Health Awareness blog

Necrotizing fasciitis is a polymicrobial infection. It is characterized by rapidly advancing deep tissue necrosis. It may arise at site of minimal trauma and postoperative incision. Urgent evaluation is crucial because this deadly skin infection has mortality of 100% without surgical intervention. Causes:

• Gram- positive bacteria
• Gram-negative bacteria
• Anaerobes
• E.g.: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aerugenosa
• 10% of cases cause by streptococci (mainly group A streptococcus)

 Risk factors:

• History of penetrating injury
• Surgery
• Irradiation
• Malignancy
• Diabetes
• Alcoholism
• Malnutrition
• Peripheral vascular disease
• Intravenous drug use
• NSAID (non steroidal anti inflammatory drug) use in setting of soft tissue infection

 Presentation:

• Minor skin infections such as furuncles (in 20% of cases)
• Pain that is disproportionate to the clinical appearance
• Bacteremia
• Low blood pressure (hypotension)
• Fever
• Toxicity; infected are red, hot, shiny, exquisitely tender
• The lesion may progress into bullae and become necrosis; pain reduce due to peripheral nerve destruction

 Diagnostic procedure:

• Wedge biopsy down to the fascia at the affected region.
• Fine needle aspiration – the fluid is used for gram staining
• Frozen section tissue biopsy
• Culture and sensitivity of surgical sample and blood will help to identify the organism and to look for the most effective antibiotics
• MRI – to identify the site and depth of necrosis

Treatment:

If there is any suspicion of necrotizing fasciitis, the treatment need to be started straight away to prevent progression because this type of infection can lead to shock and death.

• Antibiotics such as penicillin, gentamycin, clindamycin ( to cover both aerobes and anaerobes)
• Swift and vigorous debridement of necrotic tissue – urgent surgical evaluation is critical!
• Supportive measures such as proper nutrition, hydration and monitoring should  be taken seriously

Reference:

1. Harrison’s Manual of Medicine. 16th edition. 2005.
2. Medical Progress Journal, February 2008