What is that flesh eating bateria?

I am sure everyone has heard about a crazy case of a person losing a limb to "flesh eating bacteria". When I first heard about it, I thought that someone would have to be swimming in infected water or be in some exotic location to be susceptible to this issue. It was not until I started working in the ER that I discovered that this flesh eating bacteria was really necrotizing fasciitis, and anyone who simply gets a paper cut could die from it. 

Necrotizing fasciitis is a soft tissue infection that primary affects the superficial fascia and surrounding tissues, resulting in the subsequent death of those tissues (Bellapianta 2009). As we learned in anatomy, some of the functions of fascia are to compartmentalize and prevent the spread of infection, so you can imagine that if this area itself became infected, there would be extreme consequences. There are three main characteristics for clinical diagnosis which are often known as the triad: erythema, swelling, and pain out of proportion (Bellapianta, 2009). The first patient I saw that had this issue presented as a typical case as they had a very small area of erythema to the L flank with some swelling, but they were so uncomfortable which made the clinical suspicion much higher for necrotizing fasciitis when bringing together the patient's tachycardia, hypotension and extremely elevated lactic acid levels. 

There is currently a clinical scoring system used for cases where there is suspicion for necrotizing fasciitis known as the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC). This score includes labs values, see Figure 1,  that have been found to be sensitive for infections that are caused by bacteria that commonly cause necrotizing fasciitis, such as group A Streptococcus (Bellapianta 2009). If an individual has a high score with LRINEC, further studies can be performed such as CT imaging which has been found to be sensitive for detecting necrotizing fasciitis, although an MRI would be more depictive (Bellapianta 2009). 

It turns out that even though anyone can come down with this pesky infection, but it turns out that individuals that are immunocompromised, such as diabetics, chronic corticosteroid users, and IV drug users, are more susceptible than others (Bellapianta 2009). 

So how is this condition treated? First off, the patient will receive antibiotics to cover for possible bacterial culprits, then the patient will head off to the OR for surgical debridement of the area and biopsy (Bellapianta 2009). Continued observation of these patients is critical as this infection can spread quickly and the patient can also decompensate rapidly, resulting in limb loss, septic shock, renal failure or multisystem organ failure (Bellapianta 2009). Mortality of this condition widely varies but has been seen to be dependent on a few major things: time of onset to surgical debridement, immunocomprimised state, and age (Bellapianta 2009). 

So what this all means is do not cut yourself, stay healthy, and if you think something is wrong, get it checked out! If you are interested, you can of course see it in Grey's Anatomy Season 2 Episode 15 where it is so "accurately" depicted. This may be one of the episodes where surgical residents might actually be in the ER in reality. 

Figure 1: LRINEC scoring system. 

Sources:

Bellapianta JM, Ljungquist K, Tobin E, Uhl R. Necrotizing fasciitis. J Am Acad Orthop Surg. 2009 Mar;17(3):174-82. doi: 10.5435/00124635-200903000-00006. PMID: 19264710.