Snake Bite

Snake Bite
AB Rajar
Email:drabrajar@gmail.com
1

LEARNING OBJECTIVES
I. Introduction
II. Global Burden.
III. Burden in Pakistan
IV. Types of snakes
V. Types of Snake venom
VI. Clinical presentations
VII. Management of snake bite
VIII.Prevention and control
2

INTRODUCTION
• Snake bite is an injury caused by a bite from a snake, often resulting
in puncture wounds inflicted by the animal’s fangs & some times
resulting in envenomation.
• Snake bite is a medical emergency & survival of the victims depends
much on:
• Appropriate first aid measures
• Immediate transportation
• To the nearest health center:
• Anti-snake venom
• Supportive care
3

GLOBAL BURDEN
• About 5 million people bitten by snakes every year
• 100 000 to 200 000 deaths annually, and 400 000 snakebite-related
amputations
• In sub-Saharan Africa, about 30 000 people die from snake bite each
year
• The largest number of fatal snake bites occur in South east Asia,
about 25,000.
• Children suffer higher incidence and more severe effects than adults
• World Report on Child Injury Prevention (World Health Organization 2008, p.128)
4

IN PAKISTAN
• In Pakistan snake bites are common in both agriculture areas as well
as in mountains of Baluchistan.
• The incidence increases during the harvest time.
• Generally 100,000 vials of 10ml anti-venom are required per year.
• Snake envenomation is an acute public health problem,
• Amongst the five commonest causes of admission to hospitals.
5

IN SINDH
• In the THAR region of Sindh province, the problem is just as
demanding as that of infectious and communicable diseases.
• Based on the use of anti-venom, it is estimated that at least 40,000
episodes of snake bite occur every year.
• Death rate is 1.90/100,000 population would be approximately 2660
per year.
• Due to cultural traditions and socio-economic factors, not all cases
are seen by physicians.
6

COMMON VENOMOUS SNAKES OF PAKISTAN
Zoological name Common name Venom properties
Naja-Naja Cobra Primarily neurotoxin causes slight swelling but not much
pain, death ensures due to respiratory failure.
Bungarus
caeruleus
Common Krait Neurotoxin & swift acting. Anti-venom should be given
immediately.
Vipera russelli Russell's Viper Causes considerable local pain & swelling.
Echis carinatus Saw scaled
Viper.
Seldom injected in amount that are lethal to
man.However,there is local swelling & pain. Within 24 to 26
hrs,bleeding occurs from gums,kidneys,nose etc.
7

KING COBRA
8

COMMON KRAIT
9

RUSSELL'S VIPER
10

SAW SCALED VIPER.
11

CLASSIFICATION OF VENOMOUS SNAKES
Venomous Snakes
Family Colubridae Family Viperidae
Colubrinae Viperniae AH RectasphidaeElapidae Hydrophidae
• Grass Snake • Cobra
• Krait
• Coral
• Rattle Snake
• Pit Viper
• Russels Viper
• Sea Snake
12

DIFFERENCE
POISONOUS
• Fangs :
• Hollow like hypodermic needles
• Teeth :
• 2 long fangs
• Tail : Compressed
NON POISONOUS
• Short and solid
• Several small teeth
• Not much compressed
13

Various snakebites, their fatal dose, quantity of
venom injected, and time to fatality
Snake Fatal dose in human Average dose
delivered per bite
Average Fatal Period
King Cobra 12 mg 60 mg 8 hrs.
Common Krait 6 mg 20 mg 18 hrs.
Russell's viper 15 mg 63 mg 4 days
Saw scaled viper 8 mg 13-40 mg 41 days
14

TYPES OF SNAKE VENOM
A. Cardio-toxic---Due to direct toxic effect of venom
B. Hemato-toxic- Effect on Blood and blood vessels
 Nephro toxic:
I. due to direct toxic effect of venom
II. Enzymatic activities of snake venoms account for direct nephrotoxicity.
III. Immunologic.
C. Myo-toxic-has localized effect at bite site
D. Hemorrhagic Envenoming
E. Neuro toxic-T
• There are many types with differing actions, but the most common cause
flaccid paralysis of skeletal muscle by blocking transmission at the
neuromuscular junction, either presynaptically or post-synaptically.
15

