Cellulitis + necrotising fasciitis

Question 1

What is cellulitis?

Answer 1

Severe inflammation of dermal and subcutaneous layers of skin

Question 2

What causes cellulitis?

Answer 2

Staphylococcus aureus
Streptococcus pyogenes

Question 3

Gram stain of streptococcus pyogenes

Answer 3

Gram positive cocci in chains

Question 4

Gram stain of staphylococcus aureus

Answer 4

Gram positive cocci in clusters

Question 5

Symptoms of cellulitis

Answer 5

Inflammation + warm
Rash/erythema
Fever
Itchy
Fatigue
bullae
golden yellow crust (staph aureus infection)

Question 6

What is used to classify celluitis severity?

Answer 6

Eron classification

Question 7

What are the eron classifications?
What is it used for?

Answer 7

• class 1: no systemic toxicity or comorbidity
• class 2: systemic toxicity or comorbidity
• class 3: significant systemic toxicity or comorbidity
• class 4: sepsis or life threatening infection.
  .
  Used to classify the severity of cellulitis

Question 8

Management of cellulitis

Answer 8

• mild (class1/2): Oral flucloxacillin - beta lactam - inhibits cell wall synthesis
  doxycycline if penicillin allergy
• Severe (class3/4): admit + give IV co.amoxiclav or clindamycin
• Painkillers
• Monitor temp
• Rest + fluids

Question 9

What are the virulence factors of streptococcus pyogenes?

Answer 9

• Streptokinase - breaks down blood clots
• M protein - disrupts respiratory burst
• Hyaluronic acid capsules

Question 10

Acute complications of cellulitis

Answer 10

• necrotising fasciitis
• sepsis
• abscess
• myositis

Question 11

Chronic complications of cellulitis

Answer 11

• persistent leg ulceration
• recurrent cellulitis
• lymphoedema

Question 12

Causes of necrotising fasciitis

Answer 12

• type 1: mixed anaerobes + aerobes (most common)
• strep 2: strep pyogenes

Question 13

Presentation of necrotising fasciitis

Answer 13

• severe pain at site which is out of proportion to the appearance of the wound
• swelling of skin
• fever + flu like symptoms
• confusion
• blistering of skin
• fast developing/spreading red rash
• crepitus

Question 14

Treatment of necrotising fasciitis

Answer 14

• Urgent surgical debridement
• broad spectrum abx until cultures identify causative bacteria: clindamycin + tazocin or meropenem
• reconstructive surgery e.g. skin grafts
• amputation if extreme

Question 15

Risk factors of necrotising fasciitis

Answer 15

• Skin factors: recent trauma, burns, soft tissue infection
• diabetes mellitus
• IV drug use
• Immunosuppression

Question 16

Most commonly affected site of necrotising fasciitis

Answer 16

Perineum

Question 17

What test can be used to diagnose necrotising fasciitis

Answer 17

Sweep test

Question 18

Why is clindamycin used in treatment of necrotising fasciitis

Answer 18

Ribosome blocking abx to reduce toxin production in necrotising fasciitis