Snake Bite National protocol pediatrics

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SECTION I: SNAKEBITE

Titles PageGeneral:

Introduction

Snakes and snake bites:EpidemiologyEcological aspectsSocio cultural aspects of snakes and snake bitesStatistics on snakebites and ASV usage in Tamil NaduClassification of snakes

World snakes of Medical ImportanceTamilnadu snakes of Medical Importance-Distinguishing

features

Clinical aspects of snake bite:PathophysiologySymptoms and signs.Criteria for diagnosisComplications and outcomeInvestigations.

Treatment:Principles involved in the treatment

First aid for snake biteTraditional methods followed for treating snake bite.Newer methodspressure pad or Monash technique.Pharmacological aspects of Anti snake venomASV Administration- criteriaASV Administration- dosageFacts to be remember before/ while using Inj.ASVASV reactionsPrevention of ASV reaction prophylactic regimens

Repeat doses: NeurotoxicRecovery phaseRepeat doses: Anti haemostaticASV risk and wastageOther supportive measures

Clinical issues in snakebite1. Hypotension2. Persistent bleeding

3. Renal failure4. Surgical issues

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5. Heparin and botropase

Snake Bite in special situations Victims requiring life saving surgery Victims arriving late Snake bites Again Pregnancy and lactating women. Others

Management at PHC and Block PHC

Referral aspects

Welfare measures

Occupational risk for snakebite

Preventive measures and health education.

References

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SECTION I: SNAKEBITES

GENERAL:

Introduction:

Snake bites contribute to health problem in India and continue to be a

major medical concern. In India approximately every minute one person is

bitten by a Snake and every two hours one case of snakebite dies. As the facts

are alarming, one has to take active steps.

Actually an up-to-date National data, on the morbidity and mortality due

to snakebite and the related are not available. The available statistics is

incomplete and not systemically collected. In 1972, Dr. Sawai and Dr. Homma

of the Japan Snake Institute selected about 10 hospitals in India and estimated

the number of snake bite cases treated at the hospitals, and how many died

there. They also estimated number of cases died outside the hospitals. But this

of course could only be conjecture. The report concluded that about 10 per cent

of deaths are of the victims who come to the hospital and about 90 per cent die

outside, having gone for other remedies like mantra, magic, and so on.

However things are very different now in different places after 35 years.

An international expert on snakebite, the late Dr. Alistair Reid of theLiverpool School of Tropical Medicine found out that only 10 to 15 per cent of

venomous bites end in death. The possibility of survival, even without

treatment, is incredibly good in 80 to 90% of cases. There are many reasons for

this. One is that many snakebites are by non-venomous snakes. Second, a

large percentage of venomous snakebites are dry bites.

That means, the snake does not always inject venom. Sometimes, it might

inject only a tiny bit of venom. The snake can inject the quantity of venom it

wants. This is an entirely voluntary process. Hence, you never know how much

venom was injected into you except by the progress of the symptoms. In other

words the success rate of recovery in snakebite without even treatment is

greater. Every traditional healer to his / her advantage propagates his/ her

own method to treat snakebite viz., herbal, "snakestone" or mantra, or plain

soda water and most villagers would be happy to go to him.

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Also, every one should remember that the systemic action of venom and

the extent varies from one snake to another. Complications and outcome due to

snakebite may also vary from each another and can't be predicted by any

means. Moreover, the status of poisoning cannot be judged by the bite mark,

reaction to envenomation, size or the type of snake. Hence, one has to observe

for signs and symptoms which may develop within 24 to 48 hours. Many of the

first aid measures carried out at present are ineffective and dangerous. The

research also concluded that the other traditional methods followed for snake

bite are not appropriate . Hence, the primary importance is the need to

recommend the most effective first aid to the victims bitten by snakes.

It is gratifying to note that the traditional snake catcher in Tamil Nadu, the

Irulas with their own sophisticated herbal medicine system, have now

understood the position. They know that the snake injects venom which goes

deep into the system and this can be neutralised only by injection Anti snake

venom (ASV) and not by oral or locally applied remedies, no matter how

famous.

On an average, Government hospitals spends a minimum of Rs.5,000/-

per case of Snake bite and patient spends an equal amount for Socio cultural

and magico - religious aspects. The money lost due to loss of job and earning as

well as loss of lives is huge and thus has an impact in National Economy. So,

there is an urgent need to take effective steps to contain these issues.

Poisoning due to cobra and viper group are seen frequently in the state of

Tamil Nadu. Very rarely sea snakebite cases are reported. Hence, in this hand

book the focus has been made for the former two. Though the specific antidote

is not available for sea snake, the same general principles for other snakebites

are applicable here too.

Snakes and Snakebites:

Epidemiology:

In India nearly over 4,00,000 persons are bitten by snakes per year.

Envenomation happens approximately 82,000 and death occurs in 11,000

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victims. Many deaths happen before the victim reachs the hospital. Snakebite is

observed all over the country with a rural, urban ratio of 9:1, and more during

monsoon and post monsoon season. Snakebites are seen often among

agricultural workers than those going to the forest. Many of the susceptible

populations are poor and living below poverty line. They live in rural areas

with less access to health care. The ratio between male to female among the

victims is approximately 3:2. Majority are young and their age is around 25 to

44 years. Majority of the bites (90 to 95%) are noticed on the extremities

(limbs). The hospital stay vary from 2 to 30 days, with the median being 4 days.

The inhospital mortality vary from 5 to 10% and the causes are acute renal

failure, respiratory failure, sepsis, bleeding and others.

Ecological aspects:

By destroying forests and by creating agricultural land, the prey base of the

snake (that is frogs and rats) has increased. The rice fields, which harbour

millions of rats attract a lot of snakes. The number of snakes per acre in a rice

field is abnormal when compared to the natural population in the forest. Humans

going into the field every morning and coming out in the evening, just the time

when snakes are active. Thus, the chance of an encounter between farmer andsnake is very high. As more areas are inhabited at the periphery of towns, even

there the chances of human/snake interaction increase.

Cobras flourish as long as there are rice fields; there they feed mainly on

the mole rat (varapu eli in Tamil), live and lay their eggs in the rat burrow

networks. Kraits also get by very well in rice fields because they like the plentiful

small rodents such as the field mouse (sundeliin Tamil) and rock mouse (kallu

eli in Tamil). Kraits are also found in the mounds of earth and rubble near

wells. The Russell's viper lives in the rocky outcrops and hedgerows of cactus

and other bush which often form the boundaries of agricultural land. There, on

the high ground, they have a plentiful supply of common gerbil (velleliin Tamil)

which are also attracted to the wealth of food humans provide by their farming

activities! But thanks to snakes, we are not overrun by rodents.

Socio-cultural aspects of snakes and snakebites:

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In various religious system snakes have been described under different

circumstances. In many parts of India, snake is worshipped and in some areas

special prayers are performed. In Northern India on Naga Panjami day people

worship snake idol.

In certain areas of Maharastra and Goa the live snakes, rarely live cobras are

brought for worship. Snake charmers carry snakes, cobra especially door to door

for worship. At every house the snake's mouth is forced to open and some milk

is poured down in its throat. Milk is not snake food. It is also believed that

snake bites people who harmed them in their previous birth. When snakes are

killed people offer special prayers and bury them. People also believe that

snakes take revenge against those who harmed them. In view of their strong

beliefs and many associated myths, people resort to magico-religious treatment

for snake bite thus causing delay in seeking proper treatment. As a result,

valuable time is lost in some of the deserving cases. It is poignant to note that

some of the cinema and TV serial stories even now propagate the non- scientific

ideas on snakes and snakebites and display traditional treatment. Hence

health department in a multi sectoral manner has to disseminate the scientific

aspects through Information, Education and Communication (IEC) to the

community.

Statistics on snakebites and ASV usage

Government General hospital, Chennai, from January to December 2006 has

treated 281 cases of snakebites. Among them, there were 182 males and 99

females. Of the 281, 94 were referred after treatment in different hospitals and

187 were brought to the hospital directly. Numbers survived were 274 (97.5%).

Seven expired due to various complications of snakebite while they were in the

hospital. The details on the type of snakes, distribution, clinical signs,

complications, number referred, received supportive therapy and death are

provided below (Table no.1).

Table No.1 : Statistics on clinical aspects of snake bites and outcome *

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Type ofsnake

Numbertreated

Localsigns

NeuroToxicity

Hemo.Toxicity

Supportive

NumberExpired

Mechnical

ventilation

Fascioto

my.

Cobra 118 80 118 - 90 - - 2

Krait 82 - 51 82 60 30 - 2

Russell'sviper

42 42 - 42 6 23 1 1

Hump-

nosedviper

4 4 - 4 - 4 - 1

Sawscaledviper

16 16 - 16 - 3 - 1

Seasnake

3 3 - - - - - -

Nonpoisono

us

16 6 - - - - - -

* Government General hospital, Chennai (Jan Dec 2006).

