Animal Bites in Emergency Medicine Treatment & Management

Obtaining the history of the bite event is of major importance, including home treatment of wounds, body parts involved, and other symptoms (see History).

Rinse bite wounds, if possible, and cover with a sterile dressing. Tap water has been shown to be as effective for irrigation as sterile saline.^[12]

Encourage patients to seek prompt care.

Most bite wounds can be treated in the ED. Essentials of treatment are inspection, debridement, irrigation, and closure, if indicated. Complete trauma evaluation occasionally is indicated.

• Carefully inspect bite wounds to identify deep injury and devitalized tissue. Obtaining an adequate inspection of a bite wound without it first being anesthetized is nearly impossible. Care should be taken to visualize the bottom of the wound and, if applicable, to examine the wound through a range of motion.
• Debridement is an effective means of preventing infection. Removing devitalized tissue, particulate matter, and clots prevents these from becoming a source of infection, much like any foreign body. Clean surgical wound edges result in smaller scars and promote faster healing.
• Irrigation is another important means of infection prevention. A 19-gauge blunt needle and a 35-mL syringe provide adequate pressure (7 psi) and volume to clean most bite wounds. In general, 100-200 mL of irrigation solution per inch of wound is required.^[12] Heavily contaminated bite wounds require more irrigation. Large dirty wounds may require irrigation in the operating room. Isotonic sodium chloride solution is a safe, available, effective, and inexpensive irrigating solution. Few of the numerous other solutions and mixtures of saline and antibiotics have any advantages over saline. If a shieldlike device is used, take care to prevent the irrigating solution from returning to the wound, which decreases the effectiveness of the irrigation.
• Primary closure may be considered in limited bite wounds that can be cleansed effectively (this excludes puncture wounds, ie, cat bites). Other wounds are best treated by delayed primary closure. Facial wounds, because of the excellent blood supply, are at low risk for infection, even if closed primarily, but the risk of superinfection must be discussed with the patient prior to closure. Bite wounds to the hands and lower extremities, with a delay in presentation, or in immunocompromised hosts, generally should be left open.^[7]
• If a bite wound involves the hand, consider immobilizing in a bulky dressing or splint to limit use and promote elevation.

Consider tetanus and rabies prophylaxis for all wounds. Antirabies treatment may be indicated for bites by dogs and cats whose rabies status can not be obtained, or in foxes, bats, raccoons, or skunks in the Americas (see Rabies and Tetanus for treatment and dosing information).

Oehler et al have established a wound management strategy following animal bites to prevent severe complications that include the following steps:^[13]

• Culture for aerobes and anaerobes if abscess, severe cellulitis, devitalized tissue, or sepsis is present.
• Use saline solution for wound irrigation.
• Debride necrotic tissue and remove any foreign bodies.
• If fracture or bone penetration, radiography is indicated (MRI or CT may also be indicated).
• Initiate prophylactic antibiotics in selected cases (based on type and specific animal involved).
• If methicillin-resistant Staphylococcus aureus (MRSA) is suspected, first-line antibiotics include trimethoprim-sulfamethoxazole, doxycycline, minocycline, and clindamycin.
• Hospitalization is indicated if fever, sepsis, spreading cellulitis, severe edema, crush injury, or loss of function is present. Also consider hospitalization for patients who are immunocompromised or are likely to be noncompliant.
• Administer tetanus booster (if none given in past year) or initiate primary series in nonvaccinated individuals (See Tetanus for further recommendations).
• Assess the need for rabies vaccine and immunoglobulin (See Rabies for further recommendations).

For additional information, see Medscape's Wound Management Resource Center.

Extensive wounds, those involving tissue loss, or those involving complex structures may require plastic surgery consultation.

If the skull is penetrated, neurosurgery consultation is indicated.

Local public health authorities should be notified of all bites and may help with recommendations for rabies prophylaxis.