Necrotising Fasciitis

Necrotising fasciitis (NF) is a rare but serious bacterial infection that affects the soft tissue and fascia (Fournier gangrene, is NF affecting the perineum). In many cases NF progresses rapidly and early recognition and treatment is vital to halt progress. The mainstay of treatment is IV antibiotics and aggressive surgical debridement. Any delay increased the amount of tissue loss as well as the mortality.

Clinical course

NF can progress very rapidly in some cases within 0-2 hours from infection, however others may progress over days.
The main stay of diagnosis is “pain disproportinate to skin signs”, crepitus is only present in 13.5% of patients at presentation so is a poor diagnosistic sign.
- Stage 1 [Requires clinical suspicion]:
  - Intense and severe pain – which may seem out of proportion to any external signs of infection on the skin
  - Lesion – a small but painful cut or scratch on the skin
  - Fever -and other flu-like symptoms
- Stage 2 [Obvious]:
  - Swelling – of the painful area, accompanied by a rash
  - Blistering – large dark blotches, that will turn into blisters and fill up with fluid
  - Systemic symptoms – diarrhoea and vomiting
- Stage 3 [Septic Shock – mortality >40%]:
  - Hypotension – severe fall in blood pressure
  - Toxin released – from the bacteria
  - Reduced GCS

Physical findings on admission

Erythema – 100%
Tenderness – 97.8%
Warm skin – 96.6%
Tachycardia (>100bpm) – 74.2%
Fever (>38°C) – 52.8%
Bullae – 45%
Hypotension – 18%
Crepitus – 13.5%
Necrosis of skin – 13.5%

Risk Factors

Age – esp. over 50yrs
PMH – Diabetes, alcoholic liver disease, cancers, hypoalbuminaemia, renal failure, strangulated femoral hernia, peripheral vascular disease, diverticulitis
Nutrition – Obesity, malnutrition
Drugs – Steroids, NSAIDS, IVDU
Trauma/Surgery

Aetiology

Polymicrobial (71%)– in studies upto 6 organisms have been found inc; streptococci, staphylococci, E.coli, Pseudomonas and Klebsiella
Monomicrobial (29%)– often streptococcal infection

Investigation

(The following may help but early senior surgical input should be sort as early diagnosis and management is a clinical decision)

Bloods: VBG, FBC, U&E, LFT, CRP, Clotting, G&S, Cultures(2 Pairs)
Wound Swab
Imaging: (Remember: Surgical emphysema is a late sign)
- Xray
- CT

Management

Antibiotics IV – Involve microbiology early, as NF is often polymicrobial
Fluids IV
Analgesia IV
Surgical Debridement – Early senior surgical review, ideally consultant (early recognition is vital, but also these patients are often frail with many co-morbidities and decision making imay be complex). The surgical speciality involved will depend on the site.