Necrotising fasciitis

Question 1

What is necrotising fasciitis?

Answer 1

Life-threatening infection of subcutaneous soft tissue.
Spreads along fascial places
DOES NOT spread to underlying muscle

Question 2

Classifications of necrotising fasciitis and their causes?

Answer 2

Type 1 - caused by mixed anaerobes and aerobes
Type 2 - caused by Streptococcus pyogenes (group A strep)

Question 3

Most common type of necrotising fasciitis?

Answer 3

Type 1 - caused by mixed anaerobes and aerobes

Question 4

When does Type 1 Necrotising fasciitis commonly occur?

Answer 4

Post-surgery in diabetics

Question 5

RF for necrotising fasciitis?

Answer 5

Skin factors - recent trauma, burns, soft tissue infections
DM - especially if using SGLT-2 inhibitors
IV drug use
Immunosuppression

Question 6

Site commonly affected in necrotising fasciitis?

Answer 6

Perineum (Fournier’s gangrene)

Question 7

Presentation of necrotising fasciitis?

Answer 7

Acute onset - rapidly worsening cellulitis
Pain - out of keeping with physical features
Oedema and purplish rash
Dark marks form and turn into blisters filled with dark fluid
Erythema
Systemically unwell - fever, tachycardia, hypotensive, tachypnoeic

Late signs = skin necrosis and crepitus/gas gangrene

Question 8

Late signs of necrotising fasciitis?

Answer 8

Skin necrosis
Crepitus/gas gangrene

Question 9

Management of necrotising fasciitis?

Answer 9

Urgent surgical referral debridement
IV abx - broad spec - benzyl penicillin IV and clindamycin if limbs head, neck, chest. If in perineum pipperscillin/tazobactam + gentamicin
Haemodynamic support