The role of contrast enhanced computed tomography in the diagnosis of necrotizing fasciitis and comparison with the laboratory risk indicator for necrotizing fasciitis (LRINEC)

Imaging features of soft-tissue infections

Skin and soft tissues are among the most common sites of infections. Infections can involve the superficial epidermis to deep muscles and bones. Most infections spread through contiguous structures, although hematogenous spread can occur in the setting of an immunocompromised state and with atypical infections. While clinical diagnosis of infections is possible, it often lacks specificity, necessitating the use of imaging for confirmation. Cross-sectional imaging with US, CT, and MRI is frequently performed not just for diagnosis, but to delineate the extent of infection and to aid in management. Nonetheless, the imaging features have considerable overlap, and as such, it is essential to integrate imaging features with clinical features for managing soft tissue infections. Radiologists must be aware of the imaging features of different infections and their mimics, as well as the pros and cons of each imaging technique to properly use them for appropriate clinical situations. In this review, we summarize the most recent evidence-based features of key soft tissue infections.

Early diagnosis of necrotizing fasciitis: Imaging techniques and their combined application

Necrotizing fasciitis is a clinical, surgical emergency characterized by an insidious onset, rapid progression, and a high mortality rate. The disease's mortality rate has remained high for many years, mainly because of its atypical clinical presentation, which prevents many cases from being diagnosed early and accurately, resulting in patients who may die from uncontrollable septic shock and multi-organ failure. But unfortunately, no diagnostic indicator can provide a certain early diagnosis of NF, and clinical judgement of NF is still based on the results of various ancillary tests combined with the patient's medical history, clinical manifestations, and the physician's experience. This review provides a brief overview of the epidemiological features of NF and then discusses the most important laboratory indicators and scoring systems currently employed to diagnose NF. Finally, the latest progress of several imaging techniques in the early diagnosis of NF and their combined application with other diagnostic indices are highlighted. We point out promising research directions based on an objective evaluation of the advantages and shortcomings of different methods, which provide a basis for further improving the early diagnosis of NF.

Evaluation of laboratory risk indicator for necrotizing fasciitis score as an early diagnostic tool for necrotizing fasciitis: a prospective observational study

Introduction

From its historical identification to modern times with advancements in management modalities globally, the mortality of necrotizing fasciitis (NF) is high ranging from 19 to 30% for all affected sites. Although many diagnostic adjuncts have been developed to assist with the prompt and accurate diagnosis of NF, the primary diagnosis is still based on high clinical suspicion. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was developed as a tool for distinguishing NF from other soft tissue infections. The main objective of this study is to evaluate LRINEC as a tool for early diagnosis of NF and differentiating it from other soft tissue infections like cellulitis.

Methods

This is a single-centered, prospective observational study. Patients presenting with soft tissue infections of the limbs to the emergency department from November 2020 to October 2021 were included in this study. The clinical findings and blood parameters for the LRINEC score were collected and the score was calculated. Based on clinical suspicion of NF, patients underwent debridement and had a tissue biopsy to confirm the diagnosis. The data obtained was analyzed using SPSS version 24 and MS Excel. The AUC curve was used to calculate a cutoff, sensitivity, specificity, positive predictive value, and negative predictive values for the LRINEC score based on our study.

Results

Forty-five patients with 28 males and 17 females were included. The average age was 53.667 years within a range of 19-79 years. Among them 44.4% of the patients had NF and 66.6% had other minor forms of soft tissue infections. The ROC curve obtained a cutoff value of greater than or equal to 6, with an AUC of 0.751. At this cut of value study showed a sensitivity of 85% with a specificity of 52%. Similarly, positive predictive value was found to be 58.62%, negative predictive values of 81.25%, and overall accuracy of 66.67% in early diagnosis of NF.

Conclusion

In conclusion, our study showed that the LRINEC score can be a reliable tool for the early diagnosis of NF in an ED setting. This scoring system is best to be used to rule out NF.

