Bites

Dog bites

  • Dog bites are responsible for 80% of bite wounds
  • Its bacteriology are usually mixed
    • Alpha haemolytic streptococci, pasteurella species, staphylococci, Eikenella chorrodeus, actinomyces, fusobacterium, prevotella, pophyomonas species, Capnocytophaga canimorsus
  • 15-20% of wounds become infected
  • Lower limbs are most commonly affected
  • Infections occur 8 – 24 hours after bite and may manifest as:
    • Pain
    • Fever
    • Lymphadenopathy
    • Cellulitis

If the canine tooth penetrates synovium or bone, there could be:

  • Septic arthritis
  • Osteomyelitis

Cat bites

  • These are less common
  • More than 50% result in infection
  • The hands and arms are more commonly
  • Females are more affected than males
  • Usual organisms include P. mutocida and those ones following dog bites

Bites from Rats, mice, gerbils & animals that prey on them

  • Bites from these animals may transmit Streptobacillus moniliformis or Spirillus minor
  • They usually affect hunters or laboratory handle of rats
  • Manifests as:
    • Fever
    • Chills
    • Myalgias
    • Headaches
    • Severe migratory arthralgia
    • A maculopapular rash involving the palms and soles

Human bites

These may be:

  • Self-inflicted
  • Sustained by medical personnel caring for patients
  • Sustained during fights, rapes or during sexual activity
  • May become infected more than bites from other animals
  • The oral microflora include multiple species of aerobic and anaerobic bacteria
  • Those of hospitalized and debilitated patients often include
    • Enterobacteriacae
  • HIV, HBV have been reported due to human bites

Sharks and crocodiles

Bites from these animals cause death by:

  • Tissue destruction
  • Haemorrhage
  • Crush syndrome
  • Infection

Marine invertebrates

Marine invertebrates have specialized organelles called nematocysts for poisoning and capturing prey.
Their bites may cause serious ill health and death.

Initial assessment

  • Careful history
  • Contact local authorities to determine if the specie is rabid; if possible locate animal for observation
  • Antibiotic allergy, immunization of patient and other morbid condition(s) should be documented
  • Inspect wound for evidence of infection.
  • Conduct general physical examination, including vital signs

Investigations

Depend on the type of injury, the clinical
presentation and the onset/type of complications:

  • Full Blood Count
  • Electrolytes and Urea
  • Blood clotting profile
  • Arterial blood gas estimations
  • Chest radiographs
  • Wound and blood cultures

Treatment objectives

  • Neutralize envenomation
  • Local wound care
  • Limit systemic effects
  • Prevent onset of complications
  • Prevent specific infections such as rabies in high risk cases

Non-drug measures

  • Limb splinting (and rest the limb)
  • Use of venom detection kit (if available)
  • Application of pressure bandage
  • Control/care of the airway
  • Incision is discouraged; the mouth should not be used to suction
  • Wound debridement and fasciotomy for compartment syndrome may become necessary

Drug treatment

  • Administration of high flow oxygen
  • Intravenous fluid administration to
    maintain circulation: use colloids or
    cystalloids as clinically appropriate
  • Treatment of anaphylaxis with
    antihistamines (H blockers), epinephrine (adrenaline) and corticosteroids
  • Analgesia
  • Prophylactic antibiotics as appropriate
  • Tetanus prophylaxis
  • For animal bites in which rabies is
    considered a significant risk, it is imperative that anti-rabies prophylaxis be instituted
  • If the patient is not previously vaccinated, local wound cleansing should be done, rabies immune globulin administered and the vaccine given

Antirabies prophylaxis

Rabies immune globulin

  • Adult and child: 20 units/kg body weight by infiltration in and around the cleansed wound; if whole volume not exhausted, give
    remainder by intramuscular injection into anterior-lateral thigh (distant from vaccine site)
  • Half of the dose is infiltrated around the wound and the rest given intramuscularly into the gluteal muscles

Human Diploid Cell Vaccine (HDCV) or  Rabies Vaccine Adsorbed (RVA)

  • 1 mL is given into the deltoid on days 0,3,7, 14, and 28
  • Should not be administered in the gluteal area
  • If the patient has previously been vaccinated, clean the wound and give the vaccine given on days 0 and 3 only
  • Adrenaline (epinephrine), hydrocortisone must be immediately on hand for the treatment of  anaphylaxis if it occurs

 Prevention

  • Appropriate clothing and footwear while
    outdoors
  • Attention and care to observe
    general safety measures.