CLINICAL PRESENTATIONS
17

CLINICAL PRESENTATIONS
A • Progressive Painful swelling
B • Neuroparalytic
C • Vasculotoxic
D •Myotoxic
18

CLINICAL PRESENTATION - DEPENDS
1. Age and size
of the patient
2. Species of
snake
3. Number and
location of the bites
4. Quantity and
toxicity of the venom
19

ASYMPTOMATIC
• Palpitations, sweating, tremulousness, tachycardia, tachypnea,
elevated blood pressure, cold extremities and paresthesia
• Dilated pupils suggestive of sympathetic over activity
• Vasovagal shock
• Redness, increased temperature, persistent bleeding and tenderness
locally.
• Local swelling can be present in these patients due to tight ligature.
20

DRY BITE - CONCERNS
• Dry bites ranges from 10–80% for various venomous snakes.
• In at least 20% of pit viper bites and a greater percentage of elapid
and sea snake bites, no venom is injected
• Symptoms due to anxiety and sympathetic over-activity may be
present
• Panic or stress sometimes mimic early envenoming symptoms,
clinicians may have difficulties in determining whether envenoming
occurred or not.
21

LOCAL FEATURES
• Fang marks:
• Generally, the presence of two puncture wounds indicates a bite by a poisonous snake.
• Pain:
• Burning, bursting or throbbing pain may develop immediately after the bite and spread
proximally up the bitten limb. Krait and sea snake bites maybe virtually painless.
• Local swelling:
• Viper bites produce more intense local reaction than other snakes.
• Local necrosis:
• In viper bites, bruising, blistering and necrosis may appear over few days following the bite.
• Secondary infection:
• Bacterial flora in the oral cavity of the snakes contributes to secondary infection.
22

Neuroparalytic
23

NEUROPARALYTIC
• Symptoms - 2Ps plus 5 Ds
• Ptosis
• Paralysis
• Dyspnea
• Dysphonia
• Dysarthria
• Diplopia
• Dysphagia
24

NEUROPARALYTIC
• Typical symptoms within 30 min– 6 hours in case of Cobra bite.
• Krait and the hump- nosed pit viper are known for delayed
appearance of symptoms which can develop after 6–12 hours.
• Ptosis in Krait bite have been recorded as late as 36 hours after
hospitalization
25

CHRONOLOGICAL ORDER OF APPEARANCE OF SYMPTOMS
1. Furrowing of forehead and Ptosis (drooping of eyelids)
2. Diplopia (double vision)
3. Dysarthria (speech difficulty)
4. Dysphonia (pitch of voice becomes less)
5. Dyspnea (breathlessness)
6. Dysphagia (Inability to swallow)
7. Intercostal and skeletal muscles occurs in descending manner.
• Related to
3rd, 4th, 6th
and lower
cranial
nerve
paralysis
26

Ptosis And Inability To Protrude Tongue
27

BROKEN NECK SIGN
28

Vasculotoxic
(Heamotoxic or Bleeding)
General signs and symptoms of Viperine envenomation
( Vasculotoxic bites are due to Viper species )
29

LOCAL MANIFESTATIONS
• Local swelling
• Bleeding
• Blistering
• Necrosis.
• Pain at bite site
• Severe swelling
• Compartment syndrome.
• Tender enlargement of local
draining lymph node
Compartment syndrome
• 1. Pain on passive movement.
• 2. Pulselessness- Absent
• 3. Paresthesia or Hypoesthesia
• 4. Pallor
• 5. Paralysis
30

LOCAL MANIFESTATIONS
31

SYSTEMIC PRESENTATIONS
 Gingival bleeding
 Epistaxis
 Ecchymotic patches
 Vomiting
 Hematemesis
 Hemoptysis
 Bleeding per rectum
 Sub- conjunctival hemorrhages
 Continuous bleeding from the
bite site
 Bleeding from pre-existing
conditions (haemorrhoids,
bleeding from freshly healed
wounds)
32