Approach to imaging modalities in the setting of suspected infection

Imaging plays an important role in the workup of musculoskeletal infection, in conjunction with clinical history and physical exam. There are multiple imaging modalities that can be of clinical utility in the setting of suspected infection, each with their own benefits and limitations. Radiography is a low-cost, accessible modality providing a broad osseous overview, but can be insensitive for early osteomyelitis. Ultrasound plays a more limited role in the workup of musculoskeletal infection, but can be useful in the pediatric population or for real-time guidance for joint and soft tissue aspirations. Computed tomography (CT) plays an important role in the timely and accurate diagnosis of critically ill patients in the emergency setting. Its superior soft tissue characterization allows for diagnosis of abscesses, and it can help confirm the clinical diagnosis of necrotizing fasciitis when soft tissue gas is present. Magnetic resonance imaging (MRI) is often the modality of choice in the diagnosis of infection, as its superior contrast resolution allows for clear delineation of the presence and extent of both soft tissue infection and osteomyelitis. Additionally, the use of intravenous contrast and advanced imaging sequences such as diffusion weighted imaging (DWI) further increases the diagnostic utility of MRI in the assessment for infection. Familiarity with the diagnostic utility of each imaging modality will allow the radiologist to appropriately guide imaging workup in the setting of clinically suspected infection.

Necrotizing fasciitis: A highly fatal infection

BACKGROUNDS

Necrotizing fasciitis is a severe bacterial infection characterized by involvement of all skin's layers, including the superficial fascia. Diagnosis and treatment must be as quick as possible. Once suspected, extensive surgical debridement is required.

METHODS

All necrotizing fasciitis, managed in our hospital in Dijon, during the period from January 2011 to May 2021, were retrospectively analyzed. Demographics characteristics of patients, biological parameters, and type of bacteria were collected. Statistical analysis was performed on the cost of hospitalization, as well as on the death rate between type I and II NF and the speed of management. Student's t-test and Chi2 test were performed with a significant level P<0.05.

FINDINGS

A total of 65 patients were included over the period. The mean age was 68.8 years. The average length of stay was 32.4 days, with an average cost of 79,305 €. The main locations were the lower limbs (57%) and the perineum (35%). Cost of hospitalization did not differ between type I and II (P=0.21), unlike mortality rate (P=0.003). Furthermore, the mortality rate according to the speed of management did not vary in our series (P=0.45).

CONCLUSION

Necrotizing fasciitis is quickly fatal if left untreated. Early diagnosis, combined with surgical debridement and probabilistic antibiotic therapy are required. Our study shows the impact of necrotizing fasciitis in terms of cost to society and the importance of prevention of certain risk factors. A global management of the patient is necessary to increase the survival rate.

Predicting necrotising soft tissue infections in people who inject drugs: poor performance of the Laboratory Risk Indicator for Necrotising Fasciitis score and development of a novel clinical predictive nomogram in a retrospective cohort with internal validation

INTRODUCTION

Necrotising soft tissue infections (NSTI) can threaten life and limb. Early identification and urgent surgical debridement are key for improved outcomes. NSTI can be insidious. Scoring systems, like the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC), exist to aid diagnosis. People who inject drugs (PWID) are high risk for NSTI. This study aimed to assess the utility of the LRINEC in PWID with lower limb infections and develop a predictive nomogram.

METHODS

A retrospective database of all hospital admissions due to limb-related complications secondary to injecting drug use between December 2011 and December 2020 was compiled through discharge codes and a prospectively maintained Vascular Surgery database. All lower limb infections were extracted from this database, dichotomised by NSTI and non-NSTI with the LRINEC applied. Specialty management times were evaluated. Statistical analyses involved: chi-square; Analysis of "variance"; Kaplan-Meier, and receiver operating characteristic curves. Nomograms were developed to facilitate diagnosis and predict survival.

RESULTS

There were 557 admissions for 378 patients, with 124 (22.3%; 111 patients) NSTI. Time from admission to: theatre and computed tomography imaging respectively varied significantly between specialties ( P =0.001). Surgical specialties were faster than medical ( P =0.001). Vascular surgery received the most admissions and had the quickest time to theatre. During follow-up there were 79 (20.9%) deaths: 27 (24.3%) NSTI and 52 (19.5%) non-NSTI. LRINEC ≥6 had a positive predictive value of 33.3% and sensitivity of 74% for NSTI. LRINEC <6 had a negative predictive value of 90.7% and specificity of 63.2% for non-NSTI. Area under the curve was 0.697 (95% CI: 0.615-0.778). Nomogram models found age, C-reactive protein, and non-linear albumin to be significant predictors of NSTI, with age, white cell count, sodium, creatinine, C-reactive protein, and albumin being significant in predicting survival on discharge.

