Review Question - QID 211561

This patient meets the clinical criteria for the diagnosis of necrotizing fascitis, therefore the next step in management is surgical debridement with possible amputation.

Necrotizing fasciitis is an aggressive infection with rapid spread along fascial planes. Initial presentation may be consistent with cellulitis; however, rapid progression along fascial planes may result in skin necrosis, muscular invasion, and subsequent myonecrosis. The rapidity of diagnosis and emergent surgical debridement is essential. Risk factors including intravenous drug abuse, alcohol abuse, and diabetes should be assessed, and if necrotizing fascitis is on the differential, the LRINEC score may be employed for diagnosis in equivocal cases. This scoring system can be found on our associated Orthobullets page.

Wong et. al. developed the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score to assist in early diagnosis of necrotizing soft tissue infections. The authors used logistic regression to identify significant predictors of necrotizing fasciitis. The score utilizes a total white cell count, hemoglobin, sodium, glucose, serum creatinine, and CRP. A LRINEC score of 6 points or higher has a positive predictive value of 92%, and below 6 points a negative predictive value of 96%. Importantly, ESR is not a component in the scoring system as it correlated poorly with risk. The patient presented already has two positive serum findings with an LRINEC score of 6.

Stoneback et al. review the diagnosis and management of necrotizing fasciitis. They note that Group A streptococcus is one of the most prevalent organisms, but infections are typically polymicrobial. Because of the need for prompt initiation of treatment, adjunctive diagnostic tests should not impede the timing of surgical exploration and debridement. Necrotizing fasciitis is a clinical diagnosis where only emergent surgical debridement and appropriate antibiotic treatment can prevent progression and death.

Tsai et al. retrospectively reviewed 70 patients with 71 episodes of Vibrio necrotizing fasciitis and sepsis. Of the 70 patients, 68 had a history of contact with seawater or raw seafood; 66 had underlying chronic diseases. They noted that severe hypoalbuminemia, severe thrombocytopenia, and increased banded forms of leukocytes are laboratory risk indicators of necrotizing fasciitis that aid in pointing toward the initiation of early surgery and predict a higher risk of death.

Figure A is a clinical photograph of a calcaneal ulcer. Figure B shows ascending erythema and bullae consistent with a necrotizing skin infection. Illustration A demonstrates the LRINEC scoring system. The scoring system is not largely utilized as a screening tool due to its poor sensitivity in studies that attempted to validate it.

Incorrect answers:
Answer 1: There is no indication in this scenario that this patient's clinical picture is due to a vascular issue.
Answer 2: This patient will likely require ICU admission, but surgical debridement is most prudent.
Answers 3 and 5: Imaging studies can assist with the diagnosis, but advanced imaging takes valuable time and should not delay emergent surgical debridement. The incidence of gas in the subcutaneous tissues is only 13%, but its presence should trigger urgent debridement.