snakes
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Snakes. Snakes. - PowerPoint PPT PresentationTRANSCRIPT
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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