Snake bite and its management. by Dr Rizwan Saeed - ANMC - MBBS- Community Medicine- Superior University, Lahore. Pakistan.

1. Snake bite
by
Dr. Rizwan Saeed

2. Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes /ophedia (venemous)
Linnaeus, 1758

3. Snakes are elongate
legless carnivorous
reptiles of the
suborder Serpentes
that can be
distinguished from
legless lizards by
their lack of eyelids
and external ears.

5. • Snake bite is primarily a problem of the
• poorer rural populations
• farming activities.
• Poor access to health services
• fail to reach hospital in time.
• Hospital statistics on snakebites therefore
underestimate the true burden.
• In addition to mortality, some snakebite victims
survive with permanent physical squeal due to
local tissue necrosis and, sometimes psychological
squeal.
• Because most victims are young, the
economic impact of snakebite can be
considerable.

6. •Living snakes are found on every continent except
Antarctica.
•15 families
•456 genera
• over 2,900 species.
• range in size from the tiny, 10 cm long thread snake to
pythons and anacondas of up to 7.6 metres (25 ft) in
length.
•Most species are non-venomous and those that have
venom use it primarily to kill and subdue prey rather
than self-defense.
•Some possess venom potent enough to cause painful
injury or death to humans.

7. evolution
• 150 million-year-old specimens, readily
identifiable as snakes, yet with lizard-like
skeletal structures, have been uncovered in
South America and Africa. There is consensus,
on the basis of comparative anatomy, that
snakes descended from lizards.
• Fossil evidence suggests that snakes may have
evolved from burrowing lizards

9. VENOM
The term poisonous snake is mostly incorrect—poison
is inhaled or ingested whereas venom is injected
Vipera berus, one fang in
glove with a small venom
stain, the other still in place
Cobras, vipers, and closely
related species use venom
to immobilize or kill their
prey. The venom is
modified saliva, delivered
through fangs
•DRY BITE
The standard way of estimating the strength of any toxin is to inject a thin
solution into standard size laboratory mice, to establish a LD50 dose, i.e. a dose
that on average will kill half of the mice in 24 hours

10. Snake venoms
complex mixtures of proteins and are stored in
poison glands at the back of the head.
•These proteins can potentially be a mix of
•neurotoxins (which attack the nervous system),
•hemotoxins (which attack the circulatory
system),
•Cytotoxins (cell),
•Bungarotoxins (NEUROTOXIN PROTEINS-KRAITS) and
many other toxins that affect the body in
different ways.

11. • Almost all snake venom contains
hyaluronidase, an enzyme that ensures rapid
diffusion of the venom

12. SNAKE BITE
• The most common symptoms of all snakebites
are
• panic, fear and emotional instability, which may
cause symptoms such as
• nausea and vomiting, diarrhea,
• vertigo,
• fainting,
• tachycardia, and cold, clammy skin.
 Television, literature, and folklore are in part
responsible for the hype surrounding snakebites,
and a victim may have unwarranted thoughts of
imminent death.

13. SEQULAE OF SNAKE BITE
• NO EFFECT
• PSYCHOGENIC EFFECT
• ENVENOMATION
• NEUROTOXIC SEQULAE
• MYOTOXIC EFFECTS
• SEQULAE OF WRONG INDIGENOUS PROCEDURES
• OTHER COMPLICATIONS
• COMPLICATIONS OF TOURNIQUET
• COMPLICATIONS OF INCISIONS
• WOUND SEPSIS
• POSSIBLE HAZARDS OF ANTIVENIN
LOCAL EFFECT
HAEMOTOXIC

14. • i) cytotoxins causing local swelling and
tissue damage,
• ii) haemorrhagins which disturb the
integrity of blood vessels,
• iii) compounds which lead to incoagulable
blood,
• iv) neurotoxins causing in neurotoxicity
• v) myotoxins which cause muscle
breakdown

16. • Dry snakebites,
Those inflicted by a non-venomous species, are
still able to cause severe injury to the victim.
a snakebite which is not treated properly may
become infected the bite may cause
anaphylaxis in certain people, and the snake's
saliva and fangs may harbor many dangerous
microbial contaminants, including Clostridium
tetani.
 If neglected, an infection may spread and
potentially kill the victim.