CONCLUSION

There was reduced performance of the LRINEC in this PWID cohort. Diagnosis may be enhanced through use of this predictive nomogram.

Necrotising soft-tissue infections

The incidence of necrotising soft-tissue infections has increased during recent decades such that most physicians might see at least one case of these potentially life-threatening infections in their career. Despite advances in care, necrotising soft-tissue infections are still associated with high morbidity and mortality, underlining a need for continued education of the medical community. In particular, failure to suspect necrotising soft-tissue infections, fuelled by poor awareness of the disease, promotes delays to first surgical debridement, amplifying disease severity and adverse outcomes. This Review will focus on practical approaches to management of necrotising soft-tissue infections including prompt recognition, initiation of specific management, exploratory surgery, and aftercare. Increased alertness and awareness for these infections should improve time to diagnosis and early referral to specialised centres, with improvement in the prognosis of necrotising soft-tissue infections.

Diagnostic and prognostic value of the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) based on an 18 years' experience

BACKGROUND

Necrotising fasciitis (NF) represents a rare but often life-threatening condition. Early diagnosis and surgical treatment are of vital importance. The LRINEC score was developed to distinguish necrotising fasciitis from other soft tissue infections (STI) at initial evaluation using six laboratory values. In this retrospective study, we attempted to determine the diagnostic and prognostic value of the LRINEC score.

METHODS

A total of 125 patients, hospitalised in our clinic between 2003 and 2021 with a histologically confirmed diagnosis of necrotising fasciitis (NF group) and 319 patients with surgically treated soft tissue infections (STI group) were included in this study. Individual LRINEC scores were calculated and analysed retrospectively.

RESULTS

The sensitivity of the LRINEC score at the cut-off point of ≥ 6 was 59%, whereas the specificity was 82%. The positive and negative predictive values were 57% and 84%, respectively. The mean LRINEC score was significantly higher in the NF group than in the STI group (6.0 compared to 2.4, respectively). All clinical outcome parameters such as amputation and mortality rates (15% vs 1%) were found to be significantly higher in the NF group (p<0.001). Within the NF group, there was no statistically significant association between the LRINEC score and clinical outcomes except for the necessary number of operations.

CONCLUSION

In isolation, we found the LRINEC score not to be a reliable enough diagnostic tool for the differentiation between NF and other soft tissue infections, because of its low sensitivity. Although we cannot recommend it as a prognostic tool either, we do believe it can be a useful adjunct to the clinical suspicion of NF.

Rectal malignant tumor complicated with perianal necrotizing fasciitis: A case report

BACKGROUND

Perianal necrotizing fasciitis (PNF) has been reported to be caused by multiple factors, but rectal malignant tumors, as an extremely rare predisposing factor, are often easily overlooked by surgeons.

CASE SUMMARY

An elderly male patient was admitted due to "right perianal swelling and pain with fever for 3 d" and was diagnosed with PNF, rectal mass, and perianal abscess. The mass was diagnosed as rectal adenocarcinoma after debridement. According to the patient's condition, re-debridement intervention and antibiotic adjustment were given, followed by colostomy and radical resection of the adenocarcinoma. The patient recovered well after 3 mo of follow-up.

CONCLUSION

The present case suggests that high attention should be paid to etiological factors of PNF in clinical practice to avoid delayed treatment due to missed diagnosis and misdiagnosis. For patients with rectal malignant tumors and PNF, early diagnosis is very important, and it is still recommended to give priority to the treatment of PNF in the acute phase after diagnosis, followed by comprehensive treatment of rectal malignant tumors, which is of great significance for the prognosis of patients.

