within 24 to 48 hours.

5. What are the types of snakes?
Snakes are classified into three types for all practical
purposes and they are
Cobra group [Colubridae]
b) Viper group [Viperidae]
c) Sea snake group [Hydrophidae]

7. Manifestations & Response to Drugs
Item
Cobra
Kraits
Russells Viper
Saw Scaled Viper
Hump Nosed Viper
Local Pain/ Tissue Damage
YES NO
Ptosis/ Neurological Signs
YES!
Haemostatic abnormalities
NO!
Renal Problems
Response to Neostigmine
NO?
Response to ASV

8. CLINICAL ASPECTS OF SNAKE BITE
Pathophysiology of snake venom:
Snake venom is mostly water in nature. It consists of numerous enzymes, proteins, aminoacids, etc., Some of the enzymes are proteases, collagenases, arginine ester hydrolase, hyaluronidase, phospholipidase, metallo-proteinases, endogenases, autocoids, thrombogenic enzymes, etc., These enzymes also act like toxins at different tissues of the body, and are grouped under neurotoxins, nephrotoxins, hemotoxins, cardiotoxins, cytotoxins etc., resulting in organ dysfunction / destruction.

9. Symptoms and Signs General symptoms and signs of Viperine envenomation
Swelling and local pain with or without erythema or discoloration at the site of bite
Tender enlargement of local lymph nodes as large molecular weight Viper venom molecules enter the system via the lymphatics.
Bleeding from the gingival sulci and other orifices.
Epistaxis.
The skin and mucous membranes may show evidence of petechiae, purpura ecchymoses.
The passing of reddish or dark-brown urine or declining or no urine output.

10. Symptoms and Signs contd…
General symptoms and signs of Viperine envenomation
Lateralising neurological symptoms and asymmetrical pupils may be indicative of intra-cranial bleeding.
Vomiting
Acute abdominal tenderness which may suggest gastro-intestinal or retro peritoneal bleeding.
Hypotension resulting from hypovolaemia or direct vasodilation.
Low back pain, indicative of an early renal failure or retroperitoneal bleeding
Muscle pain indicating rhabdomyolysis.
Parotid swelling, conjunctival oedema, sub-conjunctival haemorrhage

11. Symptoms and Signs contd…
General symptoms and signs of Elapid envenomation:
Swelling and local pain with or without erythema or discoloration at the site of bite (Cobra).
Local necrosis and/or blistering / bullae(Cobra).
Descending paralysis, initially of muscles innervated by the cranial nerves, commencing with ptosis, diplopia, or ophthalmoplegia. The patient complains of difficulty in focusing and the eyelids feel heavy. There may be some involvement of the senses of taste and smell.
Problems of vision, breathing and speaking
Paralysis of jaw and tongue may lead to upper airway obstruction and aspiration of pooled secretions because of the patient’s inability to swallow.

12. Symptoms and Signs contd…
General symptoms and signs of Elapid envenomation
Numbness around the lips and mouth, progressing to pooling of secretions, bulbar paralysis and respiratory failure.
Hypoxia due to inadequate ventilation can cause cyanosis, altered sensoriun and coma. This is a life threatening situation and needs urgent intervention.
Paradoxical respiration, as a result of the intercostal muscles becoming paralysed is a frequent sign.
Stomach pain which may suggest submucosal haemorrhages in the stomach (Krait).
Krait bites often present in the early morning with paralysis that can be mistaken for a stroke.
Eye pain and damage due to ejection of venom in to the eyes by spitting cobra(as observed in Africa)

13. Symptoms and Signs - summary
Drooping eyelids
Double vision
Difficulty in swallowing
Difficulty in speaking
Difficulty in breathing
Bleeding from the gums
Unusual bruising
Rapid swelling, note the extent every 10 minutes with a pen
Late onset envenomation and overlapping.

14. Approach to Management

15. Discarded methods Tourniquets Cutting and Suction Washing the wound
Electrical Therapy
Cautery
Cryotherapy
Pressure immobilization method

16. Tourniquets
The use of tight tourniquets made of rope, string and cloth have been
traditionally used to stop venom flow into the body following snakebite.
However, they have the following drawbacks and problems:
Risk of ischemia and loss of the limb
Risk of necrosis
Risk of massive neurotoxic blockade
Risk of embolism if used in Viper bites.
Release of tourniquet may lead to hypotension.
Give patients a sense of false security, which encourages them to delay their journey to hospital

17. Cutting and Suction Cutting the site of bite and suctioning of
incoagulable blood increases the risk of
bleeding to death as well as increases the
risk of infection. No venom is removed by
this method

18. Washing the Wound Victims and bystanders have a tendency to
wash the wound to remove any venom on
the surface. This should not be done as
the action of washing increases the flow of
venom into the system by stimulating the
lymphatic system

19. Electrical Therapy Electric shock therapy for snakebite received a
significant amount of press in the 1980’s. The theory
behind it stated that applying an electric current to the
wound denatures the venom . Much of the support for
this method came from letters to journals and not
scientific papers. It has been demonstrated that the
electric shock has no beneficial effect and hence, it has
been abandoned as a method of first aid.

