INSECT BITES , STINGS AND SNAKE BITES

(ENVENOMATION)

• ENVENOMATION • VENOM• LOCAL EFFECTS OF VENOM include pain,

swelling, erythema, bleeding, bruising, blistering, and local tissue necrosis.

• SYSTEMIC EFFECTS LIKENEUROTOXICITY- flaccid paralysis

• Neurotoxic paralysis• ‘Sleepy’ or drooping eyelids• Difficulty swallowing, dysarthria and drooling• Limb weakness and paralysis• Respiratory distress and failure

ptosis

• For neurotoxic snakes, the cranial nerves are usually involved first, with ptosis a common initial sign

• Excitatory neurotoxicity (autonomic storm)• Sweating, salivation• Tingling around mouth, tongue or• muscle twitching• Dyspnoea (pulmonary oedema)

MYOTOXICITY muscle pain and tenderness.CARDIOTOXICITY- affects myocardial contractility COAGULOPATHYRENAL DAMAGE• NON SPECIFIC SYSTEMIC EFFECTS are– Headache– Nausea, vomiting, diarrhea– Abd. Pain– Bradycardia or tachycardia– Dizziness, collapse or convulsions– Shock or cardiac arrest

MANAGEMENT FIRST AID• Immobilization• Pressure bandage• Reassurance• Cardiorespiratory support- to support vital systems

DIAGNOSIS• History• Examination• Laboratory findings -full blood count, coagulation profile, urea and

electrolytes, creatinine, CK and ECG. • Lung function tests, pulse-oximetry or arterial blood gases

TREATMENT ANTIVENOM SUPPORTIVE TREATMENT OF ORGAN

DYSFUNCTION ANTIBIOTICS TETANUS PROPHYLAXIS ANALGESICS

SPIDER BITES

• VENOM – causes local necrosis of skin and tissues with some systemic toxicity.

• Most spider bites are painful but harmless. except fiddle spiders or widow spiders can be life threatening.

• Recluse spiders- severe tissue necrosis• Widow spiders- neurotoxic

CLINICAL FEATURES

• most bites produce sharp pin prick pain at the site of bite, with erythema and edema.

• The site becomes painful and pruritic with central induration

• The lesion resolves in few days• In severe cases the erythema spreads, centre of

lesion becomes hemorrhagic and necrotic with an overlying bulla.

• Later there is sloughing of the necrotic tissue with ulcer formation and a depressed scar.

• Severe tissue necrosis with systemic hemolysis is seen with recluse spider bites.

• Abdominal muscles rigidity with muscle cramps in trunk and extremeties is seen with widow spider bites

• Other s/s N, V, increased salivation, myalgia, tachycardia, fever, chills,weakness

• Rarely can cause cardiorespiratory arrest, renal failure , or cerebral h’ge and death

TREATMENT

• R - rest• I – ice• C - compression• E – elevation• Analgesics and antihistaminics• Tetanus prophylaxis• antibiotics

SCORPION STINGS• VENOM- local effect - neurotoxic effect• Bark scorpion produces venom that can be lethal in humans

Clinical features• Sharp burning pain and discoloration at the site with little

swelling• Paresthesia- sensation of burning, pricking , itching or

tingling• Hyperesthesia (tap test)

• Cranial nerves dysfunction• Hyper-excitability of skeletal muscles, muscle twitching and

jerky movements• Restlessness• Blurred vision, abnormal eye movements, drowsiness• Increased salivation, lacrimation, rhinorrhea• Slurred speech

• C/C – HT, cardiac arrhythmias, hyperthermia, fatal respiratory arrest

TREATMENT• Aggressive supportive care• Ice packs• Pressure dressings• Analgesics• Antihistaminics• IV midazolam infusion to control agitation and

involuntary ms movements• antivenom

BEES AND WASPS STINGS

• Venom has direct toxic effects• Clinical features include immediate sharp pain, wheal

and flare reaction with local edema.• Multiple stings can lead to vomiting, diarrhea,

laryngeal edema, dyspnea, hypotension and collapse.• Sometimes severe anaphylaxis is seen, characterized

by nausea, abdominal cramps, generalized urticaria, flushing, with upper airway edema, bronchospasm, hypotension and shock leading to death

TREATMENT

• Honeybee stinger should be removed from the skin• Site cleansed and disinfected• Ice pack• Elevation• Analgesics, antihistaminics• topical calamine lotion• Patients with multiple bee stings should be monitored for

evidence of renal failure or coagulopathy• Anaphylaxis – Iv adrenalin 0.5ml in 1:1000 dilution, with

bronchodilators, O2, and intubation.

SNAKE BITES

• Viperids – viper, pit vipers, russell’s viper• Elapids – cobras, kraits, coral snakes

• VENOM• Viperids venom – bleeding and clotting

disturbances• Elapids – neurotoxic venom

Snake venom

• Hemorrhagins –affects coagulation pathway - vascular leakage and bleeding

• Proteolytic enzymes – local tissue necrosis• Cardiotoxic• Neurotoxic

Signs and symptoms• Pain, progressive local swelling, ecchymosis and

hemorrhagic bullae

Severe tissue necrosis

Systemic findings• Hypotension • Bradycardia or tachycardia• Pulmonary edema • Hemorrhage• Rhabdomyolysis• Renal dysfunctionNeurologic symptoms• Cranial N weakness leading to ptosis, mouth numbness• Severe envenomation can lead to muscle paralysis,

respiratory paralysis and death

Evaluation of the envenomed patient• Taking a proper history• Local effects and bite marks• Symptoms and signs• Investigations - CBC, ECG, RFT, LFT,

Coagulation studies, ABG, Urine for Blood• Assessment of type and extent of

envenoming.

MANAGEMENT OF SNAKE BITE1. First Aid – Immobilization of the bitten limb and elevation.2. Pressure Bandage3. Cardio Respiratory Support (ABC)4. Endotracheal intubation and ventilatory support5. Maintaining Vitals6. Watch for cardiac rhythm, O2 saturation and urine output7. IV Line8. Vasopressors9. Determine the severity of envenomation10. antivenom11. Measure the circumference of the bitten limb every 15 min until

the swelling stabilizes12. Tetanus prophylaxis and antibiotics.

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