Chapter 61 Mammalian bites

Question 1

What are the most common mammalian bites?

Answer 1

Number 1: dogs

Number 2: cats

Question 2

List at least 5 pathogens responsible for infection from dog bites?

Answer 2

Aerobic bugs: Staph. aureus, alpha-hemolytic and beta hemolytic streptococci, klebsiella, bacillus subtilis, pseudomonas, enterobacteriaceae, and Capnocytophaga canimorsus

Anaerobic bugs: bacteroides, fusobacterium, peptostreptococcus, porphyromonas

Question 3

List 4 risk factors for overwhelming sepsis from a dog bite?

Answer 3

1) Alcoholic liver disease
2) functional or surgical asplenia
3) lung disease
4) corticosteroid use

Question 4

What first line antibiotic is a good choice for cat and dog bites?

Answer 4

Amox-clav 875mg po BID

For penicillin allergies:

• TMP-SMX
• moxifloxacin

Question 5

What are the risk factors for infection with animal bites?

Answer 5

1) Species factors: 
cat
human 
primate
pig, camel

2) Location of wound
hand
over joint or superficial tendon 
through and through oral 
below the knee

3) Wound type 
puncture 
extensive tissue damage 
contaminated or devitalized tissue
old (delayed presentation) or sutured

4) high risk patients 
immunosuppressed, HIV positive 
transplant patient, steroid dependent 
diabetes, cancer chemo
prosthetic valve patients
PVD
elderly, cirrhosis, alcoholis

Question 6

Describe the treatment of monkey bites

Answer 6

Monkey bites contain a highly virulent virus:

• Herpes virus simiae
• case fatality of 70% without antiviral therapy

Treatment:

1) mechanical debridement and vigorous irrigation immediately for 15 min
2) Prophylaxis: valacyclovir 1g PO Q8H TID x 14 days

or
acyclovir 800mg po 5 times daily x 14 days

3) Amox-clav for covering S. aureus and bacteroides (high risk for bacterial infection )

Question 7

Waterhouse-Friderichsen syndrome & Capnocytophagia related Gangrene sepsis

Answer 7

Adrenal hemorrhage from overwhelming sepsis: this is BAD! Super high mortality rates.

If you see gangrene at the site of a cat or dog bite, think about this. These patients can get SICK. DIC, renal failure, refractory hypotension. You can get metastatic endocarditis and meningitis.

Replace steroids early (eg Hydrocortisone 50-100mg IV Q6hrs). Look for adrenal hemorrhage on CT: not very sensitive. Cultures can be negative, even after 14 days of running the plates. Think about running a PCR for C. canimorsus