20. Cautery treatment Cautery treatment is followed in some
areas which is injurious and not beneficial

21. Cryotherapy
Cryotherapy involving the application of ice to the bite was proposed in the 1950’. It was subsequently shown that this method had no benefit and merely increased the necrotic effect of the venom.

22. Pressure Immobilisation Method (PIM)
PIM was developed in Australia in 1974 by Sutherland and
gained some supporters on television and in the herpetology
literature. Some medical textbooks have referred to it. Further
work done by Howarth demonstrated that the pressure, to be
effective, was different in the lower and upper limbs. The upper
limb pressure was 40-70mm of Mercury; the lower limb was 55-
70mm of mercury. Work carried out by Norris showed that only
5% of lay people and 13% of doctors were able to correctly apply
the technique! In addition, pressure bandages should not be used
where there is a risk of local necrosis, that is in 4/5 of the
medically significant snakes of India. In view of the difficulties
encountered at every level, Pressure Immobilisation method can
not be recommended for use at present.

23. Management - Investigations
20 Minute Whole Blood Clotting Test (20WBCT)
REQUIREMENTS:
Clean and dry glass test tube.
2ml disposable syringe
Cotton
Antiseptic Solution
Clean gloves one pair.
(The test tube must not have been washed with detergent,
as this will inhibit the clotting mechanism)

24. Management - Investigations
20 Minute Whole Blood Clotting Test (20WBCT) - Procedure
The most reliable test of coagulation and can be carried out, at the bedside without specialist training.
Wash hands with soap and water and wear the gloves.
Collect 2ml blood from peripheral vein of the unaffected limb.
2 ml of fresh venous blood is placed in a clean and dry glass test tube and left untouched and unshaken at ambient temperature for 20 minutes.
Note the time.
The test tube is gently tapped and if the blood is still liquid then the patient has incoagulable blood.
The test tube must not have been washed with detergent, as this will inhibit the contact element of the clotting mechanism.

25. 20 Minute Whole Blood Clotting Test (20WBCT)

26. Management - Investigations
Other useful tests:
Clinical Test – PR / BP / RR / Postural Blood Pressure
Lab Studies – Hb / PCV / PL-Count / PT / APTT / FDP /
D-Dimer / Peripheral Smear / Blood grouping / Rh typing / Urine tests for Proteinuria / RBC / Haemoglobinuria / Myoglobinuria / Bio chemistry for serum creatinine / Urea / Electrolytes / Oxygen saturation.
Imaging studies – X-ray Chest / CT / Ultrasound (whenever required)
4. Others – ECG and other special investigations when needed.

27. Management - Treatment
Currently recommended First Aid:
The first aid being currently recommended is based around the pneumonic “Do it R.I.G.H.T.
It consists of the following:
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 = Immobilize without compression. No tight bandages or ties.
G. H. = Get to Hospital fast. 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.

28. ANTI-SNAKE VENOM

29. Points to be remembered before using Anti Snake Venom ( ASV)
No alternative to Anti Snake Venom
ASV available in our hospitals is polyvalent anti venom
There is no dose adjustment for ASV administration for children
Anaphylactic or late serum sickness cannot be detected or prevented by test dose
Health staff administering the ASV should read the manufacturers information leaflet
ASV can be administered as IV infusion in Normal Saline or Glucose. It should not be given as IV bolus or IM directly
ASV is administered slowly over a period of one hour

30. Points to be remembered before using Anti Snake Venom ( ASV) contd…
ASV is required only to those who show definite signs and symptoms of envenomation
There is no prophylactic dose of ASV
ASV is a biological drug, hence anticipate reaction
ASV neutralizes the unbound venom, hence give it early
ASV administration should not be delayed or denied on the grounds of anaphylactic reactions to a deserving case
Total dose requirement cannot be decided on the basis of Whole blood clot test (or) clinical signs and symptoms
Even if the patient develops reaction the total dose required should be administered slowly after the patient recovers from the reaction.

31. Points to be remembered before using Anti Snake Venom ( ASV) contd…
There is no other drug of choice other than ASV for the treatment of snake poisoning
There is no prophylactic dose for ASV
The patient has to be closely monitored atleast for 2 hours
No interaction with Inj.ASV has been reported
Fetal risk due to Inj. ASV has not been established or studied in humans
Safety status for use of Inj.ASV during pregnancy has not been established.
Timely administration of Inj.ASV will not gurantee the recovery or protect the individual from the venom induced toxicity or complications definitely.