During 2005- 2006 a total of 19321 snake bite cases were admitted in the

secondary care hospitals alone in Tamil Nadu. Out of which 85 persons expired

at the hospitals. During 2006-2007 a total of 20677 patients were admitted and

75 persons expired. The total number of ASV vials used in this hospitals during

the respective period were 94481 and 96800 respectively

(Annexure I). The Government is spending a huge sum of money in procuringand supplying anti snake venom. Deaths due to snakebite can be prevented, if

some simple first aid measures are under taken by the public and / or by the

health care providers, when they come across snakebite cases.

An equal or more number of snake bite cases were admitted and treated at

Government Medical College Hospitals. Patients go to private hospitals mostly

for first aid purposes. Very few get adequate treatment rarely at private health

care. Over all analysis revealed that the snakebites and ASV usage in West,

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North, East, Central, South zone of Tamil Nadu were 13, 17,24,20,26 and 13%

respectively.

Classification of snakes:

There are more than 3000 species of snakes in the world. For the purpose of

clinical practice, snakes are classified in to poisonous (venomous) and non-

poisonous (non venomous) snakes. Poisonous snakes are classified under three

families and they are

1. a) Cobra group [Elapidae]

b) Viper group [Viperidae]

c) Sea snake group [Hydrophidae]

For many decades, the concept of the Big 4 snakes of medical importance has

reflected the view that 4 species and responsible for Indian snakebite mortality.

They are the Indian cobra (Naja naja), the common krait (Bungarus caeruleus),

the Russell's viper (Daboia russelii) and the saw-scaled viper (Echis carinatus).

However, a recent discovery that another species, the hump-nosed pit viper

(Hypnale hypnale), is capable of causing lethal envenomation, and that this

problem was being concealed by systematic misidentification of this species as

the saw-scaled biper, has necessitated a review of the concept of the Big 4.The concept of the Big 4 snakes has failed to include all currently known

snakes of medical significance in India, and its negative effects related to clinical

management of snakebite and the development of effective snake anti venoms

World Snakes of Medical Importance

In 1981, the W.H.O. developed the following definition of snakes of medical

importance (Table No.2). This model is more accurate and useful than definitions

such as the Big Four that are inaccurate and mislead doctors and more

importantly ASV manufacturers that there are only four medically important

species.

Table No: 2: Categorisation of snakes (W.H.O. 1981)

Class Details Name of the snakes

I Commonly cause death orserious disability

RUSSELLS VIPER/COBRA/SAWSCALED VIPER

II Uncommonly cause bites but arerecorded to cause serious effects(death or local necrosis)

KRAIT/HUMP-NOSED PITVIPER/KING COBRA/MOUNTAINPITVIPER

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III Commonly cause bites butserious effects are veryuncommon.

-

Tamil Nadu Snakes of Medical Importance - Distinguishingfeatures

A great deal is written concerning the problem of how to identify medically

significant species from non significant ones. A large amount of space is

devoted, in both medical and toxicology textbooks, to the problem of how to

identify venomous snakes. The problem with this data is that it concerned

complex subjects such a scale counts and the identification of pre or post

maxillary teeth which are not definitive and are of no use to a doctor in a

medical situation.

On the question of description, it is worth remembering that the least reliable

means of identifying a particular species of snake is to use colour. Virtually

every species of venomous snake has a huge range of colour manifestations and

even the markings can be subject to major variation. What is important

therefore is to focus on the key aspects of identification that enable the medical

professional to rapidly identify the fact that they are dealing with a venomous

species, and what that species might be.

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Picture No. 1 Tamil Nadu Snakes of MedicalImprotanceThere are six species of medically important species in Tamil Nadu shown above.

Russell's Viper (Daboia russelii)

The Russell's Viper is a stout bodied snake, the largest of which grows to

approximately 1.8 metres in length. Like all the vipers it is a nocturnal snake,

but unfortunately for humans, during the daytime hours it rests up under

bushes, at the base of trees and in leaf litter. It is therefore frequently

encountered by rural workers, as they are carrying out general agricultural

activities.

There are two key identification features that are worth noting. The first is a

series of chain-like or black edged almond shaped marks along the snakes back

and flanks. The second distinguishing mark is a white triangular mark on the

head with the apex of the triangle pointing towards the nostrils.

Saw scaled Viper (Echis carinatus)

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The southern Indian Saw Scaled Viper is a small snake, usually between 30 and

40 centimetres long. The northern Indian species (Echis sochureki) is much

larger, with an average size of 60 centimetres. It inhabits mainly dry arid

climates but can also be found in scrubland.

One of the key identification features of this species is the posture it adopts

when it is agitated. It moves its body into a figure of eight like arrangement with

its head at the centre. It rapidly moves its coils against each other and produces

a hissing like sound which gives it its name of Saw Scaled. In addition, there is

often wavy hoop like markings down both sides of the Saw Scales body. On the

head there is usually a white or cream arrow shaped mark, pointing towards the

front of the head, often compared to the shape of a birds foot.

Its venom is anti-haemostatic in nature and attacks the coagulation system.

Unlike the Russells Viper, this particular viper does not cause renal failure.

The Hump-nosed Pitviper (Hypnale hypnale)

The Hump-nosed Pitviper is one of Indias tiniest venomous snakes, its total

length ranging from 28.5-55.0cm. Its distinctive features include the presence of

five large symmetrical plate scales on the top of the head in addition to the

smaller scales typical of all vipers. There are heat sensitive pits between the

nostril and the eye.

Spectacled Cobra (Naja naja)

The Spectacled Cobra it is probably India's most well recognised snake. The

hood markings of the spectacle like mark, distinguish this snake from otherspecies, and its habit of rearing up when alarmed make it distinctive but not

definitive as other species do this, notably the Trinket Snake. The Cobras

coloration is many and varied extending from pale yellow through to black.

Common Krait (Bungarus caeruleus)

The common Krait is a nocturnal snake which usually grows to approximately

1.0 to 1.2 metres in length. Its primary diet is other snakes. It can be found all

over Peninsular India and often seeks habitation near human dwellings. During

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the day it rests up in piles of bricks, rat burrows or other buildings. The Common

Krait is India's most toxic snake and its venom is pre-synaptic neurotoxic in

nature.

There are a number of key identifiers which are worth remembering. The Krait

is a black, sometimes with a bluish tinge, snake with a white belly. It markings

consist of paired white bands which may be less distinct anteriorly. These paired

white bands distinguish the snake from another black nocturnal snake the

Common Wolf Snake. The Wolf Snakes white bands usually are thicker and are

singular bands equidistant from each other.

The second useful distinguishing feature is a series of hexagonal scales along

the top of the snakes back. This feature is only really useful if the dead snake

has been brought to the hospital and is under examinatio

King Cobra (Ophiophagus hannah)

The King Cobra is the least medically significant of the venomous snakes in

India in terms of both bites and fatalities. Epidemiologically most bites occur

among young men who represent India's growing population of snake catchers

and try unsuccessfully to capture one.

CLINICAL ASPECTS OF SNAKE BITE:

Pathophysiology:

Enormous clinical and experimental works have been published on the

pathophysiology of snake bite in relation to different species of snakes earlier.

Snake venom is mostly water in nature. It consists of numerous enzymes,

proteins, aminoacids, etc., Some of the enzymes are proteases, collagenases,

arginine ester hydrolase, hyaluronidase, phospholipidase, metallo-proteinases,

endogenases, autocoids, thrombogenic enzymes, etc., These enzymes also act

like toxins at different tissues of the body, and are grouped under neurotoxins,

nephrotoxins, hemotoxins, cardiotoxins, cytotoxins etc., resulting in organ

dysfunction / destruction.

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The quality and quantity of enzymes and other clinical constituents vary

with species and subspecies, and the response of the victims to those

substances are variable, thus resulting in dissimilar features in different

individuals. For example hyaluronidase allows rapid spread of venom through

subcutaneous tissues by disrupting mucopolysacharides, and phopholipase A2

has a esterolytic effect on the Red blood cell membrane and cause hemolysis.

Also, it promotes muscle necrosis. Thrombogenic enzymes promotes formation

of weak fibrin clot, which activates plasmin and results in consumptive

coagulopathy and hemorrhagic consequences. Apart from that some venom

causes neuromuscular blockade at pre or post synaptic level. Over all, snake

venom acts on various parts / system / organs of the body and produces

damage if not recognized and supported earlier. In addition to above it causes

endothelial cell damage which results in increased vascular permeability.

Symptoms and signs.

