Snake BiteSnake BiteIncidenceIncidence Less than 50 % of Less than 50 % of

snake bites are snake bites are poisonouspoisonous

Less than 20 % of Less than 20 % of bites by bites by poisonous vipers poisonous vipers result in result in envenomation.envenomation.

Bites by Cobra Bites by Cobra may result in no may result in no envenomationenvenomation

Types of Poisonous Snakes Types of Poisonous Snakes in Egyptin Egypt

Viperidae Viperidae Cerastes cerastes Cerastes cerastes

Echis carinatus Echis carinatus

Echis coloratusEchis coloratus

ElapidaeElapidae Naja haje Naja haje

(Egyptian (Egyptian Cobra) Cobra)

Naja Naja nigricollis nigricollis (Black (Black Spitting Spitting Cobra) Cobra)

Behavior and SensesBehavior and Senses Snakes strike from the coiled position Snakes strike from the coiled position

. Strike speed is 2 meters/ sec.. Strike speed is 2 meters/ sec. Reflex bites may occur up to 1 hour Reflex bites may occur up to 1 hour

after snake dies.after snake dies. Best sensory modalities are Best sensory modalities are vibrationvibration

and and smellsmell followed by followed by thermalthermal change. Snakes are change. Snakes are deafdeaf and have and have poor visionpoor vision..

Cobra live in a humid environment Cobra live in a humid environment (around the Nile(around the Nile Valley) while vipers Valley) while vipers distribute in all the Egyptian desertdistribute in all the Egyptian desert

Venom is injected in the Venom is injected in the victim through 2 fangs victim through 2 fangs situated in front of situated in front of upper teeth .Venom upper teeth .Venom gland is connected to gland is connected to the tips of fangs by the tips of fangs by narrow ducts carrying narrow ducts carrying the venomthe venom

Venom Composition and Venom Composition and EffectsEffects

1- Hyaluronidase1- Hyaluronidase Facilitate the rapid spreadFacilitate the rapid spread

2- Proteases2- Proteases Local tissue destructionLocal tissue destruction NecrosisNecrosis EdemaEdema

3- Phospholipases3- Phospholipases Disrupt neurotransmissionDisrupt neurotransmission HemolysisHemolysis

4- Neurotoxins4- Neurotoxins With phospholipases they produce respiratory With phospholipases they produce respiratory

paralysisparalysis5- Small peptides5- Small peptides

DICDIC Platelet aggregationPlatelet aggregation ThrombocytopeniaThrombocytopenia

6- Thrombin like enzymes6- Thrombin like enzymes Formation of microthrombiFormation of microthrombi Fibrinogen depletionFibrinogen depletion FibrinolysisFibrinolysis Formation of Fibrin Degradation Formation of Fibrin Degradation

Products Products ))FDPFDP(( AnticoagulationAnticoagulation

7- Serotonin and bradykinin7- Serotonin and bradykinin HypotensionHypotension Capillary leakCapillary leak Non cardiogenic Pulmonary Non cardiogenic Pulmonary

Edema Edema ))NCPENCPE ( (

ManifestationsManifestationsI- Local manifestationsI- Local manifestations

Fang marksFang marks: one or two punctures at the site of the : one or two punctures at the site of the bite bite

Mild local painMild local pain Local edemaLocal edema occurs within 5 minutes and may occurs within 5 minutes and may

progress to involve the progress to involve the whole limbwhole limb within 1 hour within 1 hour Tender regional lymph nodesTender regional lymph nodes

In addition vipers produce the followingIn addition vipers produce the following:: EchymosisEchymosis Vesicles and petechiaeVesicles and petechiae Skin necrosis and gangreneSkin necrosis and gangrene

Systemic Systemic ManifestationsManifestations

A- Elapidae A- Elapidae ))cobracobra(( Gradual progressive Gradual progressive muscle weaknessmuscle weakness up to up to paralysisparalysis of the of the

whole body including whole body including respiratory musclesrespiratory muscles with with cranial cranial nerves palsynerves palsy is the main and may be the only manifestation is the main and may be the only manifestation of Cobra envenomation . of Cobra envenomation .

Paralysis may be preceded by fasciculations of face and Paralysis may be preceded by fasciculations of face and neck musclesneck muscles

It starts 1-4 hours but may start as late as 12 hoursIt starts 1-4 hours but may start as late as 12 hours ConsciousnessConsciousness andand sensationssensations are retained are retained Local manifestations are milder than in viper bitesLocal manifestations are milder than in viper bites

B- ViperidaeB- Viperidae

1- General manifestations:1- General manifestations: Sweating , rigors, nausea, Sweating , rigors, nausea,

vomiting, metallic taste and vomiting, metallic taste and hypertension (hypotension may hypertension (hypotension may occur late in complicated cases).occur late in complicated cases).

2- Non Cardiogenic Pulmonary 2- Non Cardiogenic Pulmonary Edema Edema

3- Congestive heart failure3- Congestive heart failure

4- Renal failure4- Renal failure

5- Coagulopathy5- CoagulopathyA- LocalisedA- Localised

Hypofibrinogenemia and Hypofibrinogenemia and thrombocytopenia may occur without thrombocytopenia may occur without significant coagulopathy. significant coagulopathy.

