Bites and Stings

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Bites and Stings

• Dr Pavan .M
• MD(A EM), VMKVMC

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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) Naja naja,N.oxiana, N.kabuthia
• Neurotoxicity usually
• predominates.

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• Common krait(karayat)-Bungarus caeruleus

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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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Features of poisonous non-poisonous snakes

• Non Poisonous Snakes
• Head - RoundedFangs - Not presentPupils -
  RoundedAnal 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 enzymes have a trypsin-like activity.
  
• Hyaluronidase splits acidic mucopolysaccharides
  and promotes 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 muscle
• and 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-like activity, 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 approachSyndrome 1

• Local envenoming
• (swelling etc) with
• bleeding/clotting
• disturbances
• VIPERIDAE

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Syndrome 2

• Ptosis, external opthalmoplegia, facial
  paralysis etc and dark brown urineRussell's
  viper, Sri Lanka and South India

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Syndrome 3

• Local envenoming (swelling etc) with
  paralysisCobra or king cobra

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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

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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 present after 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,NV,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
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 last for 5 years
• Liquid form has to be stored at 4c with much
  shorter life span
• Each 1ml of reconstituted serum neutralise0.6 mg
  of naja naja0.45 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 110 dilutions
3 5-10 vials IV 110 dilutions
4 10-20 vials IV 110 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 1100 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 be
  required to hold allergic sequelae at bay while
  further antivenom is administered

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When to stop using ASV

• Bleeding subsides
• Lab values returns to baseline
• Signs of neurotoxicity reverses
• Local effects halts progression

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Supportive treatment

• Anticholineesterase have variable but useful role
• Trial
• Atropine sulphate 0.6 mg
• Edrophonium chloride 10 mg IV (or) Neostigmine
  1.52.0 mg IM (children, 0.0250.08 mg/kg)

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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 gt 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
  another 60 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 the
  ovipositor on the posterior aspect of the abdomen
  

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Venom

• Histamine.
• Melittina membrane 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 reaction Serum sickness

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Treatment

• Immediate removal is the important principle and
  the method of removal is irrelevant.
• Sting site should be washed thoroughly with soap
  and water to minimize the possibility of
  infection.

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Contd..

• Intermittent ice packs at the site- diminish
  swelling and delay the absorption of venom while
  limiting edema.
• Oral antihistamines and analgesics may limit
  discomfort 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
  11000 concentration) in adults and 0.01 mg/kg in
  children (never more than 0.3 mg).
• Injected IM and the injection site massaged to
  hasten absorption
• If hypotension,severe bronchospasm or laryngeal
  edema give 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 limit
  ongoing 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
  sign of 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 the Caribbean 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 incoordination
  and 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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