Animal and Human Bites

Question 1

History of events?

Answer 1

1. What bit the patient?
2. Animal’s behavior: provocation, fearfulness, aggression
3. Animal sickness: excessive drooling, difficulty swallowing, staggering, paralysis and seizures
4. Rabies vaccine status
5. When: Time since attack
6. First aid given?
7. Location
8. Duration
9. Tetanus vaccine status

Question 2

General approach to injury from the bite?

Answer 2

▪ location and extent of all injuries.
▪ swelling, crush injuries, or devitalised tissue.
▪ Range of motion of affected areas.
▪ Distal neurovascular status.
▪ signs of infection, including regional adenopathy.
▪ joint or bone involvement

Question 3

General Management of bites?

Answer 3

1. Management of Life threatening conditions
2. On-going management
   - Analgesia
   - Wound management
   - Prophylaxis e.g. Antibiotics, Tetanus, ??PEP
   - Antivenom

Question 4

General risk factors for wound infection?

Answer 4

• Injury > 8-12 hours old
• Locations with poor blood supply (Leg and thigh > arms > feet > chest > back > face > scalp)
• Contaminated wound
• Blunt mechanism
• Subcutaneous sutures
• Repair material (sutures > staples)
• High-velocity Missile injuries

Question 5

High risk species?

Answer 5

Cat
Human
Primate
Pig
Camel

Question 6

Low risk species?

Answer 6

Dog (excluding hand)
Rodent

Question 7

High risk location of wound?

Answer 7

Hand
Over joint or superficial tendon (CFI)
Through-and-through oral
Below the knee

Question 8

Low risk location of wound?

Answer 8

Face
Scalp
Mucosa

Question 9

High risk wound type?

Answer 9

Puncture
Extensive tissue damage
Contaminated or devitalized tissue
Old (delayed presentation) or sutured

Question 10

Low risk wound type?

Answer 10

Large
Superficial
Clean
Recent

Question 11

High risk patients?

Answer 11

Immunosuppressed
HIV positive
Transplant patient
steroid dependent
Diabetes
cancer chemotherapy
Prosthetic valve patients
Peripheral vascular disease
Elderly alcoholic
cirrhosis
Social and compliance Problems

Question 12

Indication for antibiotic prophylaxis?

Answer 12

1. infceted wounds
2. cat bites
3. hand injuries
4. full thickness puncture of hand, fce, or lower extremity
5. puncture wounds
6. wounds requiring surgical debridement
7. wounds involving joints, tendons, ligaments or fractures
8. immunocompromised patients
9. wounds presenting >8hr after the event

Question 13

Tetanus prophylaxis in clean and minor wounds?

Answer 13

1. <3 doses/unknown - tetanus toxoid vaccine
2. 3 doses - tetanus toxoid Only if last dose given >10 years ago

Question 14

Tetanus prophylaxis in dirty and major wounds?

Answer 14

1. <3 doses/unknown -give tetanus toxoid vaccine and human tetanus immune globulin
2. 3 doses - give tetanus toxoid vaccine Only if last dose given >5 years ago

Question 15

What is rabies?

Answer 15

• Rabies is fatal, but infection can be prevented with proper wound
  care and post-exposure prophylaxis using rabies biologics
• All bites from stray dogs, bats, foxes, raccoons, skunks should
  receive rabies vaccine and immunoglobulin

Question 16

Wound care in rabies?

Answer 16

• Wound care effective in a role in
  prevention of rabies transmission.
• Wash with soap and water all bite and scratch areas
• virucidal agent such as povidone-iodine should be applied if available

Question 17

Indication for primary closure?

Answer 17

1. Uninfected wound
2. Wounds less than 24 hours
3. Not hand, foot wounds
4. Healthy immune system

Question 18

Investigations?

Answer 18

Clinical presentation will determine the investigations to order
* RBG
* FBC
* U&E + Cr
* Wound culture
* X-Ray of the affected area

Question 19

Complications of human bites?

Answer 19

Closed-fist injury (most dangerous)
Chopping injury to the finger
Bites to nose and ear
Puncture type wounds above the head caused by clashing with tooth

Question 20

Mangement of human bites?

Answer 20

General principles of contaminated wound management apply to human bite wounds

Question 21

Causes of infection in human bites?

Answer 21

Polymicrobial infections likely:
1. Staphylococcus aureus,
2. Streptococcus
3. Eikenella corrodens

Question 22

Investigations in bites?

Answer 22

According to clinical presentation
1. Radiographs
2. Closed fist injury need exclusion of
vertical articular fracture of metacarpal head
3. Underlying osteomyelitis
4. Foreign bodies (retained teeth)

Question 23

Mangement of bites?

