NECROTISING SOFT TISSUE INFECTION- Dr. Kiran Kumar G.
• NECROTIZING SOFT-TISSUE INFECTIONS (NSTI) comprise a
spectrum of disease entities that are characterized by extensive ,
rapidly progressive soft-tissue necrosis that usually involve deep
subcutaneous tissue, superficial or deep fascia, or muscle, or
any combination of the three.
• Necrotizing soft-tissue infections are classified as fasciitis , or
myositis, based on the principal soft-tissue layer involved with
Is a soft tissue infection with an
intact blood supply and viable
Marked by an acute inflammatory
response with small vessel
engorgement and stasis,
endothelial leakage with interstitial
edema, and leukocyte infiltration
It is typically located in a more
An infectious process characterized
by a necrotic center, without a blood
Composed of debris from local
tissues, dead and dying WBC’s,
components of blood and plasma,
Pus is surrounded by a vascularized
zone of inflammatory tissue.
NON NECROTISING SOFT TISSUE INFECTIONNSTI VS
First reported by Hippocrates as “flesh, sinews, and bones fell away in large
quantities...There were many deaths.”2
They were labeled as Streptococcal gangrene, Phagedena, and Phagedena
An army surgeon was the first to report a necrotizing infection in the United
States in 1871
In 1883, FOURNIER described a gangrenous infection of the scrotum
In 1924, MELENEY documented the pathogenic role of streptococci in soft
In 1952, Wilson coined the term necrotizing fasciitis
A substantial number of classifications based on anatomic location,
microbiology, and depth of infection have been described.
The wide range of classifications makes understanding of this entity
rather confusing, when the only important factor to be determined is
the presence or absence of a necrotic component requiring surgical
Necrotizing soft tissue infections types:
1) Necrotizing fasciitis type I (Polymicrobial),
2) Necrotizing fasciitis type II (Group A streptococcal),
3) Necrotising fasciitis type III(marine vibrios)
4) Specfic syndromes:
a. Clostridial myonecrosis
b. Fourniers gangrene
Usually occurs after trauma or surgery
Subcutaneous fat and fascia overlying muscle are prominently
Primarily includes 3 categories (locations) of infection
Diabetes Mellitus- infections of the feet
Cervical necrotizing fasciitis- infection of the neck
Fournier’s Gangrene- infection of the perineum
Course of disease is usually somewhat slower than that seen with
type II (streptococcal) necrotizing fasciitis and clostridial
2/3 of cases have mixed aerobic and anaerobic infections
The bugs: The average case had 4-6 isolates
•Preveoella and Porphyromonas
Caused by virulent subtypes of streptococcus pyogenes.
The bacteria is often referred to as a flesh-eating bacteria.
The incidence of this infection increased in the last two decades,
• Improvements in diagnosis and reporting.
• Result of an organism virulence
The presence of the M1 and M3 proteins is associated with virulent
Most of the general features of NSTI
the presence of gas in tissues is unusual.
Caused by the marine vibrios(gram
Vibrio vulnificus, vibrio parahemolyticus,
vibrio damsela, vibrio alginolyticus
Puncture wound from fish, cut or insect
bite exposed to sea water, shellfish or fish
in tropical water
Synthesize an extracellular toxin
This bacteria has an alarming mortality
rate of 50%.
First described by French verenologist JEAN
ALFRED FOURNIER who witnessed a rapidly
progressing gangrene of the penis and scrotum of 5
previously healthy young men.
A polymicrobial necrotizing fasciitis (NF) of the
perinium, perianal area, or genitals. It may involve
either men or women.
Mostly age 30-60, although all ages have been
Tenderness to palpation (beyond area of
Skin fluctuation or induration
Hemorrhagic bullae or skin necrosis
Tense edema around involved skin
Crepitus (present 10% of time)
• These are all fairly specific, but have a sensitivity of
• May be erythematous, edematous, cyanotic, bronzed,
indurated, blistered, or frankly gangrenous.
• Generally the appearance of the skin underestimates
the degree of underlying disease.
Diabetes mellitus (present in up to 60% of cases)
Established by making a small skin incision and passing a haemostat or probe
through the subcutaneous tissues.
In necrotizing fasciitis the subcutaneous and fascial layers lack resistance to this
manoeuvre, a feature that indicates widespread tissue necrosis underneath seemingly
Gas may or may not be present in the soft tissues
Shows widespread necrosis of subcutaneous fat and fascia, with relative sparing of
An acute inflammatory reaction, with many Polymorphonuclear cells,
Thrombosis of blood vessels and abundant Bacteria
1. Blood samples-for TLC,DLC
2. Testing for elevated or lowered creatinine, glucose, CPK,
bicarbonate, albumin, and calcium levels.
4. CT, and MRI scanning in advanced cases
5. And most importantly antibiotic culture and sensitivity tests
This score allows early classification of patients according to disease severity
identify patients at high risk of death
Identify a high-risk patients in whom surgical decision making debridement vs
Control or attempts at limb salvage with repeat operative debridements.
A prognostic score which allow weigh the relative risks and benefits of an
Score can be used for comparisons across institutions and over time, providing a
more formal means to assess the impact of interventions
Early and aggressive surgical exploration and debridement
This should be done in the first 24 hours of symptoms
Surgical mortality 6% (<24hrs), 24% (>24hrs)
Repeat debridement should be repeated daily until all necrotic tissue
has been removed (typically 2-4 times)
Fourneir’s Gangrene may require cystostomy, colostomy, or
orchiectomy (although this is rare).
• Virtually 100% of patients will die on antibiotics without
• Antibiotics should be broad-spectrum until cultures return
• Type 1- ampicillin or ampicillin-sulbactam and clindamycin
or metronidazole. For patients with prior hospitalization
substitute ticarcillin-clavulanate or piperacillin-tazobactam
• Type 2- penicillin group + clindamycin. Add vancomycin to
cover for MRSA
• Type 2
• In the case of streptococcal toxic shock massive amounts of fluid (10-20
L/day) may be necessary to maintain perfusion. Pressors such as
dopamine may also be required
• IV Ig has also been used to neutralize the streptococcal superantigens,
however no studies have been done to support this use
• NF can progress rapidly leading to amputation or death
• A degree of suspicion is necessary to get a patient to surgery for
diagnosis and treatment
• Treatment primarily involves surgery ,surgery , and only surgery and
• Even with rapid treatment mortality remains high