4/7 Skin & Soft Tissue + Ch 6

Question 1

Focal infections like boils are usually from what? treatment should be what?

Answer 1

Usually from Staph aureus.

Treatment should cover MRSA (unless you have a culture cooking)

Question 2

Spreading infections (like cellulitis) are usually from what? Sensitive to what?

Answer 2

Usually from GAS (strep pyogenes).

Sensitive to PCN

Question 3

Cat bite: what bug?

Answer 3

Pasturella

Question 4

Human bite: what bug?

Answer 4

Eikenella

Question 5

Cellulitis after trauma: what bug?

Answer 5

Group A Strep or Staphylococci

Question 6

Fresh water trauma: what bug?

Answer 6

Aeromonas

Question 7

Salt water trauma: what bug?

Answer 7

Vibrio vulnificus

Question 8

Rose gardener: think about what bug?

Answer 8

Sporotrichosis

Question 9

Fish tank exposure: think about what?

Answer 9

Nodular skin lesions in someone with aquatic exposure including fish tanks can be from “fish tank granuloma”

bug = Mycobacterium marinum (cousin of TB)

Question 10

A spreading infection like cellulitis usually is the result of what kind of event?

What organism again?

Answer 10

A microtrauma to the skin: a caught zipper, a toenail infection, surgery.

Likely group A strep (pyogenes)

Question 11

Besides PCN, what is another antibiotic that is commonly used for Group A Strep? Is this appropriate?

Answer 11

Cephalexin (1st, PO )is commonly used for cellulitis - but it is overkill in most cases, since it covers much more than just Group A strep.

Question 12

Focal infections like boils and other abscesses: at what point do they need to be drained?

What bug are we talking about again?

Answer 12

if bigger than 1cm in diameter, need to be drained.

Staph aureus.

Question 13

Focal infections (boils, etc): what is a primary treatment?

Answer 13

• Drain if larger than 1cm
• Moist heat for comfort and to aid healing

Question 14

Focal infections: when we have to use abx, what should we use? what if the pt is in the hospital?

Answer 14

have to target MSSA as well as MRSA.

Examples (in order of desirability):

• Trimethoprim-sulfamethoxazole (TMP/SMX)
• Doxycline
• Clindamycin
• Vancomycin (hospitalized pts)

Question 15

If a pt has recurrent focal infections (staph), either due to recurrent exposure, due to close contact who sheds it, or due to chronic nasal carriage, what are preventative measures we can take?

Answer 15

Treat episodes as independent events

In between:

Treat contacts

Reduce nasal carriage via nasal mupirocin

Question 16

What is the level of tissue involvement of the following:

• Fasciitis
• Erysipelas
• Folliculitis, Furuncle, Carbuncle
• Myositis
• Cellulitis
• Impetigo

sorry Jen - i mixed it up

no worries!

Answer 16

Impetigo

Erysipelas

Cellulitis & Folliculitis/Furuncle/Carbuncle (hair follicle in this layer)

Fasciitis

Myositis

Question 17

Necrotizing Fasciitis: what is the bug? what can accompany the infection?

Answer 17

Bug: GAS or staph (OR, rarely, from gram negs)

involves the fascia, spreads quickly

If from GAS or staph, can be accompanied by shock from bacterial toxins.

Question 18

Necrotizing Fasciitis: what is the appropriate response? tx?

Answer 18

• Hospital admission
• MRI for dx
• Rapid surgical debridement
• Start with wide abx coverage, narrow down once the pathogen is identified.
• Often use clindamycin to slow the elaboration of the toxin

Question 19

Impetigo: bug?

Tx for mild cases?

More severe cases?

Answer 19

Typically Strep

Mild: topical ointment like mupirocin

Severe: think of this as cellulitis, and use cephalexin (+ possibly TMP/SMX depending on likelihood of MRSA).

Question 20

Erysipelas: bug? treatment?

Answer 20

Caused by GAS

commonly has systemic sx (fever)

Tx = systemic antibiotics like oral PCN

Question 21

What is paronychia? tx?

Answer 21

usually due to staph aureus

Inflammation of the skin around a nail bed.

Tx: moist heat, possibly drainage, abx for systemic or large lesions

(MSSA -> dicloxacillin or cephalexin)

Question 22

What is Folliculitis? tx?

Answer 22

Multiple red spots centered on hair follicles.

Usually from Staph

Topical therapy: Polymixin B or Mupirocin

Question 23

Anthrax: caused by what? what is presentation?

Answer 23

Caused by Bacillus anthracis (gram + rod).

Painless eschar with surrounding tissue edema in someone with exposures either to animal hides or terrorists.

Question 24

Common cause of secondary cellulitis?

Answer 24

infection of devitalized tissue: diabetic foot infections, decubitus ulcers (bedbound pts)

Question 25

What is a rare but serious cause of cellulitis? what are risk factors? what are clues?

Answer 25

Clostridium perfringens

Risk fx: soil or stool contamination, devitalized tissue.

Clues: gas production (on exam or XR), foul odor, tissue necrosis, rapid stread, presence of Gram + rod.

Question 26

Lyme Disease: bacterium? Tx?

What are possible sx of Lyme besides rash?

Answer 26

Bacterium = Borrelia burgdorferi (tick-borne)

Tx = doxycycline

May have Bell’s Palsy, septic monocular arthritis, meningitis, heart block.

Question 27

clostridium perferingens causes what?

how is it diagnosed?

Answer 27

bacterial infection of muscle -> myonecosis (gas gangrene)

xray - see bubbles

foul odor

tissue necrosis

Question 28

2 scenarios that might make you think of Anthrax?

How does Anthrax stain? what shape?

Answer 28

• Someone who works with animal hides (a tanner)
• Terrorist scenario

Anthrax = Gram neg rods