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Snake Bites

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Title: Snake Bites


1
Snake Bites
  • Ruma Rajbhandari and Beth Riviello
  • Rwinkwavu Hospital, Rwanda
  • November 10, 2008

2
Background
  • 125,000 deaths per year worldwide
  • Four families of snakes have venom that is toxic
    to humans
  • Atractaspididae
  • Colubridae
  • Elapidae
  • Viperidae
  • (Boidae no venom, but is lethal)

3
Background
  • Rwanda has snakes from all five families, 51
    types of snakes in total.
  • Good news only 13 of these snakes have
    potentially serious clinical syndromes
  • Bad news
  • Only 9 of these can be treated with antivenom
  • Only 6 are covered by the one antivenom that we
    hope to get at Rwinkwavu Hospital

4
Background
  • Puff adder (Viperidae) and African spitting
    cobras (Elapidae)--most death and morbidity in
    Africa
  • Nigerian study snake bite mortality 12.2
  • When a snake bites more than one human in rapid
    succession, the 2nd or 3rd victim may be more
    severely envenomed than the 1st
  • Complex venom gt20 components
  • Most Elapidae (mamba) deaths hours
  • Viper (puff adder) deaths days

5
Background Rwandas 51 snakes
6
Family Atractaspididae
  • Atractaspis irregularis (Variable Burrowing Asp)
  • Indirect cardiotoxins, local necrosis
  • No antivenom

7
Family Boidae
  • Python sebae (African rock python)
  • No venom, do constrict victims or even swallow!
  • No antivenom

8
Family Colubridae
  • Dispholidus typus (Boomslang)
  • Toxicodryas blandingii (Blanding's Tree Snake)
  • Postsynaptic neurotoxin, anticholinesterase
  • No antivenom
  • Coagulopathy and hemorrhaage
  • SAIMR Boomslang Antivenom

9
Family Elapidae
Boulengerina annulata Ngwa maamba No antivenom
Dendroaspis polylepis Black mamba
Dendroaspis jamesoni Green mamba
  • Flaccid paralysis and local necrosis
  • Our Antivenom works for 3 of 5

Naja nigricollis Black-necked spitting
cobra Ophthalmia Different antivenom
Naja melanoleuca Black cobra
10
Family Viperidae
Atheris nitschei Bush viper No antivenom
Bitis arietans Puff adder
Bitis gabonica Gaboon adder
Bitis nasicornis Rhinoceros viper Antivenom may
work
  • Coagulaopthy, shock, renal damage,
    cardiotoxicity, local necrosis,
  • neurotoxicity
  • Our antivenom for 3 of 4

11
Clinical effects
  • Possible serious syndromes from envenomation
  • Neurotoxicity
  • Systemic toxicity including hypotension and shock
  • Coagulopathy
  • Rhabdomyolysis
  • Renal failure
  • Local tissue necrosis including cobra spit

12
Neurotoxicity
  • Neurotoxins block transmission at the NM junction
  • Flaccid/Respiratory paralysis
  • Anticholinesterase drugs
  • Unphysiologic drowsiness

13
Hypotension/shock
  • Vasodilation
  • Direct action of venom on myocardium
  • Bleeding/hypovolemia
  • Vipers profound hypotension within minutes (ACE
    inhibitors)

14
Coagulopathy
  • Procoagulants and anticoagulants
  • Intravascular coagulation, consumption
    coagulopahty
  • Thrombocytopenia
  • Bleeding from old and recent wounds, gingiva,
    epistaxis, hematemesis, melena

15
Renal failure/rhabdomyolysis
  • ATN hypotension/hypovolemia, DIC, direct toxic
    effect on tubules, hemoglobinuria, myoglobinuria
  • Generalized rhabdo Release of myoglobin, muscle
    enzymes, uric acid, K (presynaptic neurotoxins)

16
Local necrosis
  • Increased vascular permeability
  • Swelling and brusing
  • Myotoxins and cytotoxins
  • Ischemia/ thrombosis
  • Venom ophthalmia

17
Snake Bite Protocol
18
Field Management
  • Remove victim from snake area
  • Place patient at rest and reassure
  • Cleanse wound
  • Immobilize the affected part of the body
  • Attempt to identify snake without endangering
    anyone
  • Transport patient to nearest medical facility
  • Do NOT use pressure immobilization unless mamba
    55mmHg
  • Do NOT do incision or suction or surgery. Can do
    worse damage

19
Treatment
  • Consider Antivenom immediately if
  • Elapidae Dendroaspis jamesoni - green mamba
  • Elapidae Dendroaspis polylepis - black mamba
  • Elapidae Naja melanoleuca - black cobra
  • Viperidae Bitis arietans - puff adder
  • Viperidae Bitis gabonica - Gaboon Viper
  • Viperidae Bitis nasicornis - Rhinoceros Viper OR
  • Severe symptoms
  • Supportive care for specific syndromes

20
Initial Hospital Management
  • Place patient at rest and reassure the patient
  • Immobilize affected part of body
  • Clean wound
  • Give tetanus toxoid
  • Try to identify type of snake website, list of
    snakes, picture book
  • If snake one of six covered by antivenom,
    consider antivenom
  • Have patient give urine

