Necrotizing fasciitis. For many people this is one of the most terrifying, invasive infections imaginable, and for one unlucky woman in Georgia this is her current reality. Reports of this disease date back to Hippocrates in 500 BC, whose early description was that “diffused erysipelas caused by trivial accidents, [where] flesh, sinews, and bones fell away in large quantities, [leading to] death in many cases1.” Many people regard the disease as a medical monster, an invasive and lethal infection that progresses at a rate straight out of science fiction.
For those of you not familiar with the story, a young Masters student named Aimee Copeland was injured while on a home-made zipline. When the line broke she fell and cut her leg on rocks in the river beneath her. What started as a small cut on her leg quickly grew into a life threatening infection that resulted in the amputation of her entire left leg and possibly her hands in order to limit the spread of the disease. How is it possible that a small injury so quickly became life threatening? To understand this we have to understand more about necrotizing fasciitis itself and the bacteria that cause it.
Necrotizing fasciitis is not caused by a single pathogen, but actually a cohort of invasive bacteria. It is most commonly caused by Streptococcus pyogenes, a spherical, gram positive bacteria that is more commonly known to cause disease such as Strep throat (pharyngitis) and cellulitis. However, when this bacteria infects the fascia it is possible for it to become a highly invasive life threatening infection. In this case the S. pyogenes begins to produce toxins that lead to death of the surrounding tissues and escape of the bacteria into the bloodstream. Once systemic, this can lead to septic shock and death if not treated immediately. Common symptoms during the first few hours are erythema, tenderness, hypersensitive skin, and myalgia. However, these symptoms can rapidly progress in the course of just a few hours to hematic or gaseous bullae, necrosis, and a purple/blueish skin color at the infected area. If treatment is not initiated quickly it is possible to progress to hypotension, mental confusion, sepsis, and eventually multi-organ failure leading to death1.
In Aimee’s case, the cut she sustained on her leg allowed for a deep-tissue infection with Aeromonas hydrophila, a bacteria associated with warm, brackish waters that is more commonly known to cause nausea if ingested. However, if this A. hydrophila gets into a deep cut and initiates an infection in the fascia it is possible for it to progress to necrotizing fasciitis. For Aimee this all began with the cut sustained while zip-lining when this bacteria entered the wound and began to grow, spreading throughout her leg.
Thankfully treatment is available, but the price paid by the infected individual is great. The most common methods used to treat necrotizing fasciitis is a combination of intravenous antibiotics and surgical debridement of infected tissues. Because the infection progresses so rapidly, by the time the patient is seeking care there is often the need to remove large segments of tissue to halt the progression of the disease. Debridement is extensive and exploratory in nature, often with large segments of tissue needing to be removed until brisk bleeding occurs at the site. In the picture below you can see how the patient presented with a necrotic region in the wrist and significant inflammation in the elbow. The figure to the right shows the result of exploratory debridement of the infected fascia from the patient’s wrist to shoulder.
Figure 2. Case 2 (A) Detail of right elbow, edematous, tender, and blistered (arrows); small necrotic area visible at wrist (*). (B) Surgical exploration and fasciotomy of right upper limb extending from neck to hand, with drainage of fluids and debridement of necrotic tissues. Skin and subcutaneous tissue necrosis is visible at wrist. 1
While this may sound like a disease from a medical nightmare it is thankfully uncommon. On average there are 500 to 1000 cases reported annually in the United States out of over 300,000,000 inhabitants, making this a very rare occurance. Of these, roughly 25% to 30% of the cases will be fatal due either to multi-organ failure or septic shock from disseminated bacteria in the system. However, there is the potential for these numbers to rise as the different species of bacteria that cause this disease become increasingly more resistant to the antibiotics we have available.
1. Lancerotto, Luca MD; Tocco, Ilaria MD; Salmaso, Roberto MD; Vindigni, Vincenzo MD, PhD; Bassetto, Franco MD. Necrotizing fasciitis: Classification, diagnosis, and management. Journal of Trauma and Acute Care Surgery. 72(3):560-566, March 2012.