Snake bite management practice guideline

Snake bite management : Practice Guideline
Dr.Venugopalan P P
Laed consultant ,Emergency Medicine , Aster DM Health Care

Snake bite : Background in India
● 562 deaths (0.47% of total deaths)
● mostly in rural areas
● More commonly among males than females
● Peaking at ages 15–29.

● 45,900 annual snakebite deaths nationally
● Annual age-standardized rate of 4.1/100,000
● Higher rates in rural areas (5.4)
● Highest rate in the state of Andhra Pradesh
(6.2)

Annual snakebite
deaths
● Uttar Pradesh (8,700)
● Andhra Pradesh (5,200)
● Bihar (4,500)
Other Indian states
with high incidence of
snakebites
● Tamil Nadu
● West Bengal
● Maharashtra
● Kerala.

Snake bite :First aid
● 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

● Reassure the patient as around 70% of all snake bites
are from non-venomous species
● Immobilize the limb in the same way as a fractured limb
● Recovery position (prone, on the left side)
● Protect airway to minimize the risk of aspiration of
vomitus
Apply splint extending to the entire length of the limb,
immobilizing all of the joints of the limb

● Use any rigid object as a
splint e.g. spade, piece of
wood or tree branch, rolled
up newspapers etc
● Do NOT block the blood
supply
● Don't apply pressure

● Nil by mouth till victim reaches a medical health
facility
● Shift the victim to the nearest health facility (PHC or
hospital) immediately.
● Arrange transport of the patient to medical care as
quickly, safely and passively as possible
● Vehicle ambulance (toll free no. 102/108/etc.)
● Boat, bicycle, motorbike, stretcher etc can be used

● Motorbike may be a feasible
alternative for rural India
where no other transport is
available but third person
must sit behind the patient.
● Victim must not run or drive
himself to reach a Health
facility.

● 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.

When the Patient is being referred
Whenever possible medical officer can accompany
with patient
1. To know the progress,manifestation of the new
symptoms(such as progress of swelling, ptosis or
new symptoms)
2. Management and treatment of shock
3. Cardiopulmonary resuscitation (CPR)

Don'ts in Snake bite
● Do not attempt to kill or catch the snake as this may be
dangerous
● Traditional remedies have NO PROVEN benefit in treating
snakebite
● Some of them may produce confusing signs and
symptoms

● 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

● 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

● Do not tie tourniquets as it may cause gangrenous
limbs.
● Elastocrepe bandage may be applied by qualified
medical personnel only
● The bandage should be wrapped over the bitten area as
well as the entire limb with the limb placed in a splint
● If trained personnel is not present , Do NOT try it

Who require urgent treatment?
1.Profound hypotension and shock
● Direct cardiovascular effects of the venom
● Secondary effects, such as Hypovolaemia, Release of
inflammatory vasoactive mediators, Haemorrhagic shock
● Primary anaphylaxis induced by the venom
2.Terminal respiratory failure from progressive neurotoxic
envenoming that has led to paralysis of the respiratory
muscles.

Venum
● More than 90% of
snake venom (dry
weight) is protein
● Each venom contains
more than a hundred
different proteins
● Enzymes (constituting
80-90% of viperid and
25-70% of elapid venoms)
● Non-enzymatic
polypeptide toxins
● Non-toxic proteins such
as nerve growth factor.

Snake venom :Enzymes
● Digestive hydrolases
● Hyaluronidase
● Kininogenase
● l-amino acid oxidase
● Phosphomono- and
diesterases
● 5’-nucleotidase
● DNAase
● NAD-nucleosidase
● Phospholipase A2
● Peptidases.

Snake venom
Zinc metalloproteinase haemorrhagins:
Damage vascular endothelium, causing
bleeding.

Snake venom
Procoagulant enzymes
● Venoms of Viperidae and some Elapidae and Colubridae
Serine proteases and other procoagulant enzymes
● Thrombin-like or activate factor X,Prothrombin and other
clotting factors.
● Enzymes stimulate blood clotting with formation of fibrin
in the blood stream.

Snake venom
Paradox
● Most of the fibrin clot is broken down immediately by
the body’s own plasmin fibrinolytic system
● Sometimes within 30 minutes of the bite, the levels of
clotting factors are so depleted (“consumption
coagulopathy”)

Snake venom
Some venoms contain multiple anti-haemostatic factors
Russell’s viper venom contains toxins that activate factors
V, X, IX and XIII, fibrinolysis, protein C, platelet aggregation,
anticoagulation and haemorrhage.
Bucherl et al., 1968,1971; Gans and Gans 1978; Lee 1979; Harvey 1991

Snake venom
Phospholipase A2 (lecithinase)
● Extensively studied of all venom enzymes.
● Damages mitochondria, red blood cells,
leucocytes, platelets, peripheral nerve endings,
skeletal muscle, vascular endothelium, and
other membranes

Snake venom
Phospholipase A2 (lecithinase)
● Presynaptic neurotoxic activity
● Opiate-like sedative effects
● Autopharmacological release of histamine and
anti-coagulation.