20. INOCULATION / INJECTION BY SNAKE
ENTERS SURROUNDING TISSUE
CAPILLARRY ABSORPTION
LYMPHATIC
BLOOD
VESSELS
TARGET ORGANS SYSTEMIC EFFECT RECOVERY
DEATH
•AUTO-PHARMACOLOGICAL
MANIFESTATION
•DIRECT VENOM ACTION

22. • Most snakebites, whether by a venomous snake or not,
will have some type of local effect.
• In over 90% of cases there is minor pain and redness,
but this varies depending on the site.
• Bites by vipers and some cobras may be extremely
painful, with the local tissue sometimes becoming
tender and severely swollen within 5 minutes.
• Other common initial symptoms of pit viper bites
include lethargy, weakness, nausea, and vomiting.
Symptoms may become more life-threatening over time,
developing into hypotension, tachypnea, severe
tachycardia, altered sensorium, and respiratory failure

23. Australian Elapids ,
Viper
coagulopathy
Cobras, Kraits,
Mambas, Sea snakes
Neurotoxicity
Victim not treated
May die of Respiratory
failure

24. • necrosis of muscle tissue
• Muscle tissue will begin to die throughout the
body, a condition known as rhabdomyolysis.
• Dead muscle cells may even clog the kidney
which filters out proteins. This, coupled with
hypotension, can lead to acute renal failure,
and, if left untreated, eventually death

25. • Interestingly, bites caused by the rattlesnake,
coral snake, and the speckled rattlesnake
reportedly cause little or no pain despite being
serious injuries.
• Victims may also describe a "rubbery," "minty,"
or "metallic" taste if bitten by certain species of
rattlesnake.
• Spitting cobras and rinkhalses can spit venom in
their victims' eyes. This results in immediate
pain, ophthalmoparesis, and sometimes
blindness

26. •Snakes do not ordinarily prey on humans and
most will not attack humans unless the snake is
startled or injured, preferring instead to avoid
contact.
•non-venomous snakes are usually not a threat to
humans. venomous snakes present far greater
hazard to humans
•Snakes are most likely to bite when
they feel threatened, are startled,
provoked, or have no means of
escape when cornered

27. DEATH WITH SNAKE BITE
Documented deaths resulting from snake bites are
uncommon. Non-fatal bites from venomous snakes
may result in the need for amputation of a limb or
part thereof. Of the roughly 725 species of venomous
snakes worldwide, only 250 are able to kill a human
with one bite.

29. TREATMENT
• The treatment for a snakebite is as variable as the bite itself. The most
common and effective method is through antivenom, a serum
made from the venom of the snake.
• Some antivenom is species specific (monovalent) while some is made
for use with multiple species in mind (polyvalent).
• In the United States for example, all species of venomous snakes are pit
vipers, with the exception of the coral snake.
• To produce antivenin, a mixture of the venoms of the different species
of rattlesnakes, copperheads, and cottonmouths is injected into the
body of a horse in ever-increasing dosages until the horse is immunized.
Blood is then extracted from the immunized horse and freeze-dried. It is
reconstituted with sterile water and becomes antivenin. For this reason,
people who are allergic to horses cannot be treated using antivenin.
• Antivenin for the more dangerous species (such as mambas, taipans,
and cobras) is made in a similar manner in India, South Africa, and
Australia with the exception being that those antivenins are species-
specific.

30. • Keep the victim calm, restrict movement.
• • The limb, which has been affected by the bite,
should be immobilized with splint and be kept
below the level of the heart. A compression
bandage (not tight) should cover the entire limb
with the splint.
• • Assure the victim and do not let him panic.
When under panic, it will enhance heart rate and
would circulate the venom faster in the body.
• • Remove any rings or constricting items; the
affected area may swell.
• • A snakebite victim is under tremendous
psychological stress. It is necessary to keep the
patient warm. However, no alcohol/hot
beverages should be given. The patient should not
be allowed to exert himself in any manner.

31. • • DO NOT COVER THE BITE AREA AND PUNCTURE
MARKS. The wound should be gently cleaned with
antiseptic.
• • Try to aspirate the venom out of the puncture
marks with standard suction devices. It has been
identified that a suction more than 270 mmHg can
initiate the flow from the puncture marks. Suction
instruments often are included in commercial
snakebite kits. But, the suction should be applied
within 5 minutes of the bite.
• • The only remedy for venomous snakebite is
the anti-venom serum, which is available at most
government hospitals and public health centers.
Some private nursing homes have also started
stocking it and treat snakebite cases.

