Necrotising fasciitis

Disease class: Fasciitis

Also known as
NecFasc or NF.

This refers to a necrotising soft tissue infection of the fascial plane of the skin. It is a surgical emergency.

 

Symptoms

• Relatively severe pain (disproportionate to appearance)

 

Signs

• Erythema 
• Oedema
• Blistering
• Rapidly advancing border
• Palpable crepitus
• Discharge: 'Dishwater pus'
• Visible necrosis (darkening tissue, losing integrity)

 

Risk factors

• Immunosuppression
• Diabetes
• Chronic disease
• Drugs, for example, steroids
• Malnutrition
• Age >60
• I.V. drug misuse
• Peripheral vascular disease
• Renal failure
• Underlying malignancy
• Obesity
• Blunt or penetrating trauma
• Soft tissue infections
• Surgery
• I.V. drug use
• Childbirth
• Burns
• Muscle injuries

 

Causes

Infection of the fascia

• Bacteria
• Type I 
• Polymicrobial
• Synergistic
• From bowel flora
• Mixed anaerobes and aerobes
• Type II 
• Monomicrobial
• From skin or throat
• Usually group A β-haemolytic streptococcus (GAS), occasionally S. aureus
• Type III
• Gram negative species
• Vibrio spp. mainly 
• From seafood, wound contamination with infected water
• Fungal
• Type IV
• Usually trauma associated
• In immunocompromised patients: Candida spp.
• In immunocompetent patients: Zygomycetes

Depth of infection

• Skin
• Epidermis
• Erysipelas
• Impetigo
• Folliculitis
• Ecthyma
• Furunculosis
• Carbunculosis
•  Dermis 
• Cellulitis

• Subcutaneous tissue
• Superficial fascia
• Subcutaneous fat, nerves, arteries, veins
• Necrotising fasciitis
• Deep fascia
• Muscle
• Myonecrosis

 

Types

• Fournier gangrene
• Chronic undermining burrowing ulcer (Meleney gangrene)

Management 

• Surgeons must be contacted for review. Plastic surgeons are ideal, but most surgical specialties have relevant training and experience.
• If NF is a serious probability:
• Adoption of an aggressive approach
• Surgical exploration as early as possible, examination of the fascia in the affected area
• Drainage
• Debridement
• Excision
• Amputation

 

Prognosis

• Mortality (in hospital): 19.3%. Predictors of mortality include : 
• Sex: female
• Age: >60 years
• Chronic heart disease, liver cirrhosis, skin necrosis
• Pulse rate: >130/min
• Systolic blood pressure: <90 mmHg
• Serum creatinine level: ≥1.6 mg/dL (1)
• Type II mortality: >32%
• Type III mortality: 30–40%
• Type IV mortality: >47% (higher if immunocompromised) (2)
• Infections with anaerobic species are associated with more surgical revisions of the wound.

See also

• Clostridial myonecrosis

Citations

1. Necrotizing fasciitis: risk factors of mortality, Risk Management and Healthcare Policy, P. Khamnuan et al., 2015.
2. Necrotizing fasciitis, Pejman Davoudian, Neil J Flint, Continuing Education in Anaesthesia Critical Care & Pain, Volume 12, Issue 5, 1 October 2012, Pages 245–250, https://doi.org/10.1093/bjaceaccp/mks033