The Benign Side of the Abdominal Wall: A Pictorial Review of Non-Neoplastic Diseases

The abdominal wall is the location of a wide spectrum of pathological conditions, from benign to malignant ones. Imaging is often recommended for the evaluation of known palpable abdominal masses. However, abdominal wall pathologies are often incidentally discovered and represent a clinical and diagnostic challenge. Knowledge of the possible etiologies and complications, combined with clinical history and laboratory findings, is crucial for the correct management of these conditions. Specific imaging clues can help the radiologist narrow the differential diagnosis and distinguish between malignant and benign processes. In this pictorial review, we will focus on the non-neoplastic benign masses and processes that can be encountered on the abdominal wall on cross-sectional imaging, with a particular focus on their management. Distinctive sonographic imaging clues, compared with computed tomography (CT) and magnetic resonance (MR) findings will be highlighted, together with clinical and practical tips for reaching the diagnosis and guiding patient management, to provide a complete diagnostic guide for the radiologist.

Imaging of Musculoskeletal Soft-Tissue Infections in Clinical Practice: A Comprehensive Updated Review

Musculoskeletal soft-tissue infections include a wide range of clinical conditions that are commonly encountered in both emergency departments and non-emergency clinical settings. Since clinical signs, symptoms, and even laboratory tests can be unremarkable or non-specific, imaging plays a key role in many cases. MRI is considered the most comprehensive and sensitive imaging tool available for the assessment of musculoskeletal infections. Ultrasound is a fundamental tool, especially for the evaluation of superficially located diseases and for US-guided interventional procedures, such as biopsy, needle-aspiration, and drainage. Conventional radiographs can be very helpful, especially for the detection of foreign bodies and in cases of infections with delayed diagnosis displaying bone involvement. This review article aims to provide a comprehensive overview of the radiological tools available and the imaging features of the most common musculoskeletal soft-tissue infections, including cellulitis, necrotizing and non-necrotizing fasciitis, foreign bodies, abscess, pyomyositis, infectious tenosynovitis, and bursitis.

ACR Appropriateness Criteria® Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot): 2022 Update

Musculoskeletal infections involve bones, joints, and soft tissues. These infections are a common clinical scenario in both outpatient and emergent settings. Although radiography provides baseline findings, a multimodality approach is often implemented to provide more detailed information on the extent of infection involvement and complications. MRI with intravenous contrast is excellent for the evaluation of musculoskeletal infections and is the most sensitive for diagnosing osteomyelitis. MRI, CT, and ultrasound can be useful for joint and soft tissue infections. When MRI or CT is contraindicated, bone scans and the appropriate utilization of other nuclear medicine scans can be implemented for aiding in the diagnostic imaging of infection, especially with metal hardware and arthroplasty artifacts on MRI and CT. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Spontaneous gas gangrene of the lower limb in a patient with rectal cancer: A fatal diagnostic pitfall

Spontaneous gas gangrene of lower limb is rare. It may complicate digestive cancer or neutropenia. We report a case of spontaneous gas gangrene of the lower limb complicating a rectal cancer, initially diagnosed as deep vein thrombosis. The diagnostic delay was fatal.

Diagnostic performance of MRI and CT in diagnosing necrotizing soft tissue infection: a systematic review

OBJECTIVE

To systematically review the accuracy of MRI and CT in diagnosing necrotizing soft tissue infection (NSTI).

METHODS

MEDLINE and Embase were searched for original studies which reported the diagnostic performance of MRI or CT in detecting NSTI. Individual study quality was assessed using the QUADAS-2 tool. Sensitivity and specificity of MRI and CT were calculated and, if supported by data from at least two studies, pooled using a bivariate random-effects model.

RESULTS

Six MRI studies and 7 CT studies were included. There were no major concerns with regard to study quality and applicability. The included studies used multiple diagnostic criteria, with sensitivities and specificities of both MRI and CT ranging between 0 and 100%. T2 hyperintensity of deep fascia was the most commonly used diagnostic MRI criterion (5 studies), yielding a pooled sensitivity of 86.4% (95% confidence interval [CI] 76.1-92.7%) and a pooled specificity of 65.2% (95% CI 35.4-86.6%). Presence of gas was the most commonly used diagnostic CT criterion (3 studies), yielding a pooled sensitivity of 48.6% (95% CI 37.1-60.2%) and a pooled specificity of 93.2% (95% CI 73.3-98.5%).

CONCLUSION

T2 hyperintensity of deep fascia at MRI has high sensitivity and moderate specificity in diagnosing NSTI. Presence of gas at CT has low sensitivity but high specificity. A combination of diagnostic criteria may improve diagnostic performance, but this needs further investigation.

