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.