Bite, Animal

Bite, Animal
Description
• Most bites are from provoked animals
• Dog bite wounds:
o Large dogs inflict the most serious wounds (pit bulls cause the most human fatalities).
o Most fatalities in children (70%) due to bites to face/neck
o Dogs of family or friends account for most bites.
• Cat bite wounds:
o Majority from pets known to victim
o 50% infection rate in those seeking care
o Puncture wounds most frequent due to sharp thin teeth causing deep inoculation of bacteria
• Cat-scratch disease:
o Three of the following four criteria:
Cat contact, with presence of scratch or inoculation lesion of the skin, eye, or mucous membrane
Positive CSD skin test result
Characteristic lymph node histopathology
Negative results of laboratory studies for other causes of lymphadenopathy
• Rat bite wounds:
o Occur in laboratory personnel or children of low socioeconomic class
o Infection rate
o Rat bites rarely transmit rabies, and prophylaxis not routine
Etiology
• Dog and cat bites:
o Pasteurella multocida is the major organism in both
Twice as likely to be found in cat bites than dog bites
Gram-negative aerobe found in up to 80% of cat infections
Infection appears in <24 hours
o Staphylococcus or Streptococcus
Infection appears in >24 hours
o Other organisms include anaerobes and Capnocytophaga canimorsus (dogs)
• Cat-scratch disease:
o Caused by Bartonella henselae
• Rat bites:
o Caused by Spirillum minus and Streptobacillus moniliformis
Diagnosis
Signs and Symptoms
• Distribution of mammalian bites:
o Dog bites represent 80-90% of all bites.
o Cat bites represent 5-15% of all bites.
o Human bites represent 2-5% of all bites (see Human Bite chapter).
o Rat bites represent 2-3% of all bites.
• Dog bites:
o Appearance
Crush injuries (most common), tears, avulsions, punctures, and scratches
o Low rates of infection compared with cat and human bites
o Infections usually present with:
Cellulitis
Malodorous gray discharge
Fever
Lymphadenopathy
• Cat bites:
o Appearance
Puncture wounds (most common)
Abrasions
Lacerations
o High infection rates (30-50%) due to deeper puncture wounds
• Cat-scratch disease:
o From the bite/scratch of a cat, dog, or monkey
o Small macule or vesicle that progresses to a papule
Begins several days (3-10) after inoculation
Resolves within several days or weeks
Regional lymphadenopathy occurs 3 weeks postinoculation
Tender
Nonsuppurative
Resolves after 2-4 months
o Low-grade fever, malaise, headache
History
• Animal's behavior, provocation, location, ownership
• Time since attack
• Past medical history: conditions compromising immune function, allergies, and tetanus status
Physical Exam
• Record the location and extent of all injuries.
• Document any swelling, crush injuries, or devitalized tissue.
• Note the range of motion of affected areas.
• Note the status of tendon and nerve function.
• Document any signs of infection, including regional adenopathy.
• Document any joint or bone involvement.
Tests
Lab
• Aerobic and anaerobic cultures from any infected bite wound
• Cultures not routinely indicated if wounds not clinically infected
• Cat-scratch disease
o Presence of elevated titers of Bartonella (Rochalimaea) henselae, or
o Positive reaction to cat-scratch antigen (CSA)
Inject 0.1 mL CSA intradermally
Induration at the site 48-72 hours later equal to or exceeding 5 mm is positive
Imaging
Plain radiograph indications:
• Fracture
• Suspect foreign body, e.g., tooth
• Baseline film if a bone or joint space has been violated in evaluating for osteomyelitis
• For infection in proximity to a bone or joint space
Differential Diagnosis
• Human bite injuries: human teeth cause crush injuries and animal teeth cause more punctures and lacerations.
• Bite injuries from other animals
• CSD-caused lymphadenopathy:
o Reactive hyperplasia (leading cause of lymphadenopathy in children younger than 16 years)
o Infection, chronic lymphadenitis, drug reaction, malignancy, and congenital conditions