Snake venom
Acetylcholinesterase
Found in most elapid venoms, it does not contribute to their
neurotoxicity
Hyaluronidase
Promotes the spread of venom through tissues

Snake venom
Proteolytic enzymes
metalloproteinases, endopeptidases or hydrolases
Polypetide cytotoxins (“cardiotoxins”)
Increase vascular permeability causing oedema, blistering,
bruising and necrosis at the site of the bite.

Snake venom
Venom polypeptide toxins (“neurotoxins”)
Postsynaptic (α) neurotoxins
● α-bungarotoxin and cobrotoxin, consist of 60-62 or
66-74 amino acids
● Bind to acetylcholine receptors at the motor endplate.

Snake venom
Venom polypeptide toxins (“neurotoxins”)
Presynaptic (β) neurotoxins
β-bungarotoxin, crotoxin, and taipoxin, contain 120-140
amino acids and a phospholipase A subunit
● Release acetylcholine at the nerve endings at NMJ
● Damage the endings
● Preventing further release of transmitter

Venom discharge
● A proportion of bites by
venomous snakes does not
result in the injection of
sufficient venom to cause
clinical effects.
● Either because of
mechanical inefficiency or
the snake’s control of venom
discharge,
● 50% of Malayan pit
vipers and Russell’s
vipers b ite
● 30% of bites by cobras
● 5%-10% of bites by
saw-scaled vipers
● Do not result in any
symptoms or signs of
envenoming.

Venom discharge
● Highly variable
● Depending on the species and size of
the snake
● Mechanical efficiency of the bite
● One or two fangs penetrated the skin
● Repeated strikes

Venom discharge
● Snakes do not exhaust their store of venom, even after
several strikes
● No less venomous after eating their prey (Tun-Pe et al.,
1991)
● Large snakes tend to inject more venom than smaller
specimens of the same species
● Venom of smaller, younger vipers may be richer in some
dangerous components, such as those affecting
haemostasis.

Victims of snake-bite may suffer any or all of
the following
(1)Local envenoming
● Confined to the part of the
body that has been bitten.
● Effects may be
debilitating, sometimes
permanently
(2)Systemic envenoming
● Involving organs and
tissues away from the part
of the body that has been
bitten.
● Effects may be life
threatening and debilitating,
sometimes permanently.

Victims of snake-bite may suffer any or all
(3) Effects of anxiety
● Frightening experience of
being bitten
● Exaggerated beliefs about the
potency and speed of action of
snake venoms.
● Symptoms can be misleading
for medical personnel.
(4) Effects of first-aid
and other pre-hospital
treatments
● Misleading clinical
features
● May be debilitating
● Rarely even
life-threatening.

Four useful initial questions
1. “In what part of your body have you been
bitten?”
2. “When and under what circumstances were
you bitten?”
3. “Where is the snake that bit you?”
4. “How are you feeling now?”

Clinical presentations
1. Progressive Painful swelling
2. Neuroparalytic
3. Vasculotoxic
4. Myotoxic

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

Asymptomatic
● Palpitations, sweating, tremulousness, tachycardia,
tachypnoea, elevated blood pressure, cold extremities and
paraesthesia
● 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.

Dry bite
1. Nonvenomous snakes
2. Venomous species are not always
accompanied by the injection of venom (dry
bites)

Dry bite - Concerns
● Dry bites ranges from 10–80% for various venomous
snakes.
● 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.

Dry bite :Concerns
● Some people who are bitten by snakes (or suspect or
imagine that they have been bitten)
● Some have doubts regarding bite may develop quite
striking symptoms and signs, even when no venom has
been injected due to understandable fear of the
consequences of a real venomous bite.
○

Neuroparalytic [ Progressive weakness, Elapid
envenomation
Symptoms - 2Ps plus 5 Ds
Ptosis
Paralysis
Dyspnea
Dysphonia
Dysarthria
Diplopia
Dysphagia

Ptosis and inability to protrude tongue

Neuroparalytic [ Progressive weakness, Elapid
envenomation
● 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.

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. Dyspnoea (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

Other signs
1. Impending respiratory failure
2. Absent deep tendon reflexes
3. Head lag.
4. Stridor
5. Ataxia
6. Hypertension and Tachycardia
may be present due to
hypoxia

How to identify impending respiratory failure?
Bedside lung function test in adults
i. Single Breath Count – number of digits
counted in one exhalation - normal >30
ii. Breath Holding Time – breath held in
inspiration – normal > 45 sec
iii. Ability to complete One sentence in
One breath.
● SBC
● BHT
● 1 in 1

How to identify impending respiratory failure ?
● Cry in a child whether loud or husky can help in identifying
impending respiratory failure
Important :
Bilateral dilated, poorly or a non-reacting pupil is not the
sign of brain dead in elapid envenoming

Decision at primary level care centers
Refer patients presenting with neuroparalytic symptoms
immediately to a higher facility for intensive monitoring
after giving Atropine+Neostigmine (AN) injection

Vasculotoxic
(Heamotoxic or Bleeding)
*General signs and symptoms of Viperine envenomation
(Vasculotoxic bites are due to Viper species)
*Local manifestations as well as Systemic
manifestations.

