Necrotizing Fasciitis can potentially be a life-threatening and limb-threatening bacterial soft tissue infection. Although it is commonly polymicrobial, one of the notorious organism is Group A Beta Hemolytic Streptococcus (GABHS). The organisms are commonly anaerobic types as these organisms thrive well under the local tissue hypoxia environment although the anaerobic organisms can co-exist with the aerobic types.
Unbeknownst to the patient, often the organism enters the subcutaneous tissue due to very trivial trauma. Nonetheless, as expected, there will be certain predisposing factors which render the host to be immunocompromised for such severe soft tissue infection to occur; viz, diabetes mellitus.
To differentiate necrotizing fasciitis which may rapidly lead to fulminant sepsis and septic shock from cellulitis, one of the key clinical feature of necrotizing fasciitis is that:
the pain and tenderness that the patient experiences may be "out of proportion" to the visible skin lesion externally (in fact, the overlying skin changes are often milder compared to the degree of necrosis occurring underneath).
Secondly, some patients with necrotizing fasciitis may have subcutaneous emphysema which probably is not present in simple cellulitis.
Thirdly, from the external look as well, the picture of necrotizing fasciitis just appear "uglier" with bullous lesions with serous discharge (as in the picture above).
Pathologically, in necrotizing fasciitis, the organisms are notoriously aggressive by invading the underlying fascia (thus the name, fasciitis). This also earns them the title "flesh eating bacteria syndrome". In contrast, in simple cellulitis, the organisms seldom go beyond the underlying fascia, although, if left untreated, necrotizing fasciitis is a sequelae of cellulitis.
Read an article from e-Medicine online here.
Download a FREE BMJ Review article on necrotizing fasciitis here.
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© 2010 by Dr. Keng Sheng CHEW.
Necrotizing Fasciitis by Dr. Keng Sheng CHEW is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
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