Treatment
Initial Stabilization
• Achieve hemostasis on any bleeding wound.
• Airway stabilization if bite located on face or neck
ED Treatment
• Wound irrigation:
o Copious volumes of normal saline irrigation with an 18-gauge plastic catheter tip aimed in the direction of the puncture
o Avoid injection of saline through tissue planes due to force of irrigation
• Debridement:
o Remove foreign material, necrotic skin tags, or devitalized tissues
o Do not debride puncture wounds
o Remove any eschar present so underlying pus may be expressed and irrigated
• Wound closure:
o Closing wounds increases risk of infection and must be balanced with scar formation and effect of leaving wound open to heal secondarily.
o Do not suture infected wounds or wounds >24 hours after injury.
o Repair of wounds >8 hours: controversial
o Close facial wounds (warn patient of high risk of infection).
o Infected wounds, those presenting >24 hours after the event, and deep hand wounds should be left open
o May approximate the wound edges with Steri-Strips and perform a delayed primary closure
• Antibiotic indications:
o Infected wounds
o Cat bites
o Hand injuries
o Severe wounds with crush injury
o Puncture wounds
o Full-thickness puncture of hand, face, or lower extremity
o Wounds requiring surgical debridement
o Wounds involving joints, tendons, ligaments, or fractures
o Immunocompromised patients
o Wounds presenting >8 hours after the event
• Elevate injured extremity.
• Tetanus prophylaxis
Rabies Immunoprophylaxis
• Not required if rabies not known or suspected
• Rodents (squirrels, hamsters, rats, mice) and rabbits rarely transmit the disease.
• Skunks, raccoons, bats, and foxes represent the major reservoir for rabies.
• Recommended in following situations:
o Dog or cat in rabies-known area unable to be quarantined for 10 days
o Previously healthy dog or cat becomes ill while being quarantined (and awaiting results of rabies fluorescent antibody test)
o An ill dog or cat while awaiting rabies test results (to be continued or halted based on results of rabies test)
• Active immunization:
o Human diploid cell vaccine (HDCV): 1 mL IM on days 1, 3, 7, 14, and 28 after exposure
• Passive immunization:
o Human rabies immune globulin (HRIG): 20 IU/kg
o Up to one half in area around wound with the rest IM
Cat-Scratch Disease
• Analgesics
• Apply local heat to affected nodes.
• Avoid lymph node trauma.
• Disease usually self-limiting
• Antibiotics controversial, consider if severe disease is present or immunocompromised victim
Medication (Drugs)
• Amoxicillin/clavulanic acid (Augmentin): 500-875 mg (peds: 40 mg/kg/24 hr) PO b.i.d. (first line for all three animals)
• Ampicillin/sulbactam (Unasyn): 1.5-3.0 g IV q6h
• Cefoxitin (Mefoxin): 2.0 g IV q8h
• Cefuroxime axetil (Ceftin): 500 mg PO b.i.d.
• Clindamycin (Cleocin): 300 mg PO q6h; 900 mg IV q8h
• Ciprofloxacin (Cipro): 500 mg PO b.i.d.; 400 mg IV q12h
• Doxycycline (Vibramycin): 100 mg PO b.i.d.
• Imipenem/cilastatin (Primaxin): 0.5-1.0 g (peds: 50 mg/kg/24h) IV q6h
• Piperacillin/tazobactam (Zosyn): 3.375 g IV q6h
• Ticarcillin/clavulanic acid (Timentin): 3.1 g IV q6h
• Trimethoprim-sulfamethoxazole (Bactrim): 1 tablet (peds: 6-12 mg TMP, 30-60 mg SMX/kg/24h) PO b.i.d.
Follow-Up
Disposition
Admission Criteria
• All bites:
o Infected wounds at presentation
o Severe/advancing cellulitis/lymphangitis
o Signs of systemic infection
o Infected wounds that have failed to respond to outpatient (PO) antibiotics
• Cat-scratch disease:
o Prolonged fever, systemic symptoms, and/or marked lymphadenopathy
Discharge Criteria
• Healthy patient with localized wound infection: discharge on antibiotics with 24-hour follow-up.
• 48-hour follow-up for noninfected wounds
References
1. Brook I. Microbiology and management of human and animal bite wound infections. Prim Care. 2003;30(1):25-39, v.
2. Galloway RE. Mammalian bites. J Emerg Med. 1998;6:325-331.
3. Griego RD, et al. Dog, cat, and human bites: a review. J Am Acad Dermatol. 1995;33: 1019-1029.
4. Klein JD. Cat scratch disease. Pediatr Rev 1994; 15(9):348-353.
5. Pickering L, Red Book: 2003 Report of the Committee on Infectious Diseases. Amer Academy of Pediatrics 2003. 26th edition.
6. Smith PF, et al. Treating mammalian bite wounds. J Clin Pharm Ther. 2000;25:85-99.