33. Snake trapping
The tribals of "Irulas" from Andhra Pradesh and Tamil
Nadu in India have been hunter-gatherers in the hot dry
plains forests and have practiced this art for
generations. They have a vast knowledge of snakes in
the field. Irulas generally catch the snakes with the help
of a simple stick
•SNAKE SKIN
•SNAKE VENOM

34. PETS : BALL PYTHON & CORN SNAKE

35. SYMBOLISM
Medusa by 16th Century
Italian artist Caravaggio
Rod of Asclepius, in which the
snakes, through ecdysis, symbolize
healing.

36. HISTORY / RELEGION
•In Egyptian history, the snake occupies a primary
role with the Nile cobra adorning the crown of
the pharaoh in ancient times. It was worshipped
as one of the gods and was also used for sinister
purposes: murder of an adversary and ritual
suicide (Cleopatra).
•The snake is one of the 12 celestial animals of
Chinese Zodiac, in the Chinese calendar.
•The cobra is seen on the neck of Shiva and
Vishnu is depicted often as sleeping on a seven-
headed snake or within the coils of a serpent

41. Snakebites
–Poisonous snakes in the U.S.
• Rattlesnake
• Copperhead
• Water moccasin
• Coral snake

42. Pit Vipers
• Rattlesnake
• Copperhead
• Water moccasin
– Characteristics:
• Flat heads that are wider than their necks
(triangular)
• “Cat eyes” (elliptical)
• Heat sensitive “pit” between the eye and nostril on
each side of the head

43. Pit Viper Bites: Signs and Symptoms
• Severe burning/ fang marks
• Swelling (occurs in 5 minutes and can involve
entire extremity)
– Mark extent of swelling on body
• 6-10 hours later: potential discoloration and
blood filled blisters

44. Coral Snake Bites
• Most venomous, but rarely bites
• Red, yellow and black band
– Every other band is yellow
–Red on yellow, kill a fellow. Red on
black, venom lack.
• Chews venom into the body

45. Cobra viper
1 Venom is neurotixic venom is vasculotoxic
2
Injects almost all venom Injects little venom
3 Local symptoms are mild Intense local pain and cellulitis
4 Effects are mainly on CNS Effects are mainly on CVS
5 Lay eggs Give birth to living ones
6 Pupils are circular Pupils are elliptical
7 head and neck of same width
Head usually with small scales &
neck narrow

46. Snake Bites: What To Do (controversial
but generally recommended)
• Pit Viper
– Get away from snake / may re-strike
• Can strike ½ the length of their body
• A decapitated head can react for 20 more minutes
– Have victim lie down and stay calm
– Do not move victim unless absolutely necessary
– Keep bitten area immobile and below the level of the
heart
– Call 1122
– Wash area with soap and water

47. –Icing is generally not helpful
–“Cut and suck method”
 Increases risk of infection
–No constriction bands
 gangrene
Old style snake bite kit that should NOT be used
NOLT TO DO

48. Application of a tourniquet to the bitten limb
is generally not recommended. There is no
convincing evidence that it is an effective first aid
tool as ordinarily applied.
Uninformed tourniquet use is dangerous, since
reducing or cutting off circulation can lead to
gangrene, which can be fatal

49. • No application of potassium permanganate
• Use of electroshock therapy. Although still advocated
by some, animal testing has shown this treatment to be
useless and potentially dangerous

50. • Until the advent of antivenom, bites from
some species of snake were almost universally
fatal. Despite huge advances in emergency
therapy, antivenom is often still the only
effective treatment for envenomation.
• The first antivenom was developed in 1895 by
French physician Albert Calmette for the
treatment of Indian cobra bites
• Immunization against snake venom ?

51. antivenom
Anti-Snake venom serum is a
sterile preparation containing
purified and concentrated
immunoglobulins obtained
from the serum of healthy
horses immunized against the
venoms of the following four
common poisonous snakes of
Pakistan namely:
1. Cobra
2. Krait
3. Russell’s viper
4. Saw scaled viper

53. Supportive and symptomatic measures
• Bed rest
• Warmth
• Analgesics and sedatives (codeine, meperedine
avoid morphine d˚ risk of respiratory failure)
• Shock (fluid electrolyte balance, blood transfusion)
• Ventilation support (O2 in hypoxia- neurotoxin, tracheotomy)
• Antibiotics
• Tetanus- gas gangrene prophylaxis
• Heparin (in DIC evidence in hemolysis, Hb drop)
• Steroids (deals allergic manifestations of antivenin)

54. Non-Poisonous Bites
• Horse shoe shaped tooth marks
• May be painful but no systemic
reactions
• What To Do?
–Minor wound treatment
–If in doubt, go to hospital or call Dr.