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
5 Ps

Systemic presentations
● Gingival bleeding
● Epistaxis
● Ecchymotic patches
● Vomiting
● Hematemesis
● Hemoptysis,
● Bleeding per rectum
● Subconjunctival hemorrhages
● Continuous bleeding from the
bite site
● Bleeding from pre-existing
conditions(haemorrhoids,
bleeding from freshly healed
wounds)
Visible systemic bleeding from the action of
haemorrhagins

Snake bite management practice guideline

● Bleeding or ecchymosis at the injection site is a common
finding in Viper bites
● Skin and mucous membranes: Petechiae, Purpura
Ecchymoses, Blebs and Gangrene.
● Swelling and local pain.
● Acute abdominal tenderness : gastro-intestinal or retro
peritoneal bleeding

● 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

Locked in Syndrome (LIS)
1. Locked in syndrome (LIS) is defined as
quadriplegia and anarthria with preserved
consciousness
2. Patients retain vertical eye movement
3. Facilitating non-verbal communication.
4. In complete locked in syndrome (LIS) patient
cannot communicate in any form.

Locked In Syndrome (LIS)
Central LIS: commonly
due to lesions in the
ventral pons
Peripheral causes of LIS
1. Severe acute
polyneuropathies
2. Neuromuscular junction
blockade due to
myasthenia gravis
3. Toxins
4. Snakebite

Importance of LIS
1. Knowing the peripheral causes are very important as one
may make a wrong diagnosis of brain death and is
treatable and complete recovery can be possible with
timely intervention
2. Confirmatory tests like EEG, cerebral blood flow, nerve
conduction velocities are recommended to avoid
misdiagnosis of coma or brain death.

Importance of LIS
3. Peripheral LIS usually occurs in Elapidae
bites, especially Krait bite
4. Such cases can be referred to a centre with
ventilator support.

Life threatening
complications

Acute Kidney Injury (AKI)
● Declining or no urine output, deteriorating blood chemistry
- serum creatinine, urea or potassium.
● Russell’s viper (Daboia sp) frequently cause acute
Kidney Injury.
● Bilateral renal angle tenderness, albuminuria, hematuria,
hemoglobinuria, myoglobinuria followed by oliguria and
anuria with AKI.

AKI in Snake bite additional causes
● Hypotension
● Hypovolaemia
● Direct
vasodilatation
● Direct
cardiotoxicity

Complications
● Parotid swelling
● Conjunctiva
oedema
● Cub-conjunctival
haemorrhage
● Renal failure
● Acute respiratory
distress
syndrome
● Leaking
syndrome
● Refractory shock.

Long term sequelae
● Pituitary insufficiency with Russell’s viper
(Daboia sp)
● Sheehan’s syndrome
● Amenorrhea in females

Idiopathic systemic capillary leak syndrome
(ISCLS)
● Hypotension-Severe
● Hypoalbuminemia
● Hemoconcentration without albuminuria
● Profound derangement of the vascular endothelium
resulting in leakage of plasma and proteins into the
interstitial compartment
.

Idiopathic systemic capillary leak syndrome
(ISCLS)
● Capillary leak syndrome is a sinister complication of
Daboia russelii bite as it is beset with an excess of
morbidity and mortality.
● Parotid swelling, conjunctival chemosis, myalgia, thirst
and systemic hypotension observed in patients of Daboia
russelii bite indicate capillary leak syndrome.
● More commonly in males as compared to females.

Early lab and Radiological markers of ISCLS
● Hemoconcentration
● Increased HCT
● Leukocytosis
● Pleural effusion[CXR]

Progressive Painful Swelling[PPS]
● Local venom toxicity
● Russel’s viper bite, Saw scaled viper bite and
Cobra bite
● Local necrosis which often has a rancid smell
● Limb is swollen and the skin is taut and shiny
● Blistering with reddish black fluid at and
around the bite site

Progressive Painful Swelling[PPS]
● Skip lesions around main lesion
● Ecchymoses due to venom action destroying
blood vessel wall.
● Significant painful swelling potentially involving
the whole limb and extending onto the trunk
● Compartment syndrome
● Regional tender enlarged lymphadenopathy.

Myotoxic envenomation
Sea snakebite
● Muscle aches
● Muscle swelling
● Involuntary contractions of
muscles.
● Passage of dark brown urine.

Myotoxic envenomation
● Compartment syndrome
● Cardiac arrhythmias
● Hyperkalaemia
● Acute kidney injury due to
myoglobinuria
● Subtle neuroparalytic signs

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.

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.

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

Krait bite vs GBS
a. Krait bite envenoming causes
descending neuroparalysis
b. GB syndrome is by ascending
paralysis.

Important :Strong clinical suspicion and careful
examination is mandatory
a. Avoiding Costly and unnecessary investigations such
as CT scan, MRI, nerve conduction studies, CSF
studies etc
b. Avoiding undue delay in initiation of a specific
treatment with ASV
c. Atropine neostigmine (AN) test helps to rule out
myasthenia gravis.

“Snakebite is a medical
emergency, history,
symptoms and signs
must be obtained
rapidly”

Part 2:
Critical arrival
Patient assessment

Critical arrival : Patient assessment
Circulation
Airway
Breathing
Deal with any life threatening
symptoms on presentation.