The symptoms and signs of Viperine and Elapid envenomation as well as Late-onset envenoming are provided below.

General symptoms and signs of Viperine envenomation

Swelling and local pain with or without erythema or discloration at the siteof bite

Tender enlargement of local lymph nodes as large molecular weight Vipervenom molecules enter the system via the lymphatics.

Bleeding from the gingival sulci and other orifices. Epistaxis. The skin and mucous membranes may show evidence of petechiae,

purpura ecchymoses.

The passing of reddish or dark-brown urine or declining or no urine output. Lateralising neurological symptoms and asymmetrical pupils may be

indicative of intra-cranial bleeding. Vomiting Acute abdominal tenderness which may suggest gastro-intestinal or retro

peritoneal bleeding. Hypotension resulting from hypovolaemia or direct vasodilation. Low back pain, indicative of a early renal failure or retroperitoneal

bleeding Muscle pain indicating rhabdomyolysis.

Parotid swelling, conjunctival oedema, sub-conjunctival haemorrhage.

General symptoms and signs of Elapid envenomation

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Swelling and local pain with or without erythema or discloration at thesite of bite (Cobra).

Local necrosis and/or blistering / bullae(Cobra) . Descending paralysis, initially of muscles innervated by the cranial

nerves, commencing with ptosis, diplopia, or ophthalmoplegia. Thepatient complains of difficulty in focusing and the eyelids feel heavy.

There may be some involvement of the senses of taste and smell Problems of vision, breathing and speeking Paralysis of jaw and tongue may lead to upper airway obstruction and

aspiration of pooled secretions because of the patients inability toswallow.

Numbness around the lips and mouth, progressing to pooling ofsecretions, bulbar paralysis and respiratory failure.

Hypoxia due to inadequate ventilation can cause cyanosis, alteredsensoriun and coma. This is a life threatening situation and needs urgentintervention.

Paradoxical respiration, as a result of the intercostal muscles becomingparalysed is a frequent sign.

Stomach pain which may sugget submucosal haemorrhages in thestomach (Krait).

Krait bites often present in the early morning with paralysis that can bemistaken for a stroke.

Eye pain and damage due to ejection of venom in to the eyes by spittingcobra(as observed in Africa)

Late-onset envenoming

The patient should be kept under close observation for at leat 24 hours. Manyspecies, particularly the Krait and the Hump-nosed pitviper are known for thelength of time it can take for symptoms to manifest. Often this can take between6 to 12 hours. Late onset envenoming is a well documented occurrence . This isalso particularly pertinent at the start of the rainy season when snakes generallygive birth to their young. Juvenile snakes, 8-10 inches long, tend to bite thevictim lower down on the foot in the hard tissue area, and thus any signs ofenvenomation can take much longer to appear.

Overlapping symptoms and signs.

Russells Viper can also manifest neurotoxic symptoms. This can sometimescause confusion and further work is necessary to establish how wide this mightbe. The neurotoxic symptoms in Russells Viper are believed to be pre synaptic orKrait like in nature. It is for this reason that a doubt is expressed over theresponse of both species to Neostigmine. Clinical aspects and therapeuticresponse in relation to some of the poisonous snakes in India is provided in tableno. 3

Table No. 3: Snakes, Clinical aspects and therapeutic responseCobras Krait Russell Saw Hump

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Feature s s Viper ScaledViper

NosedViper

Local Pain/ Tissue

Damage

YES NO YES YES YES

Ptosis/ Neurological

Signs

YES YES YES! NO NO

Haemostatic

abnormalities

NO NO! YES YES YES

Renal Complications NO NO YES NO YES

Response to

Neostigmine

YES NO? NO? NO NO

Response to ASV YES YES YES YES NO

Sea snakes:

Sea snake bites are reported rarely among fishermen and /or their familymembers living in the seashore area as well as among those who walk on theseashore. To begin with there may be local pain which may be insignificat butappears within 60 to 90 minutes. There may not be obvious local swelling .Systemic manifestations noticed among poisonous sea snake bite areneurological involvement , severe muscle pain, regidity , renal failure,hyperkalemia and finally cardiac arrest.

Criteria for diagnosisAn approach to snakebite is provided in Annexure VIII and IX. The criteria to

diagnose poisonous snakebite in a given clinical setting are:a) Systemic envenoming in the form of coagulopathy and neurotoxicity,(described vide supra) andb) Local envenoming (Table no: 4)

Table No :4 : Details of local envenomation

Swelling is seen at the site of the bites on the digits (toes andespecially fingers) also.

Local swelling develops in more than half of the bitten limb immediately( in the absence of the tourniquet).

Rapid extension of swelling occurs beyond the site of bite(eg. beyond the wrist or ankle within a few hours of bites on thehands or feet)

Development of an enlarged tender lymph node draining the bitten limb

Complications and Outcome

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Complications in snake envenomation are due to the heterogenous composition

of the venom. In addition the quantity and quality of the venom and the

response of the individual to the components of venom influence the clinical

course, complications and out come. The complications of venom are observed

in the hematological, vascular, renal, respiratory, cardiovascular, endocrine,

gastrointestinal, muscular and dermatological system.

In addition to the anti snake venom, the envenomed individual requires

supportive

treatment for the complications arising out of snakebite as well as the

consequences of the complication. One must also remember to look for

complications developing after infusion of Inj.Anti snake venom and get

prepared to treat them also.

The outcome of snakebite depends upon envenomation,bite to needle

time,individuals response to envenomation,the complications that develop

following snakebite and response to treatment.Till the patient is recovered,one

can not predict the complications and outcome.

Investigations

20 Minute Whole Blood Clotting Test (20WBCT)

The 20 Minute Whole Blood Clotting Test (20WBCT) is considered as the mostreliable test of

coagulation and can be carried out at the bedside without specialist training. Itcan also be carriedout in the most basic settings. It is significantly superior to the capillary tubemethod of establishing clotting capability and is the preferred method of choicein snakebite. The advantages, requirements and procedure for 20 WBCT are

provided in in Table no: 5

Table No . 5 : 20 Minutes Whole Blood Clotting Test(20WBCT)

Advantages Requirements Procedure

The most reliabletest of coagulation.

Can be carriedout, at the

bedside. Dose not require

specialised

Dry glass testtube(clean and new)

2ml disposablesyringe

Cotton Antiseptic

solution

Wash hands withsoap and water.

Wear the gloves Collect 2 ml blood

from the

peripheral vein ofthe unaffectedlimb

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training. Clean gloves(one pair)

(The test tube mustnot have beenwashed withdetergent, as this will

inhibit the contactelement of theclotting mechanism)

Remove theneedle and pourthe blood alongthe walls of thetest tube

Keep the test tube

untouched andunshaken in a safeplace near thepatients bedsideat ambienttemperature for20 minutes

Note the time After 20 minutes

the test tube is

gently tilted and ifthe blood is stillliquid then thepatient hasincoagulableblood.

If the 20WBCT is normal in a suspected case of poisonous snakebites, the test

should be carried out every 30 minutes from admission for three hours andthen hourly after that. If incoagulable blood is discovered, the 6 hourly cyclewill then be adopted to test for the requirement for repeat doses of ASV.

Other Useful Tests: Clinical test:

- PR/BP/ RR/ Postural Blood Pressure

Laboratory studies:- Haemoglobin/ PCV/ Platelet Count/ PT/ APTT/ FDP/ D-Dimer- Peripheral Smear / Blood grouping / Rh typing- Urine Tests for Proteinuria/ RBC/ Haemoglobinuria/ Myoglobinuria- Biochemistry for Serum Creatinine/ Urea/ Electrolytes/ Oxygen

Saturation

Imaging studies :- X-Ray Chest / CT/ Ultrasound (whenever required)

Others

- Electrocardiogram- Special investigations depending upon clinical status.

Treatment:

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First aid for snake biteThe first aid currently recommended is based around the mnemonic

'R.I.G.H.T'.The details are provided in Table no.6 .

Table no: 6 : Currently recommended First aid

R. = Reassure the patient.(70% of all snakebites are from non- venomous species. Only 50% of

bites by venomous species actually envenomate the patient)

I = Immobilise in the same way as a fractured limb.(Use bandages or cloth to hold the splints, not to block the blood supply

or apply pressure. Do not apply any compression in the form oftight ligatures, they dont work and can be dangerous!)

G. H. = Get to Hospital Immediately.(Traditional remedies have NO PROVEN benefit in treating snakebite).

T= Tell the doctor of any systemic symptoms such as ptosis thatmanifest on the way to hospital.This method will get the victim to the hospital quickly, without recourse totraditional medical approaches which can delay effective treatment.

While dealing with a case of snake bite consider mnemonicRASI.

