Tuesday, June 26, 2012

Necrotizing fasciitis -- An indiscriminant killer

Cara N. Wilder, Ph.D.

Imagine one of the happiest moments of your life turning into a fierce battle against impending death. This is the harsh reality a South Carolina woman had to face in May as she went from becoming a new mother to one of the latest victims of necrotizing fasciitis. Only days after giving birth to twins, Lana Kuykendall was admitted to the hospital after her husband, a certified EMT, noticed a rapidly expanding bruise on her leg. After enduring almost 20 surgical procedures to remove necrotic flesh and reconstruct the surface of her leg via skin grafting, she is considered fortunate to be alive and in one piece1.

Photomicrograph of Group A Streptococcus,
one of the leading causative agents of
necrotizing fasciitis. Photo provider: CDC
In the United States alone, there are approximately 250 cases of necrotizing fasciitis per year of which 20% are fatal. Recent news reports, such as that listed above, have highlighted the ever-growing concern associated with necrotizing fasciitis. This rare infection results from the subcutaneous invasion of one or more bacterial species that rapidly spread across the fascial plane, destroying surrounding muscles, nerves, fat, blood vessels, and skin. Thus far, many bacterial species, infamously dubbed as “flesh-eating bacteria” by the media, have been identified as causative agents of necrotizing fasciitis. These strains include group A Streptococcus, Klebsiella, Clostridium, E. coli, Staphylococcus aureus, and Aeromonas hydrophila2. These aforementioned strains, however, do not truly consume flesh. Rather, many of these organisms rapidly destroy flesh via the release of toxins that inhibit the immune response, directly kill tissue, or indirectly cause tissue death via hypoxia3.

Unfortunately, early diagnosis of necrotizing fasciitis is often missed due to the lack of specific clinical features2, 3. Generally, cases begin with an existing infection often found on the midsection or an extremity. This preliminary infection may stem from puncture wounds, surgical incisions, insect bites, or a minor break in the skin. Patients initially experience fever and chills accompanied by signs of inflammation, including swelling, erythema, and pain, at the site of infection. As the infection advances, the area of swelling spreads rapidly to the surrounding tissues resulting in ulceration, blisters, and excruciating pain. Without proper diagnosis and treatment at this later stage, patients often succumb to septic shock and death.

Presently, the first line of defense against this invasive infection is through intravenous administration of broad-spectrum antibiotics. Once the causative agent is identified, antibiotic susceptibility testing is performed to determine appropriate antibiotic coverage. However, because toxins produced by the invading bacterial horde can destroy soft tissue and reduce blood flow, antibiotic therapy may not be entirely effective. Therefore, amputation or the debridement of necrotic tissues is often required2, 3. This latter treatment, though, is highly invasive and may lead to subsequent opportunistic infections as well as affect the quality of life.

Overall, necrotizing fasciitis is a destructive disease with very little associated information regarding predisposition, prompt diagnosis, or effective non-debilitating treatment. Currently, the best hope a patient has at survival and avoiding amputation is through early diagnosis. Without the timely identification of necrotizing fasciitis, Lana Kuykendall, as described above, may have lost her leg to the disease. Thus, only through public awareness and further characterization of this condition and its causative agents can we hope to advance medical practices, save lives, and protect the quality of life.

1.       CNN Report, “South Carolina mom with flesh-eating bacteria improves, faces rehabilitation”. http://articles.cnn.com/2012-06-21/us/us_south-carolina-flesh-eating-bacteria_1_necrotizing-fasciitis-flesh-eating-healthy-tissue?_s=PM:US; June 21, 2012.
2.       Centers for Disease Control, “Necrotizing Fasciitis: A Rare Disease, Especially for the Healthy”. http://www.cdc.gov/Features/NecrotizingFasciitis/ Page last updated June 18, 2012.
3.       MedicineNet.com, “Necrotizing Fasciitis (Flesh-Eating Disease)”. http://www.medicinenet.com/necrotizing_fasciitis/article.htm.

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