Ferri – Bite Wounds

Mar 13, 2020 admin CƠ XƯƠNG KHỚP, NHIỄM KHUẨN 0

Bite Wounds

  • Fred F. Ferri, M.D.

 Basic Information

Definition

A bite wound can be animal or human, accidental, or intentional.

ICD-10CM CODES
T14.1 Open wound of unspecified body region
T01.9 Multiple open wounds, unspecified
S31.000A Unspecified open wound of lower back and pelvis without penetration into retroperitoneum, initial encounter
S41.159A Open bite of unspecified upper arm, initial encounter

Epidemiology & Demographics

  1. Bite wounds account for 1% of emergency department visits, and about 2% of patients need hospitalization.

  2. More than 1 million bites occur in human beings annually in the U.S.

  3. Dog bites account for 85% to 90% of all bites and result in 10 to 20 fatalities yearly in the U.S.; most dog bite victims are children. Cat bites account for 10% to 20%. The animal typically is owned by the victim.

  4. Infection rates are highest for cat bites (30%-50%), followed by human bites (15%-30%) and dog bites (5%).

  5. The extremities are involved in 75% of bites.

Physical Findings & Clinical Presentation

  1. The appearance of the bite wound is variable (e.g., puncture wound, tear, avulsion).

  2. Cellulitis, lymphangitis, and focal adenopathy may be present in infected bite wounds.

  3. Patient may have fever and chills.

Etiology

  1. Increased risk of infection: human and cat bites, closed-fist injuries, wounds involving joints, puncture wounds, face and lip bites, bites with skull penetration, bites in immunocompromised hosts

  2. Most frequent infecting organisms:

    1. Pasteurella spp.: responsible for majority of infections within 24 hr of dog (P. canis) and cat (P. multocida, P. septica) bites

    2. Capnocytophaga canimorsus (formerly DF-2 bacillus): a gram-negative organism responsible for late infection, usually after dog bites

    3. Gram-negative organisms (Pseudomonas, Haemophilus): often found in human bites

    4. Streptococcus spp., Staphylococcus aureus

    5. Eikenella corrodens in human bites

Diagnosis

Differential Diagnosis

  1. Bite from a rabid animal (often the attack is unprovoked)

  2. Factitious injury

Workup

  1. Determination of the time elapsed since the patient was bitten, status of rabies immunization of the animal, and underlying medical conditions that might predispose the patient to infection (e.g., DM, immunodeficiency)

  2. Documentation of bite site, notification of appropriate authorities (e.g., police department, animal officer)

Laboratory Tests

  1. Generally not necessary

  2. Hct if there has been significant blood loss

  3. Wound cultures (aerobic and anaerobic) if there is evidence of sepsis or victim is immunocompromised; cultures should be obtained before irrigation of the wound but after superficial cleaning

Imaging Studies

Radiographs are indicated when bony penetration is suspected or if there is suspicion of fracture or significant trauma; they are also useful for detecting foreign bodies (when suspected).

Treatment

Nonpharmacologic Therapy

  1. Local care with debridement, vigorous cleansing, and saline irrigation of the wound; debridement of devitalized tissue

  2. High-pressure irrigation to clean bite wound and ensure removal of contaminants (e.g., use saline solution with a 30- to 35-ml syringe equipped with a 20-gauge needle or catheter with tip of syringe placed 2 to 3 cm above the wound)

  3. Avoid blunt probing of wounds (increased risk of infection)

  4. If the animal is suspected to be rabid: infiltrate wound edges with 1% procaine hydrochloride, swab wound surface vigorously with cotton swabs and 1% benzalcuronium solution or other soap, and rinse wound with normal saline

Acute General Rx

  1. Avoid suturing of hand wounds and any wounds that appear infected

  2. Clenched fist injuries that develop after a punch to another’s mouth usually require hospitalization, IV antibiotics, and evaluation by a hand specialist

  3. Puncture wounds should be left open

  4. Give antirabies therapy and tetanus immune globulin (250-500 units IM in limb contralateral to toxoid) and toxoid (adult or child older than 5 yr: 0.5 ml DT given IM, child <5 yr 0.5 ml DPT IM) as needed

  5. Use empiric antibiotic therapy in high-risk wounds (e.g., cat bite, hand bites, face bites, genital area bites, bites with joint or bone penetration, human bites, immunocompromised host): amoxicillin-clavulanate 875 to 1000 mg bid for 7 days or cefuroxime 500 mg bid for 7 days

  6. In hospitalized patients, IV antibiotics of choice are cefoxitin 1 to 2 g q6h, ampicillin-sulbactam 1.5 to 3 g q6h, ticarcillin-clavulanate 3 g q6h, cefoxitin 2 g IV q8h, or ceftriaxone 1 to 2 g q24h

  7. Penicillin allergy: animal bite (doxycycline or moxifloxacin or trimethoprim/sulfamethoxazole with either clindamycin or metronidazole); human bite (moxifloxacin plus clindamycin, trimethoprim/sulfamethoxazole plus metronidazole)

