nasty big pointy teeth…

Considerations & concerns in patients with bite injuries include;

• Identification of injuries inflicted by the bite ?
• Prevention & treatment of local bacterial infection.
• Prevention, recognition & treatment of systemic illnesses.

Dogs are capable of exerting ~200 pounds per square inch into their bite !!

• Skin & soft tissue injuries are typically extensive, but may range from contusion & haematoma to large gaping lacerations with tissue loss. Punctures occur less often.
• Nerve & tendon injuries are rare but can occur (more common in bites from police dogs).
• Associated crush injuries can result in fractures.

Only ~5-10% of dog bites become infected.

• Bites to the hand however have a higher risk of infection (~12-30%)
• Dog bites are polymicrobial and include;
  • Strep & staph species
  • Pasteurella
  • Anaerobes
  • Capnocytophaga canimorsus. 

Specifically for our patient…

• The wound already appears inflamed/infected.
• This is a delayed presentation.
  • What first aid was there?
  • Irrigation will be difficult and potentially futile (auto wound closure).
• Are there child safety issues here ?

•  Primary survey – assessing for the presence of life-threatening injury.
  • Especially in young children or mauling by large (or several) animals.
  • Includes control of bleeding.
• Meticulous examination.
  • Determination of extent of underlying injury.
  • Is there evidence of neurovascular compromise?
  • Is there involvement of joint space or tendon?
  • Arrange x-rays if concern for fractures.
• Cleansing, decontamination & debridement.
  • Aggressive irrigation.
  • Debridement of devitalised tissue.
• Analgesia.
• Tetanus prophylaxis.

If a patient & their injury match the following, there is a < 5% risk of post-repair infection.

• Location: face or scalp
• Injury within 6 hours
• Simple laceration appropriate for single-layer  closure. (ie. no devitalised tissue)
• No underlying injury (eg. tendon or fracture)
• No immunosuppression (diabetes, AIDS, chemotherapy).

• Those with established infection.
• Any injury undergoing surgical repair.
• Delayed presentation (>6-8 hours).
• All cat bites.
• Deep dog bite punctures.
• Hand wounds.
• Wounds with underlying structures involved.
• All bites in the immunocompromised host.

• Low risk oral therapy:
  • Amoxycillin + clavulanate for 5 days.
• High risk therapy:
  • Piperacillin + tazobactam (OR)
  • Ticarcillin + clavulanate   (OR)
  • Metronidazole + Ceftriaxone / Cefotaxime.

I acknowledge that antibiotic therapy will vary from country to country & between local facilities.
This is our recommended guideline.

So if we apply the above risk-stratification to our little patient. She is a delayed-presentation bite to the hand and this is what happened when she tried to ‘make a fist’ …

Her x-ray excluded fractures.

With concern for deeper tissue involvement she was started on cefotaxime & metronidazole. The following morning she underwent a debridement & washout in the operating theatre.

httpv://youtu.be/H_Mgx8Ytjag

1. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.
2. Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition.
3. Therapeutic Guidelines. “Skin and soft tissue infections: bites and clenched fist injuries.”