Remember principles (Twelve As ) Address the problems clinical and social

Seek help from others when required and Inform the patient and / or care givers on the status of

illness, clinical course and outcome clearly with empathy.Principles involved in the management of snake biteThe principles while managing cases of snake bite at any Health Centre areclubbed under"12As

Table No: 7: Principles involved in the management.

Admit the victim immediately. Ask effectively. Asses quickly. Act swiftly Administer medication meticulously. Address to the wound properly. Anticipate complications carefully.

Avoid errors keenly Ascertain the status repeatedly. Amicable with patients and care givers with

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empathy. Advise on follow up accordingly. Arrange for referral early

1] Admit all victims of snake bite & Keep the victims under observation for

24 to 48 hours

2] Ask effectively to get the following A] Ask for the description of the snake, which has bitten the patient. Ifsnake is brought try to identify the snake with the help of snake picturechart.B] Ask for the site of bite and check the site. Never be carried away, withby bite marks either for diagnosis or for assessment of severity.C] Ask for the time of the bite and correlate with the progression of

symptoms and signs due to snakebite provided in page vide supra.D] Ask for the details of traditional medicines or household remedies used,as it may sometimes cause confusing symptoms or interfere with otherdrugs to be administered.

3] Assess the following quickly.

A] Assess the Airway, Breathing and Circulation

B] Assess the vitals HR, RR, BP and Pulse oximetry (if required)

C] Assess chest expansion, and the ability to put out the tongue beyondincisors and counting the numbers at the bed side.

D] Assess the site of snake bite along with regional lymphadenitis

E] Assess clinically from head to foot as well as back

F] Assess for associted co-morbid illness[es]

G] Assess for consuming any medication[s]

H] Assess the status of envenomation

[ in view of neurotoxic, hemotoxic, myotoxic or a combination ofthem].

4] Act swiftly

A] tosupport Airway, Breathing and Circulation

B ] to start IV line

C] to provide supportive measures depending upon the requirements

including blood transfusion/components if required.

D] to connect ventilator if there is a need

5] Administer medications meticulously

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A] Tetanus Toxoid injection intramuscularlyB] Anti snake venum as IV drip if needed described vide infraC] Inotropics as IV drip if requiredD] Antimicrobials if necessaryE] I.V fluids as per need.

E] Other supportive medications including medicines to relief pain as perneed .

6] Address to the wound properly Remember the surigcal issues described vide infra and table 11 in addition

to the following.

A] Wound following snake bite may show bite marks with or without laceration.

B] Sometimes venom may penetrate deep and hence deeper tissues may be

damaged which may not be visible during initial examination.C] At the site of bite bleb or vesicle may develop and end in the form of an ulcer

which is a non specific one. (Non-specific ulcers are defined as ulcers due to infection of

wounds, physical or chemical agents or due to local irritation).

D] Wound heals under three phases(Three Rs) as described below.

-Inflammatory phase (reactive) limits the damage and further injury to tissues

-Proliferative phase (repair/regenerative phase) matrix synthesis, neovascularisation and

reepithelialisation of the wound

-Maturation phase (re-modeling) collagen cross-linking, shrinking and cross contraction of the

wound takes place.

E] Consider the following while managing the wound /ulcer.

Minimize unnecessary blood loss

Avoid the formation of a hematoma

Initiate adequate cleaning with normal saline or tap water, debridement, and edema control

Remove debris and necrotic tissue, irrigate gently with water / normal saline

Expose viable tissues, excise eschar after controlling hemotoxic complications

Use topical antibacterial agents

Apply dressings after complete debridement.

Maintain proper wound environment and prevent ischemia,

Keep the bacterial count as low as possible.

Facilitate healing of acute wound by applying non adherent dressing to ensure adequate

epithelialization and to prevent contamination of the wound.

Keep wounds clean and dry.

Avoid soaking or scrubbing the wound.

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Teach & explain the care of wound to the patients

Educate on good personal hygiene and nutrition.

Control diabetes if identified.

7] Anticipate complications carefully.

A] Examine the victims at regular intervals for alterations in symptoms and signs

B] Observe for anti snake venom related systemic changes and drug toxicity andmanage them as described vide infra under treatment for ASV reactions.

8] Avoid errors keenly while assessing the case, investigating the victims ,administering medications, following the case at Hospital, undertaking anyprocedures for the patient, referring to other specialists or Hospital,communicating with patient / and care givers and planning for dischargeaswell as preparing reports, filling up the forms, reviewing the data and

conducting the audit.

9] Ascertain the status repeatedly and provide supportive measures asthese cases of snake bite victims may developed covert signs during hospitalstay while on treatment.

10] Amicable with patient and care givers with empathy in view of thesocio clinical aspects of snake bite .

11] Advise on follow up accordingly in view of the systemic toxicity and

the nature of wound following snake bite.Patients may be also motivated toattend to the nearest Health centre/Hospital for follow up care. Follow-upchecks are required for assessment of long term effects on different organs /systems and for appropriate management wherever required / needed.

12. Arrange for referral early - One should also remember the criteria forreferral and provide clear instructions while referring the case. The details onreferral aspects of snake bite is provided vide infra in Table 15.

Traditional methods followed for treating snake bite.

The traditional methods such as application of tourniquet, cutting and suction,

washing the wound, snake stone or other methods have consequences and

hence, they have to be discarded. Some of the discarded methods are described

below.

Tourniquets:

Tight tourniquets made of rope, string and cloth, have been followed

traditionally to stop venom flow into the body following snakebite. The problems

noticed with tourniquet are provided below:

Risk of ischemia and loss of the limb

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Risk of necrosis

Risk of massive neurotoxic blockade

Risk of embolism if used in Viper bites.

Release of tourniquet may lead to hypotension.

Gives patient a sense of false security, which encourages them to delay

their journey to hospital

Cutting and Suction:

Cutting the site of bite and suctioning incoagulable blood increases the risk of

bleeding to death as well as increases the risk of infection. Venom is not cleared

or removed from the snakebite site by this method.

Washing the Wound:

Victims and bystanders have a tendency to wash the wound to remove any

venom on the surface. This should not be done as the action of washing

increases the flow of venom into the system by stimulating the lymphatic

system.

Electrical Therapy :

Electric shock therapy for snakebite received a significant amount of press in the1980s. The theory behind it stated that applying an electric current to the

wound denatures the venom . Much of the support for this method came fromletters to journals and not scientific papers. It has been demonstrated that theelectric shock has no beneficial effect and hence, it has been abandoned as amethod of first aid.

Cautery treatment :Cautery treatment is followed in some areas which is injurious and notbeneficialCryotherapy:

Cryotherapy involving the application of ice to the bite was proposed in the1950. It was subsequently shown that this method had no benefit and merelyincreased the necrotic effect of the venom.

Pressure Immobilisation Method (PIM)

PIM was developed in Australia in 1974 by Sutherland and gained somesupporters on television and in the herpetology literature. Some medicaltextbooks have referred to it. Further work done by Howarth demonstrated that

the pressure, to be effective, was different in the lower and upper limbs. Theupper limb pressure was 40-70mm of Mercury; the lower limb was 55-70mm ofmercury. Work carried out by Norris showed that only 5% of lay people and

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13% of doctors were able to correctly apply the technique! In addition, pressurebandages should not be used where there is a risk of local necrosis, that is in4/5 of the medically significant snakes of India. In view of the difficultiesencountered at every level, Pressure Immobilisation method can not berecommended for use at present.

Newer MethodsPressure Pad or Monash TechniqueThere has been some initial research that has suggested that a Pressure Pad orMonash Technique may have some benefit in the first aid treatment ofsnakebite. This method should be subjected to further research in India toassess its efficacy. It may have particular relevance to the Indian Armed Forceswho carry Shell Dressings as part of their normal equipment, and would thus beideally equipped to apply effective first aid in difficult geographic settings wherethe need is great.

Pharmacological aspects of Anti snake venom

The goals of pharmacotherapy with injection Anti snake venom (ASV) areto neutralise the venom, reduce morbitity and privent comblications. Currentlyavailable Anti snake venom in India is polyvalent i.e., it is effective against all

the four common species; Russells viper (Daboia russelii), Common Cobra (Najanaja), Common Krait (Bungarus caeruleus) and Saw Scaled viper (Echiscarinatus). Indian ASV is a F(ab)2 product and has a half-life of over 90 hoursderived from horse serum. Though it is purified, it still can be immuinogenic.

At present no monovalent ASV is available primarily because there areno objective means of identifying the snake species, in the absence of the deadsnake. More over it is difficult for the physician to determine which type ofMonovalent ASV to employ in treating the patient. In addition there aredifficulties to prepare, supply and maintain adquate stock of species specificmonovalent ASV.