21
Clinical Assessment
  • Neurotoxicity Weakness? Flaccid paralysis?
    Ptosis? Dysarthria? Impaired swallow? Respiratory
    distress?
  • Shock hypotension? Tachycardia? Altered mental
    status?
  • Coagulopathy Bleeding? Epistasis? Petechiae?
    Bruising? Clotting?
  • Rhabdomyolysis Muscle pain? Weakness? Dark
    urine?
  • Renal failure Poor urine output? Edema?
  • Local tissue necrosis fang marks, pain,
    swelling, bleeding, lymphadenitis, black skin?
    Tense skin?
  • Non-specific systematic nausea, abdominal pain

22
Laboratory assessment
  • Neurotoxicity none
  • Shock none
  • Coagulopathy CBC, whole blood clotting test,
    INR, PTT, peripheral blood smear looking for
    schistocytes
  • Rhabdomyolysis urine dipstick, urine sediment
  • Renal failure creatinine
  • Local tissue necrosis none
  • Non-specific systematic none

23
Neurotoxicity
  • Consider Antivenom
  • Serial exams Weakness? Flaccid paralysis?
    Ptosis? Dysarthria? Impaired swallow? Respiratory
    distress?
  • Assisted ventilation if respiratory distress
  • Consider anticholinesterase neostigmine 50-100
    mcg/kg

24
Shock BPlt8/4 or pulsegt110
  • Consider antivenom
  • IV fluids Bolus iv fluids, Normal Saline or
    Ringer, to maintain blood pressure gt 10/6. Start
    with at least one liter.
  • Monitor urine output, goal gt 30cc/hr (foley
    catheter)
  • If actively bleeding, consider transfusion
  • Consider dopamine if blood pressure low with
    fluids

25
Coagulopathy
  • Consider antivenom. Increase dose if continued
    bleeding.
  • Transfuse whole blood only if life-threatening
    hemorrhage
  • Monitor for signs of bleeding, and labs CBC,
    whole blood clotting test, INR, PTT, peripheral
    blood smear looking for schistocytes

26
Rhabdomyolysis
  • Consider Antivenom
  • IV fluids Bolus with normal saline, 1-2 liters
    per hour. Urine output goal 200-300 cc/hr until
    urine clears
  • Monitor potassium. If gt5.5, treat hyperkalemia
    (lasix and/or kayexalate and/or insulin).
  • Monitor creatinine. If abnormal, see renal
    failure box.
  • Avoid medications that are toxic to the kidney

27
Renal failure
  • Consider Antivenom
  • IV bolus normal saline or Ringer, goal urine
    outputgt50cc/hr
  • Monitor potassium. If gt5.5, treat hyperkalemia
    (lasix and/or kayexalate and/or insulin).
  • Monitor creatinine
  • Avoid medications that are toxic to the kidney

28
Local tissue necrosis
  • Consider antivenom
  • Wound care keep site clean
  • Monitor for compartment syndrome (decreased
    pulse, severe pain or lack of sensation)
    consider fasciotomy
  • (cobras and vipers)
  • Special case cobra spit ophthalmia irrigate eye
    with copious water or saline. Apply antibiotic
    ointment

29
Nonspecific symptoms
  • Treat nausea metoclopramide, phenergan
  • Treat pain paracetamol, morphine. Avoid
    ibuprophen and diclofenac if bleeding.

30
Antivenom Protocol
31
Antivenom
Black cobra
Green mamba
Black mamba
Puff adder
Gaboon adder
Rhinoceros viper
32
Antivenom
  • Can cause severe allergic reactions
  • Give it if
  • can confirm that snake is covered by the
    antivenom OR
  • Patient is severely ill and is not responding to
    supportive care

33
Antivenom
  • Antivenom Code SAfSAI03
  • Antivenom Name SAIMR Polyvalent Antivenom
  • Manufacturer South African Vaccine Producers
    (Pty) Ltd
  • Tel 27-11-531-8600 , Fax27-11-531-8616
  • Email cillaf_at_savp.co.za
  • Homepage www.savp.co.za/default.htm

34
Antivenom
  • Prepare adrenaline 0.5 1 ml 0.1 sc
  • Give antivenom. See package for details.
  • Reassess whether need increased dose based on
  • Clinical assessment
  • Whole blood clotting test
  • Reasons for failure insufficient antivenom,
    wrong antivenom, inactive antivenom, delay in
    administration
  • Continue supportive care

35
Antivenom
  • Monitor for acute reactions
  • Hypotension
  • Urticaria
  • Wheeze
  • If present, give
  • hydrocortisone 100 mg iv
  • Adrenaline 0.3 ml sc if wheeze or hypotension

36
Snake Bite Protocol
37
Useful resources/Citations
  • Snake picture book Dr Corrados office
  • Pictures of snakeswww.afpmb.org
  • Database of snake distributions and clinical
    manifestions www.toxinology.com
  • List of antivenoms and suppliers
    http//toxinfo.org/antivenoms
  • Poison information center (from WHO)
    www.who.int/ipcs/poisons/centre/directory/en/
  • Cheng, Allen C. Principles of snake bite
    management worldwide UptoDate. June 2, 2008.

38
Murakoze!
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