Bites: Something to chew over

Question 1

How many people per year present for medical treatment after having had a dog bite?

Answer 1

250,000

Question 2

What is the max force of a dog bite?

Answer 2

31,790 kPa

Question 3

Why are dog bites so damaging?

Answer 3

and cause large wounds through a “hole and tear effect”, whereby canine teeth anchor the person while other teeth bite, shear and tear

Question 4

In which demographic are dog bites the most serious?

Answer 4

Neonates and toddlers have the highest mortality post-bite.

Question 5

Outline the epidemiology of dog bites

Answer 5

740/100,000 people are bitten by dogs in the UK every year, but only 2.6/100,000 require hospital admission. Half of all children are reportedly bitten by dogs at some time, with boys being affected more than girls.

Question 6

Give three important points to look into when taking a history from someone with a dog bite

Answer 6

• It is important to assess the risk of rabies and consider rabies prophylaxis in people coming from abroad with a dog bite.
• Rule out immunocompromising factors such as splenectomy, cirrhosis and steroid therapy.
• Note recent antibiotics, as infection despite flucloxacillin or erythromycin makes superinfection with resistant organisms such as Pasteruella multocida more likely.

Question 7

Give four important points to assess when examining dog bites?

Answer 7

• Children with facial or cranial bites need cervical immobilisation until cervical lesions are excluded
• Take careful documentation with diagrams of the wound
• Assess size and depth of the wound, degree of crush injury and devitalised tissue, nerve or tendon damage and involvement of bones and joints
• Full wound examination and debridement with local or general anaesthetic

Question 8

Give three overall steps for managing dog bites

Answer 8

• Clean
• Antibiotics
• Review

Question 9

How should you clean a dog bite?

Answer 9

Clean and irrigate the wound, removing as many foreign bodies as possible. Debride where necessary, and especially in the case of potential rabies infection – irrigation alone will not remove the virus from the wound edge. Delay closure of the wound wherever possible (inappropriate closure is a key cause of litigation).

Question 10

How should you tack the bacterial implications of dog bites?

Answer 10

Give antibiotics, depending on the risk factors for infection. Infected wounds should be swabbed and sent off for culture. Give tetanus injection.

Question 11

What should you do to avoid dog bite swelling?

Answer 11

Review bites within 24-48 hours. Keep raised to avoid swelling.

Question 12

Give three main risk factors for infection in dog bites

Answer 12

• Wound depth
• Need for surgical debridement
• Female gender

Question 13

What are the two bacteria most commonly implicated in dog bited?

Answer 13

• Pasteurella Multocida

- Capnocytophaga canimorsus

Question 14

What is pasteurella multocida?

Answer 14

Pasterurella Multocida (gram –‘ve)is the most virulentpathogen in dog bites and is the most likely pathogen in infected wounds presenting

Question 15

What is capnocytophagia canomorsus?

Answer 15

Capnocytophaga canimorsus (gram -‘ve) can also cause infection, and sepsis caused by this organism is often mistaken for fulminant meningococcal disease.

Question 16

When does infection usually occur in a patient?

Answer 16

Infection usually follows a trivial bite in an immunocompromised patient.

Question 17

When should antibiotics be used in dog bites?

Answer 17

Only 1/5th dog bites become infected and thus prophylactic antibiotics in all cases is not required – only high risk dog bites should be treated prophylactically with co-amoxiclav.

Question 18

Give five high risk features of dog bites

Answer 18

• All bite wounds after primary closure
• Puncture wounds
• Bites to hand and wrist
• Crush wounds
• Genital injuries

Question 19

Give five high risk patients with dog bites

Answer 19

• Diabetes
• Immunosuppression
• Splenectomy
• Postmastectomy
• RA and prosthetic joints

Question 20

How do you treat an established pasteurella multocida infection?

Answer 20

Treatment must cover Pasteurella multocida. For severe infections use imipenem (500mg/QDS/IV) and clindamycin (900mg/QDS/IV) for a period of weeks.

Question 21

Give three common long term complications of dog bites?

Answer 21

• Sepsis
• Endocarditits
• Meningitis

Question 22

In what demographic do head and nieck bites occur?

Answer 22

76% of bites in children are to the head and face, and exasanguination after carotid trauma is the major cause of death in those under 10. Resuscitation is the priority in these patients.

Question 23

What is dangerous about hand and extremity bites?

Answer 23

Bones and joints are very close to the surface in the hand and any infection will cause significant functional impairment. Surgical debridement and wound irrigation needs to be performed by an experienced clinician.

Question 24

How common are human bitesd?

Answer 24

Third most common behind dog and cat bites

Question 25

What is the typical location for a fight bite?

Answer 25

The typical location is the dorsal aspect of the 3rd and 4th MCP joint as a result of punching someone in the mouth with a clenched fist.

Question 26

How can complications arise in a fight bite?

Answer 26

arise if a tooth penetrates the capsule of an MCP joint and flora from the mouth enter.

Question 27

Give three common bacteria involved in fight bites

Answer 27

Staph aureus
Strep viridians
Eikenella corrodens

Question 28

How is rabies transmitted?

Answer 28

Rabies is transmitted by a transdermal bite or scratch or salivary contamination of mucosa or skin wounds

Question 29

How many people does rabies kill per year?

Answer 29

kills 30,000 to 50,000 people a year

Question 30

What is the second best way to avoid getting rabies?

Answer 30

– Flushing wound under a running tap for several minutes, washing with soapy water and using wound disinfectants is recommended. Primary suturing should be avoided.