Necrotizing Fasciitis: Clinical Suspicion Is your Only Chance

Dr. Glenn Harris discussed a case of an elderly man with diabetes and end stage renal disease who presented with sepsis from a right groin skin infection draining pus.

We used this opportunity to review our Sepsis-3 guidelines and discuss some of the newer evidence around the way we treat our septic patients.

Sepsis-3 guidelines tell us that sepsis should be defined based on the following 3 criteria:

– known or suspected infection

– organ dysfunction

– life-threatening

There are various scores we can use to increase the accuracy of our clinical judgment in our determination of the life-threatening nature of a septic patient’s disease, or in other words, their risk of mortality. The SIRS criteria is the scoring system most of our residents were taught in medical school, but according to Sepsis-3, this score has fallen out of favor. It is thought to be too nonspecific. Regardless of the underlying pathology, too many patients present to the ED meeting SIRS criteria. Sepsis-3 encourages the use of the qSOFA score, with only three binary criteria of RR, SBP, and the presence of altered mental status. However, since the guidelines came out, multiple studies have cast doubt on the utility of the qSOFA score, criticizing it as too insensitive. A large study comparing it with SIRS and the NEWS (National Early Warning Signs) score concluded that it fared worse in predicting outcomes. The NEWS score actually fared the best and we may see this score pop up in future studies or guidelines.

Treatment of sepsis includes fluid administration (30cc/kg) within three hours, cultures before antibiotics, and antibiotics within 1 hour. Fluid choice has been a hotly debated topic in the past. The evidence seems to support the use of crystalloids, but our classic dilemma is whether to us NS or LR. Normal saline carries with it a risk of hyperchloremic nonanion gap metabolic acidosis as well as a chloride load which decreases renal blood flow. These concerns lead many clinicians to resuscitate their septic patients with Lactated Ringers, but some give up to 2L normal saline and then switch to LR.

Antibiotic choice in cellulitis is guided by which type of pathogen you are concerned for. Typically, your first branch point is whether you believe the cellulitis is purulent (fluctuant, aka has a potentially drainable pocket of pus) or nonpurulent.

Purulent cellulitis is most commonly caused by staph, with a                                          high prevalance of MRSA

Nonpurulent cellulitis is most commonly caused by strep

However, if you have any suspicion for a necrotizing infection, you should cover for a polymicrobial infection. The LRINEC scoring system has been used to help guide our clinical suspicion for necrotizing fasciitis, but lacks sensitivity and does not take into account the patient’s physical exam or vital signs. The score should not be used to rule out necrotizing fasciitis. Clinical findings that should push you to consult surgery as soon as possible out of concern for a necrotizing skin or soft tissue infection are rapid progression, septic shock, crepitus, and hemorrhaghic bullae. These patients also frequently have pain out of proportion to exam. Your index of clinical suspicion is your most useful tool and you should treat for necrotizing fasciitis regardless of a LRINEC score if you are concerned. 

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