There are other known species such as the Hump-nosed pitviper (Hypnalehypnale) where polyvalent ASV is known to be ineffective. In addition, there areregionally specific species such as Sochureks Saw Scaled Viper (Echissochureki) in Rajasthan, where the effectiveness of polyvalent ASV may bequestionable. Further work has to be carried out with ASV producers to addressthis issue of preparing ASV useful against other poisonous snakes observed inIndia.

In India ASV is manufactured by Bengal Chemicals & Pharmaceuticals,

Kolkata; Bharat Serums, Mumbai; Biological Evans, Hyderabad ;CentralResearch Institute, Kausali ; Haffkins Pharmaceuticals, Mumbai; King Institute

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of preventive medicine , Chennai; Serum Institute, Pune and Vins bio-products,Hyderabad .

ASV is produced in both liquid and lyophilised forms. There is no evidenceto suggest which form is more effective and many doctors prefer one or the

other based purely on personal choice. Liquid ASV requires a reliable cold chainand refrigeration and has a 2 year shelf life. Lyophilised ASV, in powder form,requires only to be kept cool and hence, a useful one in remote areas wherepower supply is inconsistent. The details of pre hospital treatment and issuesrelated to Inj.ASV may be recorded in the form provided in Annexure IV.

ASV Administration Criteria

Inj.ASV is prepared from animal and hence, it should only be administered

when there are definite signs of envenomation. Anti-Snake Venom carriesrisks of anaphylactic reactions and should not therefore be usedunnecessarily. Unbound, free flowing venom, can only be neutralised whenit is in the bloodstream or tissue fluid. Also it is a scarce and costlycommodity. Hence, ASV may be administered if a Patient develops one ormore of the following signs / symptoms.

Systemic envenoming Evidence of coagulopathy (vide supra) Primarily detected by 20WBCT or

visible spontaneous systemic bleeding, gums etc., Further laboratory tests

for thrombocytopenia, Hb abnormalities, PCV, peripheral smear etc mayprovide confirmation, but 20WBCT is paramount. Evidence of neurotoxicity (vide supra] : ptosis, external ophthalmoplegia,

muscle paralysis, inability to lift the head etc., Cardiovascular abnormalities: hypotension, shock, cardiac arrhythmia,

abnormal ECG. Persistent and severe vomiting or abdominal pain.

Severe Local envenoming( Refer table No: 4)Purely local swelling, even if accompanied by a bite mark from an apparentlyvenomous snake, is not grounds for administering ASV. If a tourniquet ortourniquets have been applied, these themselves can cause swelling, once theyhave been removed for 1 hour and the swelling continues, then it is unlikely tobe as a result of the tourniquet and ASV may be applicable.

ASV Administration: DosageIn the absence of definitive data on the level of envenomation, symptomology isnot a useful guide to the level of envenomation. Any ASV regimen adopted isonly a best estimate. What is important is that to establish a single guidelinewhich could be adhered to, in order to enable results to be reliably reviewed.

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The recommended dosage level has been based on published research thatRussells Viper injects on average 63mg (SD 7) of venom . Logic suggests thatour initial dose should be calculated to neutralise the average dose of venominjected. This ensures that the majority of victims should be covered by theinitial dose and keeps the cost of ASV to acceptable levels. The range of venominjected is 5mg to 147 mg.

This suggests that the total required dose will be between 10 vials to 25 vials aseach vial neutralises 6mg of Russells Viper venom. Not all victims will require 10vials as some may be injected with less than 63mg. Not all victims will require25 vials. However, starting with 10 vials ensures that there is sufficientneutralising power to neutralise the average amount of venom injected andduring the next 12 hours to neutralise any remaining free flowing venom.

Warrell et al based on their study have stated that test doses for ASV shownto have no predictive value in detecting anaphylactoid or late serum reactions

and should not be used. These reactions are not IgE mediated but Complementactivated. They may also pre-sensitise the patient and thereby create greaterrisk. For Neurotoxic/ Anti Haemostatic envenomation 8 to 10 vials of ASV isrecommended to be administered as initial dose. Children receive the same ASVdosage as adults, as snakes inject the same amount of venom into adults andchildren. The ASV is targeted at neutralising the venom,

ASV may be administered in two ways over a period of one hour at a constantspeed and the patient should be closely monitored for 2 hours.:

1. Infusion: liquid or reconstituted ASV is diluted in 5-10ml/kg body weightof isotonic saline or glucose and administered as infusion usually.(Fluidrequirement for children referto annexure 2)

2. Intravenous Injection: Rarely reconstituted or liquid ASV is administeredby slow intravenous injection. (2ml/ minute). Each vial is 10ml ofreconstituted ASV.

Facts to be remembered before / while using injection of Anti SnakeVenom( ASV)

1. The ASV is available in a polyvalent form and marketed in

liquid or lyophilised manner in 10ml vial / ampoule.

Hence,ascertain before

buying/using it

2. Remember to use and maintain cold chain systm for liquid form. Users areinformed to ascertain whether the cold chain is maintained.

3. There is no dose adjustment for ASV administration for children

4. Health staff before administering the ASV should read and check the status

of vial or ampoule containing ASV.

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5. Elicit history of prior exposure to Inj.ASV. If a patient has received Inj.ASV

earlier and comes back with features of snake envonemation again , he /

she has to be considered as a fresh case and treated accordingly. However,

care should be taken while administering Inj.ASV, since he/ she has been

sensitised.

6. Inj.ASV treatment should not be initiated without adequate agents formanaging anaphylaxis or anaphylactoid reaction.

7. Anaphylactic or late serum sickness cannot be determined or

prevented by test dose

8. ASV neutralize the unbound venom, hence give it early

9. ASV administration should not be delayed or denied on the

grounds of anaphylactic reactions to a deserving case10.ASV is required only to those who show definite signs and

symptoms of envenomation

11.ASV should not be pushed as IV bolus or IM directly. ASV has to be

administered slowly as IV infusion in normal saline or glucose water over

a period of one hour

12.Local administration of ASV near the site of bite has been proven to beineffective and painful, and raises the intracompartmental pressure,

particularly in the digits. Hence , it should not be adopted.

13. There is no prophylactic dose of ASV

1. Total dose requirement cannot be decided on the basis of (WBCT)

Whole blood clotting test (or) clinical signs and symptoms

2. Even if the patient develops reaction(s), the total dose required should

be administered slowly after the patient recovers from the reaction(s).

16 . There is no other drug of choice other than ASV treatment of snake bite

17. The patient has to be closely monitored for manifestationsof reactions to ASV for atleast 2 hours continuously.

1. No interaction with Inj.ASV has been reported2. Fetal risk due to Inj. ASV has not been established or studied in

humans

3. Safety status for use of Inj.ASV during pregnancy has not beenestablished.

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4. Timely administration of Inj.ASV will not gurantee the recovery orprotect the individual from the venom induced toxicity orcomplications definitely.

ASV Reactions

Reaction to Inj.ASV develop usually within 15 to 30 minutes or with in2 hours. So monitor the case on ASV at 5 min interval for first 30 min andthen at 15 min interval for two hours.

Some times, anaphylaxis(Type I) following Inj.ASV may develop rapidly

and deteriorate into a life-threatening emergency, and hence anticipate

and observe for it in every case. If the correct guidelines are followed,

anaphylaxis can be effectively treated.

Therefore get alert if the patient develops of any reactions to ASV as shown in table no: 8.

Table No: 8: Manifestations of immediate reactions to ASV

tching (often over thescalp)

urticaria, even a singlespot

nausea, vomiting, abdominal colic/ pain

diarrhoea tachycardia (PR>120/min) (for childrenrefer age specificchart)

a fall in blood pressure low volume pulse

dry cough bronchospasm/ rhonchi stridor (rarely) angio-oedema of lips

and mucous membrane fever shaking chills (rigors) sweating

cold and clammy skin central cyanosis febrile convulsions

( in children).

Treatment for ASV reactions

Discontinue inj. ASV Maintain IV line

Administer Inj. Adrenaline 0.5ml of 1:1000 IM, ( Adults) /

Inj.Adrenaline0.01ml/Kg body weight of 1:10,000 IM(paediatric dose].

Details are provided in table no.9.

(If after 10 to 15 minutes the patient's condition has not improved or is

worsening, a second dose of 0.5 ml of Adrenaline IM is given. This can be

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repeated for a third and final occasion but in the vast majority of

reactions 2 doses of Adrenaline will be sufficient.)

Studies have shown that adrenaline reaches necessary blood plasma levels in 8minutes in the IM route, but up to 34 minutes in the subcutaneous route . Theearly use of adrenaline has been selected as a result of study evidence

suggesting better patient outcome if adrenaline is used early.In extremely rare, severe life threatening situations, 0.5mg of 1:10,000

adrenaline can be given IV. This carries a risk of cardiac arrhythmias

however, and should only be used if IM adrenaline has been tried and

the administration of IV adrenaline is in the presence of ventilatory

equipment and ICU trained staff.

