Snake Bite Vch

7/30/2019 Snake Bite Vch

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Snake Bite

Dr.Vemuri Chaitanya


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Epidemiology

> 5 million bites annually by venomous snakesworld wide

With > 1,25,000 deaths

Age : 1150 yrs

Sex : males

Mc site : lower limbs 40 %


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Classification of snakes

Colubridae

Elapidae

Viperidae

Hydrophidae

Most non venomoussnakes eg : grass snake

Cobras, krait, mambas,

coral snake American rattlesnake,

Asian pitviper, Russelsviper, aders

Sea Snake


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Snake venom

It is complex mixture ofenzymes, low.mol.wtpolypeptides,

glycoproteins, metal ions.

Component Action

Serineproteases

haemolysis

Otherproteases

haemolysis

Phospholipase

A2

Myotoxic

CardiotoxicNeurotoxic

Increases

vascularermeabilit


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Component Action/effect

Hyaluronidase Local tissue destruction

Neurotoxins

Alpha Bungarotoxin

Cobrotoxin

Post synaptic inhibition

Beta bungarotoxin

Crotoxin

Pre synaptic inhibition


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Poisonous Snakes

Neurotoxiccobra,krait & coral

Haemotoxicvipers

Myotoxicsea snake


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Common Indian venomous snakes

ELAPIDAE Common CobraNaja Naja, Indian Cobra

Common KraitBangarus Caeruleus

VIPERIDAE Saw Scaled ViperEchis Carinatus

Russells Viper Vipera Russelli

OTHER SNAKES King CobraNaja Bangarus, Hamadryad Banded KraitBangarus Fasciatus

Sea Snakes


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Poisonous Non poisonous

Head scales : small

Large and opening / pitb/w eye & nostril (pit

viper) Third labial touches eye

and nostril shield (cobra)

No pit or third labialtouches eye & nostrilshield( krait )

large


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Poisonous Non poisonous

Fangs : hollow likehypodermic needles

Teeth : 2 long fangs

Tail : compressed

Short and solid

Several small teeth

Not much compressed


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Non poisonous snake


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INDIAN COBRA COMMON KRAIT

Neurotoxic NeurotoxicFatal period8 h Fatal period : 18 h


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Indian cobra King cobra


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Coral snake


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Saw Scaled Viper Russels Viper

(Echis Carinata) ( Vipera russeli )

Venom: Vasculo & Venom: Vasculo & Haemato

Haematotoxic toxic

Fatal period : 3 days Fatal period : 5 days


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Banded Krait Common Krait

( Bungarus Fasciatus )


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Diagnosislook for fang marks


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& Identify the snake

Features of poisonous snakes

Usually dull coloured (Brown, Black, Grey)

Stout body with abruptly compressed and tapering tail

Broad belly scales extending entire width of belly

Small scales on triangular head

Pit between eye and nostril

Presence of hood with or without markings

Presence of fangs


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Clinical features

Flushing, palpitations, sweating, anxiety & fearprominent features in any snake bite victim (even if snake is non-venomous )

Specific features of venomous snakesdependupon type of snake and consists of local &systemic features of envenomation.


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Grades of envenomation

GRADE FEATURES

Non-envenomated (dry)bites

Presence of fang markswithout local / systemic

reactionsMild envenomation Local swelling & pain

without systemic reaction

Moderate envenomation Extensive local effects withmin.sys.effects / mild localeffects with markedsys.effects , mild lab.abn


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Grades of envenomation

GRADE FEATURES

Severe envenomation Extensive local effects &systemic effects & marked

lab.abn


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Bites by Elapids

Generally cause minimal local effects Swelling, local pain & local necrosis ( cobra ) Descending paralysis, initially of muscles innervated by

cranial nerves commencing with PTOSIS, DIPLOPIA,OPHTHALMOPLEGIA

Numbness around lips & mouth, progressing topooling of secretions, bulbar paralysis & resp.failure

Paradoxical respintercostal muscle paralysis Stomach pain ( Krait )submucosal hage in stomach Krait bitespresent in early morning with paralysis

can be mistaken for STROKE .


