A 2 year old infant is bought to your ED with a painful right hand. She claims to be have been bitten by the family dog 2 days earlier…
She is afebrile & systemically well. Her digits are neurovascular intact.
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
- 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.
- 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.
- Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.
- Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition.
- Therapeutic Guidelines. “Skin and soft tissue infections: bites and clenched fist injuries.”