Table No: 9 : Dosage of adrenaline for adults and children

Adults *Children (up to 25 kg)

Inject adrenaline 1:1000intramuscularly:

Weighing 100 kg give 0.75 mL

Inject adrenaline 1:10 000intramuscularly 0.1 ml per kg.

dilute 1 ampoule (1 mL) of adrenaline1:1000 with 9 mL water for injection

or normal saline.Inject intramuscularly 1:10000aadrenaline according to the guide(approximates to 0.1ml/kg).

1 year (10 kg) give 1 mL 3 years (15 kg) give 1.5 mL 5 years (20 kg) give 2 mL 8 years (25 kg) give 2.5 mL Children >25 kg as for small

adults* Approximate body weight may be calculated by the formula; 2 x Age + 9 =weight in kg.

Start an adrenaline infusion if the patient remains shocked, (preferably viaa central venous line), commencing at 0.25 microgram/kg/minute, andtitrating as required to restore blood pressure. Large doses of adrenalinemay be needed.

Consider additional measures - Administer salbutamol or terbutaline by aerosol or nebuliser (Beta2

agonists) for bronchospasm. Antihistamines:

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Administer both H1 receptor blockers Inj.Chlorpheniranine maleate 10-20 mg as IV / intramuscularly or Promethazine 0.5-1 mg/kg and H2receptor blockers ranitidine one mg/kg or famotidine 0.4 mg/kg orcimetidine 4 mg/kg slowly intravenously:

The dose for children is of Phenimarine maleate at 0.5mg/kg/ day IV orPromethazine HCl can be used at 0.3-0.5mg/kg IM or 0.2mg/kg of

chlorphenimarine maleate IV and 2mg/kg of hydrocortisoneIV.Antihistamine use in pediatric cases must be deployed with caution.

Administer corticosteroids intravenously: hydrocortisone 2-6 mg/kg ordexamethasone 0.1-0.4 mg/kg

Try nebulised adrenaline (5 mL of 1:1000) in case of laryngeal oedemawhich often will ease upper airways obstruction. However, do not delayintubation if upper airways obstruction is progressive.

IV fluids should be given for hemodynamic instability, Once the patient has recovered, the ASV can be restarted slowly for 10-15

minutes, keeping the patient under close observation. Then the normal

drip rate should be resumed. Monitor vitals and provide supportive measures

Late Serum sickness reactions (delayed hypersensitivity) to ASV

Serum sicknessmay occur one to two weeks after administration of Inj.ASV.Late Serum sickness reactions can be easily treated with an oral steroid such asprednisolone, adults 5mg 6 hourly, paediatric dose 0.7mg/kg/day. Oral H1Antihistamines provide additional symptomatic relief.

Prevention of ASV Reactions Prophylactic Regimens

There is no statistical trial evidence of sufficient statistical power to show thatprophylactic regimens are effective in the prevention of ASV Reactions. Theconclusion in respect of prophylactic regimens to prevent anaphylactic reactions,is that there is no evidence from good quality randomized clinical trials to

support their routine use. If they are used then the decision must rest on othergrounds, such as policy in the case of hospitals, which may opt for a maximumsafety policy, irrespective of the lack of definitive trial evidence.

Two prophylactic regimens normally recommended as given below: 100mg of hydrocortisone and H1antihistamine (10mg

chlorphenimarine maleate; 22.5mg IV phenimarine maleate IV or25mg promethazine hydrochloride IM ) 5 minutes before ASVadministration.

The dose for children is 0.1-0.3mg/kg of antihistamine IV and 2mg/kg ofhydrocortisone IV. Antihistamine should be used with caution

in pediatric patients.

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0.25-0.3mg adrenaline 1:1000 given subcutaneously.

If the victim has a known sensitivity to ASV, pre-medication with adrenaline,hydrocortisone and anti-histamine may be advisable, in order to prevent severereactions.

Repeat Doses: Neurotoxic

The ASV regime relating to neurotoxic envenomation has caused considerableconfusion. If the initial dose has been unsuccessful in reducing the symptoms orif the symptoms have worsened or if the patient has gone into respiratory failurethen a further dose should be administered, after 1-2 hours. At this point thepatient should be re-assessed. If the symptoms have worsened or have notimproved, a second dose of ASV should be given.

This dose should be the same as the initial dose, i.e. if 10 vials were giveninitially then 10 vials should be repeated for a second dose and then ASV isdiscontinued. 20 vials is the maximum dose of ASV that should be given to aneurotoxically envenomed patient.

Once the patient is in respiratory failure, has received 20 vials of ASV and issupported on a ventilator, ASV therapy should be stopped. This recommendationis due to the assumption that all circulating venom would have been neutralisedby this point. Therefore further ASV serves no useful purpose.

Evidence suggests that reversibility of post synaptic neurotoxic envenoming isonly possible in the first few hours. After that the body recovers by using its ownmechanisms. Large doses of ASV, over long periods, have no benefit inreversing envenomation.

Confusion has arisen due to some medical textbooks and journal articlessuggesting that massive doses of ASV canbe administered, and thatthere need not necessarily be a clear-cut upper limit to ASV. These textsare talking about snakes which inject massive amounts of venom, such as theKing Cobra or Australian Elapids. There is no justification for massive doses of

50+ vials in India, which usually result from the continued use of ASV whilst thevictim is on a ventilator.No further doses of ASV are required; unless aproven recurrence of envenomation is established, additional vials toprevent recurrence is not necessary.

Recovery Phase

If an adequate dose of appropriate antivenom has been administered, thefollowing responses may be seen:a) Spontaneous systemic bleeding such as gum bleeding usually stops within 15-

30 minutes.b) Blood coagulability is usually restored in 6 hours. (Principal test is 20WBCT)

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c) Post synaptic neurotoxic envenoming such as the Cobra may begin to improveas early as 30 minutes after antivenom, but can take several hours.d) Presynaptic neurotoxic envenoming such as the Krait usually takes aconsiderable time to improve reflecting the need for the body to generate newacetylcholine emitters.e) Active haemolysis and rhabdomyolysis may cease within a few hours and the

urine returns to its normal colour during the course of treatment.f) In shocked patients, blood pressure may increase after 30 minutes while ontreatment

Repeat Doses: Anti Haemostatic

In the case of anti haemostatic envenomation, the ASV strategy will be basedaround a six hour time period. When the initial blood test reveals a coagulationabnormality, the initial ASV amount will be given over one hour. No additionalASV will be given until the next Clotting Test is carried out. This is due to the

inability of the liver to replace clotting factors in under 6 hrs.

After 6 hours a further coagulation test should be performed and a further doseshould be administered in the event of continued coagulation disturbance. Thisdose should also be given over one hour. Clotting tests and repeat doses ofASV should continue on a 6 hourly pattern until coagulation is restored, unless aspecies is identified as one against which Polyvalent ASV is not effective.

The repeat dose should be 5-10 vials of ASV i.e. half to one full dose of theoriginal amount. The most logical approach is to administer the same dose

again, as was administered initially. Some , argue that since the amount ofunbound venom is declining, due to its continued binding to tissue, and due tothe wish to conserve scarce supplies of ASV, there may be a case foradministering a smaller second dose. In the absence of good trial evidence todetermine the objective position, a range of vials in the second dose has beenadopted.

Recurrent Envenomation

When coagulation has been restored, no further ASV should be administered,unless a proven recurrence of a coagulation abnormality is established. There isno need to give prophylactic ASVsto prevent recurrence.Recurrence has been a mainly U.S. phenomenon, due

to the short half-life of Crofab ASV. Indian ASV is a F(ab)2 product and has ahalf-life of over 90 hours, and therefore is not required in a prophylactic dose toprevent re-envenomation.

Anti Haemostatic Maximum ASV Dosage GuidanceThe normal guidelines are to administer ASV every 6 hours until coagulation hasbeen restored. However, what should the clinician do after say, 30 vials havebeen administered and the coagulation abnormality persists?

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There are a number of questions that should be considered. Firstly, is theenvenoming species one for which polyvalent ASV is effective? For example, ithas been established that envenomation by the Hump-nosed Pitviper (Hypnalehypnale) does not respond to normal ASV. This may be a cause as, in the caseof Hypnale, coagulopathy can continue for up to 3 weeks!

