Snake Bite and Stings 2012
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Transcript of Snake Bite and Stings 2012
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Dr Mohammad Naeem
Assistant Professor
Department of Community MedicineKhyber Medical College, Peshawar
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Epidemiology
3 million bites and 1,50,000 deaths/year from
venomous snake worldwide.
Bites highest in temperate and tropical regions.
3000 species of snakes, out of them only 10-15%
of snakes are venomous
97% of all snake bites are on the extremities
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Common Snakes - INDIA
Cobras(nagraj)Najanaja,N.oxiana, N.kabuthia
Neurotoxicity usually
predominates.
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Russells viper(kander)-Daboia russelii
Heat-sensing facial pits
(hence the name "pit vipers").
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Echis.carinatus(afai)-Saw scaled viper
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Non Poisonous Snakes
Head - Rounded
Fangs - Not presentPupils - Rounded
Anal Plate - Double row
Bite Mark - Row of small teeth.
Poisonous Snakes
Head Triangle
Fangs Present
Pupils - Elliptical pupil
Anal Plate - Single row
Bite Mark - Fang Mark
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Snake Venom
Snake venom is highly modified saliva
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Mechanism of toxicity
Cytotoxic effects on tissues
Hemotoxic
Neurotoxic
Systemic effects.
Toxic dose. The potency of the venom and the
amount of venom injected vary considerably.
20% of all strikes are "dry"
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Snake Venom, Necrosis
Proteolytic enzymeshave a trypsin-like activity.
Hyaluronidase splits acidic mucopolysaccharides andpromotes the distribution of venom in the extracellular
matrix of connective tissue.
Phospholipases A2-break down membrane phospholipids-causes cellular membrane damage
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Contd..
All these enzymes cause oedema, blister
formation and local tissue necrosis
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Snake Venom ,Paralysis
Blocks the stimulus
transmission from
nerve cell to muscleand cause paralysis
Does not penetrate
the blood-brain barrier
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Contd..
Postsynaptic effects are reversible with antivenom
and neostigmine.
Presynaptic nerve terminal, e.g. beta-bungarotoxin
and here neostigmine will not be effective.
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Snake venom, Hemorrhages
Activate prothrombin (e.g. ecarin from Echis carinatus)
Effect on fibrinogen and convert it into fibrin -thrombin-likeactivity, such as crotalase (rattlesnake venom)
Activate factor 5, factor 10 , Protein C
Activate or inhibit platelet aggregation
Haemmorhagins- cause endothelial damage
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Clinical syndromic approach
Syndrome 1
Local envenoming
(swelling etc) with
bleeding/clotting
disturbancesVIPERIDAE
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Syndrome 2
Ptosis, external opthalmoplegia, facial paralysis etc
and dark brown urine
=Russell's viper, Sri Lanka and South India
http://images.google.co.in/imgres?imgurl=http://www.dkimages.com/discover/previews/975/75012571.JPG&imgrefurl=http://www.dkimages.com/discover/DKIMAGES/Discover/Home/Health-and-Beauty/Medical-Examinations/Urine-Test/Urine-Test-5.html&usg=__IYSjtD2wFOFx5N34U7P8QbaT4Ws=&h=428&w=272&sz=12&hl=en&start=1&tbnid=IG29gafApDSfCM:&tbnh=126&tbnw=80&prev=/images%3Fq%3Ddark%2Bbrown%2Burine%26gbv%3D2%26hl%3Den -
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Syndrome 3
Local envenoming (swelling etc) with paralysis
=Cobra or king cobra
http://images.google.co.in/imgres?imgurl=http://www.naturemalaysia.com/snake-bite2.jpg&imgrefurl=http://www.naturemalaysia.com/snake-bites.htm&usg=__ptI-x4ZrxICISjRdBHXLVZw5aBE=&h=389&w=300&sz=41&hl=en&start=30&tbnid=GjhRM-is3Gt-zM:&tbnh=123&tbnw=95&prev=/images%3Fq%3Dviper%2Bbite%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN%26start%3D20 -
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Syndrome 4
Paralysis with minimal or no local envenoming
Krait, Sea snake
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Syndrome 5
Paralysis with dark brown urine and renal failure: Russle
viper
http://images.google.co.in/imgres?imgurl=http://www.dkimages.com/discover/previews/975/75012571.JPG&imgrefurl=http://www.dkimages.com/discover/DKIMAGES/Discover/Home/Health-and-Beauty/Medical-Examinations/Urine-Test/Urine-Test-5.html&usg=__IYSjtD2wFOFx5N34U7P8QbaT4Ws=&h=428&w=272&sz=12&hl=en&start=1&tbnid=IG29gafApDSfCM:&tbnh=126&tbnw=80&prev=/images%3Fq%3Ddark%2Bbrown%2Burine%26gbv%3D2%26hl%3Den -
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Grade 0
No evidence of envenomation
Suspected snake bite
Fang mark may be present
Pain and 1 inch edema & erythema
No systemic signs- first 12 hours
No lab changes
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Grade 1
Minimal envenomation
Fang wound & moderate pain present
1-5 inches of edema or erythema
No systemic involvement in presentafter 12 hours
No lab changes
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Grade 2
Moderate envenomation
Severe pain
Edema spreading towards trunk
Petechiae and ecchymosis limited area
Nausea,vomiting,giddiness
Mild temperature
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Grade 3
Severe envenomation
Within 12 hours edema spreads to the extremities
and part of trunk.
