| Sıra | DOSYA ADI | Format | Bağlantı |
|---|---|---|---|
| 01. | Effective Vipers Elapid Dried | pptx | Sunumu İndir |
Transkript
snakes
SNAKES ARE REPTILESmore than 2,700 species of snakes in the world of which about four fifths are non-venomous, are distributed throughout the temperate and tropical zones of the world About two thirds of all snake species belong to the family Colubridae; most of these are non-venomous.
Anatomical characterisitcsSnakes constitute the suborder Serpentes (or Ophidia). The skin, which is covered with scales, is shed, usually several times a year. The extremely long, narrow body is associated with distinctive internal features.
Jaws, teeth, sound perception.The jaws of snakes are loosely jointed and extremely flexible. The pointed, backward-curved teeth are fused to the supporting bones of the head. There are no ears or movable eyelids. They do not hear airborne sound waves, but can perceive low-frequency vibrations (100–700 Hz) transmitted from the ground to the bones of the skull.
CLASSIFICATIONSnakes are classified into two groups. i. Poisonousii. Non-Poisonous The Poisonous snakes are further classified into 3 main groups on the basis of poisons (Venom) secreted by them.1. Elapids (Neurotoxic venom) 2. Vipers (Vasculotoxic Venom) 3. Sea Snakes (Myotoxic Venom)
DIFFERENCES OF POISONOUS & NON POISONOUS SNAKESPoisonous Non-Poisonous1. Body scales (By turning Belly upward)They are large & cover the entire breadth of bellySmall or moderately large & don’t cover the entire breadth of the belly2. Head Scales Usually small but some poisonous snakes have large head scales.Usually large but some poisonous. Snake have large scales.3. Fangs Long & canalized like hypodermic needleShot & solid4. Tail Compressed Not markedly compressed5. Habits Generally NocturnalNot so6. Bite Two fang marks with or without small marks of other teeth.A number of small teeth marks in a row.
VENOM highly modified saliva that is produced by special glands of certain species of snakes. It is provided with large alveoli in which the venom is stored before being conveyed by a duct to the base of the channeled or tubular fang through which it is ejected. Snake venom is a combination of many different proteins and enzymes. Many of these proteins are harmless to humans, but some are toxins.
CHARACTERISTICS OF SNAKE VENOMIN FRESH STATEClearTransparentAmber tinted fluidDRIED UP VENOMDries into a yellow granular massRetains its activity for many yearsContains toxalbumins
VENOMThere are approximately 20 types of toxic enzymes found in snake poisonsmost snakes employ between six to twelve of these enzymes in their venom. Each of these enzymes has its own special function. Some aid in the digestive process, while others specialize in paralyzing the prey.
Chemical composition of snake venomFibrinolysins Proteolysins Neurotoxins Cholinesterase (predominant in elapid venom)Haemolyins (predominant in viper venom)ThromboplastinsAgglutininsCardiotoxins CoagulaseHyaluronidaselecithinase
VENOM CHEMISTRYScientists have identified the following chemicals from snake venom and the specific purpose of each as follows:cholinesteraseattacks the nervous system, relaxing muscles to the point where the victim has very little control.amino acid oxidase plays a part in digestion and the triggering of other enzymes(is responsible for venom's characteristic light yellowish coloring.)hyaluronidasecauses other enzymes to be absorbed more rapidly by the victim.proteinaseplays a large part in the digestive process, breaking down tissues at an accelerated rate. (causes extensive tissue damage in human victims)adenosine triphosphatase believed to be one of the central agents resulting in the shock of the victim and immobilizing smaller prey. (present in most snakes.)phosphodiesteraseaccounts for the negative cardiac reactions in victims, most notably a rapid drop in blood pressure.
VENOM EFFECTSHemotoxic venomacts on the heart and cardiovascular system. Neurotoxic venom acts on the nervous system and brain. Cytotoxic venom has a localized action at the site of the bite.myotoxic venomThe most important symptoms are rhabdomyolysis (rapid breakdown of skeletal muscle tissue) and paralysis.Many snakes incorporate both neurotoxic and hemotoxic venom in their bites so when telling them apart one goes by which type is more predominant.
ELAPIDS
ELAPIDSFound in tropical and subtropical regions , including the Indian Ocean and the Pacific.Characterized by possessing a set of hollow, short and grooved fangs through which they inject venomThese includeCobraKing cobraCommon kraitBanded kraitCoral.
ELAPID ENVENOMATION Pain is minorClinically there is unimpressive local reactionThere is more severe systemic manifestationsThe effect of the venom of elapid snakes is mainly on the nervous system.