Necrotizing Soft-Tissue Infections After Hip Arthroplasty

Necrotizing soft-tissue infections are a rare complication following hip arthroplasty procedures. These rapidly spreading infections have a high mortality rate and must be diagnosed and treated in an expeditious manner. This article discusses the epidemiology, classification, diagnosis, and treatment of these conditions and describes 2 related case reports.

Polymicrobial and monomicrobial necrotizing soft tissue infections: comparison of clinical, laboratory, radiological, and pathological hallmarks and prognosis. A retrospective analysis

Background

Necrotizing soft tissue infection (NSTI) is a life-threatening infection associated with high morbidity and mortality. Treatment consists of surgery and antibiotics. Many studies have addressed NSTI and its subtypes, but few have reviewed the clinical, radiological, and pathological differences between the polymicrobial and monomicrobial diseases. The objective of our study was to evaluate the clinical, radiological, and pathological features of patients with polymicrobial (NSTI I) and monomicrobial (NSTI II) infections and their association with outcome.

Methods

The cohort consisted of patients hospitalized with NSTI at a tertiary medical center in 2002-2019. The medical charts were reviewed for clinical, radiological, and pathological features. Findings were compared between patients in whom blood/tissue bacterial cultures yielded one or more than one pathological isolate. The primary clinical outcome measure of the study was all-cause mortality at 90 days. Secondary outcomes were duration of hospitalization, intensive care unit (ICU) admission, score on the LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis), and need for vasopressor treatment.

Results

A total of 81 patients met the inclusion criteria: 54 (66.6%) with monomicrobial NSTI and 27 (33.3%) with polymicrobial NSTI. There were no significant between-group differences in in-hospital and 90-day mortality. On multivariate analysis, the monomicrobial disease group had a significantly higher 90-day mortality rate in addition to higher rates of in-hospital mortality, ICU admission, and vasopressor use than the polymicrobial disease group.

Conclusion

Our study is the first to compare the clinical, radiological, and pathological differences between the two most common types of NSTI. The results demonstrate better prognosis for polymicrobial NSTI, with minimal ICU stay, lower mortality, and lower use of vasopressors.

Level of evidence

Prognostic and epidemiological, level III.

Necrotizing Soft-Tissue Infections: Clinical Features and Diagnostic Aspects

The term necrotizing soft-tissue infection (NSTI) encompasses a heterogenous group of patients with necrotizing infections, involving any body part. NSTI is diagnosed by surgical exploration, where necrosis of the subcutaneous tissue and/or muscle tissue, undermining of the skin, thrombosis of the superficial veins, and deliquescent tissue can be seen. Patients can present with vague symptoms, and approximately half of patients experience severe pain. The clinical presentation and microbiological etiology vary according to affected body site, with NSTI located to the extremities being dominated by monomicrobial group A streptococcal infections, and NSTI located to the anogenital area dominated by polymicrobial infections. No set of diagnostic criteria exists, and suspicion of the diagnosis should come from careful clinical examination and signs of local or systemic severity. Laboratory blood values show no distinct pattern but resemble those of sepsis. Imaging can aid the diagnostic process but must not delay surgical intervention.

Evaluation of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score for detecting necrotizing soft tissue infections in patients with diabetes and lower extremity infection

AIMS

The aim of this pilot study was to assess the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC), a scoring system for Necrotizing Soft Tissue Infections, to diagnose Necrotizing Soft Tissue Infections of the lower extremity in patients with diabetes.

METHODS

Sixty-nine patients with lower extremity infections were prospectively enrolled. The Laboratory Risk Indicator for Necrotizing Fasciitis was calculated and logistic regression was performed for each laboratory value.

RESULTS

The Laboratory Risk Indicator for Necrotizing Fasciitis was associated with Necrotizing Soft Tissue Infection diagnosis in patients with diabetes (p = 0.01). Sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 69%, 16.6%, and 100% respectively. Elevated C-reactive protein (OR 1.01, p = 0.02, 95% CI [1.002-1.23]) and white blood cell count (OR 1.34, p < 0.01, 95% CI [1.1-1.7]) were associated with Necrotizing Soft Tissue Infection.

