A&E(VMH) 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
A&E(VMH) Common Snakes - INDIA Cobras(nagraj) –Naja naja,N.oxiana, N.kabuthia Neurotoxicity usually predominates.
A&E(VMH) Common krait(karayat)-Bungarus caeruleus
A&E(VMH) Russell’s viper(kander)-Daboia russelii Heat-sensing facial pits (hence the name "pit vipers").
A&E(VMH) Features of poisonous & non-poisonous snakes Approximately 2500 different species of snakes are known. Approximately Non Poisonous Snakes Head - Rounded Fangs - Not present Pupils - 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
A&E(VMH) Snake Venom Snake venom is highly modified saliva
A&E(VMH) 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"
A&E(VMH) 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 A 2 - break down membrane phospholipids -causes cellular membrane damage
A&E(VMH) Contd.. All these enzymes cause oedema, blister formation and local tissue necrosis
A&E(VMH) Snake Venom,Paralysis Blocks the stimulus transmission from nerve cell to muscle and cause paralysis Does not penetrate the blood-brain barrier
A&E(VMH) Contd.. Postsynaptic effects are reversible with antivenom and neostigmine. Presynaptic nerve terminal, e.g. beta-bungarotoxin and here neostigmine will not be effective.
A&E(VMH) 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
A&E(VMH) Donts No Tornique No Suction apparatus to be used(Sawyers) Do not run No role of Ice application
A&E(VMH) ASV When to use ASV? How much to use? What if a reaction occurs? When to stop ASV?
A&E(VMH) When to use ASV Hemostatic abnormalities(lab and clinical) Progressive local findings Neurotoxicity Systemic signs and symptoms Generalised rhabdomyolysis
A&E(VMH) Polyvalent antivenin Manufactured by hyper immunizing horses against venoms of four standard snakes Cobra (naja naja) Krait (B.caerulus) Russel’s viper(V.russelli) Saw scaled viper(Echis carinatus)
A&E(VMH) Contd.. Lyophilised form: stored in a cool dark place & may last for 5 years Liquid form: has to be stored at 4°c with much shorter life span Each 1ml of reconstituted serum neutralise 0.6 mg of naja naja 0.45 mg of Bungarus caerulus 0.6 mg of V.russelli 0.45 mg of Echis carinatus
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) 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.
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) When to stop using ASV Bleeding subsides Lab values returns to baseline Signs of neurotoxicity reverses Local effects halts progression
A&E(VMH) Supportive treatment Anticholineesterase have variable but useful role Trial Atropine sulphate 0.6 mg Edrophonium chloride 10 mg IV (or) Neostigmine: 1.5–2.0 mg IM (children, 0.025–0.08 mg/kg)
A&E(VMH) 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
A&E(VMH) Contd Hypotension Administration of crystalloid (20–40 mL/kg) Trial of 5% albumin (10– 20mL/kg) CVP guided fluids Inotropic support and invasive monitoring
A&E(VMH) Contd.. Oliguria & renal failure- fluids,diuretics, dopamine no response-fluid restriction- Dialysis Local infection- TT,antibiotics Haemostatic disturbances-FFP,fresh whole blood,cryoprecipitates
A&E(VMH) Cobra spit opthalmia Topical antimicrobial 0.1% adrenaline relieves pain No need for ASV
A&E(VMH) 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 another 60 min, consider fasciotomy
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) Presentations Local reaction Toxic manifestation and anaphylaxis Delayed reaction –Serum sickness
A&E(VMH) 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.
A&E(VMH) 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
A&E(VMH) Severe systemic reaction Epinephrine 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 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
A&E(VMH) 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.
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) 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.
A&E(VMH) Mechanism of action Venom can open neuronal sodium channels and cause prolonged and excessive depolarization
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) Treatment Pain Management Ice pack Immobilization of limb Local anaesthetics are better than opiates Tetanus prophylaxis, wound care and antibiotics Benzodizepines for motor activity.
A&E(VMH) 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
A&E(VMH) 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
A&E(VMH) Newer modality Insulin has shown to improve cardiopulmonary status in case of scorpion envenomation
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