Bites, Human


Article Author:
Kenneth Maniscalco


Article Editor:
Mary Ann Edens


Editors In Chief:
Dustin Constant
Donald Kushner


Managing Editors:
Avais Raja
Orawan Chaigasame
Khalid Alsayouri
Kyle Blair
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Navid Mahabadi
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Abbey Smiley
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beenish Sohail
Hajira Basit
Phillip Hynes
Sandeep Sekhon


Updated:
11/15/2018 3:58:32 PM

Introduction

Human bites account for a relatively low percentage (3%) of the total bites encountered in the ED, but they have the potential for severe morbidity due to challenges in identifying the injuries and late presentations complicated by established infection. The greater cost of care in these injuries is from infection and post-infection treatment, and therefore all efforts should be made to make the diagnosis early and prevent further deterioration. [1][2]

Etiology

Unlike other animal bites, human bites are commonly acquired as a closed-fist injury where one individual punches another in the face and lacerates their hand on the other’s teeth. Occlusion bites have the same risk profile as closed-fist injuries but are more easily recognized and have less prevalence of skin penetration over areas with structures directly below the skin. [3]

Epidemiology

Human bites represent about 3% of the total bite injuries seen in the emergency department and are most commonly closed-fist injuries.  Bites in children are most often occlusion bites to the face and upper body from rough playing, while bites in the other age ranges are commonly at the metacarpal-phalangeal joint from striking another individual in the face or contact with another person’s teeth. These wounds are most typically found on the third, fourth, and fifth fingers at the MCP-joint. Occlusion bites predominate in presentation though this distribution may be skewed due to occlusion bites presenting as a known bite while closed-fist injuries (fight bites) typically present under altercation, assault, or other complaints that do not lend themselves to data collection and may only be incidentally found amongst other injuries. Fight bites are most commonly found in the teenage to young adult males. [4]

Pathophysiology

The physical trauma from a human bite is rarely spectacular with relatively minor lacerations and occlusion bruising being the main initial findings.  Human oral flora and contagious disease spread to account for the greater amount of morbidity with human bites. Eikenella corrodens, as well as more common aerobic and anaerobic bacteria, are normal human flora.  Herpes, hepatitis, and human immunodeficiency viruses are all transmissible through bite injuries.  Closed-fist injuries show a predication for infection due to the injury overlying the joint capsule of the MCP and the extensor tendon sheath. Direct joint and tendon sheath inoculation after the fist is relaxed allow bacteria deep penetration to normally sterile anaerobic environments.  Local infection, disseminated infection, tenosynovitis, and septic arthritis are all possible complications from human bite wounds.  

History and Physical

Focused H&P should determine the circumstances surrounding the bite, location of the bite, whether the bite was contaminated with blood, the infectious state of both individuals involved, time since the occurrence, whether the patient has been febrile, local erythema, swelling, warmth, or purulent drainage from the bite site.  Careful examination and measurement of occlusion bites in children are important as any bite with an intra-canine distance great than 3cm most likely came from an adult and should raise suspicion of abuse.  Any patient arriving after or due to an altercation should have his or her hands examined for possible fight bites.  Conversely, anyone with lacerations on their hands, or especially over the MCP joint should be questioned about the source of the injuries and educated on the danger of not having human bites treated as some patients are apprehensive to admit to the altercation.  Immunization status of the person with an injury is important in cases where transmission of disease is a concern. 

Evaluation

Wounds that were recently acquired are usually minor, less than 2cm long, and rather superficial which makes them easy to overlook or dismiss especially in light of other injuries or complaints. Contaminated or otherwise obscured skin on hands should be cleaned thoroughly to evaluate for a possible fight bite especially in intoxicated individuals who cannot provide a reliable history.  Infected joints or tendon sheaths are more apparent but also warrant surgical consultation and IV antibiotics. If a bite in a child is suspicious for abuse a thorough exam should be performed, a broadened history should be taken, and CPS should be contacted.[1][3]

Treatment / Management

All wounds should be extensively irrigated and the patient’s tetanus status updated if necessary.  Provide appropriate pain management before exploration, irrigation, or debridement of the wounds.  All human bite wounds that pierce the skin should receive amoxicillin-clavulanate prophylaxis for a week, and the patient is given strict wound care precautions.  The patient's TDaP status should be updated if necessary.  Any laceration to the MCP-joint is a closed-fist injury until proven otherwise.  If signs or symptoms of infection in a joint space or tendon sheath are present orthopedics should be consulted for evaluation for surgical washout and inpatient treatment with IV antibiotics.  Repair of lacerations from human bites should follow the same principles as that of other bites and in most cases should be left to heal by secondary intention to prevent providing a more hospitable environment for bacteria to reproduce. [5][6]

Complications

  • Cosmetic deformity
  • Loss of function
  • Infectious tenosynovitis
  • Necrotizing fasciitis
  • Abscess formation
  • Amputation
  • Osteomyelitis
  • Septic joint

Consultations

  • Hand Surgeon
  • Plastic surgeon
  • Infectious disease consult

Pearls and Other Issues

The transmission of HIV through bite wounds is concerning though exceedingly rare.  HIV prophylaxis is only indicated if the wound is percutaneous and the mouth was contaminated with blood.  Otherwise, the side effect profile of prophylaxis is more dangerous than the risk of transmission.  A thorough discussion with the patient about the risks and benefits is warranted and should be documented with the appropriate outpatient follow up recommended/referred.  For medical professionals, there has been no reported transmission of HIV from any occupational exposure. 

