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.
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.