Animal Bites and Stings

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 Animal Bites and Stings: Wounds or punctures of the skin made by any animal or insect.
There are different causes of bites and stings caused by the following:

Animal bites

  • Human bites
  • Dog, foxes and cat bites
  •  Snake bites
  • Crocodile bites

Stings

  •  Bee
  • Scorpion
  • Spider
  • Centipede

Snake bites and stings result in injection of venoms. Type of venom depends on the
causative agent of the bite or sting.

Types of Toxins/Venom                                                                                                                             

 Cytotoxins

cause local tissue damage.

  • Haematotoxins cause internal bleeding.
  • Neurotoxins affect the nervous system.
  • Cardiotoxins act directly on the heart muscles.
  • Myotoxins act directly on skeletal muscles.

Bites                                                                                                                                                                  • Human bite

  • The wound is usually contaminated by mixed organisms.
  • Dogs, fox bites and cat bite
  • There is danger of transmission of bacterial infection and rabies.
  • One should suspect rabies from animal bites.
  • Snake bites
  • Extremities usually are the sites of the bite.
  • Venom is a mixture of enzymes and non-enzyme compounds.
  • Most snake bites are not poisonous.
  • Many bites from poisonous snakes do not result in poisoning (about 25%).
  • Bites by non-venomous snakes can cause infection and allergic reactions.
  • Bites by venomous snakes result in a wide range of effects, from simple puncture
    wounds to life-threatening illness and death.
  • The findings following a venomous snakebite can be misleading. A victim can have
    no initial significant symptoms, and then suddenly develop breathing difficulty and
    shock.

Also read

Signs and Symptoms of Snake Toxins/Venom                                                                                • Local effects

  • Pain and tenderness
  • Swelling
  • Blisters
  • Wounds
  • Numbness
  • Necrotic tissue around the site of the bite
  • Bleeding from bite site and internal organs (unchecked bleeding can cause shock or
    even death)

Nervous system effects

  • Cobra and black mamba snakes produce neurotoxic venom that can act particularly
    quickly by stopping the breathing muscles, resulting in death without treatment.
  • Initially, victims may have vision problems, speaking and breathing trouble, and
    numbness.

Muscle death

  • Venom from Russell’s Vipers, sea snakes, spitting cobras, and some Australian
    Elapids contain myotoxins that can directly cause muscle death in multiple areas of
    the body.
  • The debris from dead muscle cells can clog the kidneys, which try to filter out the
    proteins. This can lead to kidney failure.

Eyes

  • Spitting cobras and Ringhals (cobra like snakes from Africa) can actually eject their
    venom quite accurately into the eyes of their victims, resulting in direct eye pain and
    damage.

Heamorrhage

  • Boomslang snakes produce a heamotoxin that causes poor blood coagulation leading
    to bleeding in internal organs, under the skin and at the bite site.

Signs and Symptoms of Stings

  • Most of the signs and symptoms are caused by bees, scorpions, spiders and centipedes
    which may result in local effects, systemic effects, or both.

Local effects include:

  • Pain and tenderness
  • Swelling
  • Blister and erythematous rash
  • Wounds
  • Numbness
  • Ischaemic local lesion
  • Local necrosis
  • Systemic effects include:
  • Nervous system effects (transient fever, headache, vomiting, coma)
  • Cardiovascular system effects (anaphylactic reaction)
  • Respiratory system effects (pulmonary oedema, airway obstruction).

Management of Animal Bites and Stings                                                                               

Primary Survey Assessment

Remember ‘A-B-C’:

  • Airway: Ensure patent airway and beware of excess secretions
  • Breathing: Look out for dyspnea (difficulty breathing)
  • Circulation: Look out for bleeding and hypotension

Reassure patient to reduce anxiety

  • Patient should not walk to avoid spread of venom
  • No tourniquet or constriction bands.

Secondary Assessment

  •  Look for systemic signs
  • Assess affected limb and site of bite
  • General treatment
  • Reassure patient
  • IV line/fluids
  • Antibiotics
  • Tetanus Toxoid prophylaxis
  • Analgesic

Specific Treatment

Neurotoxicity – may require oxygen and ventilation

  • Neostigmine and atropine may prevent the use of ventilation

Systemic poisoning – antivenom (beware of anaphylaxis)

  • Give prophylactic antihistamine and steroids before antivenom
  • Adrenaline is helpful for severe cases of anaphylaxis

Titrate dose according to clinical response
Extreme swelling – may need fasciotomy
Monitor vital signs.
Mammalian, dog and fox bite

  • Elevate extremity with sling if edema is present
  • Examine the wound for possible nerve or tendon damage, or bone injury
  •  Clean the wound with water and antiseptics solution and remove any damaged tissue
  • Perform surgical debridement and wound should be left open
  • Prescribe an antibiotic and Tetanus toxoid
  • Give human rabies immunoglobulin
  • Give rabies vaccine on days 0, 3, 7, 21, and 28

Snakebite treatment

  •  Treat the breathing problems and shock
  • Wash the wound with large amounts of soap and water. Inspect the wound for foreign
    bodies (e.g. broken teeth or dirt)
  • Even a bite from a non venomous snake requires excellent wound care
  • The victim needs a tetanus booster if he or she has not had one within five years
  • The victim is monitored for worsening signs at the wound site, or worsening systemic
    symptoms in the breathing or cardiovascular systems
  • Do not cut and suck. Cutting into the bite site can damage underlying organs, increase
    the risk of infection and bleeding, and does not result in venom removal
  • Do not use ice. Ice does not deactivate the venom
  • Do not use alcohol. Alcohol may deaden the pain, but it also makes the local blood
    vessels bigger, which can increase venom absorption
  • Do not use tourniquets or constriction bands. These have not been proven effective
    and may cause increased tissue damage

The specific treatment of snake bite

  • Give by very slow intravenous (IV) injection 20 – 30 mls of snake polyvalent antisera
    diluted in 3 volumes of normal saline: 100 -150 mls may be given in severe
    invenomination with symptoms of neurotoxicity and heamotoxicity. This therapy can
    be life-saving.
  • Antivenom can cause allergic reactions, even anaphylactic shock, a life-threatening
    type of shock requiring immediate medical treatment with hydrocortisone 200- 500
    mg IV, or Adrenaline 1:1000 subcutaneous (S.C.) or IV 1-2 mg stat.

Stings treatment

  • Treatment will depend on the severity of the condition. It is important to note that no
    specific antivenom is available to counteract the poison injected by the insect.
  • Allergic reaction to the sting causes the majority of problems requiring medical
    treatment.
  • In case of a single sting with no allergic symptoms, remove any stings remaining in
    the skin (most likely from bees).
  • Application of ice to the sting site may provide some mild pain relief.
  • Give an antihistamine such as diphenhydramine (Benadryl) for itching.
  • Give non-steroid antinflamatory for pain relief as needed.
  • Wash the sting site with soap and water.
  • In severe allergic reaction (such as low blood pressure, swelling blocking air getting
    into the lungs, and/or other serious breathing problems), treatment may include
    intubation, antihistamines, steroids, epinephrine and IV fluids.

 

 

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