CONCLUSIONS

The Laboratory Risk Indicator for Necrotizing Fasciitis was useful as a negative predictor of Necrotizing Soft Tissue Infection while C- reactive protein and white blood cell count may have value as individual predictors. We recommend high clinical suspicion of Necrotizing Soft Tissue Infections in diabetics as laboratory evaluation may be non-specific.

Necrotizing Soft Tissue Infections

Necrotizing soft tissue infections occur after traumatic injuries, minor skin lesions, nonpenetrating injuries, natural childbirth, and in postsurgical and immunocompromised patients. Infections can be severe, rapidly progressive, and life threatening. Survivors often endure multiple surgeries and prolonged hospitalization and rehabilitation. Despite subtle nuances that may distinguish one entity from another, clinical approaches to diagnosis and treatment are highly similar. This review describes the clinical and laboratory features of necrotizing soft tissue infections and addresses recommended diagnostic and treatment modalities. It discusses the impact of delays in surgical debridement, antibiotic use, and resuscitation on mortality, and summarizes key pathogenic mechanisms.

Clostridial Gas Gangrene - A Rare but Deadly Infection: Case series and Comparison to Other Necrotizing Soft Tissue Infections

Objective

Clostridial gas gangrene (GG) or clostridial myonecrosis is a very rare but life‐threatening necrotizing soft tissue infection (NSTI) caused by anaerobic, spore‐forming, and gas‐producing clostridium subspecies. It is the most rapidly spreading and lethal infection in humans, also affecting muscle tissue. The high mortality, of up to 100%, in clostridial GG is mediated by potent bacterial exotoxins. Necrotizing fasciitis (NF) is an important differential diagnosis, most often caused by group A streptococci, primarily not affecting musculature but the subcutaneous tissue and fascia. In the early stages of the infection, it is difficult to distinguish between GG and NF. Therefore, we compare both infection types, identify relevant differences in initial clinical presentation and later course, and present the results of our patients in a retrospective review.

Methods

Patients diagnosed with GG from 2008 to 2018 in our level one trauma center were identified. Their charts were reviewed retrospectively and data analyzed in terms of demographic information, microbiological and histological results, therapeutic course, outcome, and mortality rates. The laboratory risk indicator for NF (LRINEC) score was applied on the first blood work acquired. Results were compared to those of a second group diagnosed with NF.

Results

Five patients with GG and nine patients with NF were included in the present study. Patients with GG had a mortality rate of 80% compared to 0% in patients with NF. In eight patients with NF, affected limbs could be salvaged; one NF underwent amputation. LRINEC did not show significant differences between the groups; however, C‐reactive protein was significantly increased (P = 0.009) and hemoglobin (Hb) was significantly decreased (P = 0.02) in patients with GG. Interleukin‐6 and procalcitonin levels did not show significant difference. Patients with GG were older (70.2 vs 50 years). Of the isolated bacteria, 86% were sensitive to the initial calculated antibiotic treatment with ampicillin‐sulbactam or imipenem plus metronidazole plus clindamycin.

Conclusion

Both GG and NF need full‐scale surgical, antibiotic, and intensive care treatment, especially within the first days. Among patients with NSTI, those with clostridial GG have a significantly increased mortality risk due to early septic shock caused by clostridial toxins. In the initial stages, clinical differences are hardly detectable. Immediate surgical debridement is the key to successful therapy for NSTI and needs to be performed as early as possible. However, patients should be treated in a center with an experienced interdisciplinary intensive care team based on a predetermined treatment plan.

Necrotizing fasciitis of the upper back presenting with left shoulder pain

Necrotizing fasciitis is a severe and progressive infection of deep soft tissues which results in destruction of the fascia and overlying subcutaneous fat. We report a case of a 45-year-old diabetic gentleman who initially presented with left shoulder pain, which was treated symptomatically. Upon representation, he had fever and the pain extended to his left upper back. There was a warm, firm and mildly tender purplish swelling on his mid to the left upper back. Blood tests revealed significantly elevated white cell counts and C-reactive protein. A CT thorax showed extensive soft tissue gas within the deep and superficial fascial layers of his left upper back. Necrotizing fasciitis was confirmed intraoperatively. The diagnosis of this condition is often difficult as early symptoms can be mild and nonspecific. A high Laboratory Risk Indicator for NECrotizing fasciitis (LRINEC) score may be helpful to rule in this diagnosis and guide further management.

