This document summarizes information about venomous snakes in India. It begins by defining snakes and classifying venomous species. It then describes the four most common venomous snakes in India - the common krait, Russell's viper, saw-scaled viper, and common cobra - and provides details on their physical characteristics and venom types. The document discusses the pathophysiology of snake envenomation and associated clinical manifestations. It also outlines the diagnosis, treatment including antivenom therapy, and prevention of venomous snake bites. The treatment section emphasizes supportive care, immobilization of the bitten limb, and criteria for antivenom administration.

1. PRESENTED BY:
DR.VISHNU.R.NAIR,
PHARM.D,
NATIONAL COLLEGE OF PHARMACY(NCP).

2.  What are snakes?
 Classification of venomous snakes
 Common Indian venomous snakes
 Pathophysiology of snake envenomation
 Clinical manifestations of snake bite
 Diagnosis of venomous snake bite
 Treatment of venomous snake bite
 How to prevent a snake bite?

3. WHAT ARE SNAKES?

4. Also known as “serpents”
Limbless creatures
Elongated bodies, covered with scales
Body of snakes  divided into head, trunk and tail
Venomous snakes  found all over the world, except New
Zealand, Ireland and some parts of the Arctic and Antarctic
regions.
Among 14 families of snakes studied  5 are poisonous in
nature!

5. CLASSIFICATION OF
VENOMOUS SNAKES

6. Family & genera Common name Important catchpoints
COLUBRIDAE • Mountain racer
• Western hognose snake
• Eastern hognose snake
• Parrot snake
• Rat snake
• Wandering garter snake
- Comprise 78% of snake species in the world
- Short immobile fangs
- Fangs consist of toxic saliva delivered via
chewing motion
- Found in all continents EXCEPT
AUSTRALIA
ATRACTASPIDIDAE • Mole vipers(adders)
• False vipers
• Side-stabbing snakes
- Have very long fangs
- Mainly found in Africa and Middle East
countries.

7. Family & genera Common name Important catchpoints
ELAPIDAE • Cobra(Naja)
• Kraits(Bungarus)
• Coral snakes(Calliophis, etc)
• Mambas(Dendroaspis)
- Have short fangs, which may
extend to huge lengths.
VIPERIDAE • Viperinae(true vipers): Vipers,
adders
• Crotalinae(pit vipers): Rattle
snakes, Asian pit vipers.
- Have highly developed long
fangs
- Channelized in the form of a
hypodermic needle.
HYDROPHIDAE • Sea snakes - Have short, fixed fangs.

8. COMMON
VENOMOUS
INDIAN SNAKES
(THE BIG FOUR)
SAW-SCALED VIPER COMMON KRAIT
RUSSELL’S VIPER COMMON COBRA

9. CHARACTERISTIC DESCRIPTION
SCIENTIFIC NAME Naja naja
GEOGRAPHICAL DISTRIBUTION All over India
PHYSICAL APPEARANCE & NATURE - Brown/black in colour
- Distensible neck  expands in the form of a hood
- Monocellate/binocellate mark on dorsal side of
hood
- Although diurnal  bites can occur at both day &
night!
NATURE OF VENOM Predominantly neurotoxic!

10. CHARACTERISTIC DESCRIPTION
SCIENTIFIC NAME Bungarus caeruleus
GEOGRAPHICAL DISTRIBUTION All over India
PHYSICAL APPEARANCE & NATURE - Steel-blue in colour (also grey/dark-brown)
- Whitish bands or half-rings throughout its back
- Belly is very white
- Nocturnal in nature
NATURE OF VENOM Predominantly neurotoxic(Most venomous snake in
India)!!!

11. CHARACTERISTIC DESCRIPTION
SCIENTIFIC NAME Vipera russelli
GEOGRAPHICAL DISTRIBUTION All over India
PHYSICAL APPEARANCE & NATURE - Brownish stout snake
- Grows up to several feet in length
- Triangular head, with a “V”-mark
- Fangs are long
- Hisses loudly when agitated
- Nocturnal, but may attack at daytime while
uncovered!
NATURE OF VENOM - Vasculo and hemo-toxic
- May also produce neurotoxic effects
- Acute renal failure also attributed to its venom!