Pre paralytic stageParalytic stageBulbar paralysisRespiratory failureDeath
MECHANISM OF ACTION OF NEUROTOXIC VENOMInjection of elapid venomAcetylcholine receptor are blocked by cobra venom. A similar effect can be achieved by high doses of curare or nicotine
SYSTEMIC EFFECTS SIGN/SYMPTOMS OF ELAPID ENVENOMATION LOCAL SYMPTOMS Mild in reaction Fang marksBurning painSwelling and discolorationBlood tinged fluid
SYSTEMIC EFFECTS SIGN/SYMPTOMS OF ELAPID ENVENOMATION PRE PARALYTICnauseasalivationvomitingeuphoriaweaknessgiddinessdizziness
SYSTEMIC EFFECTS SIGN/SYMPTOMS OF ELAPID ENVENOMATION PARALYTICSpreading paralysisPtosisOphthalmoplegiadiplopiadyspneadrowsinessmuscle tendernessconvulsionsRespiratory paralysisDeath
FATAL DOSE FATAL PERIOD15 MG OF DRIED COBRA VENOMAMOUNT OF DRIED COBRA VENOM IN A BITE = 200 – 350 MGIN COBRASFEW MINUTES TO FEW HOURS
VIPERS
VIPERSTHESE ARE FURTHER CLASSIFIED INTOPIT VIPERSe.g. bamboo snake.PITLESS VIPERSe.g. Russell viperSaw scaled viper
PIT VIPERStriangular head, wider than the neck.Pupils are vertical.Tail is tapering.FANGS .These are long movable and canalizedSo a viper can bite through the clothes and give a complete dose.
PIT VIPERSThe ‘pit’ is a special organ in between the eyes and the nostrils. The pit senses body heat from animals and gives the snake a ‘picture’ of that animal. This helps these snakes to find prey in the dark, which is when most snakes like to hunt.
PITLESS VIPERSTHIS INCLUDESRUSSELL’S VIPERSAW SCALED VIPER
VIPER VENOM VARIOUS PROTEINSPEPTIDESLIPIDSCARBOHYDRATES ENZYMESNEUMEROUS UNIDENTFIED PROTEOLYTIC ENZYMESPROCOAGULANTSANTICOAGULANTS CARDIOTOXINSHEMOTOXINS
LOCAL REACTIONSevere local symptoms includeIntense local painRapid swellingSevere oozing of hemolytic bloodBlisters appear on entire limb even trunkWhich may beSerous serosanguinous
SYSTEMIC SIGNSWhen the venom is injected subcutaneously It travels byLymphaticsSuperficial venous channelsAnd spreads rather slowly to reach the general circulation.
INTRAVASCULAR ENVONOMATIONThis produces significant systemic symptoms in a matter of minutes includingNON-SPECIFICWEAKNESSMALAISENAUSEARESTLESSNESS
INTRAVASCULAR ENVONOMATIONSpecificPetechial haemorrhagesBleeding from gumsHemoptysisBleeding from mucus membrane of rectum and other orifices of the body
FINALLY IN VIPER ENVENOMATIONCOLLAPSE SETS IN WITH Cold clammy skinRapid feeble pulseDilated pupils insensitive to lightTHIS IS FOLLOWED BYCOMADEATH IN EVENT OF RECOVERYLocal lesion suppuratesUndergoes superficial necrosis
RARELY PATIENT MAY EXHIBIT Disseminated Intravascular Coagulation [DIC]Along with spontaneous bleedingSignificant hypotensionMulti organ system failure
FATAL DOSE FATAL PERIOD 20 MG VIPER VENOM 6 MG KRAIT VENOM8 MG SAW-SCALED VIPERAMOUNT OF DRIED VIPER VENOM IN SINGLE BITE YIELDED IS150-200 MG VIPER VENOM20 MG KRAIT VENOM25 MG SAW-SCALED VIPER VENOM IN VIPERSA FEW DAYS
DIFFERENCES BETWEEN ELAPIDS & VIPERSElapids Vipers1. Body Long & cylindrical Short2. Head Nearly of the same width as neckTriangular & wider than neck3. Pupils Round Vertical4. Maxillary bonesCarries fangs + other teethOnly fangs5. Fangs Short, fixed & groovedLong, movable & canalized6. Tail Round Tapering7. Venom Neurotoxic Vasculotoxic8. Other CharacteristicsOviparous Ovi-viviparous
SEA SNAKES
ANATOMYHead is small.Belly plates are not broad.Back has dull, tuberculated scales.Fangsare delicate very shortfixedsituated posteriorlynostrils are situated dorsally on the top of the snout.have valves that consist of a specialized spongy tissue to keep water out.The windpipe can be drawn up to where the short nasal passage opens into the roof of the mouth.an important adaptation for an animal that must still come to the surface to breathe air, but may have its head partially submerged when doing so.