Vasculotoxic patients
Bleeding from multiple
orifices with
hypotension, reduced
urine output, obtunded
mentation (drowsy,
confused), cold
extremities
1. Need urgent attention
2. ICU care
3. Volume replacement
4. Pressor support
5. Dialysis
6. Infusion of blood and blood
products

Neuroparalytic patients
Respiratory paralysis,
tachypnoea or bradypnoea
or paradoxical respiration,
obtunded mentation, and
peripheral skeletal muscle
paralysis
1. Need urgent ventilator
management
2. Endotracheal
intubation
3. Ventilation bag or
Ventilator assistance.

Other cases
● Establish large bore intravenous access
● Start normal saline infusion.
● Before removal of the tourniquet/ligatures, test
for the presence of a pulse distal to the
tourniquet.

Tourniquet removal
● In case of clinically confirmed venomous
bite, remove tourniquet only after starting of
loading dose of ASV and keep Atropine
Neostigmine injection ready.
● In case of multiple ligatures, all the ligatures
can be released in Emergency Room EXCEPT
the most proximal one; which should only be
released after admission and all preparations.

Critical arrival : Assessment
● Carry out a simple medical
assessment including
history and physical
examination
● Record Vitals and Medical
assessment repeat every
1-2 hourly

Critical arrival : Assessment
● Bite site local swelling
● Painful tender
● Enlarged local lymph
glands
● Persistent bleeding from
the bite wound
● Blood pressure
● Pulse rate
● Bleeding (gums, nose,
vomit, stool or urine)
● Level of consciousness
● Drooping eyelids (ptosis)
and other signs of
paralysis

Check for and monitor the following
1. Pulse rate, respiratory rate, blood
pressure ,SpO2 in every 20
minutes
2. Whole Blood clotting test (20
WBCT) every hour for first 3 hours
and every 6 hours for remaining
24 hours.
3. Distal pulse and signs of
compartment syndrome

Glasgow Coma scale cannot
be used to assess the level of
consciousness of patients
paralyzed by neurotoxic venom

Non Critical arrival: Determine
1.Time elapsed since the snakebite
2.What the victim was doing at the time of the bite
3.History of sleeping on floor bed in previous night.
4.Any traditional medicines have been used.

Non critical arrival : AMPLE - History
A - Allergy
M- Medications
P- Past medical and surgical history
L - Last meal , Last Tetanus and Last
Menstrual Period
E -Events

Pregnant women
Monitor
1. Uterine contractions
2. Foetal heart rate.
Lactating women
● Encouraged to continue
breastfeeding.

Red flags in Snake bites
1.Rapid early extension of local swelling from the site of
the bite.(Cobra bite on finger, necrosis may start in few
minutes)
2.Early tender enlargement of local lymph nodes(spread
of venom in the lymphatic system)
3.Visible signs of neurological impairment such as ptosis,
muscular weakness, respiratory distress or respiratory arrest.

Red flags in Snake bites
4.Early spontaneous systemic bleeding especially bleeding
from the gums, bite site, haematuria, haemoptysis, epistaxis
or ecchymoses.
5.Unconsciousness either with or without respiratory arrest.
6.Passage of dark brown urine
7.Snake identified as a very venomous one i.e., Cobra,
Russel’s viper.

Identification
of Snake??
Difficult???

Poisonous snakes
● All poisonous snakes are generally brightly
coloured
● Venomous snakes have a very distinctive
head,looks like hand or triangular and side
portion is wide.
● Cobra group of snakes are Highly Venomous
● Venomous snakes has heat sensitive pit
http://www.walkthroughindia.com/know-the-difference/difference-poisonous-non-poisono
us-snakes/

Poisonous snakes
● All sea snakes are Highly Poisonous
● Poisonous snakes Family- Elapidae,Colubridae
and Viperidae
● Highly Venomous snakes in India– King
Cobra,Indian Cobra,Russell’s Viper,Saw
Scaled Viper,Malabar pit viper and Krait.
http://www.walkthroughindia.com/know-the-difference/difference-poisonous-non-poisono
us-snakes/

Non Poisonous snakes
● Non Poisonous Snakes are not brightly
coloured
● Non Poisonous Snake head is usually narrow
and elongated
● Usually Non-venomous snake do not have
Fangs but few snakes do have Fangs
http://www.biologydiscussion.com/zoology/reptiles/difference-between-poisonous-snake
s-and-non-poisonous-snakes-reptiles/41078

Non Poisonous snakes
● Pythons are Non Venomous but
equipped with rows of teeth
● Common non Poisonous Snakes in
India– Rat snake,Banded kukri,Bronze
back tree snake,Sand boa and Indian
Python
http://www.biologydiscussion.com/zoology/reptiles/difference-between-poisonous-snake
s-and-non-poisonous-snakes-reptiles/41078

Identification of Snake??
● Many cases the biting snake is not seen, and very often
its description by the victim is often misleading
● Identification of the type of snake should not hold the
treatment.
● At times the bite mark might not be visible (e.g., in the
case of Krait)
● Clinical manifestations of the patient may not correlate
with the species of snake brought as evidence

Identification of Snake??
● Examine carefully the snake, if brought, and identified if
possible.
● Discourage bringing the killed snake into the emergency
department.
● Identification of the species even if killed should be
carried out carefully, since crotalids can envenomate
even when dead.