12. CHARACTERISTIC DESCRIPTION
SCIENTIFIC NAME Echis carinatus
GEOGRAPHICAL DISTRIBUTION All over India(especially plains and deserts)
PHYSICAL APPEARANCE & NATURE - Small-snake(1.5-2 feet long)
- Brownish
- Diamond-shaped markings extend over its back
- Triangular head, with small scales
- Extremely aggressive and may bite with the
slightest provocation!
NATURE OF VENOM Vasculo and hemotoxic!

13. PATHOPHYSIOLOGY OF
SNAKE ENVENOMATION

14.  Usually  snake venom consists of toxic saliva  secreted by modified parotid
salivary glands of venomous snake
 Venom appearance: Clear, and amber-coloured
Venom contents:
A. Toxins: Low molecular weight peptides & proteins
B. Enzymes: Proteinases, hydrolases, hyaluronidase, cholinesterase,
phospholipase, ATPase, ribonuclease, deoxyribonuclease, etc.
C. Miscellaneous: Neurotoxin, cardiotoxin, hemolysin, hemorrhagins.

15.  Concentration of snake venom  shows diurnal and seasonal variations
 Bites inflicted at night & immediately after hibernation  most severe!!!
 Polypeptide toxins(neurotoxins)  found more in elapid and hydrophiid venoms
Postsynaptic alpha neurotoxins(alpha-bungarotoxins & cobrotoxin)
Bind to ACh receptors
Block neurotransmission at NMJ

16. Pre-synaptic beta neurotoxins(beta-bungarotoxin, cobrotoxin, taipoxin)
Causes initial release of Ach
Damages nerve terminal
Prevents further ACh release
Thus
Krait victims take longer time for recovery, as compared to cobra victims!

17. Russell’s viper venom  consists of 2 proteases :
a. RVV-X (Glycoprotein)
b. RVV-V (Arginine ester hydrolase)
 RVV-X  activates Factor X, Factor IX & protein C
 RVV-V  activates Factor V.
 Russell’s viper  may also produce neurotoxicity!
 Echis venom  contains zinc metalloprotein (ecarin)  activates prothrombin.
Activate blood-clotting
cascade!

18. Hyaluronidase  promotes venom spread through tissues
Proteolytic enzymes(hydrolases)  alter vascular permeability  lead
to edema, blistering, bruising & necrosis!
Biological amines (histamine, 5-HT)  contribute to local pain &
permeability changes at bite site!

19. Sea snake venom  consists of:
a. Hyaluronidase b. Acetylcholinesterase c. leucine
aminopeptidase
d. 5- nucleotidase e. Phosphodiesterase f. Phospholipase A.
 Sea-snake venoms  highly toxic!!!

20. CRITERIA VENOMOUS SNAKE NON-VENOMOUS SNAKE
TAIL ORIENTATION Abruptly tapering Gradually tapering
BELLY SCALES Broad Small
HEAD ORIENTATION Triangular in shape Rounded/ oval
HEAD SCALES Small Large
TEETH
ORIENTATION
Modified to form fangs All teeth are uniformly small in size
SALIVA TOXICITY Contains toxic peptides and enzymes Saliva is non-toxic

21. CLINICAL MANIFESTATIONS
OF SNAKE BITE

22. CHARACTERISTIC DESCRIPTION
LOCAL FEATURES - Indistinct fang marks
- Burning pain
- Swelling and discoloration
- Blood-stained discharge
SYSTEMIC FEATURES Pre-paralytic stage - Vomiting
- Headache
- Loss of consciousness
Paralytic stage - Ptosis
- Drowsiness
- Dysphagia
- Convulsions
- Respiratory failure
- Bulbar paralysis

23. CHARACTERISTIC DESCRIPTION
LOCAL FEATURES - Rapid swelling
- Discoloration & blister
- Frank bleeding from the bite-site
- Severe pain.
SYSTEMIC FEATURES - Generalized bleeding tendency(epistaxis,
hemoptysis & bleeding gums)
- Hematuria
- Malaena
- Purpuric spots in the skin
- Renal failure.

24. CHARACTERISTIC DESCRIPTION
LOCAL FEATURES - Minimal swelling & pain
- Frank bleeding from bite-site
- Severe pain
SYSTEMIC FEATURES - Myalgia
- Muscle stiffness
- Myoglobinuria
- Renal tubular necrosis
- Renal failure.