Answer 23

1. General principles apply here
2. Cleanse wound and debridement
3. Tetanus prophylaxis as indicated
4. Antibiotics prophylaxis
5. Leave wound open for delayed primary closure
6. Bulky dressing, splintage, elevation,
   physiotherapy

Question 24

Most common animal bites?

Answer 24

Most commonly dogs and cats. Other less common bites are from crocodiles, hyenas, skunk, bat, raccoon

Question 25

Most common locations for animal bites?

Answer 25

1. fingers of dominant hand 2. Defense mechanism

Question 26

Types of injuries in animal bites?

Answer 26

It may cause crushing and tearing injury to underlying bone, muscle, tendons, ligaments and nerves Note: Risk of infection is high

Question 27

Animal bite crushing injury?

Answer 27

dogs, large, herbivores, reptiles

Question 28

Animal bite puncture injury?

Answer 28

cats

Question 29

What kind of bite has a low risk of infection?

Answer 29

Highly vascularised areas have low risk of infection

Question 30

Microbiological causes of infection in animal bites?

Answer 30

1. Polymicrobial: bacteria, viruses, rickettsia, spirochetes, fungi 2. Bacterias commonly found are Pasteurella spp, Capnocytophaga spp, Bartonella henselae

Question 31

Microbiology of dog wounds?

Answer 31

1. Polymicrobial infections. Sources are the oral flora, environment and human skin normal flora 2. Pasteurella, streptococci, staphylococci, Neisseria species, Moraxella species, Fusobacterium, Bacteroides, Capnocytophaga Canimorsus 3. Capnocytophaga Canimorsus causes systemic infection; vomiting, diarrhoea, abdominal pain, headache, confusion, peripheral gangrene and cellulitis - MPatients may develop sepsis and DIC

Question 32

Microbiology of cat wounds?

Answer 32

Pasteurella species are highly prevalent in cat wounds than other bacterias such as streptococci, staphylococci, Moraxella, Bacteroides, Fusobacterium, Porphyromonas, and Prevotella - Pasteurella species mostly present with cellulitis. Additional less likely clinical features are regional lymphadenopathy and purulent discharge on the wound

Question 33

Assessment of animal bites?

Answer 33

* Distal neurovascular status * Tendon or tendon sheath involvement * Bone injury * Joint space violation * Visceral injury * Foreign bodies in the wound eg teeth, fur

Question 34

Management of animal bites?

Answer 34

1. Inspection: identify depth, devitalised tissue 2. Cleansing: copious irrigation of wound 3. Debridement 4. Closure: - If indicated in limited bite wounds that can be cleansed effectively - Contraindicated in puncture wounds, high risk animals eg cats, primates, pigs 5. Facial wounds can be closed - Highly vascularised 6. Tetenus and rabies prophylaxis for all wounds

Question 35

Complications of animal bites?

Answer 35

Complications of bite wounds include: * Wound infection * Sepsis * Cosmetic deformity * Loss of limb * Loss of function

Question 36

Venom classification in snake bites?

Answer 36

1. Local toxins * Swelling, blisters, tissue necrosis and pain 2. Systemic * Neurotoxic, * Cytotoxic * Heamatoxic * Myotoxin

Question 37

Death from snake bites result from?

Answer 37

1. Respiratory failure due to muscle paralysis 2. haemorrhage 3. renal failure

Question 38

Investigations of snake bites?

Answer 38

FBC Coagulation studies Fibrinogen, d-dimer Electrolytes, BUN/creatinine Glucose Creatine phosphokinase (CPK) Urinalysis Group and cross-match

Question 39

Management of snake bites?

Answer 39

1. Immobilise body part 2. Analgesia 3. Antivenom 4. Steroids and antibiotics not routinely required

Question 40

Bite wound disposition; surgery?

Answer 40

1. ICU, HDU, main wards, theatre 2. ICU Critical condition 3. HDU -Severe condition 4. Main ward -Moderate and mild condition 5. Theatre -Wounds requiring immediate debridement

Question 41

Bite wound disposition for critical conditions?

Answer 41

1. Hemodynamic instability (e.g septic shock requiring vasopressors), hemorrhagic shock ( requiring massive transfusion) 2. Respiratory compromise requiring intubation 3. All cardio-respiratory arrests 4. Reduced level of consciousness plus any of the above

Question 42

Bite wound disposition in severe condition?

Answer 42

1. Hypoxia responding oxygen 2. Haemodynamic instability responding to crystalloids or colloids 3. All patients requiring close monitoring