How to identify snakes
Snake is not available for identification
1. Showing specimens of snakes preserved in formalin in
glass jars
2. Pictures of snakes would help the patient or the witness
3. Smartphone photograph of the snake, dead or alive, if can
be taken safely and bring

Websites and Apps are available

20WBCT - Bedside 20 minutes whole blood clotting Test
● Place 2 ml of freshly sampled venous blood in
a small glass test tube
● Leave undisturbed for 20 minutes at ambient
temperature
● Gently tilt the test tube to see if the blood is
still liquid

20WBCT - Bedside 20 minutes whole blood clotting Test
● Patient has hypofibrinogenaemia
(“incoagulable” blood or “not clotted”) as a
result of venom-induced consumption
coagulopathy
● Caution: Use clean new dry glass test tube
only to avoid false positive tests.

20WBCT: Interpretations
1. If blood clot is formed but signs and symptoms of
neurotoxic envenomation present, classify as
neurotoxic envenomation.
2. 20WBCT result is inconsistent with the patients’ clinical
condition, repeat the test in duplicate, including a “control”
(blood from a healthy person)
3. If the blood has clotted , the patient has passed the
coagulation test-No ASV is required at this stage

20 WBCT may remain negative (clotting) in patients with
evolving venom –induced DIC
● The patient must be re-tested
● Every hour for the first three hours
● Then 6 hourly for 24 hours
● Until either test result is not clotted or clinical evidence of
envenomation to ascertain if dose of ASV is indicated

● Antivenom treatment should not be delayed if there is
other evidence of spontaneous systemic bleeding
distant from the bite site
● In case test is non-clotting, repeat 6 hour after
administration of loading dose of ASV.
● In case of neurotoxic envenomation repeat clotting test
after 6 hours

Practice tips
1. Counsel patient and relatives in the beginning that,
20WBCT may be repeated several times before giving
any medication.
2. The first blood drawn from the patient should be typed
and cross-matched, as the effects of both venom and
ASV can interfere with later cross-matching.

Other useful tests at PHC level
1. Peak flow meter in patients (adolescents and adults)
presenting with neuroparalytic syndrome
2. Peak flow meter is not available in PHC then assess
respiratory function using bedside tests - Single breath
count, Breath holding time and Ability to complete
one sentence
3. Urine examination for albumin and blood by dipstick.

Other tests in District hospital level
1. Prothrombin time
2. Platelet count,
3. Clot retraction time
4. Liver function test
(LFT)
5. Renal Function test
(RFT)
6. Serum Amylase
7. Blood sugar
8. ECG
9. Abdominal ultrasound
10. 2D Echo (if available)

Labs and Tests in a
tertiary care center

Neuroparalytic Envenomation
1. Arterial blood gases.
Caution: Arterial puncture is contraindicated in
patients with haemostatic abnormalities.
2. Pulmonary function tests

Vasculotoxic venomation
● Coagulopathy- BT, CT, PT, APTT, Platelet, Serum
Fibrinogen, FDP D-Dimer assay, LDH, peripheral blood
smear
● Hemolysis -Urine for myoglobin, Urine haemoglobin
● Renal failure- Urine microscopy for RBC, casts, RFT,
urinary proteins, creatinine ratio

Vasculotoxic venomation
● Hepatic injury – LFTs including SGOT, SGPT, Alkaline
phosphatase, serum proteins
● Cardiotoxicity- CPK-MB, 2D Echo, BNP
● Myotoxic – CPK, SGOT, Urine myoglobin, compartment
pressure
● Infection- Serum procalcitonin, culture (blood, urine,
wound) and sensitivity

Labs and Tests
“Arterial blood gases and urine examination
should be repeated at frequent intervals during
the acute phase to assess progressive systemic
toxicity”

Part 3: Anti Snake
Venom Therapy

Anti SnAke
Venom (ASV)
therapy:
TEN FACTS

Anti Snake Venom (ASV) Therapy
1. ASV is indicated i.e. signs and symptoms of
envenomation with or without evidence of laboratory
tests, administer FULL dose without any delay.
2. Do NOT wait for any test report
3. 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

4. No absolute contraindications to ASV
5. Do not routinely administer ASV to any patient claiming to
have bitten by a snake
6.Do not delay or withhold ASV on the grounds of
anaphylactic reaction to a deserving case
7. Do NOT give incomplete dose.

8. Local swelling, accompanied by a bite mark from an
apparently venomous snake, is not an indication for
administering ASV.
9. Swelling, a number of hours old is also not an indication
for giving ASV
10. Rapid development of swelling indicates bite with
envenoming requiring ASV.

● Carry out a more detailed clinical and
laboratory assessment including biochemical
and haematological measurements, ECG or
radiography, as indicated to get a baseline
data.

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

ASV
Presence of coagulopathy
● Polyvalent ASV freeze-dried (heat stable; to be stored at
cool temperature; shelf life 3-5 years)
● Neat liquid ASV (heat labile; ready to use; requires
reliable cold chain [2-8 degree C and NOT frozen] with a
refrigeration shelf life of 2 years but costlier)
● Use depending on the availability before expiry date.