25. DIAGNOSIS OF VENOMOUS
SNAKE BITE

27.  Identification of fang marks
 Identification of snake(not always applicable)
Laboratory investigations:
A. Hematological tests(anemia, leukocytosis, thrombocytopenia, prolonged CT
and PT)
B. ECG changes(bradycardia, QT- prolongation, etc.)
C. Metabolic abnormalities(hyperkalemia, metabolic acidosis, lactic acidosis,
etc.)
D. Urine(Hematuria, proteinuria, hemoglobinuria and myoglobinuria)
E. Renal(Azotemia)
F. Chest X-ray(Pulmonary edema, etc.)

28. TREATMENT OF VENOMOUS
SNAKE BITE

29. Reassurance(very important)!!
Keep the patient warm, and at rest
Immobilize bitten limb
Use paracetamol (non-sedating, non-salicylate)
Avoid incision & suction
Cryotherapy is contraindicated!

30.  TORNIQUET:
- Should be applied LIGHTLY
- Apply proximal to bite-site  helps to prevent lymphatic spread of venom
- Once tourniquet is applied  never loosen it, unless:
a. Antivenom therapy is initiated
b. Bite is confirmed to be non-venomous
Sutherland wrap:
- Modified version of tourniquet
- In this method  a broad constrictive crepe bandage is applied over the
affected area(including entire limb)  limb is placed on a splint.

31. Torniquet application measure(note the finger
inserted into it, which signifies that it should NOT
be tightly bound!)
Sutherland Wrap method

32.  Observe patient for at least 24 hours before discharging
Monitor the following:
- Pulse rate, RR, BP, WBC count (every hour)
- Blood urea
- SCr
- UOP
- Vomiting, diarrhea, abnormal bleeding
- Extent of local swelling & necrosis
- ECG
- Blood gas analysis.

33. ANTIVENOM THERAPY:
- Since antivenom therapy may precipitate serious allergenic reactions  do not
directly go for antivenom therapy (as part of routine measure)
- Indications for antivenom therapy:
a. Incoagulable blood i. ECG changes.
b. Spontaneous systems bleeding
c. Hypotension
d. Persistent or recurring shock, refractory to treatment
e. Neurotoxic/myotoxic features
f. Reduced consciousness
g. Acidosis
h. Pregnant women, small children

34. NATURE OF ANTIVENOM:
- In India  only polyvalent antivenom is available
- Effective against the following snakes:
a. Common cobra
b. Common krait
c. Russell’s viper
d. Saw-scaled viper.

35. Each milliliter of antivenom  has power to neutralize the venoms of
following snake species:
a. 0.60 mg of dried Indian Cobra venom
b. 0.45 mg of dried Common Krait venom
c. 0.60 mg of dried Russell’s Viper venom
d. 0.45 mg of dried Saw-scaled Viper’s venom.

36. DOSING OF ANTIVENOM:
- Begin with 8 to 10 vials
- After infusion is over  check for improvement (wait for 6 hours)
- If no improvement(even after 6 hours)  administer additional 5 to 8 vials
- If no improvement yet  give another 5 to 8 vials
- After 25 to 30 vials  if no improvement  stop antivenom therapy
 focus on:
a. Respiratory support(elapid bite)
b. Hemodialysis(hydrophid/ viperid bite)
ADVERSE REACTIONS OF ANTIVENOM:
- Anaphylaxis(always keep adrenaline loaded & ready)
- Serum sickness.

37. OTHER TREATMENT MEASURES:
- Clean bite site using povidone-iodine solution
- Avoid dressings
- Leave blisters alone
- For local necrosis  excise slough  do saline dressing
- Tetanus toxoid
- Paracetamol (for pain)
- Rehydration & nutrition

38. MANAGEMENT OF SPECIAL CASES:
- For severe bleeding  blood or fresh frozen plasma may be required
- For features of neurotoxicity(elapid bite)  give neostigmine (0.25-
0.5 mg i.v, half-hourly)
- Before giving neostigmine  give atropine 0.6 mg, i.v
- For respiratory failure: Oxygen, assisted ventilation, etc.

39. 1. Wear shoes (long trousers & leather boots) while walking amid long grass
2. Carry electric torch or flashlight when walking outside at night
3. Be careful while collecting firewood or moving rocks or debris, since they can be
hiding places for a snake
4. Use repellants in basements, attics & storerooms to ward off rodents &
snakes(DDT, naphthalene, pyrethroids, etc)
5. Do not move near a snake or make sudden movements while it is near. Just slip
away quietly!

40. THANK YOU!!!!