Introduction

Patients regularly present to the emergency department with animal bites. This article aims to help guide you through managing these patients and what factors you might want to consider.

Epidemiology

The number of animal bites presented to A&E is largely underestimated, as many who are bit don’t present to receive medical care¹ or won’t receive treatment in a hospital setting so they are not counted in the statistics for bites². Nevertheless, approximately 1-2% of attendances per year to A&E are from bites³.

The majority of bites presenting to A&E are from dogs⁴, with children being mainly affected⁵. Cats are the next most likely culprit⁶, with their bites leading to more hospital admissions due to the risk of infection being double that of a dog’s⁵; this is due to dogs’ teeth being larger which causes more of a crush injury with soft tissue damage, whereas cats’ teeth are sharper with a point, causing a puncture wound that inoculates bacteria much deeper³.

Humans are questionably the smartest animal whose bites you might see in A&E, with these bites tending to be either clenched fist bite injuries known as ‘fight bites’ which are more common in males, or occlusive bite injuries which are more common in females¹.

Assessment of a bite

History of presenting complaint

A detailed history of the event is key in deciding which treatment option is appropriate and includes:

• Time and mechanism of event.
• Where?
  • Which country the bite happened is used to determine the risk of rabies as per government guidance, which indicates if rabies coverage is potentially needed⁷.
• Anatomical location of all injuries sustained (including minor ones)
• Animal involved
  • Wild vs domesticated.
  • Is the vaccination history of the animal known?
  • Dogs: information regarding breed is important, as the size of the dog correlates with the size of the laceration and can be a good indicator of the severity of injury⁸.
• Details of any first aid performed prior to the hospital visit
  • This includes wound irrigation and management of considerable bleeding.

Systemic symptoms

• Assess the clinical status of the patient
  • Any fevers, rigours, nausea or vomiting.

Past medical history

• Vaccination status of the patient, specifically, tetanus
  • Puncture injuries are tetanus-prone wounds¹⁰.
  • Assess Hepatitis B cover in case of human bites.
• Comorbidities
  • Diabetes and immunosuppression increase infection risk and severity¹¹.
• Allergies.
• Regular medications.

Social history

• For hand bites: Hand dominance, profession, & hobbies
  • If the patient needs surgery (for example in fractures), this could influence which operation is performed in cases where restoration of hand function is paramount e.g. in musicians⁹

Examination

It is important to document both positive and negative findings in the examination as there may be future litigations with injuries of this type⁶.

Always consider an ATLS approach to the assessment.

Look:

• Expose the wound to view the extent of the injury
  • Note: local anaesthetic might need to be used for analgesic relief to properly assess the wound, however always assess neurological status before administering local anaesthetic as it may otherwise confound findings if assessed afterwards.
• Visualise the wound base
  • Irrigation with either with warm running water or normal saline may aid this^6.

Feel:

• Palpate the area of the bite to feel for areas of tenderness as this could indicate a fracture or infection.
• Assess neurovascular status distal to the bite.
• Assess the temperature of the skin surrounding the bite and compare it to the contralateral side which can indicate presence of vascular injury and infection.
• Feel for any swelling/collection/abscess.

Move:

• Assess the range of motion of the surrounding joints to help determine the involvement of adjacent structures.
• Assess active and passive movement of the joint.

Document clearly:

• The location of all wounds
  • Medical photography or drawn labelled diagrams can aid in explaining the exact location.
• Classification of the wounds
  • Puncture, crush, laceration, amputation (partial/complete), abrasion.
• The size of the wounds
  • Length and depth.
• Involvement of any structures
  • Tendons, nerves, blood vessels, bone, and muscle.
• Neurovascular status distal to bite.
• Range of motion of adjacent joints.
• Obvious foreign bodies identifiable.
• Signs of cellulitis/infection.

Following the examination, cover the wound with an appropriate dressing, ensuring a non-adherent dressing is placed first.

Investigations

X-ray imaging should be performed in cases where the bite is sustained to the hands, in cases of deep wounds, or if the bite is in a location close to bony prominences to rule out any fractures or retained foreign bodies such as teeth. There should be a minimum of 2 views in the plain film, or 3 in the hands if there is a suspicion of a fracture.

If the patient needs to be admitted due to infection, severe soft tissue damage, fracture, or a bite from a high-risk animal, then the following investigations should be considered:

• Bloods
  • FBC, CRP, U&E, coagulation panel.
  • Viral screen: In the case of human bites, discuss the possible need to screen for Hepatitis B and C, and HIV.
• Microbiology
  • Swabs of the wound and any pus that is present are important as they help guide antibiotics rationale.

Management

The management is guided by the examination findings which are covered in the respective chapter, this section will delve into the importance of a number of those steps, as well as further long-term care.

Always consider management as per ATLS protocol and SEPSIS 6 if relevant.

Ensure the wound has been adequately washed out.

• This crucial step is done to reduce the risk of infection by reducing bacterial load, removing debris/contamination, and disrupting biofilm activity^12,13,14.
• This can be done by either warm running water or normal saline⁶.
• Note that local anaesthetic might be required if pain prevents the wound from being adequately irrigated.

Hand elevation (e.g. with a Bradford sling) can help in reducing swelling and facilitating drainage¹⁵.

Antibiotics should not be routinely offered in cat/dog bites that have not broken the skin or have not drawn blood unless the wound is deep⁶.