33

• Lateralizing neurological
symptoms (asymmetrical pupils)
:Intra-cranial bleeding
• Consumption coagulopathy
detectable by 20WBCT …..>
• Develops as early as within 30
minutes from time of bite.
• It may be delayed sometimes
• Twenty-minute whole blood clotting test (20WBCT)
34

MYOTOXIC
35

MYOTOXIC ENVENOMATION
• MYOTOXICITY:
• Sea snake venom contains myotoxins that cause myalgias,
myopathy and rhabdomyolysis.
• Generalized aching, stiffness and tenderness of muscles develop
0.5 to 3.5 hours after the bite.
• Trismus (lockjaw) is common.
• Myoglobinuria secondary to rhabdomyolysis appears 3 to 8 hours
after the bite.
• Myotoxins damage skeletal muscle and cardiac tissue.
36

Occult bite
• Krait bite victims often present in the early morning with
paralysis with no local signs with no bite marks.
• Snakebite victim gets up in the morning with severe
epigastric/umbilical pain with vomiting persisting for 3 – 4
hours and followed by typical neuroparalytic symptoms
within next 4- 6 hours.
• There is no history of snakebite.
37

Occult bite
• Unexplained respiratory distress in children in the presence
of ptosis or sudden onset of acute flaccid paralysis in a child
(locked-in syndrome) is highly suspicious symptoms in
endemic areas particularly of Krait bite envenomation.
• Patients may present with throat, chest or joint pain.
38

DD
• Early morning symptoms of
acute pain abdomen with or
without neuroparalysis can be
mistaken for
● Acute appendicitis
● Acute abdomen
● Stroke
● GB syndrome
● Myasthenia gravis
● Hysteria
39

FIRST AID DO IT
• Check history of snakebite
• Look for obvious evidence of a
bite
• Krait bite no local marks may be
seen
 Evidences of bite
• Fang puncture marks
• Bleeding
• Swelling of the bitten part
• It can be noted by magnifying lens as a pin head bleeding spot with
surrounding rash
40

FIRST AID- DO IT R.I.G.H.T
• R – Reassure the patient . 70 % snake bites – nonvenomous species.
Only 50 % of bites by venomous species actually envenomate the pt.
• I – Immobilize in the same way as # limb. Use bandages / cloth to
hold splints, not to block blood supply / apply pressure. Do not apply
any compression in the form of tight ligatures
• GH – Get to the hospital immediately
• T- Tell the doctor of any systemic symptoms that manifest on way to
the hospital.
41

FIRST AID DO IT
• Remove shoes, rings, watches,
jewellary and tight clothing
from the bitten area
• It can act as a tourniquet
when swelling occurs
• Leave the blisters
undisturbed.
• Inform the doctor if progress of swelling, ptosis or new symptoms
that manifest on the way to hospital.
• Apply splint extending to the entire length of the limb, immobilizing all of
the joints of the limb
42

DON'TS IN SNAKE BITE
• Do not do traditional first aid
methods (black stones,
scarification)
• Do not use alternative
medical/herbal therapy
• Do not wash the wound
Do more harm than good by
delaying treatment
43

• Do not interfere with the bite
wound
• (Incisions, suction, rubbing,
tattooing, vigorous cleaning,
massage, application of herbs or
chemicals, cryotherapy, cautery)
• Do NOT apply or inject anti
snake venom (ASV) locally.
• 1.Introduce infection
• 2. Increase absorption of the
venom
• 3. Increase local bleeding
44

• Tourniquets traditionally used to stop venom flow. ( increased risk of
ischemia , loss of limb, necrosis, massive neurotoxic blockade when
tourniquet is released, embolism – viper , false sense of security )
• Incision & Suction – increases risk of severe bleeding as clotting
mechanism is ineffective & infection . No venom is removed by this
method
• Washing the wound – it increases the flow of venom into system by
stimulating the lymphatic system.
45