Prospective Validation of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) Score for Necrotizing Fasciitis of the Extremities

OBJECTIVES

The Laboratory Risk Indicator for Necrotizing Fasciitis score was developed as a clinical decision tool for distinguishing necrotizing fasciitis from other soft tissue infections. We prospectively evaluated the performance of the Laboratory Risk Indicator for Necrotizing Fasciitis score for the diagnosis of patients with necrotizing fasciitis in the extremities.

METHODS

We conducted a prospective and observational cohort study of emergency department patients with necrotizing fasciitis or severe cellulitis in the extremities between April 2015 and December 2016. The Laboratory Risk Indicator for Necrotizing Fasciitis score was calculated for every enrolled patient. The sensitivity, specificity, positive predictive value, and negative predictive value of cut-off scores of 6 and 8 were evaluated. The accuracy of the Laboratory Risk Indicator for Necrotizing Fasciitis score was expressed as the area under the receiver operating characteristic curve.

RESULTS

A total of 106 patients with necrotizing fasciitis and 825 patients with cellulitis were included. With an Laboratory Risk Indicator for Necrotizing Fasciitis cut-off score ≥6, the sensitivity was 43% (95% confidence interval 34% to 53%), specificity was 83% (95% confidence interval 80% to 86%), positive predictive value was 25% (95% confidence interval 20% to 30%), and negative predictive value was 92% (95% confidence interval 91% to 93%); with an Laboratory Risk Indicator for Necrotizing Fasciitis cut-off score ≥8, the sensitivity was 27% (95% confidence interval 19% to 37%), specificity was 93% (95% confidence interval 91% to 94%), positive predictive value was 33% (95% confidence interval 25% to 42%), and negative predictive value was 91% (95% confidence interval 90% to 92%). The area under the receiver operating characteristic curve for accuracy of the Laboratory Risk Indicator for Necrotizing Fasciitis score was 0.696 (95% CI 0.640 to 0.751).

CONCLUSION

The Laboratory Risk Indicator for Necrotizing Fasciitis score may not be an accurate tool for necrotizing fasciitis risk stratification and differentiation between severe cellulitis and necrotizing fasciitis in the emergency department setting based on our study.

Imaging musculoskeletal soft tissue infections

Musculoskeletal soft tissue infections are not uncommonly encountered in both the clinic and Emergency Department setting. The clinical diagnosis is not always evident as these infections can have variable presentations depending on the duration and depth of disease extension through the soft-tissue layers. Imaging often plays an important role in diagnosing the infection, defining the extent of involvement, directing tissue sampling, and in monitoring treatment response. After initial radiographs, ultrasound (US) is often the next modality utilized to evaluate patients with suspected soft tissue infections given its low cost, availability, portability, and potential for real-time guidance of fluid aspiration. The widespread use of cross-sectional imaging with magnetic resonance imaging (MRI) and computed tomography (CT) has greatly increased the radiological diagnosis in conditions where US may be limited. In addition, CT and MRI allow a thorough evaluation of disease extension, including assessment of joint spaces, tendons, and osseous changes indicative of bone involvement. This review will focus on the radiological findings of soft tissue infections on US, CT, and MRI.

Necrotizing Soft Tissue Infection: Diagnostic Accuracy of Physical Examination, Imaging, and LRINEC Score: A Systematic Review and Meta-Analysis

OBJECTIVE

We sought to summarize accuracy of physical examination, imaging, and Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score in diagnosis of necrotizing soft tissue infection (NSTI) in adults with a soft tissue infection clinically concerning for NSTI.

SUMMARY OF BACKGROUND DATA

NSTI is a life-threatening diagnosis. Delay to diagnosis and surgical management is associated with increased mortality.

METHODS

We searched 6 databases from inception through November 2017. We included English-language studies reporting diagnostic accuracy of testing or LRINEC Score. Outcome was NSTI confirmed by surgery or histopathology. Two reviewers screened all citations and extracted data independently. Summary measures were obtained from the Hierarchical Summary Receiver Operating Characteristic model.