ASV
● If integrity of the cold chain is not
guaranteed, use lyophilized ASV
● Patients with severe envenoming
recently expired antivenoms may
be used if there is no alternative
(WHO 2015).

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.

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.

Dose of ASV for vasculotoxic snake bite
Two regimens
1. Low dose infusion therapy
2. High dose intermittent bolus therapy
“Low dose infusion therapy is as effective as high dose
intermittent bolus therapy and also saves scarce ASV
doses” (Expert Consensus):

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

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

How much venom ? How much ASV?
● Range of venom injected is 5 mg-147 mg
● Dose range is between 10 and 30 vials
● Each vial neutralizes 6 mg of Russell’s Viper
venom
● Depending on the patient condition, additional
vials can be considered

How much venom ? How much ASV?
● Capillary leak syndrome required higher
dose of ASV
● Early recognition and effective treatment like
infusion of fresh frozen plasma and
reduction of hemoconcentration has a key
role to reduce mortality
(Menon and Joseph 2014; Atkinson, et al 1977).

MONITORING OF
PATIENTS AND
PRECAUTIONS
DURING ASV
ADMINISTRATION

ASV administration
● Give ASV only by the IV route, and slowly
● Physician must be at the bedside during the initial
period
● Intervene immediately at the first sign of any reaction
● Observe all patients carefully every 5 min for first 30 min
● Then at 15 min for 2 hours for manifestation of a reaction

ASV administration
● STOP infusion @ the earliest sign of
an adverse reaction
● Rate of infusion can be increased
gradually in the absence of a reaction
until the full starting dose has been
administered
● Administration over a period of ~1 hour

Prophylactic epinephrine
● 0.25 mg of 0.1% solution by
subcutaneous injection
● Children 0.005 mg/kg body
weight of 0.1% solution

ASV administration
● Hold epinephrine in known
hypertensive or patients with
cardiovascular disease and draw
● Epinephrine (adrenaline) in
readiness in two syringes before
ASV is administered

ASV infusion and dosage preparation
● Each vial of AVS be dissolved in
10 ml of distilled water
● Then added to an infusion medium
such as normal saline (10 vials of
AVS dissolved in 100 ml of
distilled water and added to 400ml
of normal saline)

ASV infusion and dosage preparation
○ Volume of infusion is
reduced according to the
body size and the state of
hydration of the patient
○ Oliguric patients restrict
fluids and use infusion
pump to give full dose of
ASV over 30 minute

ASV administration
● NEVER give ASV by IM route
● Never inject the ASV locally at the bite
site
● Maintain all aseptic precautions
before starting ASV to prevent any
pyrogenic reactions
● Maintain a strict intake output chart
● Monitor colour of urine to detect acute
kidney injury early
2 N
3 M

ASV administration in pregnancy
● Pregnant women are treated in
exactly the same way as other
victims
● Dosage of ASV is same
● Refer for an OBG assessment of
any impact on the foetus

ASV administration in children
● Exactly the same dose of ASV as
adults
● Snakes inject the same amount of
venom into children and adult
● Infusion: liquid or reconstituted ASV is
diluted in 5-10 ml/kg body weight of
normal saline
● Reduce amount of fluid in running
bottle to 200 ml to avoid fluid overload

ASV DOSAGE IN VICTIMS REQUIRING LIFE
SAVING SURGERY
● Intracranial bleeding: Requires a life
saving surgery
● Coagulation must be restored before
surgery to avoid catastrophic bleeding
during surgery
● Higher initial dose of ASV (up to 30
vials) can be administered

ASV - Repeat doses
● Repeat clotting test every 6 hours
until coagulation is restored
● Repeat ASV every 6 h until
coagulation is restored
● Patients who continue to bleed briskly
repeat ASV within 1-2 hours (WHO
2015)

ASV - Repeat doses
● Hump-nosed Pit viper bite does
not respond to normal Indian
polyvalent ASV
● Coagulopathy may continue for up
to 3 weeks
If 30 vials of ASV have been administered reconsider whether
continued administration of ASV is serving any purpose,
particularly in the absence of proven systemic bleeding

Persisting coagulopathy in spite of large doses ASV
1. Fresh frozen plasma (FFP)
2. Cryoprecipitate (fibrinogen, factor VIII)
3. Fresh whole blood- when FFP and
cryoprecipitate are not available

Repeat doses in Neurotoxic envenomation
● Initial dose of ASV 10 vials stat as infusion
● 2nd dose of 10 vials if no improvement within 1st hour
● Repeat 2nd dose may be required even after 2-3 hours if
relapse of signs of neurotoxicity(may be due to delayed
absorption)
● Maximum dose is 20 vials

Late arrived victims : ASV dose protocol
1. Late after the bite
2. After several days
3. With acute kidney injury

Late arrived victims : ASV dose protocol
● Determine current venom
activity
● Bleeding- viperine
envenomation
● Perform 20WBCT
● Determine if any
coagulopathy is present
● If YES , administer
ASV.
● If NO coagulopathy is
evident NO ASV
● Treat kidney injury
● Treat any other
complications

ASV Reactions
Management Protocols

ASV Reactions
20%-60% patients treated with ASV develop either early or late
mild reactions
(Deshpande et al.2013; Deshmukh et al 2014)

ASV Reactions
● NO ASV TEST DOSE MUST BE
ADMINISTERED
● SKIN/CONJUNCTIVAL
HYPERSENSITIVITY TESTING DOES
NOT RELIABLY PREDICT EARLY OR
LATE ANTI SNAKE VENOM
REACTIONS AND IS NOT
RECOMMENDED.