Herpetic whitlow is caused by transmission of the herpes virus to the finger and appears as painful grouped vesicles on an erythematous base.  It is most typically from a child sticking fingers into adults’ mouths and should be considered whenever a child presents with lesions on the distal fingers. 

There is no post-exposure prophylaxis for Hepatitis C exposure, simply monitoring for signs of infection with outpatient follow-up.  Hepatitis B exposure requires immune globulin only if the person bitten by an infected individual has never been immunized or is a known non-responder to the vaccine.  Anyone who has never had their response to the vaccine measured and is exposed should be tested for the anti-HBs response and treated if negative. 

Enhancing Healthcare Team Outcomes

Human bites can be very serious and are best managed by a team of healthcare professionals. Loss of function and cosmetic deformity are very common complications. All patients should be educated on signs of an infection following a human bite and when to seek treatment. Patients need to understand that long-term follow-up is necessary to prevent loss of function of the hand or fingers. In addition, the pharmacist should emphasize the importance of antibiotic compliance. Finally, all patients must be told that they may require a plastic surgery procedure later to improve function or cosmesis.[7]

Outcomes

Patients who seek immediate care after a human bite have excellent outcomes. However, patients who delay treatment tend to have adverse outcomes. In most cases, a florid infection develops which can involve the entire hand. In delayed cases, not only is there is a significant cosmetic deformity, but there is also a functional loss of the hand and fingers. Human bites on the nose, ear, or tips of the finger are difficult to cure and often require extensive plastic surgery. Scarring is another major complication of a human bite.


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Bites, Human - Questions

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A patient complains of pain and swelling over the third metacarpophalangeal joint. She reports she was in a fight and hit her opponent, knocking out a couple of teeth. The area is swollen and red with decreased range of motion secondary to pain. Which of the following would not be appropriate management?



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What is the most appropriate choice for antibiotic prophylaxis after a human bite wound?



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A 56-year-old diabetic was injured in a bar argument. He had several cuts on his left hand when he punched someone in the mouth. Which antibiotic is indicated to prevent infection in this patient?



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In the treatment of a human bite, what is the first critical step?



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Which one of the following is most likely to get infected?



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A child with significant developmental disabilities bites others. Select the best intervention.



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A 3 year-old male presents with his mother who reports that he came home from visiting their next door neighbor and playing with the two children with a bruise on his shoulder that looked like teeth marks. The child has no significant previous medical history, takes no medications, and has no allergies. On examination there is a small, raised, bruised area on the child's left shoulder with apparent teeth marks and an intercanine distance of 3.1cm. There is no bleeding or break in the skin. Otherwise the child is well and the mother has no other complaints. She has heard that human bites are dangerous and they need antibiotic treatment. What is the most appropriate next step in treatment?



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A 28 year-old man, his 6 year-old son, and wife present to the emergency department after the father was tossing the child in the air thirty minutes ago and the child slipped while being caught. The father is adamant the child did not his the ground, his head, or lose consciousness, simply that he was caught awkwardly. The child has a small laceration on the mucosa of his upper lip which is oozing blood, the lip is swollen, and the child is crying. The father has a small wound to the distal aspect of his radial styloid which is hemostatic and well approximated. Neither father nor son have any known medical history, allergies, or other injuries, though the wife has implied this isn't the last trauma which will occur today. Which of the following actions is most critical to proper patient care?



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A medical student is working in the emergency department one night when a patient she is examining grabs her arm and bites her. The patient is immediately restrained and the emergency department staff promptly examines the student. She has an occlusion wound with two epidermal punctures 3.3 cm apart in the soft tissue of her dorsal arm. She has a history of type 1 diabetes mellitus managed with an insulin pump and sliding scale boluses, and her tetanus vaccination status is current. A review of the patient's chart reveals he is HIV-positive. There was no blood in the patient's mouth when he bit the student, and the student immediately flushed the wounds with a liter of normal saline. What is the most appropriate management of her wounds?



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Bites, Human - References

References

Bula-Rudas FJ,Olcott JL, Human and Animal Bites. Pediatrics in review. 2018 Oct     [PubMed]
Saul D,Dresing K, [Surgical treatment of bites]. Operative Orthopadie und Traumatologie. 2018 Oct     [PubMed]
Ng D,Chan T,Pothiawala S, A Human Bite on the Scrotum: Case Report and Review of Management in the Emergency Department. The Journal of emergency medicine. 2018 Apr     [PubMed]
Contreras-Marín M,Sandoval-Rodríguez JI,García-Ramírez R,Morales-Yépez HA, [Mammal bite management]. Cirugia y cirujanos. 2016 Nov - Dec     [PubMed]
Jenkins GW,Isaac R,Mustafa S, Human bite injuries to the head and neck: current trends and management protocols in England and Wales. Oral and maxillofacial surgery. 2018 Mar     [PubMed]
Fisher-Owens SA,Lukefahr JL,Tate AR, Oral and Dental Aspects of Child Abuse and Neglect. Pediatric dentistry. 2017 Jul 15     [PubMed]
Oladokun R,Brown BJ,Osinusi K,Akingbola TS,Ajayi SO,Omigbodun OO, A case of human bite by an 11-year old HIV positive girl in a paediatrics ward. African journal of medicine and medical sciences. 2008 Mar     [PubMed]

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