Snake Bite Vch
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Transcript of 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