Derm

Animal Bite

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Animal Bite, Mammalian Bite

  • Indications
  • Epidemiology
  1. Dog Bites account for 80-90% of Animal Bites in U.S.
  2. Cat Bites account for 5-10% of Animal Bites in U.S.
  • Risk Factors
  • Bite site infection
  1. Vascular compromise in affected wound
    1. Peripheral Arterial Disease
    2. Venous Insufficiency
    3. Lymphedema
    4. Longstanding Tobacco Abuse
  2. Distal extremity wounds have diminished vascular supply (Hand bite, Foot Bite)
  3. Bite site near a prosthetic joint
  4. Crush injury or Puncture Wound
  5. Cat Bite (long slender fangs risk deep space infection)
  6. Delayed presentation
    1. Arm or leg bite site >6-12 hours
    2. Facial bite site >12-24 hours
  7. Diabetes Mellitus or other immunosuppressed state
  • Exam
  1. See Hand Exam
  2. Neurovascular injury
    1. Extremity pulses and Capillary Refill
    2. Motor and senory exam
    3. Compartment Syndrome
  3. Structural injury
    1. Tendon Injury
    2. Open Fracture
    3. Joint penetration
  4. Retained Foreign Body
  • Imaging
  1. XRay affected bite site
    1. Evaluate for Retained Foreign Body (esp. Avulsed Teeth)
  2. Head Imaging (e.g. Head CT)
    1. May be indicated in severe bites to the head
    2. Penetrating skull bites can generate enough force for Skull Fracture (risk of CNS Infection, abscess)
  • Management
  • General
  1. Control bleeding first
  2. Inject 1% Lidocaine through intact skin
  3. Copious wound irrigation with Normal Saline
    1. Set up 500 ml saline bag with 20 gauge angiocatheter (or 20 ml or larger syringe)
    2. Place bag into BP cuff and pump up to 300 mmHg
    3. Irrigate wound with 500 cc of Normal Saline
      1. Consider irrigation with dilute povidone-Iodine solution if the animal is suspected to be rabid
  4. Wound closure
    1. Indications for closure by Secondary Intention
      1. Cat Bite
      2. Human Bite
      3. Puncture Wounds
      4. Infected wounds
      5. Wounds older than 24 hours
      6. Crush wounds with structural injury (urgent Consultation)
      7. Distal extremity wounds with poor perfusion
    2. Indications for Sutured closure
      1. Wound less than 12 hours old
      2. Wounds located on face less than 24 hours old
  5. Wounds near joint or bone
    1. Obtain baseline XRay of puncture
    2. Obtain Orthopedic Consultation
  6. Wound exploration
    1. Explore wound for tendon, joint or bone injury
    2. Explore wound for foreign bodies (e.g. teeth fragments, which may break off in older animals)
      1. XRay wound if suspected Radiopaque Foreign Body
  7. Referral Indications
    1. Wounds near bone or joint
    2. Crush wounds with structural injury
    3. Infected wounds
    4. Wounds with significant edema
    5. Neurovascular compromise (emergent Consultation)
  8. Immunization
    1. Tetanus Vaccine
    2. Rabies Prophylaxis
      1. See Rabies Postexposure Prophylaxis for full list of indications
      2. Indicated if dog or cat with Unknown Vaccination status
        1. Unprovoked attack
        2. Animal cannot be quarantined for 10 days
          1. Do not euthanize animal prior to completion of 10 day observation
      3. Immediate wound management (see Rabies Prophylaxis)
      4. Start Vaccine within 48 hours
  9. Antibiotic
    1. See Dog Bite Infection
  • References
  1. Cowling and House (2017) Crit Dec Emerg Med 31(5): 15-20
  2. Ellis (2014) Am Fam Physician 90(4):239-43 [PubMed]