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Bamboo Snake Bite with Defibrination

Bamboo Snake Bite with Defibrination. By Dr. Wong Oi Fung. Case History. 5/F Attended A&E of TMH at 22:13 on 7/9/2004 Bamboo snake bite over dorsum of right foot at 21:45 on 7/9/2004 Vital signs: pulse 110/min; afebrile; GCS 15/15 Cat. 3

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Bamboo Snake Bite with Defibrination

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  1. Bamboo Snake Bite with Defibrination By Dr. Wong Oi Fung

  2. Case History • 5/F • Attended A&E of TMH at 22:13 on 7/9/2004 • Bamboo snake bite over dorsum of right foot at 21:45 on 7/9/2004 • Vital signs: pulse 110/min; afebrile; GCS 15/15 • Cat. 3 • Disposal: admitted into pediatric ward for further management

  3. Progress • Initial assessment: • Alert and conscious • 2 small fang marks over dorsum of right foot • No obvious swelling over other parts of lower limb • Circulation and pulse--->normal • Other systems--->normal

  4. Progress…….. • Initial investigation: • CBP, L/RFT--> normal • INR--> 1.1 • Fibrinogen-->low • D-dimer-->high • Cardiac enzyme--> normal • ECG-->no arrhythmia

  5. Progress…….. • Treatment: • Antivenom • One dose given ( in view of rapid progression of local reaction) • Tetanus booster • Antibiotics (Cloxacillin, Claforan, Flaygl)

  6. Progress…….. • Outcome of initial treatment • Significant swelling over right lower limb from toe to thigh noticed • ??Pulses of dorsalis pedis and popliteal artery were negative • Capillary refill ~ 1 sec • Orthopedic surgeon consulted and suggested for conservative treatment

  7. Progress…….. • Further Investigation • USG of right lower limb done: • femoral and popliteal veins patent • no intraluminal filling defect • no fluid collection

  8. Progress……... • Transferred to PICU for close monitoring (11to 16/9/2004) • Developed prolonged INR >4.5 • Given repeated doses of antivenom and FFP • First 2 doses from Shanghai institute; last dose from Thai Red Cross • INR return to 1.2 on 14/9/2004 • Discharged on 18/9/2004 • Defaulted WFU on 24/9/2004

  9. Progress of blood result and Therapy given

  10. Discussion

  11. Discussion • Why the patient developed prolonged defibrination?? • ?? Highly potent venom of the snake • ?? High venom load per body mass ratio • ?? Administration of coagulation factors for the unneutralized venom produced more degradation products, which are also anticoagulant • ?? Antivenom from Shanghai institute was not potent enough

  12. Discussion • General information for snake bite: • ~3000 species of snake found worldwide • ~15 % considered to be dangerous to humans • 14 common venomous species in Hong Kong • White-lipped pit viper/ bamboo snake is the commonest species involved ~95% • Often occurs in summer and autumn

  13. White-lipped pit viper snake(Trimeresurus albolabris) • General information: • vipers are venomous snake • generally short with thick body • 2 subfamilies : • typical vipers ( Viperinae) e.g. Russell’s viper • pit vipers ( Crotalinae) e.g White-lipped pit viper

  14. Descriptions of Bamboo Snake • Length-->15 to 25 inches; max. 36 inches • Female >male • First upper lip shield fused with nasal shield • White lateral line in males only • Upper lip is pale green, yellow or white • Body is green • Iris are yellows • Tail is dark red

  15. Clinical Features for bamboo snake envenomation • Degree of illness : • >20% are dry bite • Amount of venom injected • Size of snake • Mechanical efficiency in which the bite occurred ( e.g. both fangs penetrated the skin, repeated strikes) • **repeated bites do NOT result in a depletion of venom stores.** • Primary effect--->coagulopathy, thrombocytopenia, hypotension and local swelling

  16. Venom properties • Chemically complex mixtures of proteins ranging from 6 to 100KD • Highly stable, resistant to temperature changes, drying and drugs • 80 to 90 % of viper venom and 25 to 70% of elapid venom consists of enzymes e.g. phospholipase A. • damages mitochondria, red blood cells, leucocytes, platelets, peripheral nerve endings, muscle, vascular endothelium, produces presynaptic neurotoxic activity, opiate-like sedative effect, autopharmacological release of histamine