ENVENOMATIONThe majority of sea snakes are highly venomous. Bites in which envenomation does occur are usually painless and may not even be noticed when contact is made. Teeth may be left in the wound. There is usually little or no swelling involved and it is rare for any nearby lymph nodes to be affected.
BITE FROM A SEA SNAKEThis is felt as a sharp initial prick which becomes painless later.Early symptoms include headache, a thick-feeling tongue, thirst, sweating,vomiting. Symptoms that can occur after 30 minutes to several hours post bite includegeneralized aching, stiffness, tenderness of muscles .
SYMPTOMS OF ENVENOMATIONAfter 3-8 hours myoglobin as a result of muscle breakdown may start to show up in the blood plasma, which can cause the urine to turn a dark reddish, brown, or black color, eventually lead to acute renal failure. After 6-12 hoursSerum transaminase becomes elevated Severe hyperkalemia, also the result of muscle breakdown, can lead to cardiac arrest.
MYOTOXIC PHOSPHOLIPASE A2 (PLA2-H1) A toxic phospholipase A2 (PLA2-H1), isolated from the venom of the sea snake induces myonecrosis.Induction of myonecrosis occurs by the ability of phospholipase to release creatine kinase (CK) from damaged muscle fibers.
FATAL DOSE FATAL PERIOD1.5 milligrams. Most Sea Snakes produce an average of 10-15 mg of venom so they should always be approached with caution as this venom is 10x more lethal than the venom of the land based Rattlesnake or Africa's deadly Black Mamba. 24- 48 HOURS
MANAGEMENT OF SNAKE BITE
EXTENT OF ENVENOMATIONCLINICAL OBSERVATION ANTIVENOM RECOMMENDATIONOTHER TREATMENT DISPOSITIONNONE [DRY BITE]FANG MARKS MAY BE SEEN, BUT NO LOCAL OR SYSTEMIC SYMPTOMS AFTER 8-12 HOURS.NONE LOCAL WOUND CARETETANUS PROPHYLAXISDISCHARGE AFTER 8-12 HOURS OF OBSERVATIONMINIMAL MINOR LOCAL SWELLINGDISCOMFORT ONLYWITH NO SYSTEMIC SYMPTOMSNO HEMATOLOGIC ABNORMALITIESNONE LOCAL WOUND CARETETANUS PROPHYLAXISADMIT TO MONITORED UNIT FOR 24 HOUR OBSERVATIONMODERATE PROGRESSION OF SWELLING BEYOND AREA OF BITELOCAL TISSUE DESTRUCTIONHEMATOLOGIC ABNORMALITIESSYSTEMIC SYMPTOMSYES INTRAVENOUS FLUIDSCARDIAC MONITORINGANALGESICSFOLLOW LABORATORY VALUESTETANUS PROPHYLAXISADMIT TO ICUSEVERE MARKED PROGRESSIVE SWELLING AND PAINBLISTER FORMATIONNECROSISSYSTEMIC SYMPTOMS INCLUDINGVOMITINGFASCICULATIONSWEAKNESSTACHYCARDIAHYPOTENSIONSEVERE COAGULOPATHYYES INTRAVENOUS FLUIDSCARDIAC MONITORINGANALGESICSFOLLOW LABORATORY VALUESOXYGENVASOPRESSORTETANUS PROPHYLAXISADMIT TO ICU
MANAGEMENT OF SNAKE BITEINITIAL OBJECTIVEDETERMINE THE PRESENCE OR ABSENCE OF ENVENOMATION.TO PROVIDE BASIC SUPPORTIVE THERAPY.TO TREAT THE LOCAL AND SYSTEMIC EFFECTS OF ENVENOMATION.TO LIMIT OR REPAIR TISSUE LOSS AND OR FUNCTIONAL DISABILITY.MEDICAL THERAPYSUPPORTIVE CAREANTIVENOM WHEN WARRENTEDCONSERVATIVE SURGICAL TREATMENTDEBRIDEMENT OF DEVITALIZED TISSUE WHEN INDICATED AS INDIVIUALIZED FOR EACH PATIENTHENCE AS A RULE THE FASTER THE TREATMENT IS INSTITUTED THE BETTER IS THE FINAL OUTCOME.