1
2
3
ASV
Reactions
Early Anaphylactic reactions
Pyrogenic Reactions
Late ( Serum Sickness like )
reactions

Early anaphylactic reactions
● Within 10–180 min of start of
therapy
● Characterized by itching,
urticaria, dry cough,
nausea and vomiting,
abdominal colic, diarrhoea,
tachycardia, and fever
Few patients may have
severe life-threatening
anaphylaxis
● Hypotension
● Bronchospasm
● Angio- oedema

Pyrogenic reactions
Develop 1–2 h after
treatment
Symptoms
● Chills
● Rigors
● Fever
● Hypotension
Caused by contamination of
the ASV with pyrogens during
the manufacturing process

“Any new sign or
symptom after
starting the ASV in
drip should be
suspected as a
reaction to ASV”

Late (serum sickness–type) reactions
● Develop 1–12 (mean 7) days after treatment
● Clinical features
● Fever
● Nausea
● Vomiting
● Diarrhoea
● Itching
● Recurrent urticaria
● Arthralgia
● Myalgia
● Lymphadenopathy
● Immune complex
nephritis
● Encephalopathy

Premedication before ASV
Prophylactic adrenaline is recommended before ASV
Adult : adrenaline (epinephrine) is 0.25 mg of 0.1% solution
by subcutaneous injection
Children: 0.005 mg/kg body weight of 0.1% solution
NO EPINEPHRINE Premed:
1. Hypertensive:BP more than 140/90 mm of Hg
2. Evidence of underlying cardiovascular disease.

Premedication before
ASV
“Use of histamine, anti-H1 and anti-H2 blockers,
corticosteroids and the rate of intravenous infusion
of antivenom between 10 and 120 minutes), do not
affect the incidence or severity of early
antivenom reactions”
(de silva 2011)

Treatment of early reaction
● Stop ASV temporarily
● Oxygen
● Start fresh IV Normal Saline infusion with a new IV set
● Epinephrine (adrenaline) (1 in 1,000 solution, 0.5 mg (i e
0.5 ml) in adults intramuscular over deltoid or over
thigh

● Epinephrine : Children 0.01 mg/kg body weight) for early
anaphylactic and pyrogenic ASV reactions
● Chlorpheniramine maleate (adult dose 10 mg, in children
0.2 mg/kg) intravenously
● Hydrocortisone can be given but it is unlikely to act for
several hours

Once the patient has recovered
● Re-start ASV slowly for 10-15
minutes
● Keeping the patient under close
observation
● Then resume normal drip rate

High risk patients
1. History of hypersensitivity
2. Previous Exposure to
animal serum such as
equine ASV,
tetanus-immune globulin
or rabies-immune
globulin
3. Severe atopic conditions
● Give ASV only if they
have signs of systemic
envenoming
Premedication
● Inj. Hydrocortisone 200
● Chlorpheniramine
maleate 22.75 mg

Treatment of late reactions[Serum sickness]
● Inj. Chlorpheniramine 2 mg in adults
● Children 0.25 mg/kg/day) 6 hourly for 5 days.
Patients who fail to respond within 24–48 hrs
Prednisolone
● 5 mg 6 hourly in adults
● 0.7 mg/kg/day in children
● Divided doses
● 5 days course

Desensitization procedure
● Only in case of severe
anaphylaxis reaction to ASV
with shock
● Generalised anasarca after
injection of very few ml of ASV
usually less than 5 ml of diluted
ASV
● Change the batch of ASV
● Pre-medication
1. Inj. Hydrocortisone
100 mg I.V.
2. Inj. Adrenaline 0.5
ml sc/im
3. Inj.Promethazine

ASV dilution and
injection in
desensitization
procedure

Steps of
dilution
Instructions Total Volume Solution Dilution
1 Dilute 1 ml of ASV in a vial in
9 ml of 0.9% Nacl
10ml A
2 1 ml of solution A+9 ml of
Normal Saline
10ml B 1:10
3 1 ml of solution B + 9 ml
Normal Saline
10ml C 1:100
4 1 ml of solution C + 9 ml of
Normal Saline
10ml D 1:1000
5 1 ml of solution D + 9 ml of
Saline
10ml E 1:10,000

Inject 0.1 ml of Solution E
intravenously
Watch for Anaphylaxis for 15 mts
No Reaction
Inject another 0.1 ml of Solution E
intravenously
No Reaction
After dilution &
preparation of
Solution E,
follow the
injection
protocol

After dilution &
preparation of
Solution E,
follow the
injection
protocol
Inject Entire Solution E
intravenously
No Reaction
● After solution E is injected continue the
same process as follows for other
solutions is the following sequence:
● Solution D followed by
● Solution C
● Solution B
● Solution A
● Then full dose.

