Skin and Soft Tissue Infections

Question 1

What is the main bug that causes purulent infections?

Answer 1

Staph aureus

Question 2

What is the cornerstone of management for purulent infections?

Answer 2

Incision and drainage

Send a sample of pus to lab for gram stain and culture

Question 3

2 abx for MSSA

Answer 3

Cloxacillin

Cefazolin

Question 4

Purulent infection empiric abx for

1. No systemic toxicity/immunocompromise
2. Yes ystemic toxicity/immunocompromise

Answer 4

1. TMP-SMX or Doxycycline

2. Vancomycin

Question 5

4 signs of systemic toxicity

Answer 5

Temp > 38
HR > 90
RR > 24
WBC < 12 000

Question 6

Non-bullous impetigo

Answer 6

Highly infectious
Mostly in school age children
Staph aureus > GrpA strep but cover both
Clinical dx 
Topical abx if localized (Mupirocin) or cephalexin
Post-strep GN RARE complication

Question 7

Bullous impetigo

Answer 7

Neonates most commonly
From toxin producing staph aureus (exfoliative toxin A and B)
Dx is clinical and blood cultures
Oral or IV anx (cephalexin, cefazolin or vanco)
Risk of dehydration and sepsis

Question 8

Erysipelas

Answer 8

Non purulent infection
Limited to upper dermis and superficial lymphatics
Sharp, raised, well-demarcated erythema
Rapid onset, fever and signs of systemic toxicity
Facial involvement common
Almost always group A strep!
Oral: penicillin, amoxicillin, cephalexin. IV: penicillin, cefazolin

Question 9

Cellulitis

Answer 9

Lower extremities most common
Normal skin flora invades a break in the skin to cause infection in the dermis and subcutaneous tissue
Can be simple and localized or severe

Question 10

What is the microbiology of non-purulent cellulitis?

Answer 10

> 75% is streptococcus
Staph aureus is less common, more so with injection drug users, penetrating trauma, and open wounds
MRSA is NOT a common cause of non-purulent cellulitis

Question 11

Which empiric abx to choose for non purulent cellulitis

1. No systemic toxicity, immunocompromised, or failed abx
2. Yes systemic toxicity, immunocompromised, or failed abx
3. 2, plus signs of sepsis or necrotizing faciitis

Answer 11

1. Cephalexin or amoxicillin or penicillin V
2. Cefazolin
3. Pip-tazo and Vancomycin

Question 12

Clinical triad of septic arthritis

Answer 12

Fever
Pain
Decreased ROM

Question 13

Most common micro cause of septic arthritis

Answer 13

Staph aureus

Question 14

Tx for septic arthritis

1. Gram + cocci
2. Gram - bacilli
3. Gram stain negative or mixed

Answer 14

1. Vanco
2. Ceftriaxone
3. Vanco and Ceftriaxone

Question 15

What abx is used to treat biofilms?

Answer 15

Rifampin

Question 16

Most common cause of

1. Cat bites
2. Dog bites

And how to treat them

Answer 16

1. Pastuerella multocida
2. Pastuerella canis

Amoxicillin-clavulanate

Question 17

What is the best test for osteomyelitis?

Answer 17

MRI!

But x-ray is pretty good with chronic wounds