Thrombocytopenia reaches maximum Thrombocytopenia reaches maximum after 2-4 days and may last for 1 week. after 2-4 days and may last for 1 week.

Fibrinolysis may be absent (no Fibrin Fibrinolysis may be absent (no Fibrin Degradation Products FDP). Degradation Products FDP).

Bleeding tendency is mild with anemia Bleeding tendency is mild with anemia and hypotension.and hypotension.

B- DisseminatedB- Disseminated Full blown consumption coagulopathy. Full blown consumption coagulopathy. It is a lethal picture that usually reaches It is a lethal picture that usually reaches

hospital in very serious condition or hospital in very serious condition or commonly dies before reaching it. commonly dies before reaching it.

Patient presents with petechiae , bleeding Patient presents with petechiae , bleeding from all orifices and site of the bite.from all orifices and site of the bite.

Laboratory results show: Laboratory results show: Very high PTT, very low platelets and Very high PTT, very low platelets and

fibrinogen, high FDPs and anemia. fibrinogen, high FDPs and anemia. It is usually complicated by multiple It is usually complicated by multiple

organ failure, ARDS, renal failure and organ failure, ARDS, renal failure and shockshock

TreatmentTreatment

A- First aid measuresA- First aid measures

Reassurance of the patientReassurance of the patientImmobilization of the affected Immobilization of the affected limblimb

Light tourniquet may be applied Light tourniquet may be applied proximal to site of the biteproximal to site of the bite

B- At hospitalB- At hospitalI- Stabilization of the patientI- Stabilization of the patientII- Antidote : Polyvalent AntivenomII- Antidote : Polyvalent Antivenom

It neutralizes the venom but don't reverse It neutralizes the venom but don't reverse local injurylocal injury

It should be given within the first 4 hours It should be given within the first 4 hours to prevent local injuryto prevent local injury

Skin sensitivity test must be done before Skin sensitivity test must be done before administration.administration.

Initial dose is Initial dose is 3 - 5 vials3 - 5 vials to be repeated to be repeated according to the severity and the follow up according to the severity and the follow up of the patient. of the patient.

It is given in normal saline up to 1: 1 It is given in normal saline up to 1: 1 dilution . dilution .

III- Supportive treatmentIII- Supportive treatment IV Fluids for hypotension IV Fluids for hypotension Blood for bleeding and hemolysisBlood for bleeding and hemolysis Platelets concentrates Platelets concentrates Fresh frozen plasma to replenish coagulation Fresh frozen plasma to replenish coagulation

factors factors Artificial ventilation for the paralytic Artificial ventilation for the paralytic

syndrome of Cobra or the pulmonary edema syndrome of Cobra or the pulmonary edema of vipersof vipers

Antibiotics and antitetanic serum Antibiotics and antitetanic serum

Care of the woundCare of the wound Cleansing, debridement of necrosed tissues Cleansing, debridement of necrosed tissues

and fasciotomy if peripheral vascular and fasciotomy if peripheral vascular impairment follow limb edema and impairment follow limb edema and compartment syndrome.compartment syndrome.

Scorpion StingScorpion Sting Scorpions are yellowish, Scorpions are yellowish,

brown or black in brown or black in colour. colour.

They live in desert, hide They live in desert, hide at day time under rocks at day time under rocks and stones and emerge and stones and emerge at night for hunting. at night for hunting.

Scorpions are blind but Scorpions are blind but possess sensitive possess sensitive thermoreceptors.thermoreceptors.

Accidents predominate Accidents predominate in summer, rare in in summer, rare in winter when scorpions winter when scorpions are hibernating.are hibernating.

PathogenesisPathogenesis1.1. Excessive catecholamine Excessive catecholamine

releaserelease

2.2. Acetyl choline releaseAcetyl choline release

3.3. Release of kinins and serotoninRelease of kinins and serotonin

4.4. Direct central toxic effectDirect central toxic effect

5.5. Direct peripheral effectDirect peripheral effect MyocarditisMyocarditis NCPENCPE

Clinical PictureClinical Picture

A- Factors affecting severityA- Factors affecting severity1- Age1- Age

Serious manifestations are seen in infants (younger Serious manifestations are seen in infants (younger age),age),

2- Site of sting2- Site of sting Stings affecting central location (neck , back , face) are Stings affecting central location (neck , back , face) are

more dangerousmore dangerous

3- Number of stings3- Number of stings Victims receiving more than one sting usually show Victims receiving more than one sting usually show

more severe manifestationsmore severe manifestations

B- Onset of manifestationsB- Onset of manifestations RapidRapid Severe sting produces symptoms within half an hour.Severe sting produces symptoms within half an hour.

ManifestationsManifestationsI- GeneralI- General

AgitationAgitation Fever Fever SweatingSweating DehydrationDehydration Conjunctival congestionConjunctival congestion Peripheral cyanosisPeripheral cyanosis Cold extremities ( 2ry to peripheral vasospasm caused Cold extremities ( 2ry to peripheral vasospasm caused

by catecholamines)by catecholamines) Priapism.Priapism.