The next point to consider is whether the coagulopathy is resulting from theaction of the venom. Published evidence suggests that the maximum venomyield from say a Russells Viper is 147 mg, which will reduce the moment thevenom enters the system and starts binding to tissues. If 30 vials of ASV havebeen administered that represents 180 mg of neutralising capacity. This shouldcertainly be enough to neutralise free flowing venom. At this point the clinicianshould consider whether the continued administration of ASV is serving anypurpose, particularly in the absence of proven systemic bleeding.At this stagethe use of Fresh Frozen Plasma (FFP) or factors can be considered, if available.

ASV risk and wastageDefinitive diagnosis and proper utilisation of Inj.ASV help the patient .Otherwise the patients are subjected to risk of receiving excessive/inadequatedosage of Inj.ASV . More over the availability of ASV and doctors views andexperience may influence the utilisation of ASV for a given patient. Thus there isa possibility of first aid wastage of Inj.ASV . The details of provided in TableNo.10.

Table No: 10 ASV Risk and Wastage ( Ian D.SimpsonModel )

Low wastage High wastage

High risk Inj.ASV -Not available- Insufficientadministratio

n

Inj.ASV Too little supplySpecies are different

Low risk Effective dose ofInj.ASV

to envenomed patients

Receive Inj.ASVwhen not required

Too much Inj.ASVwhen not required

Unnecessary Inj. ASV

Clinical issues in snakebite:Hypotension

Hypotension can have a number of causes, particularly loss of circulating volumedue to haemorrhage and vasodilation due to the action of the venom or direct

effects on the heart. Test for hypovolaemia by examining the blood pressurelying down and sitting up, to establish postural hypotension.Usually crystalloids

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are used for volume expansion. However, there is no conclusive trial evidenceto support a preference for colloids or crystalloids.

In cases where generalised capillary permeability has been established avasoconstrictor such as dopamine can be used. dose being is 5- 10 /kg/minutein normal saline or glucose solutions as IV drip. The flow rate may be adjusted

to maintain blood pressure adequately. Rarely Russell's Viper bites are knownto cause acute pituitary and / or adrenal insufficiency . This condition may alsocontribute to shock. Hence, this entity has to be remembered while dealing withhypotension in snakebite

Persistent or Severe bleedingIn the majority of cases the timely use of ASV will stop systemic bleeding.However in some cases the bleeding may continue to a point when furthertreatment with appropriate should be considered. The major point to note isthat clotting must have been re-established before additional measures are

taken. Adding clotting factors, FFP, cryoprecipitate or whole blood in thepresence of un-neutralised venom will increase the amount of degradationproducts with the accompanying risk to the renal function.

Renal Failure and ASVRenal failure is a common complication of Russell's viper and Hump-nosed pitviper bites. The contributory factors are intravascular haemolysis, DIC, directnephrotoxicity, and hypotension and rhabdomyolysis.

Renal damage can develop very early in cases of Russells Viper bite and even

when the patient arrives at hospital soon after the bite, the damage may alreadyhave been done. Studies have shown that even when ASV is administered within1-2 hours after the bite, it is incapable of preventing ARF. Declining renalparameters require referral to a higher centre with access to dialysis. Peritonealdialysis could be performed in secondary care centres.

Surgical issuesThe surgical issues observed in snake bite cases are

Ulcer following snakebite Necrosis of the skin and underlying tissues Gangrene of the toes and fingers Debridement of necrotic tissues Compartment syndrome and others

The details and approach to some of the surgical issues are provided in Tableno. 11.

Table No: 11: Surgical issues: Assessment and action required.

Assessment Action required

* Assess for internal and externalsurgical issues related to envenomationcarefully and observe for the same

* Care of the wound- Apply appropriate topical agentsand dressing

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while the victim is at hospital and / orduring follow up care.* Wound status* Use of topical agents / traditionalmedicine* Compartment syndrome

- Less common- Consider compartment

syndrome if any of the following 6 Ps.or a combination of them appear.

Pain on passive stretching Pain out of proportion Pulselessness Pallor Parasthesia Paralysis

The limb can be raised in the initialstages to see if swelling is reduced.However, this is controversial as thereis no trial evidence to support itseffectiveness.

- Maintain proper woundenviroment

- Do surgical debridement, ifneeded refer to surgeon* Prepare and proceed to skin graftinglater (if required)* Measure intra compartmentalpressure (ICP) in suspected cases byIntra compartmental monitoringmachine(Stryker pressure monitor) orby use of a saline monitor* Monitor ICP every 30 to 120 minutesif required* Proceed with fasciotomy if the ICPexceeds greater than 30 to 40 mm ofHg.* Restore coagulation time beforecommencing the procedures.

Fasciotomy does not remove or reduce any envenomation. Visual impression is an unrealistic guide to estimate the ICP. Tissue injury after compartment syndrome.may be disproportionate to the

clinical status Fasciotomy is not required for every case.

Use of Heparin and Botropase in Viper Bites

Heparin has been proposed as a means of reducing fibrin deposits in DIC .However, heparin is contraindicated in Viper bites. Venom induced thrombin isresistant to Heparin, the effects of heparin on antithrombin III(AT) are negated

due to the elimination of ATIII by the time Heparin is administered and heparincan cause bleeding by its own action. Clinical trial did not show any beneficialeffect

Botropase is a coagulant compound derived from the venom of one of two SouthAmerican pit vipers. It should not be used as a coagulant in viper bites as itsimply prolongs the coagulation abnormality by causing consumptioncoagulopathy in the same way as the Indian viper venom currently affecting thevictim.

Snake Bite in special situations

ASV Dosage in Victims Requiring Life Saving Surgery

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In very rare cases, symptoms may develop which indicate that life savingsurgery is required in order to save the victim. An example would be a patientwho presents with signs of an intracranial bleed. Before surgery can takeplace, coagulation must be restored in the victim in order to avoid catastrophicbleeding. In such cases a higher initial dose of ASV is justified (up to 25 vials)solely on the basis on guaranteeing a restoration of coagulation after 6 hours.

Victims Who Arrive Late

A frequent problem is victims who arrive late after the bite, often after severaldays, usually with acute renal failure. Should the clinician administer ASV? Thekey determining factor is, are there any signs of current venom activity?Venom can only be neutralised if it is unattached! Perform a 20WBCT anddetermine if any coagulopathy is present. If coagulopathy is present,

administer ASV. If no coagulopathy is evident assess the case for evidences forone or other complications and consequences secondary to complication ofsnake bite. Such cases require appropriate supportive measures.

In the case of neurotoxic envenoming where the victim is evidencing symptomssuch as ptosis, respiratory failure etc, it is probably wise to administer one doseof 8-10 vials of ASV to ensure that no unbound venom is present. However, atthis stage it is likely that all the venom is bound and respiratory support ornormal recovery will be the outcome.

Snake bites Again !

If a patient has been bitten by a poisonous snake and received Inj.ASV earlierand comes back with features of repeat snake bite, he / she may be consideredas a fresh case and treated accordingly.(Whatever the interval between thesnakebite) However, care should be taken while administering Inj.ASV, since he/she has been sensitised.

Snake bite in Pregnancy

There is very little definitive data published on the effects of snakebite duringpregnancy. Though spontaneous abortion of the foetus has been reported, thisis not the outcome in the majority of cases. It is not clear if venom can passthe placental barrier. Pregnant women are treated in exactly the same way asother victims. The same dosage of ASV is given. The victim should bereassessed for the impact on the fetus. One should be alert and rule out retroplacental clot. The effects of venom and antivenom on the mother and fetusneed further exploration.

Others:

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Even if the patients belong to any of the following category viz.,autoimmune disorders,debilitating status,endocrine disorders,Immunosuppressed status,HIV/AIDS, Cancer ,asthma and allergic disorders or any otherillness arrive with features of snake envenomation, they also require Inj.ASV inthe same manner like any other case of poisonous snake bite.

Management in Primary Health Care Centres and Block PHCA key objective of this guideline is to enable even the doctors working inPrimary Care Institutions as well as private practitioners to treat snakebite withconfidence. Evidence suggests that doctors are not willing to make use of ASVand other medications, even when equipped, due to lack the confidence andguidelines. The present handbook on guidelines is prepared to suite their needs

and outlines how they should proceed within their context and setting. Theprinciples envisaged to treat snake bite at all Health Centres / Hospitalsirrespective of the status Government or private are given below in table no: 7.

The initial evaluation and systemic manifestations following envenomation, andtreatment aspects are provided in table 12, 13 and 14 respectively.

Table 12 : Initialevaluation - No

Systemic Envenomation

ASSESS CLASSIFY TREATMENT

Vital signs1. -Pulse

2. -BP3. -RespirationSYMPTOMS AND SIGNS

4. Bite marks5. Ptosis6. Double vision7. Difficulty in swallowing8. Bleeding sites9. Reduced urine output

10. Swelling and local pain11. Local necrosis12. Descending paralysis13. Unconsciousness14. Any other notedown

Vital signs (Adult)*15. Pulse rate: 60-100/min

16. BP 110 / 70 to 140/9517. Respiratory rate


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If the patient has any systemic manifestations refer to Table.13 and 14 forHeamotoxic and Neurotoxic envenomation respectively. The details of localenvenomation is provided in Table 4.

