Necrotizing soft tissue
was first described in 500BC by Hippocrates.
1871 Joseph Jons, an American army surgeon during the American Civil
War, described this infection as hospital gangrene and in 1951, Wilson
proposed the term of necrotizing fasciitis and included both gas
forming and nongas forming necrotizing infections.
Necrotizing fasciitis is commonly known as "flesh-eating disease".
infection of the subcutaneous tissue causes rapid destruction of
fascia and fat and can eventually lead to death of the patient
Necrotizing fasciitis is classified into broadly into two types,
Polymicrobial and Monomicrbial.
Type I NF refers to
mixed infections (Polymicrobial) involving anaerobes (Bacteroides
and Peptostreptococcis species),
and one or more facultative anaerobes, such as streptococci (non-group
A β-hemolytic Streptococcus) and
members of the Enterobacteriaceae family (eg,
Escherichia coli, and
Type II NF (Monomicrbial)
refers to infections that are caused by invasive group A β-hemolytic
Streptococcus. Type II can also be
caused by S. aureus,
Aeromonas hydrophila, and various
fungi such as Mucor,
Necrotizing fasciitis can occur in soft tissues, but most common areas
of expansion are the extremities, (particularly the lower legs) where
it commences as a poorly defined erythema, serosanguineous
blisters develop and subsequently necrosis occurs at the centre.
Trunk, abdomen, head,
neck area, or anal region are also often infected after surgery.
Lesions on the perineum and genital area with possible infection of
the abdominal wall are called "Fournier's gangrene".
Histopathology Image of Necrotizing fasciitis :
Septic vasculitis with
inflammation of the walls of vessels. There is occlusion of the
lumen by thrombus.
Common triggers are trivial trauma, burns, surgery, decubital ulcers,
perirectal abscesses or Fournier's gangrene and risk factors
include diabetes mellitus, immunosuppression, malnutrition, age,
intravenous drug misuse, peripheral vascular disease, renal failure,
malignancy, and obesity.
Patients with Necrotizing fasciitis usually present with severe pain
around the affected area and signs of skin infection (erythema,
swelling, oedema, subcutaneous plaques, or surface nodes).
These physical findings
may rapidly evolve into a haemorrhagic infarction of the subcutis, the
fascia and the dermis with the formation of painless gangrene.
Image of Necrotizing fasciitis :
Mixed inflammatory cell
infiltrate in the viable tissue
Microbial invasion of the soft tissues occurs either through external
wound from trauma or direct spread from injured hollow viscus
(particularly the lower gastrointestinal tract including the colon and
rectum) or genitourinary organs.
within the soft tissues releases a mixture of cytokines and endotoxins/exotoxins,
causing the spread of infection through the superficial and deep
This process causes
poor microcirculation and ischemia in affected tissues, ultimately
leading to cell death and tissue necrosis.
death rate may be as high as 30%–70% with death being due to sepsis,
respiratory failure, kidney failure, or multiorgan system failure.
Image of Necrotizing fasciitis :
Necrotic tissue and areas of
mixed inflammation in the subcutis.
Mortality rate is higher in women over 60 years of age, having chronic
heart disease, liver cirrhosis, skin necrosis, pulse rate >130/min,
systolic blood pressure <90 mmHg, and serum creatinine level ≥1.6 mg/dL.
Necrotizing fasciitis is
a serious infection of skin and soft tissues that rapidly progresses along
the deep fascia. It becomes a fatal soft tissue infection with high death
rate if treatment is delayed. Early diagnosis for emergency surgical
debridement and broad-spectrum antibiotic therapy are necessary treatments
to reduce death rate in this deadly infectious disease.