II- Local II- Local Severe local pain Severe local pain Tender regional lymph nodesTender regional lymph nodes NumbnessNumbness

III- NeurologicalIII- Neurological Confusion and agitationConfusion and agitation Tremors, fasciculations and rigorsTremors, fasciculations and rigors ConvulsionsConvulsions Hypertensive encephalopathyHypertensive encephalopathy Coma Coma Malignant hyperthermia (> 41 C)Malignant hyperthermia (> 41 C) Cranial nerve palsy:Cranial nerve palsy:

6th Nerve is usually affected 6th Nerve is usually affected ReversibleReversible Secondary to cerebral edemaSecondary to cerebral edema

IV- CardiovascularIV- Cardiovascular TachycardiaTachycardia Hypertension Hypertension Myocarditis Myocarditis Shock : usually follow severe myocarditisShock : usually follow severe myocarditis Cardiac ArrestCardiac Arrest

V- RespiratoryV- Respiratory TachypneaTachypnea Respiratory distress and respiratory failureRespiratory distress and respiratory failure Acute pulmonary edema:Acute pulmonary edema:

VI- GastrointestinalVI- Gastrointestinal Severe vomiting and diarrheaSevere vomiting and diarrhea Gastric distensionGastric distension Acute erosive gastritis , hematemesis and Acute erosive gastritis , hematemesis and

melenamelena

VII- MetabolicVII- Metabolic Metabolic acidosisMetabolic acidosis HyperkalemiaHyperkalemia Stress hyperglycemiaStress hyperglycemia

Manifestations of Grave Manifestations of Grave PrognosisPrognosis

1.1. Acute pulmonary edemaAcute pulmonary edema

2.2. Respiratory failureRespiratory failure

3.3. MyocarditisMyocarditis

4.4. Metabolic acidosisMetabolic acidosis

5.5. Malignant hyperthermiaMalignant hyperthermia

6.6. ConvulsionsConvulsions

ManagementManagement

A- First aid measures A- First aid measures B- At hospitalB- At hospital

I- Stabilization of the I- Stabilization of the patientpatient

II- AntidoteII- Antidote Best given in the first 4 h but can still be given as Best given in the first 4 h but can still be given as

late as 24 hourslate as 24 hoursIndicationsIndications

All children, and senile patientsAll children, and senile patients Adults presenting with any of the systemic Adults presenting with any of the systemic

manifestations manifestations Patients with previous cardiovascular disease, Patients with previous cardiovascular disease,

hypertension or diabeteshypertension or diabetesDoseDoseAdultAdult

3 - 5 amp slow IV or IM after negative skin 3 - 5 amp slow IV or IM after negative skin sensitivity test to be repeated every 30 minutes if sensitivity test to be repeated every 30 minutes if signs still progress or do not regresssigns still progress or do not regress

PediatricPediatric The same dose as adults (Dose is not related to The same dose as adults (Dose is not related to

body weight but to neutralizing power of the body weight but to neutralizing power of the circulating venom)circulating venom)

III- Supportive treatmentIII- Supportive treatmentPainPain

NSAIDsNSAIDs Local anesthesia.Local anesthesia.

CorticosteroidsCorticosteroidsIndicationsIndications

StridorStridor MyocarditisMyocarditis Non cardiogenic pulmonary edemaNon cardiogenic pulmonary edema Cranial palsy (cerebral edema)Cranial palsy (cerebral edema)

IV vasodilatorsIV vasodilators To control hypertensionTo control hypertension Careful monitoring of the patient to avoid Careful monitoring of the patient to avoid

hypotension or shock that may occur with hypotension or shock that may occur with catecholamine depletion or after myocarditis.catecholamine depletion or after myocarditis.

They include Na nitroprusside, hydralazine or They include Na nitroprusside, hydralazine or prazocinprazocin

Mechanical ventilationMechanical ventilationIndicationsIndications

Respiratory failureRespiratory failure Non cardiogenic pulmonary edema in Non cardiogenic pulmonary edema in

which PEEP mode is used.which PEEP mode is used.

Dehydration, hypotension and Dehydration, hypotension and shockshock IV fluidsIV fluids Dobutamine if cardiogenic shock 2ry to Dobutamine if cardiogenic shock 2ry to

myocarditis complicates the picturemyocarditis complicates the picture

Anticonvulsants e.g. diazepamAnticonvulsants e.g. diazepamMalignant hyperthermiaMalignant hyperthermia

Cooling measures and chlorpromazine Cooling measures and chlorpromazine

Spider StingSpider StingThe most important is theThe most important is the

black widow spiderblack widow spider of of mediterranean distributionmediterranean distribution. .

ManifestationsManifestations Local painLocal pain Profuse sweatingProfuse sweating Severe myalgiaSevere myalgia Weakness and Weakness and

rhabdomyolysis.rhabdomyolysis. Excess catecholamine release Excess catecholamine release

with hypertension, irritability, with hypertension, irritability, tachycardia and vomitingtachycardia and vomiting

TreatmentTreatment SupportiveSupportive