Features reported to be indicative of NF on the computed tomography scan include deep
fascial thickening, enhancement, and fluid and gas in the soft tissue planes. Negative deep
fascial involvement on MRI effectively excludes NF. Fine-needle aspiration, frozen section of
tissue biopsy, fascial biopsy, and skin biopsy for histopathology are all useful in the diagnosis
of NF. The lack of bleeding may be seen or murky dishwater pus exudates may ooze from the
incision site.
Pathognomonic for NF is a positive “finger” test. The finger test can be used to delineate
the extent of infection into the adjacent normal appearing skin. A 2-cm incision down to the
deep fascia is made under local anesthesia. Probing of the level of the superficial fascia is then
performed. The lack of bleeding, foul smelling dishwater pus, and minimal tissue resistance to
finger dissection constitute a positive finger test, which is diagnostic of NF (53,56).
Treatment
If a diagnosis of NF is made, emergent surgical debridement and/or fasciotomy should be
considered (Figs. 5 and 6). Debridement beyond the visible margin of infection is necessary.
Repeated debridements may be required and should continue until the subcutaneous tissue
can no longer be separated from the deep fascia. Fasciotomy may be performed at the time of
debridement. If infection progresses despite serial debridements and antibiotics, amputation
may be life saving. Close monitoring of the physiology of the patient as well as serial
laboratory data should be performed. Aggressive fluid resuscitation is often required during
postoperative period. A combination of broad-spectrum antibiotics, such as penicillin, and an
aminoglycoside or a third-generation cephalosporin, and clindamycin or metronidazole can be
started depending on the clinical presentation. IfS. aureusis a consideration vancomycin or
linezolid should be included. Once the Gram stain culture and sensitivity results are obtained,
the antibiotic regimen can be altered on the basis of these findings. The use of intravenous
immunoglobulins (IVIGs) as an adjunctive treatment for patients with streptococcal toxic
shock syndrome (STSS) has been used on the basis of retrospective studies and one small
prospective randomized trial, but conclusive evidence supporting its use remains limited. IVIG
contains many antibodies, which neutralize the exotoxins/superantigens secreted by the
Streptococcusand are involved in the pathogenesis of STSS. Since STSS and NF are mediated by
the streptococcal toxins and inflict their tissue destruction via some of the same cytokines, it
was postulated that IVIG would be as effective a treatment in NF as it was in STSS. This has yet
to be conclusively demonstrated in a clinical trial. Hyperbaric oxygen has been advocated by
Figure 5 Necrotizing fasciitis of left arm and shoulder in an IVDU patient who injected in the left arm. Patient
underwent disarticulation. One set of blood culture grewGemella morbillorumand second set grewStreptococcus
constellatus. Operative cultures obtained from left arm grewKlebsiella oxytoca, Peptostreptococcus micros, and
Peptostreptococcus prevoti.Abbreviation: IVDU, intravenous drug user.
304 Sharma and Saravolatz