WORKUP
Lab Studies:

• Laboratory testing is rarely helpful when patients with dog bites present immediately after injury. Hemodynamically unstable patients are an obvious exception.

• Additional laboratory testing should be performed as indicated. Usually, patients presenting with infection require further workup.

• Consider culturing tissue of a nonseptic patient presenting with a wound infection.

• Obtain a CBC and blood culture in patients with more severe infections.

Imaging Studies:

• Radiographs generally are not helpful but may be useful for certain bite wounds.

• Dog bites to the head may penetrate the skull. At the minimum, obtain a skull radiograph in a child with a dog bite to the head, especially in a bite from a large dog.

• Foreign bodies, such as tooth fragments, may be demonstrated on radiographs. Obtain a radiograph if the possibility of a foreign body cannot be excluded by examination.

• Patients with deep tissue injuries may have fractures. The hand and joint spaces are particularly vulnerable.

• Patients who present with signs of infection may have osteomyelitis or septic arthritis. Bone scans may reveal osteomyelitis even in patients in whom radiograph findings are negative.

• Children with penetrating skull injuries should have a head CT scan.

Procedures:

• Joint aspiration may aid in the diagnosis of septic arthritis.

TREATMENT
Medical Care:

• Address ABCs immediately in the event of facial and neck wounds.

• Wounds should be irrigated copiously with isotonic sodium chloride solution under high pressure (usually with an 18- or 19-gauge needle or angiocatheter). Wounds may require more than 200 mL/in of isotonic sodium chloride solution.

• Infection is a feared complication of animal bites, especially cat bites. Studies have shown that infections are polymicrobial. Antibiotic coverage for staphylococci and anaerobes is necessary.

• Consider tetanus prophylaxis.

• Consider rabies prophylaxis in certain circumstances (eg, raccoon bites, bat bites, unprovoked attack by an unknown animal).

Surgical Care: Surgical treatment may be appropriate.

• Debridement is useful for removing foreign bodies and devitalized tissue, which can serve as a nidus for infection. Remove blood clots, and inspect the wound further during the procedure.

• Careful wound excision may improve the cosmetic appearance of the scar and decrease the incidence of wound infection.

• Perform primary closure in certain wounds. Facial wounds rarely become infected because the face is well vascularized. Clean wounds also can be closed. Wounds on the hands or lower extremities should be left open. Patients who have a wound older than 6 hours are treated best using delayed primary closure in lieu of primary closure.

Consultations:

• Plastic surgeon for potentially disfiguring injuries

• Hand specialist for injuries to the hand

• Orthopedist for bone and joint injuries or deep structural injuries

• Neurosurgeon for penetrating wounds to the skull

• Vascular specialist for neck wounds

• Infectious disease specialist for immunocompromised patients

MEDICATION
Amoxicillin combined with a beta-lactamase inhibitor is the oral antibiotic used most frequently. Patients who are allergic to penicillin and are tolerant of cephalosporins may be treated with ceftriaxone. Patients who are intolerant to cephalosporins may be treated with a combination of trimethoprim and sulfamethoxazole plus clindamycin. Prophylaxis also may be provided with erythromycin or a tetracycline. A 3- to 7-day course of antibiotic therapy commonly is used for prophylaxis.
 

Drug Category: Antibiotics -- Used for prophylaxis and treatment of infection. Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

FOLLOW-UP
Further Inpatient Care:

• Patients requiring inpatient care include those with airway compromise, hemodynamic instability, penetrating skull injury, or severe soft tissue injuries.

• Appropriate surgical subspecialties should be involved in treating patients admitted to the hospital. Decisions to incise, drain, and explore tissue should be made after surgical consultation.

• Patients who may not be compliant with outpatient antibiotic therapy may require admission. Patients who have developed signs of infection may benefit from admission.

• If osteomyelitis is suspected despite normal radiograph findings, consider a bone scan.

Further Outpatient Care:

• Follow-up care is necessary within 24-48 hours for all bite wounds because of risk of infection.

Transfer:

• Transfer patients who are hemodynamically unstable, have airway compromise, or have massive trauma to a tertiary care center.

Deterrence/Prevention:

• Pet owners should watch animals when children are present. Children should be discouraged from approaching animals, especially when the animal is not the family pet. Children should avoid animals that are eating.

• Citizens should insist on leash laws, and pet owners should keep their animals on a leash.

• Physicians can educate parents about the potential dangers of certain breeds and the need to be vigilant if they own a pet.

Complications:

• Meningitis

• Sepsis

• Septic arthritis

• Osteomyelitis

• Cellulitis

• Wound infection

• Facial/neck deformities

• Limb deformities

• Limb loss

Prognosis:

• Most patients with animal bites have a good-to-excellent prognosis.

Patient Education:

• Patients and their families should receive instructions that clearly outline the signs of infection.

• Inform patients of the risk of infection as a consequence of the animal bite despite treatment with irrigation and antibiotics.

• Emphasize the need for follow-up care as well as the need to receive immediate medical attention if signs of infection develop.

MISCELLANEOUS
Medical/Legal Pitfalls:

• Failure to consider the possibility of skull penetration

• Failure to consider the possibility of inoculation of bacteria into a joint space

• Improperly closing wounds (eg, cat bite to the hand)

• Failure to adequately document the patient's history

• Failure to adequately document treatment (eg, irrigation, antibiotic use)

• Failure to report the injury to police or the local animal control agency

Special Concerns:

• If the animal is a family pet, a danger exists that it may attack the child again. Consider discussing the removal of the pet with the family.

• Dogs that are left off a leash and have bitten individuals constitute a menace to the community. Dogs should always be on a leash. Aggressive dogs may require a muzzle.