WHO REQUIRE URGENT TREATMENT?
1. PROFOUND HYPOTENSION AND SHOCK
 Direct cardiovascular effects of the venom
 Secondary effects, such as Hypovolemia, Release of inflammatory
vasoactive mediators, Hemorrhagic shock
 Primary anaphylaxis induced by the venom
2. TERMINAL RESPIRATORY FAILURE from progressive neurotoxic
envenoming that has led to paralysis of the respiratory muscles.
46

EXAMINATION
● To rule out ptosis
Evidence of early external ophthalmoplegia .
● Size and reaction of the pupils.
● Early paralysis of pterygoid muscles.
● “broken neck sign
47

LOCAL EXAMINATION
• Oedema petechiae bullae oozing from the wound should be
noted
• Extent of swelling
• Circumference of the bitten limb should be noted every 15
minutes- spreading
48

MONITOR VITAL SIGNS
 OBSERVE EVERY PATIENT FOR MINIMUM 24 HOURS
 Pulse, BP, Respiration
 Urine output
 Blood urea, Creatinine
 Bleeding tendency
 Local swelling
 Vomiting
 Diplopia, Ptosis, Muscle Weakness, Breathlessness
49

INVESTIGATIONS
• Complete Blood Count – Anemia, Leukocytosis, Thrombocytopenia,
• Evidence of Heamolysis – Fragmented RBCs
• Prolonged Clotting Time – Ampoule method Prolonged APTT
• Serum Electrolytes – Hyperkalemia
• Raised Urea, Creatinine
50

INVESTIGATIONS
• Urine for RBC – Viper Bite – Hematuria, Proteinuria, Hemoglobinuria,
Myoglobinuria
• ECG – Normal, Bradycardia with ST elevation or depression, T
inversion, QT prolongation
• ABG (Arterial blood gases) – Hypoxemia with Respiratory Acidosis,
Metabolic / lactic Acidosis
• Chest X- ray – Normal, Pulmonary Oedema, Intrapulmonary
Hemorrhages, Pleural Effusion
51

TREATMENT PROTOCOL
őAttend to AIRWAY , BREATHING, CIRCULATION(ABC)
őTetanus toxoid TT
őRoutine antibiotic is not necessary
őIdentify the snake responsible
őAll patients should be kept under observation for a minimum period
of 24 hrs.
őDetermine the exact time of bite
őAsk the victim as to what he was doing at the time of bite
52

TREATMENT PROTOCOL
͌ Pain – give PARACETAMOL
͌ Not Aspirin & NSAIDS
͌ 5o mg TRAMADOL can also be used
͌ Care must be taken when removing tight tourniquets tied by victim.
͌ Sudden removal can lead to massive surge of venom leading to
neurological paralysis, hypotension d/t vasodilatation.
53

EVIDENCE OF SYSTEMIC ENVENOMATION
ѻ CT> 10 MINUTES
ѻ Bleeding manifestations
ѻ Oliguria /haematuria
ѻ Hypotension
ѻ Ptosis
ѻ Circumoral paresthesia
ѻ Aphonia/Dysarthria
54

ANTI SNAKE VENOM THERAPY
55

Anti Snake Venom [ASV]
• Anti snake venom treatment is the only specific treatment.
• It should be given as soon as it is indicated
• Reverse systemic envenomation abnormality even when this has
persisted for several days or, in the case of haemostatic abnormalities,
persisting for two or more weeks.
• Dosage required varies with the degree of envenomation
56

Anti Snake Venom (ASV) Therapy 10 FACTS
• ASV is indicated i.e. signs and symptoms of envenomation with or
without evidence of laboratory tests, administer FULL dose without
any delay.
• Do NOT wait for any test report
• History of Bite; known or unknown, if there is spontaneous abnormal
bleeding beyond 20 minutes from time of bite, start ASV, Do NOT
wait for 20 WBCT report
• No absolute contraindications to ASV
• Do not routinely administer ASV to any patient claiming to have bitten
by a snake
57

