- Epidemiology and Risk Factors:
- Dog bites are most common (85-90%), followed by cats (5-10%), humans (2-3%), and rodents (2-3%).
- Risk factors for dog bites include children under 5, male gender, households with male unsterilized dogs.
- Majority of dog bite victims are bitten by their own or a known dog; often unprovoked.
- Complications of Mammalian Bites:
- Tissue damage, infection, psychological distress.
- Dog bite wounds usually are crush injuries, lacerations, abrasions.
- Cat bites often cause puncture wounds, risking bone, joint, tendon penetration.
- Infectious Risk According to Species:
- Risk varies with animal species; most infected bite wounds are polymicrobial.
- Specific pathogens are characteristic of different animals, influencing antibiotic choice.
- following factors place wounds at a high risk of infection:
- puncture and crush wounds (particularly if inflicted by a cat)
- wounds that penetrate bone, joint, tendons, vascular structures or that overly a prosthetic joint
- wounds on the hands, feet, face or genitals
- wounds with a delayed presentation of greater than 8 hours, and
- patients who are immunocompromised or have oedema or lymphoedema.
- Management of Mammalian Bites:
- Includes wound cleaning, irrigation, exploration, debridement.
- Recognize high-risk wounds (e.g., puncture, crush wounds, sensitive areas like hands, face).
- Antibiotics recommended based on bite type and infection presence.
- Prophylactic antibiotics suggested for high-risk wounds.
- Patient Education and Review:
- Instructions on wound care, identifying infection signs.
- Prevention of Bites:
- Education on avoiding future bite injuries, ensuring up-to-date immunizations.
- Specific Considerations for Various Animal Bites:
- Dog Bites:
- Infection rate up to 18%, higher if the hand is involved.
- Polymicrobial infections, commonly involving Pasteurella species.
- Pasteurella can cause rapidly progressive skin and soft tissue infections.
- Capnocytophaga canimorsus may be present, especially dangerous for immunocompromised individuals.
- Methicillin-resistant Staphylococcus aureus (MRSA) emerging as a concern.
- Cat Bites:
- Infection rate between 28-80%, with Pasteurella multocida present in 75% of cases.
- Bartonella henselae, the causative agent of cat scratch disease, can be transmitted.
- High risk of penetrating deeper structures due to puncture wounds.
- Rodent Bites:
- Approximately 10% infection rate.
- Risk of rat bite fever caused by Streptobacillus moniliformis or Spirillum minus, presenting with fever, rash, and septic arthritis.
- Treatment typically successful with penicillin or doxycycline.
- Monkey Bites:
- High risk of infection and serious damage.
- Potential transmission of rabies and herpes B virus (Herpes simiae).
- Prophylaxis and specialist consultation recommended for moderate to high-risk exposures.
- Bat Bites:
- Risk of transmission of Australian bat lyssavirus (ABL), similar to rabies.
- Postexposure prophylaxis for rabies recommended for all bat bites, irrespective of the time elapsed since the bite.
- Human Bites:
- Higher complication and infection rate than animal bites.
- Can transmit hepatitis B/C and HIV, especially in cases involving bloody saliva and late-stage HIV disease.
- Infections usually polymicrobial; Eikenella corrodens known for causing septic arthritis.
- Laboratory Testing and Imaging:
- Wound cultures from clinically infected wounds.
- Imaging to identify foreign bodies, fractures, deep tissue penetration.
- Wound Closure and Antibiotics:
- Assess on a case-by-case basis; primary closure for selected wounds.
- Broad-spectrum antibiotics for established infection.
- Hospital Referral Indications:
- Severe injuries
- systemic infection signs
- involvement of bone/joint/tendon
- immunocompromised patients.
- Wound requires surgical intervention (debridement, drainage reconstruction)
- Cellulitis – severe or rapidly spreading or advancement past one joint
Related