Venomous snakes are undoubtedly the most significant cause of both major morbidity and mortality among all terrestrial venomous and poisonous animals. Although poisoning by other animals may affect large numbers of people, mortality is comparatively rare, and thus venomous snakes are the leading cause of death from venomous and poisonous animals in all environments.

In some parts of the rural tropics,snakebite is in the top 10 to 15 most important health problems. 2.54 million venomous snakebite and at

least 125000 death per year.Even though there are aproximately 3000

species of snakes globally, only about 600 species are venomous, and all of them are found in some snake families:

Colubridae

Elapidae: Walterinnesia aegyptia , Naja spp. or African and Asian cobras)

Hydrophidae

Viperidae (Cerastes spp., Echis spp., Pseudocerastes spp.)

Crotalidae( Agkistrodon spp., crotalus spp.

Aglyphous (Nonvenomous snakes)

phyton and boa

Opistoglyphous (Colubridae)African tiger snake

Solenoglyphousviperidae-crotalidae

Proteroglyphouselapide-hydrophidae

Snake venome generally consist of a complex mixture of substances, each of witch may exhibit one or more distinc toxic action. Function: acquisition, digestion, defense.water soluble Acidy

Toxin ClassToxin ClassClinical EffectsClinical Effects

Polypeptide toxins Polypeptide toxins Autonomic, neurotoxic, cardiotoxic, myotoxic

Phospholipase toxinPhospholipase toxinPresynaptic neurotoxic, myolitic, cardiotoxic, necrotic, hemolytic

Enzyme toxinEnzyme toxinOxidoreductases, transferases, hydrolases

Interfer with hemostasis, necrotic, hemolytic

Other toxinOther toxinLectin, Nerve groth factor, Proteinase inhibitors, compleman inhibitor

Other componenets Other componenets Amino acids, carbohydrates, Lipids, Aninons, cations,…

1)Neurotoxin Paralytic effect mediated at the neuromuscular

junction.

Postsynaptic neurotoxinPresynaptic neurotoxinAnticholinesterase

2) MyotoxinSystemic myolysis of skeletal muscle Massive release of myoglobin, creatin kinase

and potassium

3) Hemostatic system toxinInterference with normal hemostasis causing either

bleeding or thrombosis

4) Hemorrhagins Vascular wall damage(endothelium ) causing

bleeding 5) NephrotoxinsDirect renal damage6) NecrotoxinDirect tissue injury at the bite site/bitten limb

Local effect Local effect Bit mark vary from a single fang puncture

to classic double puncture from paired fangs. Local swelling, erythma, hemorrhage, blistering, frank necrosis.

General effectGeneral effectHeadache, nausea, vomiting, abdominal

pain, diarrhea, dizziness, collapse, hypotension/hypertension, tachycardia/bradycardia and ….

Specific effectSpecific effect

Paralysis:Paralysis: That caused by neurotoxins affects skeletal muscle and respiration muscle.

Ptosis, dysphonia, droolin and diplopia.

MyolysisMyolysis: Muscle pain, tenderness, weakness and paralysis, myoglubinuria.

CardiotoxicityCardiotoxicity: arrhythmias to cardiac arrestCoagulopathy and hemorrhaging effectCoagulopathy and hemorrhaging effect

Pain; Inflammation (++)Nausea & vomitingDrowsinessBlurred visionLethargyWeaknessParalysis of skeletal and respiratoryLower necrosis and hemorrhage of the site

Pain and inflammation(+++) improve in organ

Higher necrosis and hemorrhage at the siteHemorrhage from Other site (GI, GU, ORAL)Nausea & vomitingWeaknessDrowsinessLower paralysisCoagulation disorder

Pain and inflammation (+)

High muscle pain

Drowsiness

Nausea and vomiting

Paralysis skeletal and respiratory

Myoglubinuria (urine color)

Pressure Immobilization? For bites by

nonnecrotic species includig many

elapidae ( but not most cobras) is both

safe and effective.

Incision and suction?

Cutting :× or ІІІ and suctionTourniquet(±): good for hydrophideaIce compress(-)Gently washing : N/S or diluted betadinNSAIDTetabulinFFP (after antiserum)Prophylaxy antibiotic (no recommended)AB: ( metronidazol, cephalosporine)

AntiserumMinimal: 2-5 vialModerate: 5-10 vialSever:10-20 vial

Dilute With N/S (1:10)50 % within first hour Slow rapid infusion 50 % within 24 h Prevention of anaphylaxy:chlorpheniramin- hydrocortizone Dose no dependent to weight

Minimal: Minor local swelling and discomfort only,

without systemic symptoms or hematologic

abnormalities.