Anti Snake Venom (ASV) Therapy 10 FACTS
• Do not delay or withhold ASV on the grounds of anaphylactic reaction
to a deserving case.
• Do NOT give incomplete dose
• Local swelling, accompanied by a bite mark from an apparently
venomous snake, is not an indication for administering ASV.
• Swelling, a number of hours old is also not an indication for giving
ASV.
• Rapid development of swelling indicates bite with envenoming
requiring ASV.
58

ANTI SNAKE VENOM (ASV) DOSE
• Reconstitute ASV supplied in dry powder
form by diluting in 10 ml of distilled water/
normal saline
• Mixing is done by swirling only
• Do not shake vigorously
• Caution: Do not use, if reconstituted
solution is opaque to any extent
59

Dose of ASV for Neuroparalytic Snakebite
• ASV 10 vials stat as infusion
over 30 minutes
• 2nd dose of 10 vials after 1
hour if no improvement within
1st hour
60

Dose of ASV for vasculotoxic snake bite
Low dose infusion therapy
• 10 vials for Russel’s viper
• 6 vials for Saw scaled viper
• Stat, as infusion over 30 minutes
• 2 vials every 6 hours as infusion
in 100 ml of normal saline
• Continue till clotting time
normalizes or for 3 days
whichever is earlier.
High dose intermittent bolus therapy
• 10 vials of polyvalent ASV stat
over 30 minutes as infusion
• Followed by 6 vials 6 hourly as
bolus therapy till clotting time
normalizes and/or local swelling
subsides
Two regimens 1. Low dose infusion therapy
2. High dose intermittent bolus therapy
61

No ASA available
• Sea snakebite
• Green Pit snakebite (even
if with signs of envenomation)
• Available ASV do not contain
antibodies against them
62

HOW TO GIVE ASV ?
⦿ No test dose is required
⦿ One vial is added with 100 ml of normal saline.
⦿ After 10 -15 minutes 9 vials can be added in the same fluid over
one hour
63

ASV REACTION
⦿Urticaria ,itching ,fever , shaking chills ,nausea ,vomiting ,diarrhea
abdominal cramps ,tachycardia hypotension , bronchospasm and
angioedema
⦿ ASV is discontinued
⦿ 0.01mg/kg of Adrenaline is given
(1:1000)as IM should be given
64

LONG TERM REACTION
 100mg of Hydrocortisone (2mg/kg) and
10mg of H1 antihistamine
(children- 0.2mg/kg) IV
 2nd dose of Adrenaline 0.5 mg (1:1000) IM
can be repeated
 Patient is recovered ASV can be restarted slowly within 10 – 15
minutes
65

TIMING OF ASV
⦿Best effect – used within 4 hours
⦿Can be administered up to 48 hours
⦿Efficacy is seen up to 6- 7 days
66

RESPONSE TO ASV
⦿Normalization of BP
⦿Bleeding stops within 15 – 30 mts
⦿Normalization of coagulation parameters within 6 hours
⦿Neurological sign will be resolving within 30-48 hours
67

PREVENTION
68

PREVENTION
⦿Best way to a manage
Is to prevent a snake bite…..!
69

HOW TO PREVENT SNAKE BITES
⦿A WORLD WITHOUT SNAKES
⦿NEARLY A QUARTER OF US WOULD GO HUNGRY
⦿THEY ARE IMPORTANT ELEMENTS IN FOOD CHAIN THAT CONTROL
RODENT POPULATION
70

PREVENTION
• Half of the snake bites are bellow the knee, so wearing of knee high
boots is valuable.
• lantern, or torches should be used when walking or watering the field
at night in snake infested areas.
• People especially children should be advised not to put their hands
into hollow logs or animal burrows.
• The residential areas must be kept clean and surveyed for holes.
71

PREVENTION
• During camping the military & scouts, they must be advised to
examine their boots, beddings & sleeping bags.
• Stay out of all grass.
• Be alert during climbing rocks.
• Leave snake alone,
• Mass public education in First Aid management of snake bite.
• Antivenin must Be made available in health centers where large cases
of snake bite present.
72

THANK YOU
73

Snake Bite

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