INITIAL TREATMENT REASSURANCEIMMOBILIZATION OF THE AFFECTED AREABITTEN PART SHOULD BE IMMOBILIZED AS ACTIVITY INCREASES SPREAD OF VENOM.CLEANSING OF THE WOUND SHOULD BE DONE WITHPLAIN WATERSALINETOURNIQUET OR PRESSURE BANDAGE
TORNIQUETApplication of torniquet is only possible when the bite is on the limbs.If the bite is on face, neck, or trunk firm pressure over bitten area may be applied.APPLICATION OF THE TORNIQUET.It should be applied 5 cm proximal to the biteIt should be tight enough to exclude the Venous circulation lymphatic flow Without impeding the Arterial deep venous flow
TORNIQUET INSTRUCTIONSA CONSTRICTION BAND IS NOT A TRUE TORNIQUET.A broad firm constrictive wrap [elastic bandage] placed over the bitten area and encircling the entire immobilized limb will slow the systemic absorption of venom and improve outcome of neurotoxic envenomations.
IMMEDIATE IN-HOSPITAL THERAPY PAIN AND ANXIETY ANALGESICSANXIOLYTICSTETANUS PROPHYLAXISIMMOBILIZE THE EXTREMITY IN A WELL-PADDED SPLINT IN NEAR FULL EXTENSION AND ELEVATED TO AVOID DEPENDENT EDEMA.
ANTIVENOM THERAPYTHIS THERAPY IS GIVEN TO AMELIORATE THE EFFECT OF LOCAL BITE SYSTEMIC ENVENOMATION AND IT IS CONSIDERED TO BE LIFE SAVING HOWEVER PROPHYLACTIC ADMINISTRATION IS NOT RECOMMENDED
THE MAJOR INDICATIONS FOR ANTIVENOM THERAPY ARERapid progression of swellingSignificant coagulopathyThrombocytopeniaNeuromuscular toxicityHemodynamic compromiseNo dose adjustment is required as venom required for neutralization is not dependent on patient’s weight.
SPECIFIC ANTIVENIN.Is prepared by hyper immunizing horses against venom of a specificsnake.POLYVALENT ANTIVENIN.Is prepared by hyper immunizing horses against venoms of four commonsnakes CobraCommon KraitRussell’s viperSaw scaled viperANTIVENIN
POLYVALENT ANTIVENOM STRENGTH OF POLYVALENT ANTI-VENOM1 ml of anti-venom will neutralize 0.6 mg of dried cobra venom0.45 mg of dried krait venom0.6 mg of dried Russell viper venom0.45 mg of dried saw scaled viper venom
ADULT DOSE OF ANTI-VENOMTotal dose 60 ml in adults 1/3rd S/C.or around the bite.1/3rd 1/m.1/3rd I/V.The intravenous dose can be repeated any time if collapse appearsOREvery 6 hours till symptoms disappear.
IF THE PATIENT IS SENSITIVE TO SERUMDesensitization is achieved by injectingMultiple small doses under cover of AdrenalineAntihistaminescorticosteroids
ACTION OF ANTI-VENOMAnti-venom can neutralize the circulating toxin only.The toxin action at the tissue level[ fixed in tissues] may be antagonized byIN ELAPID BITENeostigmine-atropine therapyIN VIPER BITEHeparin along with supportive fibrinogen transfusionSea snake anti-venom can be effective even when started several hours after onset of poisoning.
GENERAL MEASURESSTIMULANTS in paralytic casesARTIFICIAL RESPIRATION.TRANSFUSION OF WHOLE BLOOD OR FFP in hemorrhagic casesSTEROIDS in allergic manifestations of anti-venom therapyFOR SECONDARY INFECTIONantibiotic prophylaxis
POSTMORTEM APPEARANCE Marks of snake bite Swelling & cellulitis at the site NEUROTOXIC VENOM produces signs of asphyxia IN VIPER BITE Oozing of blood Blood is fluid & haemolysed causing early staining of blood vessels Haemorrhage in lungs, serous membranes & left ventricle
POSTMORTEM APPEARANCE Petechial Haemorrhage in kidney, pelvis and mucosa of urinary bladder, stomach and intestines. Arterioles & capillaries have blurred walls and swollen endothelial cells Necrosis of renal tubules Cloudy swelling and granular changes in cells of other organs
MEDICOLEGAL ASPECTUsually accidental Rarely Homicidal Very rarely Suicidal
Effective Vipers Elapid Dried
Yıl : 2020
Anahtar Kelimeler
Daha fazla görüntüle