  8. Prophylactic therapy for persons bitten by others with HIV and hepatitis B (see Section V)

  9. Table 1 summarizes the treatment of mammalian bites

    TABLE1 Treatment of Mammalian BitesFrom Adams JG, et al.: Emergency medicine: clinical essentials, ed 2, Philadelphia, 2013, Elsevier.
    Type Wound Care Antibiotic PR Tetanus PR Rabies PR HIV PR Hepatitis PR
    Human High-pressure irrigation of the wound with normal saline or dilute (<1%) povidone-iodine solution; débride devitalized tissue or ragged edges Amoxicillin-clavulanate, second-generation cephalosporin with anaerobic activity, penicillin plus dicloxacillin, clindamycin plus ciprofloxacin or trimethoprim-sulfamethoxazole Tetanus immunoglobulin (250 units IM) and tetanus toxoid (0.5 mg IM) if never had a tetanus vaccine or have not had 3 doses of tetanus toxoid; tetanus toxoid (0.5 mg IM) if >5 yr since previous tetanus booster None ART therapy started within the first 48-72 hr and continued for 28 days or bite source tested HIV negative; refer to the hospital for the specific drugs used in ART therapy HBIG (0.06 ml/kg IM); HBV given at separate site from HBIG
    Cat High-pressure irrigation of the wound with normal saline or dilute (<1%) povidone-iodine solution; débride devitalized tissue or ragged edges Amoxicillin-clavulanate, second-generation cephalosporin with anaerobic activity, penicillin plus a first-generation cephalosporin, clindamycin plus a fluoroquinolone or trimethoprim-sulfamethoxazole Tetanus immune globulin (250 units IM) and tetanus toxoid (0.5 mg IM) if never had a tetanus vaccine or have not had 3 doses of tetanus toxoid; tetanus toxoid (0.5 mg IM) if >5 yr since previous tetanus booster HRIG (20 IU/kg) injected IM and/or around the bite site; rabies vaccine (1 ml IM) given in the deltoid in adults and in the thigh in children, on days 0, 3, 7, 14, and 28 None None
    Dog High-pressure irrigation of the wound with normal saline or dilute (<1%) povidone-iodine solution; débride devitalized tissue or ragged edges Amoxicillin-clavulanate, second-generation cephalosporin with anaerobic activity, penicillin plus a first-generation cephalosporin, clindamycin plus a fluoroquinolone or trimethoprim-sulfamethoxazole Tetanus immune globulin (250 units IM) and tetanus toxoid (0.5 mg IM) if never had a tetanus vaccine or have not had 3 doses of tetanus toxoid; tetanus toxoid (0.5 mg IM) if >5 yr since previous tetanus booster HRIG (20 IU/kg) injected IM and/or around the bite site; rabies vaccine (1 ml IM) given in the deltoid in adults and in the thigh in children, on days 0, 3, 7, 14, and 28 None None

    ART, Antiretroviral therapy; HBIG, hepatitis B immune globulin; HBV, hepatitis B vaccine; HIV, human immunodeficiency virus; HRIG, human rabies immune globulin; IM, intramuscularly; PR, prophylaxis.

Disposition

  1. Prognosis is favorable with proper treatment.

  2. Important prognostic factors are type and depth of wound, which compartments are entered, and pathogenicity of inoculated bacteria.

  3. Punctures that are difficult to irrigate adequately, carnivore bites over vital structures (arteries, nerves, joints), and tissue crushing that cannot be debrided have a worse prognosis.

  4. In general, human bites have a higher complication and infection rate than do animal bites.

  5. Nearly 50% of the anaerobic gram-negative bacilli isolated from human bite wounds may be penicillin resistant and beta-lactamase positive.

Prevention

  1. Box 1 provides advice for avoiding the bites and attacks of common pets.

    BOX 1Advice for Avoiding the Bites and Attacks of Common Pets∗

    Dogs

    1. Do not leave a young child alone with a dog.

    2. Never approach or try to pet an unfamiliar dog, especially if it is tied up or confined.

    3. Always ask the dog’s owners if you can pet the dog.

    4. Do not lean over a dog or pet it directly on the head.

    5. Do not kiss a dog.

    6. Avoid quick or sudden movements that may startle a dog.

    7. Never pet or step over a sleeping dog.

    8. Never try to take a bone or toy away from a dog (other than your own dog).

    9. Know the appearance of an angry dog: barking, growling, snarling with teeth showing, ears laid flat, legs stiff, tail up, and hair on the back standing up.

    10. Never step between two fighting dogs; if you need to separate them, use a bucket of water or a hose.

    11. Do not approach a female dog that is nursing her pups.

    12. Teach injury prevention advice to children from an early age.

    Cats

    1. Be aware that some cats do not like prolonged petting.

    2. Know warning signs of an impending bite: twitching of the tail, restlessness, and “intention” bites (i.e., the cat moves to bite but does not bite).

    Ferrets

    1. Do not sell or adopt a ferret that is known to bite.

    2. Do not push your fingers through the wires of a ferret cage.

    3. Reach for a ferret from the side with the palm upward rather than from above.

    4. Do not handle food and then handle young ferrets without washing your hands first.

    5. Do not poke a ferret or pull on its tail or ears.

    6. Never leave a ferret alone with a child or infant.

    7. If a ferret bites and locks on very tightly, pour cold and fast-running water over its face.

    From Auerbach P: Wilderness medicine, expert consult, premium edition—Enhanced online features and print, Philadelphia, 2012, Elsevier.

Referral

  1. Hospitalization and IV antibiotic therapy for infected human bites; bites with injury to joints, nerves, or tendons; or any animal bites unresponsive to oral therapy.

  2. Human bites with tendon involvement should go to operating room for washout.

  3. In the outpatient setting, bite wounds should be reevaluated within 48 hr to assess for signs of infection.

Suggested Reading

  • R. Ellis, C. Ellis: Dog and cat bites. Am Fam Physician. 90 (4):239–243 2014 25250997

Related Content

  1. Animal and Human Bites (Patient Information)

 

 

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