| History Situation, pet ownership/identity Geographic location |
| Examination Nerve, tendon function Blood supply (pulses) Presence of edema, crush injury Proximity to joint and bone penetration |
| Wound care Irrigation Debridement, if necessary Elevation |
| Antimicrobials Prophylaxis, 5–7 days (orally) Therapy for established infection Empirical versus specific (animal specific) |
| Culture (if infected) |
| Baseline radiograph (if suspect bony injury) |
| Tetanus immunization if required |
| Rabies prophylaxis if needed |
| Health department report (if required) |
| Decision regarding the need for hospitalization |
| Local defense defects Pre-existing edema Prior lymph node dissection Prior radiation therapy |
| Medications Systemic steroids Immunosuppressives |
| Diseases/conditions Chronic alcoholism Asplenia Cirrhosis Leukemia Lymphoma Mastectomy (radical or modified radical) Myeloma Neutropenia Systemic lupus erythematosus |
Cat scratches are more prone to infection than dog scratches, which are generally minor and rarely cause infection. Any eschar of a wound should be removed if there is more than 1 to 2 mm of erythema surrounding it or if it is obviously infected. Puncture wounds are prone to infection, especially when associated with edema. They should be irrigated with sterile normal saline (no added iodine or antimicrobials) using an 18-gauge needle or catheter tip with a 20-mL syringe. This system functions as a high-pressure jet and reduces bacterial inoculum, whereas surface cleansing may not. Tears or avulsion should be copiously irrigated, any debris removed, and necrotic tissue cautiously debrided. Overly aggressive debridement can cause a defect that requires subsequent surgery.
Closure of infected wounds is generally not recommended. Wounds to the head and neck seen less than 8 hours after injury may be closed if there is copious irrigation, debridement, no undue tension on the suture lines, and antimicrobials are given. Approximating the edges with a tape bandage or delayed primary closure is often used.
Elevation is vital to decrease edema and prevent the spread of infection and cannot be overemphasized. The failure of the patient to properly elevate the area is a common cause of therapeutic failure. In the hospital, elevation of the hand should be carried out using a 4-inch tubular stockinette, numerous safety pins, and an intravenous pole. A knot is placed at the elbow and the forearm placed between two layers of uncut stockinette held together by strategically placed safety pins.
If there is a need, tetanus immunization should be updated. Rabies prophylaxis will depend on local patterns of infection among the animals, the circumstance leading to the bite, mode of contact, and the patient’s prior history of rabies immunization (refer to Chapter 192, Rabies, for details of rabies prophylaxis).
Antimicrobial selection
The pre-emptive selection of antimicrobials should take into account the microbiology of these wounds. Fortunately, most dog and cat bite isolates are susceptible to penicillin and ampicillin. Antimicrobial selections are outlined in Table 23.3. Of note is the relatively poor activity of cephalexin, cefaclor, cefadroxil, and erythromycin against Pasteurella multocida.
| Pasteurella multocida | Staphylococcus aureusa | Streptococci | Capnocytophaga | Anaerobes | |
|---|---|---|---|---|---|
| Penicillin | + | − | + | + | V |
| Ampicillin | + | − | + | + | V |
| Amoxicillin–clavulanate | + | + | + | + | + |
| Ampicillin–sulbactam | + | + | + | + | + |
| Dicloxacillin | − | + | + | − | − |
| Ertapenem/carbapenems | + | + | + | + | + |
| Cephalexin | − | + | + | − | − |
| Cefuroxime | + | + | + | + | − |
| Cefoxitin |