Miscellaneous
See also: Rabies
Codes
ICD9-CM
879.8
ICD10
T14.1

Burns

Burns

Description

Burn injuries represent an acute disruption of the skin.

Etiology

Burns can be classified into six categories:

• Scald = hot liquids, grease, or steam
• Contact = hot or cold surfaces
• Thermal = fire or flames
• Radiation burns
• Chemical burns
• Electrical burns

Diagnosis

Signs and Symptoms

• Most burns will have external signs of integumentary damage.
• Inhalation injury:
• Facial burns
• Carbonaceous sputum
• Pharyngeal injection
• Wheezing
• Hoarseness
• Singed nasal hair
• Electrical burns may have minimal external findings.

History

• Information from emergency medical services (EMS), family, friends, or witnesses may be required.
• Medical history, surgical history, medications, allergies, social history, tetanus immunization status
• Carbon monoxide poisoning with exposure to combustion
• Cyanide poisoning from burning wool, silk, nylon, and polyurethane found in furniture and paper

Physical Exam

• Focus on airway, breathing first, then head-to-toe secondary survey for concurrent injuries.
• Evaluate face and oropharynx for signs of inhalation injury.
• Assess need for immobilization of cervical spine.
• Eye examination for corneal burns
• Determine severity of partial- and full-thickness burns by assessing size and depth of burn:
• Estimate surface area involved.

Pediatric Considerations

Specific patterns of injury may indicate nonaccidental injury (stockinglike or glovelike appearance of wounds, cigarette burns, etc.)

Essential Workup

The severity of the burn should be assessed by determining the size and depth.

Size

• Reported as percent involvement of total body surface area (TBSA) in one of three ways:
• 1. Rule of nines:
• TBSA of body parts is estimated by multiples of 9%; applies to adults only.
• Adult estimates of percentage of TBSA:
• Head and neck: 9
• Arms: right, 9; left, 9
• Legs: right, 18; left, 18
• Trunk: front, 18; back, 18
• Perineum, palms: 1
• In infants and children, the head contributes more to the percentage of TBSA and legs contribute less.
• Infants/children:
• Head and neck: 18
• Arms: right, 9; left, 9
• Legs: right, 14; left, 14
• Trunk: front, 18; back, 18
• 2. Lund and Browder chart, divides body into areas and assigns percentage of BSA based on age
• 3. Palm surface area, patient's palm is approximately 1% of TBSA:
• Estimate size in terms of number of patient's palms that cover burn.
• Helpful in assessing smaller, scattered burns