55. PREVENTION
Sign at Sylvan Rodriguez
Park in Houston, Texas
warning of the presence
of snakes

56. Snake Bite Prevention
– Use caution around wood piles, rock crevices etc.
– Watch where you step
– Do not reach into holes or hidden ledges
– Wear boots (50%BITES BELOW KNEE), long pants, long sleeved shirts
– Don’t sit or step over logs without checking it out
– Use a walking stick, Torches
– When camping, keep tent zipped at all times (float trip)
(child sat on snake)
– Take a friend along
– Stay out of tall grass
– Leave snakes alone
– Public education (first aid management)

57. Prevention (cont..)
• 1) Any unknown snake is potentially dangerous; do not play, avoid
any contact with any snake including those of small size, baby,
lethargic, dead. A cut off head can keep poisonous activities for
several minutes. Make yourself familiar with the description of
poisonous snakes in the place where you live.
• 2) Attention!!! Use torchlight at night – all local poisonous snakes
are active in the evening and at night. Pay more attention in the
forest, close to bushes, tall plants, etc.
• 3) Snakes usually don't bite you without alarm:
• - Cobra – lifts vertically front part of the body (1/3), opens hood,
makes hiss, rushes to the aim.
• - Vipers - make a spiral from a tail, bend like zigzag front part of
the body, and make a strong hiss.
• 4) If you meet a snake, go back slowly, don't do sudden
movements, do not turn your back to the snake, do not run, and
give the possibility for a snake to go away

58. • Reassurance and immobilization of the affected limb with prompt
transfer to a medical facility are the cornerstones of the immediate care
of snakebite.
• Pressure immobilization is used for some elapid species. The mainstay
of treatment of snakebite is the infusion of an appropriate antivenom.
Snake venoms are diverse, and therefore the efficacy of antivenoms is
geographically and biologically restricted, meaning that a large number
of antivenoms have been developed for use in different settings
• Antivenoms are manufactured by immunizing horse or sheep with
venom from a particular species and then processing the serum from
the animal.
– Both monospecific and polyspecific antivenoms are available;
monospecific antivenoms are produced using the venom of a single
species, whereas polyspecific antivenoms are produced against the
venoms of several species that are prevalent in a geographic region.
– In the rural tropics, victims are often bitten in an agricultural
field or jungle, and in many instances the biting species is not
identified. In such situations, treatment with polyspecific
rather than monospecific antivenoms may be more
appropriate

59. Snakes: Additional Information
• Poor vision, especially when shedding
• Prime time for crawling snakes in this area: August
• Baby snakes have stronger venom
• Snakes just out of hibernation have stronger venom
• Many organizations, including the American Medical
Association and American Red Cross, recommend
washing the bite with soap and
water. However, do not attempt to clean the area
with any type of chemical

60. • To train farmers, students and traditional
healers in first-aid for snakebite
• To discourage dependency on traditional
healers
• To familiarize people with venomous snake
• To know the impact of snakebite first-aid
education.
We need to :

61. Pressure immobilization

62. Estimates vary from 1.2 to 5.5 million snakebites, 421,000
to 2.5 million envenomings, and 20,000 to 125,000 deaths.
Since reporting is not mandatory in much of the world, the
data on the frequency of snakebites is not precise.
Many people who survive bites have permanent tissue
damage caused by venom, leading to disability.
Most snake envenomings and fatalities occur in South
Asia, Southeast Asia, and sub-Saharan Africa,
with India reporting the most snakebite deaths of any
country.
Most snakebites are caused by non-venomous snakes.
Of the roughly 3,000 known species of snake found
worldwide, only 15% are considered dangerous to humans.
Snakes are found on every continent except Antarctica.
Worldwide, snakebites occur most frequently in the
summer season when snakes are active and humans are
outdoors.
Agricultural and tropical regions report more snakebites
than anywhere else.
EPIDEMIOLOGY

65. COBRA MAP PAKISTAN

66. DEATH / 100,000 DUE TO SNAKE BITE
•PAKISTAN = 1.901.1
•INDIA = 5.40
•BURMA = 15.40
•TRINIDAD & TOBAGO = 2.49
(2007)

68. •Most snakebites are caused by non-venomous snakes. Of the
roughly 3,000 known species of snake found worldwide, only
15 % are considered dangerous to humans
•Since reporting is not mandatory in many regions of
the world, snakebites often go unreported.