Petechiae and ecchymosis may be generalized
Tachycardia
Hypotension
Subnormal temperature
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Grade 4
Envenomation very severe
Sudden pain rapidly
Progressive swelling which leads to ecchymosis all
over trunk Bleb formation and necrosis
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Grade 4 contd
Systemic manifestations within 15 min after the
bite
Weak pulse,N&V,vertigo
Convulsions, coma
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What investigation to do?
CBC
RFT
Coagulation studies
Blood grouping & cross matching
Sr.electrolytes
Urinalysis
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20 min whole blood clotting time
A few milliliters of fresh blood are
placed in a new, plain glass receptacle
(e.g., test tube) and left undisturbed for
20 min.
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Contd
The tube is then tipped once to 45 to determine
whether a clot has formed. If not, coagulopathy is
diagnosed
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Hess's test
Blow up a blood pressure cuff to 80 mm Hg and
leave it on for 5 minutes.
If a crop of purpuric spots appears below the cuff,
the test is positive.
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First Aid
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Donts
No Tornique
No Suction apparatus to be used(Sawyers)
Do not run
No role of Ice application
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ASV
When to use ASV?
How much to use?
What if a reaction occurs?
When to stop ASV?
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When to use ASV
Hemostatic abnormalities(lab and clinical)
Progressive local findings
Neurotoxicity
Systemic signs and symptoms
Generalised rhabdomyolysis
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Polyvalent antivenin
Manufactured by hyper immunizing horses against
venoms of four standard snakes
Cobra (naja naja)
Krait (B.caerulus)
Russels viper(V.russelli)
Saw scaled viper(Echis carinatus)
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Contd..
Lyophilised form: stored in a cool dark place & may lastfor 5 years
Liquid form: has to be stored at 4c with much shorter lifespan
Each 1ml of reconstituted serum neutralise0.6 mg of naja naja
0.45 mg of Bungarus caerulus0.6 mg of V.russelli0.45 mg of Echis carinatus
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Guide for initial dose of antivenin
Grade Amount of
Antivenin
Route
0 None None
1 None None
2 5 vials IV 1:10 dilutions
3 5-10 vials IV 1:10 dilutions
4 10-20 vials IV 1:10 dilutions
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Dose in Paediatric
Same as adult as the amount of venom
does not change-hence the dose of
antivenom should be the same
Only the dilution changes
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Skin testing- Done if patient is stable
and time available
0.02ml of 1:100 solution of serum is injected sc
A positive reaction occurs within 5 to 30 mins.
Appearance of wheal & surrounding erythema
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What to do in case of anaphylactic reaction to
ASV
Adrenaline 0.5 to 1ml IM
If hypotension,severe bronchospasm or laryngeal
edema give 0.5 ml of adrenaline diluted in 20 ml of
isotonic saline over 20 mins iv.
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contd..
A histamine anti H1 blocker-chlorpheniramine
maleate-10 mg IV
Pyrogenic reactions-antipyretics
Late reactions-respond to CPM-2 mg, 6 hrly or
oral prednisolone-5 mg 6 hrly
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What if the patient needs ASV
following reaction
Dose should be further diluted in isotonic saline
and restarted as soon as possible.
Concomitant IV infusion of epinephrine may berequired to hold allergic sequelae at bay while
further antivenom is administered
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Contd..
If objective improvement is evident at 5 min
continue neostigmine at a dose of 0.5 mg
(children, 0.01 mg/kg) every 30 min as needed
with atropine by continuous infusion of 0.6 mg over 8 h
-children, 0.02 mg/kg over 8 h
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Contd
Hypotension
Administration of crystalloid (2040 mL/kg)
Trial of 5% albumin (10 20mL/kg)
CVP guided fluids
Inotropic support and invasive monitoring
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Contd..
