Necrotizing Fasciitis: Let’s scare you into using POCUS shall we?
Warning: Scary article ahead.
It’s one of those diagnoses that scares us. Hard to figure out clinically in many cases at initial presentation. Adjunctive tests can be false negative. How can we increase our sensitivity? Use your POCUS skills of course!
This article reminds me of two of my own cases. The first was in a homeless male patient in his 60’s who was a smoker and had untreated diabetes. He presented with a minimally painful, erythematous left foot with early skin ulcerations on the dorsum. Simple answer right? Diabetic ulcer, perhaps some cellulitis and/or stasis changes related to peripheral vascular disease. However, being the POCUS keener I applied my trusty probe to that foot and found this:
Lots of air artifact within the tissue layers. Cobblestoning of the superficial tissues consistent with edema or cellulitis but the air indicates a gas forming pathology. This guy was getting debrided in the O.R. a few hours later for his necrotizing fasciitis. Nice pick up!
Second case involved a gentleman in his early 40’s who again liked to smoke and not make optimum use of his pancreas (DM II). He had just got off a plane from a tropical vacation and had a hot, painful right leg. Hmmm, probably a DVT right? If it’s after hours, give him some empiric anticoagulation and arrange a doppler ultrasound within the next 24 hours or so. Except for one problem: the POCUS showed no sign of DVT, but a large pocket of fluid extending from groin to popliteal fossa. What the heck? Asked for an urgent ultrasound from the radiologists. The report stated no DVT. And that’s it. No mention of the fluid pocket. I wasn’t happy about that so a quick talk with I.D. doc and surgeon led to an immediate aspiration in the ED which revealed purulent material. The patient went to the O.R. within the next hour for a large necrotizing fasciitis. Life and limb saved!
Bottom line: no single test is going to rule out necrotizing fasciitis. But POCUS can be used to enhance your clinical skills and help RULE IN a few cases or discover an alternate diagnosis. I really don’t think it will be defensible in the future to not use this modality on the front lines for the undifferentiated soft tissue infection. The stakes are too high.
Some more quick reads:
Necrotizing fasciitis: early sonographic diagnosis.