Necrotising Fasciitis

Definition

 

Infection of skin and subcutaneous tissue

- spreads across fascial planes

- many microbes can be responsible

 

Types

 

Type 1 Polymicrobial

 

Type 2 Monomicrobial

 

Aetiology

 

Group A Beta Hemolytic Strep (S. pyogenes)

- most common cause monomicrobial

 

S. Aureus / MRSA

 

Vibrio

- wound contaminated with saltwater

 

Clostridium

 

Anaerobes

 

Predisposing factors

 

Trauma

- insect bite

- skin laceration

- needle injection

- IVDU

 

Post operative

 

Diabetes

 

Clinical

 

History of trauma / surgery / IVDU

 

Pain out of proportion

 

Skin

- initially swollen and red

- superficial nerves destroyed / skin anaesthetic

- becomes necrotic

 

Patient febrile and unwell / septic / in shock

- high temperatures

- altered levels of consciousness

 

MRI

 

Can distinguish between cellulitis and necrotising fasciitis

- increased T2 signal along fascia

 

Management

 

High index clinical suspicion

 

Surgery

 

Debridement of infected skin and subcutaneous tissue

- tissue and fluid sent for immediate MCS

- exclude myonecrosis

 

Antibiotics

 

Broad spectrum

- penicillin / vancomycin

 

Hyperbaric Oxygen

 

Skin cover

- becomes late problem

- patient may need extensive skin flaps

 

Prognosis

 

Mortality rates up to 25%