Correspondence and communication

Validation of the laboratory risk indicator for necrotising fasciitis scoring system (LRINEC) in a Northern European population

La fascitis necrosante es una infección de partes blandas potencialmente letal que afecta principalmente a la fascia y a los planos profundos, con una tasa muy alta de mortalidad y de complicaciones graves derivadas.

Evaluar las características clínicas y demográficas de pacientes con fascitis necrosante en nuestro centro y describir su manejo diagnóstico y terapéutico.

Revisión retrospectiva de historias clínicas de 21 pacientes diagnosticados de fascitis necrosante con afectación de extremidades entre enero de 2003 y febrero de 2021 en nuestro centro. Se recogieron datos demográficos y clínicos del proceso y de la evaluación del manejo en cada paciente.

De 21 pacientes incluidos, 15 eran varones (71,43%), con una edad media al diagnóstico de 54,38 ± 19,55 años. Las comorbilidades más frecuentes fueron diabetes mellitus insulinodependiente en 7 pacientes (33,33%) y procesos oncológicos en 5 pacientes (23,81%). La infección fue monomicrobiana en 14 casos (66,66%), siendo Streptococcus pyogenes el microorganismo más frecuente; en 2 casos (9,52%) fue polimicrobiana, y en 5 pacientes (23,81%) no se identificó el patógeno causante. Todos los pacientes fueron intervenidos en nuestro centro, con una media de 4,14 ± 3,98 cirugías, con un único caso de amputación de la extremidad afecta. La estancia hospitalaria media fue de 23,14 ± 16,44 días, situándose la mortalidad global en el 47,62% (10 casos).

Pese a tratarse de una condición poco frecuente, la fascitis necrosante es una patología muy agresiva, con una elevada tasa de mortalidad, especialmente en pacientes inmunocomprometidos. Una edad avanzada y padecer un cuadro oncológico son factores potenciales de peor pronóstico en la evolución de este cuadro.

Necrotising fasciitis is a potentially life-threatening soft tissue infection that mainly affects the fascia and deep planes, with a very high mortality rate and severe related complications.

To evaluate clinical and demographic characteristics of patients with necrotising fasciitis in our hospital and to describe their diagnostic and therapeutic management.

Retrospective review of medical records of 21 patients diagnosed with necrotising fasciitis with limb involvement between January 2003 and February 2021 in our hospital. Demographic data, clinical features and details of management and prognosis were collected for each patient.

Of 21 patients included, 15 were male (71.43%), with a mean age at diagnosis of 54.38 ± 19.55 years. The most frequent comorbidities were insulin-dependent diabetes mellitus in 7 patients (33.33%) and a history of cancer in 5 patients (23.81%). Infection was monomicrobial in 14 cases (66.66%), with Streptococcus pyogenes being the most frequent microorganism; multiple pathogens were isolated in 2 patients (9.52%) and no microorganism was identified in 5 patients (23.81%). All patients underwent surgery at our hospital, with a mean of 4.14 ± 3.98 surgeries. Only one patient underwent amputation of the affected limb. The mean hospital stay was 23.14 ± 16.44 days, with an overall mortality of 47.62% (10 cases).

Despite being a rare disease, necrotising fasciitis is a very aggressive pathology, with a high mortality rate, especially in immunocompromised patients. Advanced age and oncological disease are potential factors of worse prognosis in the evolution of this condition.

This review and meta-analysis aims to assess the prognostic value of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score for detecting necrotizing fasciitis in the extremities. The LRINEC score has been validated in multiple studies as a clinical tool for differentiating necrotizing fasciitis from non-necrotizing infections however many studies do not specify the location of infection. As the prevalence of diabetes and diabetic foot infections continues to rise, the utility of LRINEC scores in these populations becomes of increased importance. Four databases were reviewed for citations between January 2010 and December 2020. English, full text articles reporting the diagnostic effects of LRINEC were utilized in the systematic review portion of this paper. Further inclusion of 2 × 2 tables and discussion specific to the extremities were applied for citations implemented in the meta-analysis. Of the 111 results, 12 citations (n = 932) were included in this review. The diagnostic sensitivity of the LRINEC score ranged from 36% to 77% while specificity ranged from 72% to 93%. Cumulative odds ratio for LRINEC ≥6 among the 4 studies assessing extremity necrotizing fasciitis was 4.3 with p value of <.05. Sensitivity, specificity, positive predictive value, and negative predictive value was 49.39%, 83.17%, 34.91%, and 89.99%, respectively. Accuracy, the classification by whether a patient was correctly classified, was 77.95%. LRINEC score is effective at distinguishing necrotizing fasciitis from other soft tissue infections however the LRINEC's score greatest clinical application may be its ability to rule out necrotizing fasciitis while its ability to accurately identify the presence of infection remains suboptimal.

The LRINEC score was introduced in 2004 but it has not yet been incorporated as a reliable diagnostic tool in the management of Necrotising Fasciitis. NF is uncommon and proportionately the evidence is limited, but the contradictory literature has resulted in varying individual concepts and clinical practices. This article is aimed to evaluate the reliability of the LRINEC score and determine its effectiveness based on the current available evidence.

Eighteen clinical studies published during 2004–2018 were identified after an extended literature search and critically appraised to determine the validity, reliability and applicability of the individual pieces of evidence. The recommendations for practice were formulated after summative analysis of the evidence.

The systemic review and observational studies report the LRINEC score has a variable range of sensitivity (43.2–80%), positive predictive value (57–64%) and negative predictive value (42–86%) which is lower than the initial results by Wong et al. (2004). The LRINEC score ≥6 correlates well with diagnosis of NF but 7.1 was found to be statistically significant. Higher LRINEC score correlates with higher SOFA score, prolonged ICU and hospital stay, and mortality. It is not sensitive in immunocompromised patients.

There is Level 3 evidence that LRINEC score is a reliable tool which can aid the clinical diagnosis of NF. It can stratify the high-risk patients and predict outcome; however, it should be correlated with the clinical assessment and radiological diagnostic modalities should be simultaneously used when doubt exists (grade C).

Cellulitis is a common clinical condition with low rates of morbidity and mortality if treated appropriately. Mimics of cellulitis presenting with erythema, edema, warmth, and pain can be associated with grave morbidity and mortality if misdiagnosed.

This review investigates the signs and symptoms of cellulitis, mimics of cellulitis, and an approach to the management of both cellulitis and its mimics.

The current emergency medicine definition of cellulitis includes erythema, induration, warmth, and swelling. Given the common pathophysiologic pathways, cellulitis mimics often present in an analogous manner. These conditions include septic bursitis, septic joint, deep vein thrombosis, phlegmasia cerulea dolens, necrotizing fasciitis, flexor tenosynovitis, fight bite (closed fist injury), orbital cellulitis, toxic shock syndrome, erysipelas, abscess, felon, paronychia, and gouty arthritis. Many of these diseases have high morbidity and mortality if missed by the emergency physician. Differentiating these mimics from cellulitis can be difficult in the fast-paced emergency setting. A combination of history, physical examination, and focused diagnostic assessment may assist in correctly identifying the underlying etiology. For many of the high mortality cellulitis mimics, surgical intervention is necessary.

Cellulitis and its mimics present similarly due to the same physiologic responses to skin and soft tissue infections. A combination of history, physical examination, and diagnostic assessment will help the emergency physician differentiate cellulitis from mimics. Surgical intervention is frequently needed for high morbidity and mortality mimics.