Moderate: Progression of swelling, with local

tissue destruction, hematologic abnormalities, or

systemic symptoms.

Severe: Marked progressive swelling and pain,

with blisters, bruising, and necrosis; systemic

symptoms.

For Crotaline envenomations, antivenom should be considered as first-line therapy for patients with moderate- to- severe envenomations

The infusions are initiated at a slowslow rate. If no signs of anaphylactoid reaction develop, the rate is increased to complete the infusion over 1 hour.

ScorpionScorpion

Scorpions are arthropods with a hard exoskeleton, two anterior pinchingclaw and a tail ending with bulbous enlargement. The poison gland and stinger are located at he distal part of the tail. Their habitat is warm and arid areas.

Scorpion venom is a mixture of mucopolysaccharides, hyaluronidase,

serotonin, histamine, phospholipase, protease inhibitors, histamine releasers,

neurotoxins, and ….

ToxinToxin: soluble in water and pH=7-8

Mechanism:

Increase of neuronal Na+ influx

Increase of current Ca+ to presynaptic

neuron Release NEP and Ach

sympathetic/parasymphatetic stimulation

low relation between color and toxicity

Scorpionidae: hemiscorpius lepturousعقرب هفت دم (گادیم)

Butidae: androctonus crassicauda عقرب سیاه

Usually only pain at the site (70%)Scorpionidae Burning, pain, edema, vesicle, necrosis, coagulation disorder, hemolysis and arrest of cardiac and respiratory.ButidaeHigher pain and burning, lower vesicle and necrosis, arrest of cardiac and respiratory.

Both of them: Sympathic : Cardiotoxicity (CVS)

Parasympathic: NMJ ,GI ,GUseizure

NSAID local anesthetic injectionCold compress (+) if low local injuryWashing N/STetanusFFP (after antiserum)Skeletal spasm (methocarbamol)GI spasm (hyoscine) diazepam

Antiserum : 1-2 vial no dependent to child and adult and weight

Hypertension : no ACEI bradykinin and toxicity

Choice : SNP, hydralazine, prazocinBRADYKININ VASCULAR PERMEABILITY

IN RESPIRATORY SYSTEM PULMONARY EDEMA

BeesBees

Apoidea: honey bee , bumble bee

Vespoidea: wasp , hornet , yellow jacket

Melitin : 50% dry weightCytolysis - hemolysis - rhabdomylysis PainInflammationInhibition of Ach , Na/K/ATPase

Phospholipase A2:10-12% inflammation Apamine: 3% inhibit of Ca-dependent K channelMast cell degranualating: 2% inflammationOthers: serotonin, kinin, dopamine

WASP: like honey without melitin , apamine

PainEdemaPruritus, urticariaAnaphylaxyMany sting: respiratory depressoin, CVS complicatoin (hypotension, arrhythmia) , seizure

Remove sting with sac (caution)Honey bee: rinse with lemon juice, vinegarWasp: rinse Na bicarbonate, cigarette remnantAntihistamineNSAIDGlucocorticoidSalbutamolAdrenaline (under tongue)

SpidersSpiders

Spiders Loxoscele Brown recluse spiderLatrodectus

Black widow spiderFemale are larger and

danger than male

SphingomyelinaseCytotoxic for RBC release HbCytotoxic for skin cells necrosisCytotoxic for endothelial vascular system

bleeding and adhesion of neutrophils

inflammation and damage to tissueHyaluronidaseFacilitate spreading in tissue

Low pain at bite

Erythema, edema, blister, necrosis and

hemorrhagic (increase in lesion diameter)

Nausea, vomiting, fever,weakness,

internal bleeding, hemolysis (blood in urine),

convulsion

Clean the lesion (N/S , betadin)

Analgesic ( NSAID, opioid)

Anti tetanus

Anti venom

Antibiotic (high spectrum)

α - latrotoxin

Bind to presynaptic

receptors(neurenin, latrophilin)

INFLUX OF Ca2+ release NEP,

Ach and neurotransmitters

Low pain at biteLower local reactionMostly NeurotoxicMuscle spasm and pain in many part

of bodySympathic and parasympathic

stimulation (GI,CVS,GU)

NSAIDOPIOIDBZD MethocarbamolHyoscineAntivenomAntitetanus

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