Necrotising fasciitis

Necrotising fasciitis is an infection of the subcutaneous tissue/fat and fascia of the skin. It spreads rapidly along the fascial plane. Muscles are less commonly affected/ affected later in the disease due to better blood supply.

Type 1 – polymicrobial/synergistic

• Aerobic and anaerobic bacteria (Often derived from gut/bowel)

Type 2 – monomicrobial

• Group A Streptococcus (Strep pyogenes), occasionally Staph aureus (especially in neonates).

Type 3

• Vibrio spp mainly;

• Other organism – Pasteurella multocida, Haemophilus influenzae , Klebsiella spp. and Aeromonas spp.

• Common in Asia, associated with seafood/seawater.

Type 4

• Fungal

• Candida in immunocompromised or zygomycetes in immunocompetent patients.

• Type 1 is the commonest (up to 80% of cases).

• Type 4 has the highest mortality.

• Some authorities classify the necrotising fasciitis as only of two types –
  Type 1 – polymicrobial.
  Type 2 – monomicrobial (NF caused by Vibrio, fungus etc., falls into this category).

Approx 20%. It is a surgical emergency

• Perineum and lower extremities (commonest)

• Surgical site,

• Upper extremities,

• abdomen,

• Mouth

• Face

• Trauma – including surgery

• Burns

• Skin and soft tissue infection

• Immunosuppression

• Obesity/malnutrition

• Alcoholism

• Peripheral vascular disease

• Intravenous drug abuse and

• Diabetes mellitus - the most common preexisting medical condition

• Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• Recent varicella-zoster - especially in children.

• Common sign/symptoms are – swelling (75%), pain (72.9%), and erythema (66.3%) [Diab, BMJ 2020].

• The skin changes often do not reflect the extent of the damage.

• Pain could be out of proportion to skin changes.

• Anaesthesia over the infected area also could be present.

• One-fifth of patients have influenza-like symptoms characterised by fever and myalgia

• Inflammatory markers (WCC, CRP) could be raised along with creatine kinase and creatinine.

• Patients may deteriorate rapidly, developing signs of sepsis. In the later stage NF could present with visible bruising, bullae and cutaneous necrosis

It is a surgical emergency – an immediate surgical referral must be done.
Inform the intensive care about potential post-operative care and organ support.

• Debridement.

• Haemodynamic support.

• Broad-spectrum empirical antibiotic.

Infection control and public health:

• Isolation of the patient until group A Streptococcus is excluded as a pathogen

• If group A Streptococcus isolated - the patient should be isolated as per local policy for invasive group A Streptococcus infection.

• If group A Streptococcus is isolated – inform public health.