Oliguria & renal failure- fluids,diuretics,
dopamine
no response-fluid restriction- Dialysis
Local infection- TT,antibiotics
Haemostatic disturbances-FFP,fresh whole
blood,cryoprecipitates
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Cobra spit opthalmia
Topical antimicrobial
0.1% adrenaline relieves pain
No need for ASV
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Compartment syndrome
If signs of compartment syndrome are present and
compartment pressure > 30 mm Hg:
Elevate limb
Administer Mannitol 1-2 g/kg IV over 30 min
Simultaneously administer additional antivenom,
4-6 vials IV over 60 min
If elevated compartment pressure persists another60 min, consider fasciotomy
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Bee Sting
Honey bee belong
Family- Hymenoptera
Sub Family-Apidae
Only the females have adapted a stinger from theovipositor on the posterior aspect of the abdomen
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Venom
Histamine.
Melittinamembrane active polypeptide that can
cause degranulation of basophils and mast cells,constitutes more than 50 percent of the dry weight
of bee venom
Venom commonly causes pain, slight erythema,
edema, and pruritus at the sting site
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Presentations
Local reaction
Toxic manifestation and anaphylaxis
Delayed reactionSerum sickness
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Treatment
Immediate removalis the important principle and themethod of removal is irrelevant.
Sting site should be washed thoroughly with soap andwater to minimize the possibility of infection.
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Contd..
Intermittent ice packs at the site- diminishswelling and delay the absorption of venomwhile limiting edema.
Oral antihistamines and analgesics may limitdiscomfort and pruritus.
Nonsteroidal anti-inflammatory drugs(NSAIDs) can be effective in relieving pain
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Severe systemic reaction
Epinephrine 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000concentration) in adults and 0.01 mg/kg in children (nevermore than 0.3 mg).
Injected IM and the injection site massaged to hastenabsorption
If hypotension,severe bronchospasm or laryngeal edemagive 0.5 ml of adrenaline diluted in 20 ml of isotonic saline
over 20 mins
Observation for 24 hours in ICU
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Contd
Parenteral antihistamines (diphenhydramine 25 to
50 mg IV, IM, or PO) and H2-receptor antagonists
(ranitidine 50 mg IV)
Steroids (methylprednisolone 125 mg) -to limitongoing urticaria and edema and may potentiate
the effects of other measures.
Bronchospasm is treated with -agonist
nebulization.
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Contd..
Hypotension
-massive crystalloid infusion, and central venous
pressure monitoring may be helpful in these
patients.-Persistent hypotension require dopamine.
-If dopamine is ineffective, an intravenous infusion
of epinephrine can be used
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Preventive Care
Every patient who has had a systemic reaction -
insect sting kit containing premeasured
epinephrine and be carefully instructed in its use.
Patient must inject the epinephrine at the first signof a systemic reaction.
Medic alert tag
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Scorpion sting- C. exilicauda
Scorpions have a world-wide distribution.
Highly toxic species are found in the Middle East,
India, North Africa, South America, Mexico, and theCaribbean island of Trinidad.
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Mechanism of action
Venom can open neuronal sodium channels
and cause prolonged and excessive depolarization
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Symptoms and sign
Somatic and autonomic nerves may be affected
Initial pain and paresthesia at the stung
extremity that becomes generalised
Cranial nerve- abnormal roving eye movements,
blurred vision, pharyngeal muscle incoordinationand drooling and respiratory compromise
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Contd
Excessive motor activity
Nausea, vomiting, tachycardia, and severe
agitation can also be present.
Cardiac dysfunction, pulmonary edema,pancreatitis, bleeding disorders, skin necrosis, and
occasionally death can occur
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Treatment
Pain Management
Ice pack
Immobilization of limb
Local anaesthetics are better than opiates
Tetanus prophylaxis, wound care and antibiotics
Benzodizepines for motor activity.
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Contd..
Stabilize Airway Breathing and Circulation
Hyperdynamic circulation
Always combination of alpha blocker with beta
blocker to prevent unopposed alpha action
causing tachycardia
Nitrates for Hypertension/MI
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Contd..
Hypodynamic Circulation:
CVP guided fluids
Decrease preload with furosemide (not hypovolumic)
Reduction of afterload improves outcome-Prazosin,nitroprusside, hydralizine, ACE inhibitor
Dobutamine is the best inotrope, avoid Dopamine
Noradrenaline can be used
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Newer modality
Insulin has shown to improve cardiopulmonary status in
case of scorpion envenomation
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THANK YOU