Depth

• Superficial or first-degree burns (epidermis only): local erythema and pain only, no blisters; healing occurs in several days
• Partial-thickness or second-degree burns (epidermis and dermis): divided into superficial partial-thickness and deep partial-thickness burns:
• Superficial partial-thickness: epidermis and superficial dermis:
• Skin is red, moist, painful, good capillary refill, develop blisters
• Heals in 14-21 days
• Deep partial-thickness: epidermis and deep dermis:
• Skin may be blistered, with dermis white to yellow; absent capillary refill, and pain sensation
• Heals via epithelialization within 3-12 weeks
• Full-thickness or third-degree burns (epidermis and dermis, extends into subcutaneous tissue):
• Skin is charred, leathery and pale, no blisters.
• Sensation absent
• Lesions will not heal spontaneously; needs surgical repair and skin grafting.
• Full-thickness burns with damage to underlying muscle or fourth-degree burns:
• Full-thickness plus involvement of underlying fascia, muscle, bone, and other tissues
• Requires extensive debridement
• Resultant disability

Tests

Lab

• For severe burns, obtain CBC, serum electrolytes, glucose, BUN, creatinine, and PT/PTT, type and cross-match, pregnancy test (female)
• Blood gas with carbon monoxide level for closed space or inhalation exposures
• Cyanide level if suspected

Imaging

• Chest radiograph
• Fiber optic bronchoscopy to assess inhalation injury

Differential Diagnosis

• Electrical injury
• Chemical injury
• Associated trauma or intoxication

Treatment

Pre Hospital

• Stop the burning process, remove smoldering clothes/jewelry.
• Establish patent airway; frequent reassessment:
• Intubate early for signs of respiratory distress.
• Initiate early IV fluid therapy.
• Relieve pain.
• Protect the wound with clean sheets.
• Transport to burn center (for major burns) if transport time shorter than 30 minutes.
• Immobilize spine if decreased sensorium or trauma.

Initial Stabilization

• Airway control paramount:
• Early intubation for patients with signs of upper airway injury, significant nasolabial burns, or circumferential neck burns
• IV access, supplemental 100% oxygen, monitor, pulse oximetry
• Evaluation for concurrent injuries
• Provide adequate analgesia.

ED Treatment

Fluid Resuscitation: Partial and Full-thickness Burns (>20% TBSA)

• Parkland formula: 4 mL of lactated Ringer solution or normal saline (NS) per kilogram per percentage of BSA burned IV; one half of this total is given in the first 8 hours and the remaining half over the next 16 hours:
• Example: 70-kg patient with a 40% TBSA burn requires 4 mL × 70 kg × 40% = 11,200 mL over 24 hours, with 5,600 mL over first 8 hours or 700 mL/h.
• For large burns, >20% TBSA, IV fluid therapy should be guided by invasive hemodynamic monitoring or urine output; maintain urine output of 0.5 to 1.0 mL/kg/h for adults and 1.0–1.5 mL/kg/h for children.

Escharotomy

• Circumferential burn eschar may lead to neurovascular compromise:
• Monitor pulses; may need Doppler flow probe.
• Elevate burned extremity.
• If circulation is compromised, escharotomy incisions on extremities should be made medially and laterally along the long axis of the limb just to the subcutaneous layer through the entire length of the burn eschar.
• A circumferential burn of the chest wall may prevent adequate ventilation unless escharotomy is performed:
• Make longitudinal incisions at anterior axillary line from the second rib to the level of the twelfth rib; connect with two transverse incisions across the chest.

Wound Care

• Cover the wounds with sterile moist saline dressings.
• If disposition is delayed, cleanse with sterile saline or poloxamer 188 product (e.g., Shur-Clens), debride blisters except those on palms or soles, and apply topical antibacterial agent (e.g., silver sulfadiazine, bacitracin, or mafenide acetate).
• Do not delay transfer to burn unit for wound care.
• Prophylactic antibiotics not indicated

