Necrotizing fasciitis natural history, complications and prognosis

If left untreated, the acute inflammatory changes spread quickly, accompanied by high fever and extreme weakness leading to necrosis of soft tissue. Common complications of necrotizing fasciitis include limb loss, sepsis, toxic shock syndrome, disseminated intravascular coagulation (DIC). Depending on the extent of the necrotizing fasciitis at the time of diagnosis, the prognosis may vary. The prognostic factors associated with necrotizing fasciitis include diabetes mellitus, acute renal failure, admission serum creatinine >2mg/dl and admission white blood cells >30,000 cells mm3.

• If left untreated, the acute inflammatory changes spread quickly, accompanied by high fever,extreme weakness and may progress to death.^[1]
• The overlying skin becomes smooth, tense and shiny. Diffuse erythema without distinct borders is seen.
• First 1 or 2 days, the lesions develop with progressive color changes from red to purple to blue and then becomes frankly gangrenous, first turning black, then greenish-yellow.
• If the patient has survived, a line of demarcation between viable and necrotic tissue would become sharply defined from days 7 to 10.
• Sloughing of necrotic skin would reveal the underlying pus and extensive liquefactive necrosis of subcutaneous tissues, which will be significantly more extensive than would be suspected with the overlying area of necrotic skin.
• Metastatic abscesses and pulmonary distress may develop as well.

Common complications of necrotizing fasciitis include:^[2]

• Limb loss
• Sepsis
• Kidney failure
• Compartment syndrome
• Extensive scarring and disfigurement
• Toxic shock syndrome
• Rapid advancement of disease resulting in death
• Disseminated intravascular coagulation

• Most of Type 2 NF cases are associated with streptococcal toxic shock syndrome which increases the mortality of streptococcal NF alone from <40% to 67% with up to half of patients needing amputation.
• The superantigens cause massive activation of T-cell, cytokine release, tissue damage, and toxic shock-like syndrome

Depending on the extent of the necrotizing fasciitis at the time of diagnosis, the prognosis may vary.^[3]

• The prognostic factors associated with necrotizing fasciitis include:

• Timing to operative intervention (most important prognositic factor)
• Age older than 60 years
• Female gender
• Number of comorbidities
• Acute renal failure
• Underlying malignancy
• Coagulopathy or acidosis on admission
• Clostridial or group A streptococcal infection
• Vibrio vulnificus infection
• Admission white blood cells >30,000 cells/mm3
• Diabetes mellitus
• Shock on admission
• Admission serum creatinine >2mg/dl
• Associated streptococcal toxic shock syndrome
• Over expression of cytokines in host
• Immunodeficiency
• High APACHE (Acute physiology, Age, and chronic health evaluation) II scores (>13)
• Use of NSAIDs