Distinguishing Periorbital Necrotizing Fasciitis from Orbital Cellulitis Using Admission Laboratory Values

To evaluate the diagnostic performance of 7 composite complete blood count-derived indices-systemic immune-inflammatory response index, systemic immune-inflammation index, systemic inflammation response index, platelet-to-lymphocyte ratio, platelet-to-monocyte ratio, hemoglobin-to-platelet ratio, and hemoglobin-to-lymphocyte ratio-in distinguishing periorbital necrotizing fasciitis (PNF) from orbital cellulitis at initial emergency department presentation.

This retrospective case-control study reviewed adult patients diagnosed with either PNF or orbital cellulitis. Diagnoses were confirmed via clinical, radiographic, intraoperative, histopathologic, and microbiologic findings. Leukocyte, neutrophil, monocyte, lymphocyte, platelet, and hemoglobin count from initial complete blood count upon presentation to the emergency department at a single academic medical center were used to calculate systemic immune-inflammatory response index, systemic immune-inflammation index, systemic inflammation response index, platelet-to-lymphocyte ratio, platelet-to-monocyte ratio, hemoglobin-to-platelet ratio, and hemoglobin-to-lymphocyte ratio values. Group comparisons were performed using Mann-Whitney nonparametric analysis, and receiver operating characteristic curve analysis was conducted for indices with statistically significant differences.

Twenty-two PNF patients (mean age 57.8 years) and 18 orbital cellulitis patients (mean age 47.2 years) were included, with no significant differences in age or gender. Systemic immune-inflammation index, systemic inflammation response index, hemoglobin-to-platelet ratio, and hemoglobin-to-lymphocyte ratio were significantly higher in the PNF group ( p = 0.0341, 0.0108, 0.0127, and 0.0099, respectively) with receiver operating characteristic area under the curve values ranging from 0.6970 to 0.7374. Systemic immune-inflammatory response index, platelet-to-lymphocyte ratio, and platelet-to-monocyte ratio showed no significant differences between groups.

Systemic immune-inflammation index, systemic inflammation response index, hemoglobin-to-platelet ratio, and hemoglobin-to-lymphocyte ratio may serve as inexpensive, readily available biomarkers for differentiating PNF from orbital cellulitis at presentation. When interpreted alongside clinical and radiographic findings, elevated values may prompt earlier recognition of PNF and facilitate rapid and appropriate management to reduce morbidity and preserve vision.