8. Anatomy of Snakes
Characteristic anatomical features include
• Shape of head
• Pupils
• Nostrils
• Tail
• Upper and lower jaws contain teeth
9. Fangs along with small teeth two or
more fangs may be present ,which are
specialized,canulated teeth used to inject
venom in to prey. Fangs are connected to the
salivary glands,which produce saliva that is
poisonous for other animals and human beings .
10. Identification of Poisonous snakes
Elapid
• Head has the same width as that of neck.
• Pupils are rounded.
• Fangs are short , fixed and grooved.
11. vipers
• Pit-less vipers are more dangerous than pitted
ones.
• Head is triangular and wider than neck.
• Pupils are vertical
• Fangs are long , moveable and canalized.
12. Sea snake
• Head is small
• Tail is flat
• Fangs are short and fixeds
13. Snake venom
• Venom is the toxic saliva produced by the
parotid salivary galnds of the poisonous
snakes.
15. Mode of action
Elapids they produce neurotoxic
poisons .Their acts on motor nerve cells and acts
in a similar manner to tubocurarine poison i.e.
compete with acetylcholine at nicotinic
receptors, rendering acetylcholine inactive thus
leading to muscular weakness especially of legs
that progress to generalized paralysis.
16. vipers
Vipers produce vasculotoxic poison . Venom
produces enzymatic destruction of cell
membranes and coagulation disorders.
These actions result in
• Destruction of endothelial cells of blood
vessels
• Lyses of RBCs
• Failure of blood clotting
17. Sea snakes
They produce myotoxic poison
Venom produces
• Muscular pains
• Myoglobinuria
• respiratory failure due to muscular weakness.
19. vsculotoxic
•Local effects
• Fang mark at the site of injection.
• Intense local pain.
• Swelling.
• Oozing out of haemolyzed blood.
• Blisters may appear.
20. General effects
• Haemoglobinuria
• Petechial haemorrhages
• Bleeding from gums, mucus membranes such
as rectum and body orifices
• Haemoptysis
• Cold, clammy skin
• Death due to circulatory failure
21. Myotoxic
• Four fang marks are present
• At the site of bite no pain and swelling
• Muscle weakness
• Ptosis develops
• Generalized muscle paralysis
• Urine is brown in colour
• Respiratory muscle weakness leads to death
• Hyperkalemia may result in cardiac failure
23. General effects
• Neurotoxic effects lethargy ,
giddiness , muscular weakness and spreading
paralysis
• Increased salivation and vomiting
• Ptosis and paralysis of extra ocular muscles
• Breathing becomes slow and laboured
• Patient remains conscious but unable to speak
• Finally respiratory paralysis consequently death
24. Fatal dose 4mg of krait venom
• 16mg of dried venom of cobra
• 40mg of viper venom
Fatal period Death occurs within few
min to few to few hours in cobra poisoning and few
says in viper poisoning
26. Steps of Treatment
• Shifting the victim to medical aid center
• Allaying anxiety and fright
• Prevention of spread of venom
• Use of antivenin
27. Allaying anxiety and Fright
To prevent the shock due to fright it is
desirable to reassure the victim by clarifying
that
• All snakes are not poisonous
• Even poisonous snakes are not fully charged
with poison all the time
• Even a snake with fully charged with poison
does not always inject it’s lethal dose
28. Prevention of spread of Venom
Through
• Immobilization
• Application of tourniquet
• Cleaning the wound
• Local emetine injection
• Incision and suction at the site
29. Use of Antivenin
Types of antivenin
• specific antivenin
• polyvalent antivenin
strength of polyvalent antivenin is
1ml will neutralize 0.6mg of dried cobra venom
0.45mg of dried krait venom,0.6mg of dried
russel’s viper venom and 0.45mg of dried saw-
scaled viper venom
30. Neutralize Toxin at Tissue Level
• Neostigmine and atropine administration in
elapid snakebite.
• Heparin and fibrinogen in viper snakebite.
31. General Measures
• Artificial respiration
• Blood Transfusion
• Steroids
• Antihistamines
• Antibiotics
• Stimulants are helpful in paralytic cases
• Aspirin short acting barbiturates
32. Postmortem Appearance
• One or two bite marks.
• Some swelling and cellulitis about the bitten part.
• In case of neurotoxic venom signs of asphyxia.
• In case of viper bite local appearances are amore striking due to
severe oozing of blood from puncture site.
• Haemorrhages in the lungs and in the serous membranes.
• Endocardial haemorrhages are seen especially in left ventricle.
• Petechiae are also found within the kidney pelvis,and mucosa of
urinary bladder,stomach, and intestines.
• Blood fails to clot normally even after addition of thrombin.
• Arterioles and capillaries are characterised by blurred walls and
swollen endothelial cells.
• Necrosis of renal tubules and cloudy swelling and granular changes
in the cells of other organs.