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Bites by Viperidae

Severe local effectsas early as within 15 min of bite Extensive swellingspreading quickly to involve whole

limb. Asso with blistering , necrosis & regional tender

lymphadenopathy. Hemostatic abnpersistant ooze & bleeding from

venepuncture sites, fang marks & later bleeding fromgums, epistaxis, petechiae, purpura & ecchymoses

Abdominal tendernessgi / retroperitoneal bleed Passage of reddish / dark brown urine / diminishing /

nil urine output.


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Bites by Viperidae

Lateralising neurological symptoms like asymmetricalpupilsintracranial bleed

Hypotensionresulting from hypovolemia / directvasodilation

Low back pain , indicative of early renal failure Muscle painrhabdomyolysis Parotid swelling, conj.edema, sub.conj.hage Renal failurerussels viper, hump nosed pit viper . Long term comp : hypopituitarism & cardiotoxicity Saw scaled viper doesnt cause renal failure generally


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Hydrophid bites

Stiffness, ache, tenderness in muscles

Later, rhabdomyolysis, myoglobinuriaresulting in acute renal failure .

FEATURE Russels Saw Hump


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FEATURE

Cobra Krait

Russels

viper

Saw

scaled

viper

Hump

nosed

viper

Local pain /tissue damage

YES NO YES YES YES

Ptosis/Neurological signs

YES YES YES NO NO

Hemostatic abn NO NO YES YES YES

Renal Comp NO NO YES NO YES

Response toNeostigmine

YES NO? NO? NO NO

Response to ASV YES YES YES YES NO


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First Aid- Do it R.I.G.H.T

RReassure the patient . 70 % snake bitesnonvenomous species. Only 50 % of bites by

venomous species actually envenomate the pt.

IImmobilise in the same way as # limb. Usebandages / cloth to hold splints, not to block bloodsupply / apply pressure. Do not apply any compressionin the form of tight ligatures

GHGet to the hospital immediately T- Tell the doctor of any systemic symptoms that

manifest on way to the hosp


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Traditional Methods to be

DISCARDED

Tourniquets traditionally used to stop venom flow. (increased risk of ischemia , loss of limb, necrosis,massive neurotoxic blockade when tourniquet is

released, embolismviper , false sense of security ) Incision & Suctionincreases risk of severe bleeding as

clotting mech is ineffective & infection . No venom isremoved by this method

Washing the woundit increases the flow of venominto system by stimulating the lymphatic system.


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Treatment protocol

Attend toAIRWAY , BREATHING, CIRCULATION

Tetanus toxoid

Routine antibiotic is not necessary

Identify the snake responsible

All patients should be kept under observation for a minperiod of 24 hrs.

Determine the exact time of bite Ask the victim as to what he was doing at the time of

bite


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investigations

20 minute whole blood clotting testconsidered most reliable test of coagulation

Single breath count


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investigations

Urine for RBCViper BiteHematuria,Proteinuria, Hemoglobinuria, Myoglobinuria

ECGNormal, Bradycardia with ST elevationor depression, T inversion, QT prolongation

ABGHypoxemia with Respiratory Acidosis,

Metabolic / lactic Acidosis Chest X- rayNormal, Pulmonary Oedema,

Intrapulmonary Hemorhages, Pleural Effusion


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Monitor vital signs

Observe every patient for minimum 24 hours

Pulse, BP, Respiration

Urine output

Blood urea, Creatinine

Bleeding tendency

Local swelling

Vomiting

Diplopia, Ptosis, Muscle Weakness, Breathlessness


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Anti Snake Venom

ASV is prepared by hyperimmunising horsesagainst venoms of snake

It neutralises the free, unbound venom & tosome extent also dissociates the bound toxin

ASV is manufactured in India by the HaffkineCentral Research Institute, Kasauli & Serum

Institute of India, Pune & both arePOLYVALENT.