Atropine: Neostigmine (AN) Dose schedule
Adult
● Atropine 0.6 mg followed by
Neostigmine (1.5mg) IV stat
● Repeat dose of Neostigmine 0.5
mg with Atropine every 30
minutes for 5 doses

Children
● Inj. Atropine 0.05 mg/kg
followed by Inj.
Neostigmine 0.04 mg/kg
Intravenous
● Repeat dose of NS 0.01
mg/kg every 30 minutes for
5 doses
● A fixed dose combination
of Neostigmine and
Glycopyrolate IV can
also be used.

● Tapering dose at 1 hour, 2 hour, 6 hours and 12 hour.
● Majority of patients improve within first 5 doses
● Observe the patient closely
● An observation for 1 hour to determine if the
neostigmine is effective
● After 30 minutes, the improvement should be visible by an
improvement in ptosis.

Atropine:
Neostigmine
(AN) Dose
schedule
❖ Positive response to
“AN” trial is measured
as 50% or more
recovery of the ptosis
in one hour.

When to Stop Atropine neostigmine (AN) dosage
schedule?
1. Complete recovery from
neuroparalysis.
2. Side effects in the form of
fasciculations or
bradycardia
3. No improvement after 3
doses
★ Carefully watch
patients for
recurrence.

● Improvement by atropine neostigmine
indicates Cobra bite
● Few Nilgiri Russel’s viper bites victims
also improve with this regimen

● No improvement after 3
doses of Atropine
Neostigmine
● Probable Krait bite
● Krait affects Presynaptic
fibres where calcium ion
acts as neurotransmitter

● Inj. Calcium gluconate 10ml
IV slowly over 5-10 min every 6
hourly
● Continue till neuroparalysis
recovers which may last for
5-7 days
● Children 1-2 ml/kg (1:1
dilution)

Other Managements in Snake bite
● Mechanical ventilation
● Volume Replacement
● Forced alkaline
Diuresis(FAD)
● Management of
Hyperkalemia
● Management of Severe
Acidosis
● Dialysis
● Management of shock
and Myocardial damage
● Management of Local
severe envenoming

Snake bite :Indication of Dialysis
● Blood urea >130 mg/dl (27 mmol/L) (BUN 100
mg/dl)
● Sr. Creatinine > 4 mg/dl (500 μmol/L)
● Daily rise in blood urea 30 mg/dl (BUN > 15)
● Sr. Creatinine > 1 mg/dl
● Sr. Potassium > 1 mEq/L
● Fall in bicarbonate >2 mmol/L

Snake bite :Indication of Dialysis
● Fluid overload leading to Pulmonary oedema
● Hyperkalaemia (>7 mmol/l or Hyperkalaemic ECG
changes- tall peaked T waves, prolonged P-R
interval, absent P wave, wide QRS complexes)
● Unresponsive to conservative management.
● Uremic complications – Encephalopathy,
Pericarditis.

Surgical procedures in Snake bite
● Debridements of
necrotic tissues
● Fasciotomy in
Compartment
syndrome

How to monitor Compartment pressure?
● Insert a 16 no. needle in the
suspected compartment at a
depth of 1 cm
● Connect to a simple tubing
irrigated with normal saline
Measure rise in the saline
column in the tubing

How to monitor Compartment pressure?
● Rise more than 40 cm of
saline corresponds to 30 mm
Hg of lymphatic/ capillary
pressure
● Suggestive of excessive
compartment pressure
● Necessitates fasciotomy
procedure.

Suspected snake bite
Overt bite
History of bite Nonvenomous (70%)
/ Venomous (30%)
Occult bite
No history of bite
Asymptomatic
Anxiety, palpitations,
tachycardia, Paraesthesia
Observe 24 hrs
● Neuroparalytic
symptoms with no
local signs
● Severe abdominal
pain, vomitingKrait
Dry Bite Symptomatic-
Predominant symptom manifestations
1. ASV
2. AN
3. Ventilation
Progressive Painful
swelling
Neuroparalytic
Myotoxic
Vasculotoxic
Flat tailed
sea snake
Russel’s
Viper,Saw
scaled Viper
Cobra,
Krait
Viper

● Local
necrosis
● Ecchymosis
● Blistering
● Painful
swelling
● Compartment
syndrome
Viper
ASV
● Ptosis
● Diplopia
● Dysarthria
● Dysphonia
● Dyspnoea
● Dysphagia
● Paralysis
Cobra,
Krait
1. ASV
2. AN
3. Ventilation
Russel’s
Viper,Saw scaled
Viper
➢ Bleeding
➢ Demonstrable
coagulopathy
(20WBCT
incoagulable)
➢ Shock
➢ Acute kidney
injury (not
seen with Saw
scale viper)
A. ASV
B. Blood transfusion
C. Continuous supportive
care
D. Dialysis
Flat tailed
sea snake
● Muscle ache
● Muscle
swelling
● Muscular
Involuntary
contractions
● Compartment
syndrome
3MC
A. ASV
B. Continuous
supportive Care
C. Dialysis

Thank you so much
for your patient
listening
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Snake bite management practice guideline

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Snake bite management practice guideline