Table 13 : Heamotoxic envenomation

ASSESS CLASSIFY TREATMENTVital signs

Pulse BP RespirationSYMPTOMS ANDSIGNS

Bite marks No Ptosis Double vision Difficulty in

swallowing

Bleeding sites Reduced urine

output

Swelling and localpain

Local necrosis Descending

paralysis

Unconsciousness Any other note

down

Vital signs(Adult)*

Pulse rate >120 perminute, feeble (a responseto hypotension)

Respiratory rate > 20/min

Hypotension < 90/60

SYMPTOMS AND SIGNSSwelling and local pain orpainful enlargement ofnearby lymph nodes

Bleeding from the

Gingival sulsi

Epistaxis

Petechiae, purpura,ecchymoses

Heamaturia

Intracranial bleeding:

-asymmetrical pupils

-unconciousness

- convulsions

Persistent and severevomiting or abdominal pain

Low back pain

No urine output ordecreased urine output

Laboratory test:

20 Minute Whole bloodClotting Test

-Blood clot not formed

If above findings are thereat the time of examinationclassify as

Heamotoxicenvenomation

Treat the patient with Anti Snake

Venom(ASV)- Start IV Normal Saline with wide boreneedle- Begin with one Vial of ASV in one pintof NS and start 10-15 drops perminute for 15 minutes & watch forreactions.

- If signs and symptoms of anaphylactic shock (cold and clammyskin, rapid pulse, dyspnoea, etc.)develop, stop the ASV drip temporarilyand treat the shock with:Inj Hydrocortisone 100 mg IV orInj Dexamethasone 8 mg IVInj.Phenaramine maleate 2ml IVInj,Adrenaline 1:1000(0.5 ml)IMInj .Deriphyline 2ml IV

Oxygen administrationIV.Normal saline as life line- As soon as the patient recovers or- If the patient is not having signs andsymptoms of anaphylactic shockcontinue the ASV drip with remainingseven vials/ampoules

- Continue to monitor the vital signs atfive minutes interval for first 30minutes and then at 15 minutes

interval for two hours

- Stabilise the patient and refer to thehigher institution

Aspirin should not be used

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Fluidrequirements per day should be kept in mind while giving ASV. For childrenreaders are requested to seethe fluid requirement chart provided in AnnexureII.*Vital signs for children (see age specific chart) are provided in Annexure III.

Table 14 : Neurotoxic envenomation:

ASSESS CLASSIFY TREATMENT

-Asmentionedin Table 13

SYMPTOMS AND SIGNS-Swelling and local pain-Local necrosis-Descending paralysis startingfrom ptosis, externalophthalmoplegia-Numbness around the lips andmouth progressing to pooling of

secretions, difficulty to talk andrespiratory failure

-Paradoxical respiration-Paralysis-Belly pain

Lab.test:

20 Minute Whole Blood Clotting Test(WBCT) -Blood clot formed

If above signs & symptoms are

present at the time of admissionclassify as Neurotoxicenvenomation

Treat the patient withAntisnake venom (ASV)as mentioned in Table 7and add the following:

Inj.Neostigmine 1.5 mg(Test dose) as I.M and

Inj.Atropine 0.6 mg(Testdose) as I.VAfter that observepatients for every fiveminutes for 30 minutesfor signs of response

Patients have to be assessed for features of local evenomation as described intable 4

Referral aspects:The medical officer who is treating the cases of snake bite should take

meticulous care to look in to the patient's status and provide first aid as well as

supportive measures before referring the cases to higher centre/speciaslist. Thedetails are furnished in Table 15 below.

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Table No :15 : Referral aspects for snakebite

Who needs When W here

Patient requiring

Respiratory support

Surgical intervention-Necrosis /Fasciotomy

Spontaneouspersistent bleeding

Co-morbid diseases Acute impending

kidney failure

Refer the patientafter stabilising thecase and aftergiving injection ASV

Refer to higherinstitution having

Ventilator Dialysis facilities Measures to provide

further supportivetreatment.

Referral Criteria for Haemotoxic envenomationOnce the ASV is finished and the adverse reaction dealt with the patient shouldbe automatically referred to a higher centre with facilities for blood analysis todetermine any systemic bleeding or renal impairment. The 6 hour rule ensuresthat a six hour window is now available in which to transport the patient.

Referral Criteria for Neurotoxic envenomation

If after one hour from the end of the first dose of ASV, the patients symptomshave worsened i.e. paralysis has descended further, a second full dose of ASV isgiven over one hour. ASV is then completed for this patient. If after 2 hours thepatient has not shown worsening symptoms, but has not improved, a seconddose of ASV is given over 1 hour. Again ASV is now completed for this patient.

Instructions while referring Inform the need for referral to the patient and/ care giver [ family

member or the accompanying attendant ] Give prior intimation to the receiving center using available

communication

facilities

Arrange for an ambulance

Transfer in a vehicle to Secondary Care Hospital or Tertiary Care

hospital. where mechanical ventilator and dialysis facilities are available

Continue life supporting measures

Provide airway support with the help of an accompanying staff

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Send the referral note with details of treatment given

Instruct one staff to accompany the patient during transportation if

required.

Hand over the referral slip with details regarding treatment given

Mention the clinical status clearly in the referralat the time of referral.

Welfare measures:

The Government of Tamil Nadu is providing solatium to the family members of

the deceased snake bite victims. The amount is disbursed by the respective

district collector based on the application made by the family members along

with the medical certificate mentioning the cause of death as complications

following snakebite in a clear manner (as observed while on treatment). The

amount vary from state to state. Treating doctor should inform the family

members of the deceased, and guide them the ways and means for getting

the welfare measures provided by the Government to the poor and

downtrodden.

Occupational risk for snake bite

The normal perception is that rural agricultural workers are most at risk andthe bites occur first thing in the morning and last thing at night. However, this isof very little practical use to rural workers in preventing snakebite since itignores the fact that often snakebites cluster around certain bio-mechanicalactivities, in certain geographic areas, at certain times of the day.

Grass-cutting remains a major situational source of bites. In rubber, coconut, palmyra and arecanut plantations clearing the base

of the tree to place manure causes significant numbers of bites. Harvesting high growing crops like Millet which require attention focused

away from the ground. Rubber tapping workers are susceptible and it happens often in the earlyhours 03:00-06:00.

Agricultural workers involved in Vegetable harvesting/ fruit picking. Tea and coffee plantation workers face the risk of arboreal and terrestrial

vipers when picking or tending bushes. Clearing weeds exposes workers to the same danger as their grass-

cutting colleagues. Walking at night without a torch barefooted or wearing sandals accounts

for a significant number of bites. Bathing in ponds, streams and rivers, in the evening. It should not be

assumed that because the victim is bitten in water that the species is

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non-venomous. Cobras and other venomous species are good swimmersand may enter the water to hunt.

Walking along the edge of waterways. Plucking flowers in areas of flower cultivation Plucking hay/straw from bundle of hay/straw Persons involved in picking up dry fire wood , loose stones, heaps of

paddy, sugar cane or jowhar husk.

Preventive measures and health education

Walk at night with sturdy footwear and a torch and use the torch! Whenwalking, walk with a heavy step as snakes can detect vibration and willmove away!

Carry a stick when grass cutting or picking fruit or vegetables or clearingthe base of trees. Use the stick to move the grass or leaves first. Give thesnake chance to move away. If collecting grass that has previously beencut and placed in a pile, disturb the grass with the stick before picking thegrass up.

Keep checking the ground ahead when cutting crops like Millet, which areoften harvested at head height and concentration is fixed away from theground.

Pay close attention to the leaves and sticks on the ground when woodcollecting.

Keep animal feed and rubbish away from your house. They attract ratsand snakes will follow.

Try to avoid sleeping on the ground. Keep plants away from your doors and windows as plants help snakes to

climb up and into windows.

References

1. Agarwal P.N., Agarwal A.N., Gupta. D., Behera.D., Prabhakar.S., Jindal. S.K. Management of Respiratory Failure in SevereNeuroparalytic Snake Envenomation. Neuro India 2001: 49: 25 28.

2. Alvares R. (Goanet) Myths and Snake bites.http :// lists/ whatwg .org / goanet - goanet .org/2004-

september/017828. html accessed on 28.01.08.

3. Amarel CFS, Campllina D, Dias MB, Bleno CM, Razende NA.Tourniquet ineffectiveness to reduce the severity ofenvenoming after crotalus durissus snakebite in Belo

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