Snake Bite and Stings 2012

7/28/2019 Snake Bite and Stings 2012

1/68

Dr Mohammad Naeem

Assistant Professor

Department of Community MedicineKhyber Medical College, Peshawar


2/68

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


3/68

Common Snakes - INDIA

Cobras(nagraj)Najanaja,N.oxiana, N.kabuthia

Neurotoxicity usually

predominates.


4/68


5/68

Russells viper(kander)-Daboia russelii

Heat-sensing facial pits

(hence the name "pit vipers").


6/68

Echis.carinatus(afai)-Saw scaled viper


7/68

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


8/68

Snake Venom

Snake venom is highly modified saliva


9/68

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"


10/68

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


11/68

Contd..

All these enzymes cause oedema, blister

formation and local tissue necrosis


12/68

Snake Venom ,Paralysis

Blocks the stimulus

transmission from

nerve cell to muscleand cause paralysis

Does not penetrate

the blood-brain barrier


13/68


14/68

Contd..

Postsynaptic effects are reversible with antivenom

and neostigmine.

Presynaptic nerve terminal, e.g. beta-bungarotoxin

and here neostigmine will not be effective.


15/68

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


16/68


17/68

Clinical syndromic approach

Syndrome 1

Local envenoming

(swelling etc) with

bleeding/clotting

disturbancesVIPERIDAE


18/68

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


19/68

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


20/68

Syndrome 4

Paralysis with minimal or no local envenoming

Krait, Sea snake


21/68

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


22/68

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


23/68

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


24/68

Grade 2

Moderate envenomation

Severe pain

Edema spreading towards trunk

Petechiae and ecchymosis limited area

Nausea,vomiting,giddiness

Mild temperature


25/68

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


26/68

Grade 4

Envenomation very severe

Sudden pain rapidly

Progressive swelling which leads to ecchymosis all

over trunk Bleb formation and necrosis


27/68

Grade 4 contd

Systemic manifestations within 15 min after the

bite

Weak pulse,N&V,vertigo

Convulsions, coma


28/68

What investigation to do?

CBC

RFT

Coagulation studies

Blood grouping & cross matching

Sr.electrolytes

Urinalysis


29/68

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.


30/68

Contd

The tube is then tipped once to 45 to determine

whether a clot has formed. If not, coagulopathy is

diagnosed


31/68

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.


32/68

First Aid


33/68

Donts

No Tornique

No Suction apparatus to be used(Sawyers)

Do not run

No role of Ice application


34/68

ASV

When to use ASV?

How much to use?

What if a reaction occurs?

When to stop ASV?


35/68

When to use ASV

Hemostatic abnormalities(lab and clinical)

Progressive local findings

Neurotoxicity

Systemic signs and symptoms

Generalised rhabdomyolysis


36/68

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)


37/68

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


38/68

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


39/68

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


40/68

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


41/68

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.


42/68

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


43/68

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


44/68


45/68


46/68

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


47/68

Contd

Hypotension

Administration of crystalloid (2040 mL/kg)

Trial of 5% albumin (10 20mL/kg)

CVP guided fluids

Inotropic support and invasive monitoring


48/68

Contd..

Oliguria & renal failure- fluids,diuretics,

dopamine

no response-fluid restriction- Dialysis

Local infection- TT,antibiotics

Haemostatic disturbances-FFP,fresh whole

blood,cryoprecipitates


49/68

Cobra spit opthalmia

Topical antimicrobial

0.1% adrenaline relieves pain

No need for ASV


50/68

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


51/68

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


52/68

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


53/68

Presentations

Local reaction

Toxic manifestation and anaphylaxis

Delayed reactionSerum sickness


54/68

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.


55/68

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


56/68

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


57/68

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.


58/68

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


59/68

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


60/68

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.


61/68

Mechanism of action

Venom can open neuronal sodium channels

and cause prolonged and excessive depolarization


62/68

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


63/68

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


64/68

Treatment

Pain Management

Ice pack

Immobilization of limb

Local anaesthetics are better than opiates

Tetanus prophylaxis, wound care and antibiotics

Benzodizepines for motor activity.


65/68

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


66/68

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


67/68

Newer modality

Insulin has shown to improve cardiopulmonary status in

case of scorpion envenomation


68/68

THANK YOU

Documents

Snake Bite and Stings 2012