• High-risk areas where antibiotic prophylaxis should be given include:
  • Hands, feet, genitals, face, areas of poor circulation, or skin overlying bony prominences/cartilage/joints
• NICE guidelines at the time of writing this article recommend the following 1^st line antibiotic therapy:
  • In adults and children above 1 month of age: Co-amoxiclav for 3 days.
  • If allergic to Penicillin:
    • Adults and children above 12 years old: Doxycycline and Metronidazole for 3 days.
    • Children under 12 years old: Co-trimoxazole for 3 days.
  • Extension of all above-stated courses to 5 days in infected bite wounds.
• The patient will need to be admitted for IV antibiotics if they are systemically unwell or have a severe infection.
• Note, please follow your local antibiotic policy for animal bites for up-to-date management in your trust.

Provide Tetanus cover as needed, government guidance on the level of cover indicated is laid out in the guidelines for the management of suspected tetanus cases and the assessment and management of tetanus-prone wounds by the UK Health Security Agency. Cover is based on the immunisation status of the individual whether they had received all doses of the vaccine previously, or if they had received a booster dose within the last 10 years. Depending on the degree of current cover, either the vaccine, tetanus immunoglobulin, or both are indicated¹⁶.

Indications for surgery:

• Exploration and Identification of vital structures to ensure there is no damage, with washout of the wound.
• Repair of damaged structures.
• Debridement of devitalised and unhealthy tissue.
• Reduce bacterial load.

Follow-up is important in these patients.

• If the patient is being sent home, ensure they are safety-netted to return if symptoms do not improve within 24-48 hours of starting antibiotics.
• If the wound is infected, re-review at 24-48 hours to ensure adequate response to treatment.
• Additional follow-up, depending on the structures injured, may be required which is guided by the relevant specialities.

References

1. Kennedy, S. A., Stoll, L. E., & Lauder, A. S. (2015). Human and other mammalian bite injuries of the hand: evaluation and management. The Journal of the American Academy of Orthopaedic Surgeons, 23(1), 47–57. https://doi.org/10.5435/JAAOS-23-01-47
2. Jakeman, M., Oxley, J. A., Owczarczak-Garstecka, S. C., & Westgarth, C. (2020). Pet dog bites in children: management and prevention. BMJ paediatrics open, 4(1), e000726. https://doi.org/10.1136/bmjpo-2020-000726
3. Evgeniou, E., Markeson, D., Iyer, S., & Armstrong, A. (2013). The management of animal bites in the United Kingdom. Eplasty, 13, e27.
4. Tulloch, J.S.P., Owczarczak-Garstecka, S.C., Fleming, K.M. et al. English hospital episode data analysis (1998–2018) reveal that the rise in dog bite hospital admissions is driven by adult cases. Sci Rep 11, 1767 (2021). https://doi.org/10.1038/s41598-021-81527-7
5. Animal Bites WHO. 2024. [Retrieved from WHO: https://www.who.int/news-room/fact-sheets/detail/animal-bites]
6. How common are bites? NICE. 2024. [Retrieved from https://cks.nice.org.uk/topics/bites-human-animal/background-information/prevalence/]
7. Rabies Post-Exposure Prophylaxis Management. UK Health Security Agency. (2023). [Retrieved from https://www.gov.uk/government/publications/rabies-post-exposure-prophylaxis-management-guidelines/rabies-summary-of-risk-assessment-and-treatment]
8. Nygaard, M., & Dahlin, L. B. (2011). Dog bite injuries to the hand. Journal of plastic surgery and hand surgery, 45(2), 96–101. https://doi.org/10.3109/2000656X.2011.558735
9. Chu, D. Y., Eftekari, S. C., Nicksic, P. J., & Poore, S. O. (2023). Management of Common Conditions of the Musician: A Narrative Review for Plastic Surgeons. Journal of Plastic Surgery and Hand Surgery, 58, 89. https://doi.org/10.2340/jphs.v58.7314
10. Guidance on the management of suspected tetanus cases and the assessment and management of tetanus-prone wounds. UK Health Security Agency. 2024. Gov.uk. [Retrieved from https://www.gov.uk/government/publications/tetanus-advice-for-health-professionals/guidance-on-the-management-of-suspected-tetanus-cases-and-the-assessment-and-management-of-tetanus-prone-wounds]
11. Dryden, M., Baguneid, M., Eckmann, C., Corman, S., Stephens, J., Solem, C., Li, J., Charbonneau, C., Baillon-Plot, N., & Haider, S. (2015). Pathophysiology and burden of infection in patients with diabetes mellitus and peripheral vascular disease: focus on skin and soft-tissue infections. Clinical microbiology and infection: the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 21 Suppl 2, S27–S32. https://doi.org/10.1016/j.cmi.2015.03.024
12. Quinn, J. V., McDermott, D., Rossi, J., Stein, J., & Kramer, N. (2010). Randomized controlled trial of prophylactic antibiotics for dog bites with refined cost model. The western journal of emergency medicine, 11(5), 435–441.
13. Lewis, K., & Pay, J. L. (2023). Wound Irrigation. In StatPearls. StatPearls Publishing.
14. Rowley, Stephen & Clare, Simon. (2014). Wounds International. Wounds International. 5. 31.
15. Malahias, M., Jordan, D., Hughes, O., Khan, W. S., & Hindocha, S. (2014). Suppl 1: Bite Injuries to the Hand: Microbiology, Virology and Management. The Open Orthopaedics Journal, 8, 157-161. https://doi.org/10.2174/1874325001408010157
16. UK Health Security Agency. (2024). Guidance on the management of suspected tetanus cases and the assessment and management of tetanus-prone wounds. Retrieved from https://www.gov.uk/government/publications/tetanus-advice-for-health-professionals/guidance-on-the-management-of-suspected-tetanus-cases-and-the-assessment-and-management-of-tetanus-prone-wounds

Written by Shayan Nadjarpour, FY2 & reviewed by Mr Jonathan Van (Plastics Registrar)