Skin and Soft Tissue Infections

Question 1

What is impetigo?

Answer 1

Superficial skin infection
Common in children
Golden crust is highly suggestive of this diagnosis

Question 2

Which bacteria commonly cause impetigo?

Answer 2

Staph aureus

Strep pyogenes

Question 3

Treatment of impetigo

Answer 3

Small areas with topical antibiotics

Large areas topical and oral antibiotics

Question 4

What is erysipelas?

Answer 4

Infection of the upper dermis

Question 5

Symptoms of erysipelas

Answer 5

Painful, red area
Associated fever
Regional lymphadenopathy and lymphangitis
Typically has distinct elevated borders

Question 6

Which bacteria commonly cause erysipelas?

Answer 6

Strep pyogenes

Question 7

What is cellulitis?

Answer 7

Diffuse skin infection involving deep dermis and subcutaneous fat
Presents as a spreading erythematous area with no distinct borders
Fever is common
Regional lymphadenopathy and lymphangitis
Possible source of bacteraemia

Question 8

Which bacteria commonly cause cellulitis?

Answer 8

Strep pyogenes

Staph aureus

Question 9

Treatment of erysipelas and cellulitis

Answer 9

Combination of anti-staphylococcal and anti-streptococcal antibiotics

Question 10

Hair associated infections

Answer 10

Folliculitis
Furunculosis
Carbuncles

Question 11

What is folliculitis and what is the most common cause?

Answer 11

Benign condition
Constitutional symptoms not often seen
Staph aureus

Question 12

What is furunculosis and what is the most common causative organism?

Answer 12

Deep infection of the hair follicle leading to abscess formation with accumulation of pus and necrotic tissue
Staph aureus

Question 13

What is a carbuncle?

Answer 13

A cluster of furuncles

Question 14

Treatment of folliculitis

Answer 14

None required

Question 15

Treatment of furunculitis

Answer 15

If no improvement, oral antibiotics might be necessary

Question 16

Treatment of carbuncles

Answer 16

Often require admission to hospital, surgery and intravenous antibiotics

Question 17

What causes necrotising fasciitis?

Answer 17

EMERGENCY
Type I - mixed aerobic and anaerobic infection (diabetic foot infection, Fournier’s gangrene)
Streptococci
Staphylococci
Enterococci
Gram negative bacilli
Clostridium
Type II - monomicrobial
Normally associated with strep pyogenes

Question 18

Treatment of necrotising fasciitis

Answer 18

Surgical review mandatory

Broad spectrum antibiotics

Question 19

What is pyomyositis?

Answer 19

Purulent infection deep within striated muscle, often manifesting as an abscess
Infection is often secondary to seeding into damaged muscle

Question 20

Commonest cause of pyomyositis

Answer 20

Staph aureus

Also gram positive/negatives, TB and fungi

Question 21

What is infectious tenosynovitis?

Answer 21

Infection of the synovial sheats that surround tendons

Penetrating trauma most common inciting event

Question 22

Most common causative organism of infectious tenosynovitis

Answer 22

Staph aureus

Streptococci

Question 23

Diagnostic criteria for staphylococcal TSS

Answer 23

Fever
Hypotension
Diffuse macular rash

Three of the following organs involved:
Liver
Blood
Renal
Gastrointestinal
CNS
Muscular

Question 24

Treatment of TSS

Answer 24

Remove offending agent (ex tampon)
Intravenous fluids
Inotropes
Antibiotics
Intravenous immunoglobulins

Question 25

What causes toxin-mediated syndromes?

Answer 25

Staphylococcus aureus | Streptococcus pyogenes

Question 26

What is staphylococcal scalded skin syndrome?

Answer 26

Infection due to a particular strain of Staph aureus producing the exfoliative toxin A or B Characterised by widespread bullae and skin exfoliation Usually occurs in children but rarely in adults as well

Question 27

Treatment of staphylococcal scalded skin syndrome

Answer 27

IV fluids and antimicrobials

Question 28

Most common organism in IV catheter associated infections

Answer 28

MRSA MSSA Commonly form a biofilm which then spills into bloodstream

Question 29

``` Surgical wounds class I ```

Answer 29

Clean wound

Question 30

``` Surgical wounds class II ```

Answer 30

Clean-contaminated wound

Question 31

``` Surgical wounds class III ```

Answer 31

Contaminated wound

Question 32

Surgical wounds class IV

Answer 32

Infected wound

Question 33

Causes of surgical site infections

Answer 33

``` Staph aureus Coagulase negative Staphylococci Enterococcus Escherichia coli Pseudomonas aeruginosa Enterobacter Streptococci Fungi Anaerobes ```