Outpatient Management of Minor Burns

• Sterile technique for cleansing and debridement
• Remove loose, necrotic skin; debride broken, tense, or infected blisters.
• Topical antibacterial agents: (e.g., silver sulfadiazine, bacitracin, mafenide acetate) recommended in deep partial-thickness or full-thickness burns only
• Three-layer burn dressings should keep the wound moist and absorb exudate:
• Inner layer should be nonadherent porous mesh gauze saturated with a non-petroleum-based lubricant, or use a mild ointment (e.g., bacitracin or Polysporin) under a nonadherent porous gauze.
• The next layer should be fluffed coarse-mesh gauze.
• The outer wrap should keep the dressing in place without constricting.
• Dressings should be changed at least daily.
• Silver wound dressings (Silverlon and Acticoat):
• Thin coating of metallic silver applied to knitted fabric backing
• Requires dressing to remain moist
• May leave on for up to 3 days

Pediatric Considerations

• Parkland formula underestimates fluid requirements in children; the Galveston formula may be used instead: 5,000 mL/m² BSA burned plus 2,000 mL/m².
• TBSA of 5% dextrose in lactated Ringer solution IV over the first 24 hours, half in the first 8 hours and the other half over the next 16 hours
• Consider nonaccidental trauma, particularly with burns on the back of hands or feet, buttocks, the perineum, and the legs.
• Avoid hypothermia:
• Children have greater BSA/mass ratio and lose heat more rapidly.
• Avoid hypoglycemia:
• Children are more prone to hypoglycemia owing to limited glycogen stores.

Pregnancy Considerations

• Significant morbidity to mother and child
• Fluid requirements may exceed estimations.
• Fetal monitoring and early obstetric consultation recommended

Medication (Drugs)

• Bacitracin ointment: Apply to wound one-four times per day.
• Mafenide (Sulfamylon) acetate cream: Apply to wound one or two times per day.
• Morphine: 0.1-0.2 mg/kg titrated to effect for pain control after shock
• Silverlon and Acticoat: Cut sheet to size of burn; moisten with sterile water.
• Silver sulfadiazine cream: Apply to wound one or two times per day.
• Tetanus toxoid or immunoglobulin: 0.5 mL IM; 250 U IM once along with toxoid

Follow-Up

Disposition

Admission Criteria

N/A

Injuries Requiring Admission

• Partial-thickness burns of noncritical areas (not the eyes, ears, face, hands, feet, or perineum) involving 10-20% of BSA in adults (older than 10 years and younger than 50 years)
• Partial-thickness burns of noncritical areas involving 5-10% of BSA in children younger than 10 years
• Suspicion of nonaccidental trauma
• Patients unable to care for wounds in outpatient setting (e.g., homeless patients)

Injuries Requiring Transfer and Admission to a Burn Center

• Partial-thickness and full-thickness burns involving ±10% of BSA in patients younger than 10 years or older than 50 years
• Partial-thickness and full-thickness burns over >20% of BSA in any patient
• Full-thickness burns involving >5% of BSA
• Partial-thickness and full-thickness of face, hands, feet, genitalia, perineum, or major joints
• Electrical burns, including lightning injury
• Significant chemical injury
• Inhalation injury
• Burn injury in patients with pre-existing illness that could complicate management
• Burn injury in patients with a concomitant trauma or social barrier

Discharge Criteria

Partial-thickness burns of <15%>

References

1. Committee on Trauma, American College of Surgeons. Guidelines for the operation of burn units. Resources for Optimal Care of the Injured Patient 1999.1998:55.

2. Holm C, et al. A clinical randomized study on the effects of invasive monitoring on burn resuscitation. Burns. 2004;30(8):798-807.

3. Kavanagh S, et al. Care of burn patients in the hospital. Burns. 2004;30(8):A2-6.

4. Schwartz LR. Thermal burns. In: Tintinalli JE, Kelen GD, Stapczynski JS. Emergency Medicine: A Comprehensive Study Guide. 6th ed. New York: McGraw-Hill, 2004:1220-1226.

5. Tompkins D, et al. Care of out patient burns. Burns. 2004;30(8):A7-9.

Codes

ICD9-CM

940.0-949.0