69. CONCLUSION
snakebite mainly affects the rural men of developing
countries.
 Availability of anti-venom at primary healthcare
centre's and rapid transportation facilities may change the
morbidity associated with snakebites.
Early administration of the polyvalent anti-venom has
reduced morbidity and mortality but is associated with
anaphylaxis in small group of patients.
There is need to educate the rural population about the
hazards and treatment of snake bites.
randomized controlled trials are needed to investigate
the issue of rationale of anti-venom treatment.

70. REMEMBER
• As a common man, one should know how to administer proper
first-aid to a snakebite victim, without losing precious time.
• Never try to assess whether it was venomous snakebite or not.
As a layman one should treat every snakebite as
venomous snakebite, as some snake venom (like that of
common krait) does not show immediate effect even in the case of
a serious bite, it is wise to rush to a hospital.
• Even if in doubt about whether it is a snakebite or not, do the
first-aid and rush the victim to the nearest hospital.
• Educate your children that putting one's hand into any kind of
burrow could be dangerous.

71. • Never get into a dark bathroom; first switch on a light and then
see around you before you enter.
• Not all bites from venomous snakes lead to death; many
venomous snakes (and as many as 85% of snakes are non
venomous) deliver only a dry bite to humans. Even in the case of a
full bite, with appropriate first-aid, care and treatment a snake bite
victim can fully recover. Very few venomous snakebites are fatal.
Just as every mosquito bite does not cause malaria, so every
snakebite does not cause death.
• No attempt should be made to kill the snake to carry it along to
the hospital. It would result in delaying the arrival of the patient to
the hospital and is potentially dangerous for the person who will
attempt killing the snake.
Qualified doctor can diagnose observing the patient for clinical
symptoms and pathological tests. Viperine bites cause consumption
coagulopathy and the best method of diagnosing this is the 20 Minute Whole
Blood Clotting Test (20WBCT).

72. All snakes are not venomous – so every snakebite is not
going to result in death – it would save people from
quacks. And reduce the amount of panic and chaos.
Even a venomous bite is not always fatal – because the
severity of snakebite depends on many factors like the
size of the snake, whether the bite could be completed,
whether it was a dry bite or not, the age, physique and
affected limb of the victim. Cobra injects 50% venom
usually in a single bite.
First Aid would enable a person to buy more time to reach
medical aid on time.
The only cure which is available is anti-venom
serum injection and not quacks.
First Aid - if not done properly could cause more harm
than benefit.

73. In Pakistan the criteria for ASV administration
1. Incoagulable blood determined by the 20WBCT
2. Visible neurological signs such as ptosis or ophthalmoplegia or
other evidence of descending paralysis.
3. Clear evidence of current systemic bleeding e.g. haemoptysis.
Pre medications with either hydrocortisone and antihistamine
or subcutaneous adrenaline are commonly used methods by
doctors in Pakistan to prevent adverse reactions to ASV.

74. Equipment tray
1. Anti snake venom.
2. Test tubes, new, clean, dry and glass for 20WBCT. 24 vials are required for all patients.
3. Neostigmine and atropine. 20 ampoules of 0.5mg neostigmine should be obtained for
the average number of victims who present visible neurological signs per month. Three will
be used in the initial neostigmine test and others will be required for continuing treatment.
The actual number held will vary by location as some districts such as Mirpurkhas have
higher levels of neurotoxic envenomation than others.
4. Adverse reaction drugs. Adrenaline (1:1000) is priority and 10 vials of 1mg should be kept
on the snakebite tray. 5 vials of 100mg hydrocortisone and 5 vials of 22.5mg Phenimarine
maleate should be available for longer term protection and support.
5. Pain medication. Paracetamol tablets 500mg are the preferred pain medication, and not
aspirin.
6. Resuscitation bag.
7. Airway support Kit.
If such a tray is made available in each hospital, including Basic Health Units (BHU) and Rural
Health Centers (RHC), snakebite mortality will be dramatically reduced.

75. #1 - Taipans (genus Oxyuranus)
#2 - Krait (Bungarus coeruleus)
TOP FIVE DEADLIEST SNAKES
#3 - Philippine Cobra (Naja naja philippinensis)
#4 - King cobra (Ophiophagus hannah)
#5 - Russell's viper (Daboia russelli)

76. THANK YOU