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1 ml of ASV neutralises

Cobra0.6 mg

Common krait0.45mg

Russels viper0.6 mg Saw scaled viper0.45 mg


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Indications

As perW.H.O Guidelines ONLY if a pt devoleps one/ more of the following signs/symptoms ASV shouldbe administered :

SYSTEMIC ENVENOMING

Evidence of coagulopathy: detected by 20WBCT orvisible spontaneous systemic bleeding

Evidence of neurotoxicity : ptosis, ext.ophthalmoplegia CVS abn : hypotension, shock, arrhythmias ARF Hemoglobinuria / myoglobinuria Persistant severe vomiting / abd.pain


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LOCAL ENVENOMING :

Local swelling > of involved limb

Rapid extension of swelling Enlarged tender lymph nodes draining the bitten

limb.


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ASV administration

NO ASV TEST DOSE MUST BEADMINISTERED .

Recommended initial dosages are 100 ml( 10vials) of polyvalent ASV for adults & childrenbased on published research that russells viperinjects on an avg of 63 mg of venom.

Our initial dose must be calculated to neutralizethe avg dose of venom injected.


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Range of venom inj = 5mg147 mg

Sugg ASV dose = 100 -250 ml

Initial dose of 100 ml must be diluted in 100 mlof NS & given over 1 hour.

Pt should be carefully monitored for 2 hrs.

Local adm of ASV, near the bite siteineffective, painful, raises intracompartmentalpressure.SHOULD NOT BE DONE.

Victim who arrives late ?


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Victim who arrives late ?

Often after several days , usually with ARF

Are there any signs of current venom activity ?

Perform 20WBCT & determine if anycoagulopathy is +, if + adm ASV.If - , treat ARFdialysis

Neurotoxic envenominglook for ptosis, respfailure , + adm 1 dose of ASV , resp support


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ASV reactions

Pt should be monitored closely

First sign of any one of the following :

1. Utricaria 6. Vomiting 11.Bronchospasm

2. Itching 7. Diarrhoea 12.Angioedema3. Fever 8. Abd.cramps

4. Chills 9. Tachycardia

5. Nausea 10. Hypotension

Discontinue ASV & give 0.5 mg of 1 :1000 adrenalineIM


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ASV reactions

Long term protection :100 mg Hydrocortisone IV

10 mg H1 Antihistaminic IVAfter 10 -15 min , pt not improved /worsened :

give 2 nd dose of 0.5 mg of 1:1000 adrenaline

IM Once pt has recovered , restart ASV slowly for

10-15 min , close observation & later normally.


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Repeat doses of ASV

HEMATOTOXIC POISONING :

20 WBCTabninitial dose given over 1 hr.

Repeat 20WBCT after 6 hrs

Abnanother dose to be given. Repeat samedose again.

20WBCT & Repeat doses of ASVto becontinued on 6 hrly manner untill coagulation isrestored.


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Repeat doses of ASV

NEUROTOXIC POISONING :

Assess the pt 1-2 hrs after the initial dose

If symptoms persist / worsen , 2 nd dose whichis same as 1st dose is to be given & then ASVcan be discontinued.

R l f N i i i N i


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Role of Neostigmine in Neurotoxic

poisoning

Anticholinestrase & prolongs life of Ach - which canreverse resp.failure & neurotoxic symptoms ( postsynaptic )

Neostigmine test : 1.5 -2.0 mg IM preceeded by 0.6 mgatropine IV

Observe for 1 hr

If victim responds , continue 0.5 mg Neostigmine IM

hrly with 0.6 mg Atropine IV over 8 hrs If no improvement in symptoms after 1 hr ,

stop Neostigmine


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Supportive Therapy

RESPIRATORY FAILURE :

ABG

Intubate & Ventilate

Neostigmine & Atropine

HYPOTENSION :

Plasma expanders Dopamine 2.55 micrograms/Kg/min


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Supportive Therapy

PERSISTANT / SEVERE BLEEDING :

Majoritytimely use of ASV will stop sys.bleed

ASV + Blood Transfusion

RENAL FAILURE

Hemodialysis / peritoneal dialysis

COMPARTMENT SYNDROME :

Fasciotomy

SURGICAL DEBRIDEMENT OF WOUND


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Thank You

Snake Bite Vch

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