32. ASV Administration: Dosage Risk and Wastage ( Ian D.Simpson Model )
Low wastage
High wastage
High risk
Inj.ASV -Not available
- Insufficient
administration
Inj.ASV – Too little supply
Species are different
Low risk
Effective dose of Inj.ASV
to envenomed patients
Receive Inj.ASV
when not required
Too much Inj.ASV
Unnecessary Inj. ASV

33. Recommended Dose of ASV
Haemotoxic Envenomation:
Treat the patient with Anti Snake Venom(ASV)
Start IV Normal Saline with wide bore needle
Begin with one Vial of ASV in one pint of NS and start drops per minute for 15 minutes & watch for reactions.
If the patient is not having signs and symptoms of anaphylactic shock continue the ASV drip with remaining seven vials/ampoules
Continue to monitor the vital signs at five minutes interval for first 30 minutes and then at 15 minutes interval for two hours

34. Recommended Dose of ASV
Neurotoxic Envenomation:
Treat the patient with Antisnake venom (ASV) with the same dose for Haemotoxic Envenomation  plus
Inj.Neostigmine 1.5 mg (Test dose) as I.M and
Inj.Atropine 0.6 mg(Test dose) as I.V
After that observe patients for every five minutes for 30 minutes for signs of response

35. Repeat Dose
For Haemotoxic Envenomation: 5 vials after 6 hours (if the toxicity persists)
For Neurotoxic Envenomation: 5 vials after 2 hours (if the toxicity persists)
Most of the victims do not require more than 18 to 20 vials.

36. ASV in special situations
Victims requiring life saving surgery.
Victims who arrive late
Repeat snake bites
Snake bite in pregnancy and lactating women
Victims having other comorbid conditions – Autoimmune disorders, debilitating status, endocrine disorders, immuno supressed status, HIV AIDS, cancer, asthma and allergy disorders, etc.,

37. ASV Reactions itching (often over the scalp)
urticaria, even a single spot
nausea,
vomiting,
abdominal colic,
diarrhoea
tachycardia
fall in blood pressure, low volume pulse
dry cough
bronchospasm / Rhonchi / Stridor (rarely)
angio-oedema of lips and mucous membrane.
fever / shaking chills (rigors)
febrile convulsions in children
sweating / cold and clammy skin / central cyanosis

38. Management of Allergic Reactions
If signs and symptoms of anaphylactic shock develop,
Stop the ASV drip temporarily and treat the shock
with:
Inj Hydrocortisone 100 mg IV or
Inj Dexamethasone 8 mg IV
Inj.Phenaramine maleate 2ml IV
Inj,Adrenaline 1:1000 (0.5 ml)IM
Inj .Deriphyline 2ml IV
Oxygen administration
IV.Normal saline as life line
As soon as the patient recovers or
If the patient is not having signs and symptoms of anaphylactic shock continue the ASV drip with remaining seven vials/ampoules slowly.
Continue to monitor the vital signs at five minutes interval for first 30 minutes and then at 15 minutes interval for two hours
Stabilise the patient and refer to the higher institution – if needed

39. Surgical Issues The surgical issues observed in snake bite cases are
Ulcer following snakebite
Necrosis of the skin and underlying tissues
Gangrene of the toes and fingers
Debridement of necrotic tissues
Compartment syndrome and others

40. Surgical Issues Assessment:
* Assess for internal and external surgical issues related to envenomation carefully and observe for the same while the victim is at hospital and / or during follow up care.
* Wound status
* Use of topical agents / traditional medicine
* Compartment syndrome
- Less common
- Consider compartment syndrome if any of the following 6 Ps. or a
combination of them appear.
Pain on passive stretching
Pain out of proportion
Pulselessness
Pallor
Parasthesia
Paralysis
The limb can be raised in the initial stages to see if swelling is reduced. However, this
is controversial as there is no trial evidence to support its effectiveness.

41. Surgical Issues Action Required: * Care of the wound
- Apply appropriate topical agents and dressing
- Maintain proper wound enviroment
- Do surgical debridement, if needed refer to surgeon
* Prepare and proceed to skin grafting later (if required)
* Measure intra compartmental pressure (ICP) in suspected cases by Intra compartmental monitoring machine(Stryker pressure monitor) or by use of a saline monitor
* Monitor ICP every 30 to 120 minutes if required
* Proceed with fasciotomy if the ICP exceeds greater than 30 to 40 mm of Hg.
* Restore coagulation time before commencing the procedures.

42. Points to be remembered
Fasciotomy does not remove or reduce any envenomation.
Visual impression is an unrealistic guide to estimate the ICP.
Tissue injury after compartment syndrome.may be disproportionate to the clinical status
Fasciotomy is not required for every case.

43. Referral Aspects Who needs: Patient requiring Respiratory support
Surgical intervention-Necrosis / Fasciotomy
Spontaneous persistent bleeding
Co-morbid diseases
Acute impending kidney failure

44. Referral Aspects When: Refer the patient
after stabilizing the case and
after giving injection ASV – 1st dose

45. Referral Aspects Where: Refer to higher institution having Ventilator
Dialysis facilities
Measures to provide further supportive treatment.

46. Instructions while referring
Inform the need for referral to the patient and/ care giver [ family member or the accompanying attendant ]
Give prior intimation to the receiving center using available communication facilities
Arrange for an ambulance
Transfer in a vehicle to Secondary Care Hospital or Tertiary Care hospital. where mechanical ventilator and dialysis facilities are available
Continue life supporting measures
Provide airway support with the help of an accompanying staff
Send the referral note with details of treatment given
Instruct one staff to accompany the patient during transportation if required.
Hand over the referral slip with details regarding treatment given
Mention the clinical status clearly in the referralat the time of referral.

51. Thank you