  17. Viper venoms • Causes haemostatic defects by • Venom procoagulant enzymes activate the blood clotting cascade at various sites • Thrombin-like fibrinogenases remove fibrinopeptides from fibrinogen directly • Activate endogenous plasminogen • Inhibit platelet aggregation • Combination of consumptive coagulopathy, defibrination, thrombocytopenia, vessel damage result in massively incontinent bleeding

  18. Clinical Features for bamboo snake envenomation • Local effect: • Immediate severe pain, erythema and swelling • Tissue necrosis due to proteolytic enzymes and phospholipases A • more likely to develop in fingers and toes due to poor systemic absorption • Blistering eruption • presence of blister more likely to lead to necrosis or secondary infection • Local infection of wound

  19. Clinical Feature for bamboo snake envenomation • Systemic effect: • Haematological: • Disseminated intravascular coagulation DIC due to the disorder of platelet aggregation and coagulation-fibrinolysis system • Increased fibrin degradation product (FDP), increased APTT and PT, thrombocytopenia • Systemic bleeding or local bleeding

  20. Clinical Feature for bamboo snake envenomation • Musculoskeletal: • Rhabdomyolysis ( Russell’s Viper ) • Compartment syndrome (rare after viper bite) • Cadiovascular: • Hypotension • Arrhythmia due to myocardial toxicity • Respiratory: • Not characteristic of viper envenomation • May occurred after Russell’s viper bite

  21. Clinical Feature for bamboo snake envenomation • Neurological: • Cerebral hemorrhage • Endocrine: • Sheehan’s syndrome (anterior pituitary gland haemorrhage) in Russell’s viper bite • GI: • Nausea, vomiting and abdominal pain • Renal: • Acute renal failure; hyperkalaemia • Other: e.g. anaphylaxis

  22. Management in AED • Physical Examination: • Local signs: • fang marks, swelling, ecchymosis, blister, bleeding, skin necrosis, sign of compartment syndrome, regional lymphadenopathy • Systemic signs: • severe coagulopathy e.g. gum bleeding, epistaxis, haematuria, GIB • hypotension • paralysis

  23. Management in AED • Investigation: • Blood testes: CBP, L/RFT, Clotting profile, muscle enzyme, Cross-match • Urinalysis for haemoglobin/myoglobin • ECG +/- CXR • +/-FVC if available

  24. Management in AED • Release bandage for examination • Ideally pressure dressing should NOT be removed until: • patient is at a medical facility • resuscitation equipment is at bedside • antivenom therapy has begun if systemic envenomation present • Analgesic • Aspirin and NSAID is CONTRAINDICATED • Wound management • Tetanus prophylaxis, antibiotic +/- debridment

  25. Management in AED • Close monitoring: • Any patient who has been bitten by a proven or suspected venomous viper should be admitted into hospital or stay in observation ward for close monitoring for at least 12 hours • Repeat the measurements of extent of swelling and ecchymosis • Close monitor distal circulation • Repeat CBP, RFT and clotting profile every 6 hours( avoid arterial puncture) • Urine output+/- cardiac monitoring

  26. Management……. • Administration of FFP, platelet count if indication • Renal replacement therapy • Ventilation support

  27. Assessment of Severity Envenomation for Viperidae

  28. Antivenom therapy • Indications: • Severe local envenomation • Systemic Toxicity • Coagulopathy • Rhabdomyolysis • Neurotoxicity • **Antivenom can reverse systemic envenomation even after several hours after bite but is NOT effective for local envenomation unless given within several hours after bite**

  29. Administration of Antivenom • From Thai Red Cross or Shanghai institute • Dilute before infusion • Slow rate • Preferably in ICU for close monitoring

  30. Response to antivenom • Often marked symptomatic improvement soon after administration • Spontaneous systemic bleeding usually stops within 15 to 30 min • Restoration of blood coagulability within 6 hours • Recurrence of systemic envenomation may be due to the continuing absorption of venom form the injection site • Half-life of antivenoms range from 26 to 95 hours

  31. References • Dr. WS Ng. COC guidelines for Management of snake bites (revised September 2000) • Gold, BarryS.; Dart, Richard C.; Barish, Robert A. Current Concepts: Bites of Venomous Snakes. The New England Journal of Medicine. Vol. 347(5), August 2002, 347 to 356 • Poisindex Management : Asian Snakes-Viperidae • Oxford Textbook of Medicine 4th edition Vol. 1 pp923 to 936

  32. Thank You

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