RESULTS

From 2,290 citations, we included 23 studies (n = 5982). Of physical examination signs, pooled sensitivity and specificity for fever was 46.0% and 77.0% respectively, for hemorrhagic bullae 25.2% and 95.8%, and for hypotension 21.0% and 97.7%. Computed tomography (CT) had sensitivity of 88.5% and specificity of 93.3%, while plain radiography had sensitivity of 48.9% and specificity of 94.0%. Finally, LRINEC ≥ 6 had sensitivity of 68.2% and specificity of 84.8%, while LRINEC ≥ 8 had sensitivity of 40.8% and specificity of 94.9%.

CONCLUSIONS

Absence of any 1 physical examination feature (eg, fever or hypotension) is not sufficient to rule-out NSTI. CT is superior to plain radiography. LRINEC had poor sensitivity, and should not be used to rule-out NSTI. Given the poor sensitivity of these tests, a high clinical suspicion warrants early surgical consultation for definitive diagnosis and management.

Necrotizing Soft Tissue Infections: A Focused Review of Pathophysiology, Diagnosis, Operative Management, Antimicrobial Therapy, and Pediatrics

Background: Necrotizing fasciitis is a major health problem throughout the world. The purpose of this review is to assist providers with the care of these patients through a better understanding of the pathophysiology and management options. Methods: This is a collaborative review of the literature between members of the Surgical Infection Society of North America and World Society of Emergency Surgery. Results: Necrotizing fasciitis continues to be difficult to manage with the mainstay being early diagnosis and surgical intervention. Recognition of at-risk populations assists with the initiation of treatment, thereby impacting outcomes. Conclusions: Although there are some additional treatment strategies available, surgical debridement and antimicrobial therapy are central to the successful eradication of the disease process.

Preoperative assessment of simple and complex anorectal fistulas: Tridimensional endoanal ultrasound? Magnetic resonance? Both?

PURPOSE

The purpose of the study is to evaluate the diagnostic value of tridimensional endoanal ultrasound (3D-EAUS) and magnetic resonance (MR) in the preoperative assessment of both simple and complex anorectal fistulas.

METHODS

All the patients referred for the treatment of anal fistulas were enrolled in this study and underwent, as preoperative assessment, anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS and MR. The results of imaging evaluation were compared with surgical findings, considered as reference standard.

RESULTS

During the study period, 124 patients operated on for anal fistulas underwent complete preoperative imaging assessment. Perfect agreement between 3D-EAUS and surgery in the anal fistulas' severity grading was found (K = 1). The fistulas were classified as simple in 68/126 (53.9%) and complex in 58/126 (46.03%) cases, according to fistulas' Parks' classification and the most recent American Guidelines. In both simple and complex anal fistulas, 3D-EAUS did not show a significantly higher accuracy in the evaluation of internal openings, if compared with MR (P = 0.47; McNemar's Chi-square test). In the complex anal fistulas, MR showed a significantly higher accuracy in the evaluation of secondary extensions if compared with 3D-EAUS (P = 0.041; McNemar's Chi-square test), whereas in the simple anal fistulas, no significant difference was found.

CONCLUSION

In the preoperative work-up of patients with anorectal fistulas, 3D-EAUS may represent the first-line diagnostic tool. In cases of fistulas classified as complex by 3D-EAUS, MR may be indicated as adjunctive diagnostic imaging examination, to more carefully describe the fistulas' complete anatomy.

Streptococcal toxic shock syndrome in the intensive care unit

The streptococcal toxic shock syndrome is a severe complication associated with invasive infections by group A streptococci. In spite of medical progresses in the care of patients with septic shock during the last decades, this condition has remained associated with a high mortality. Early recognition and multidisciplinary management are key to the care of patients with streptococcal toxic shock syndrome, with intensive and appropriate intensive support of failing organs, rapid diagnosis of infectious source(s), and surgical management. The epidemiology and risk factors for streptococcal toxic shock syndrome remain to be better studied, including the possible causal role of exposure to nonsteroidal anti-inflammatory drugs. In this review article, the authors review the current knowledge of streptococcal toxic shock syndrome and discuss the pathophysiology as well as its supportive and specific treatment.

Evaluation and Management of Necrotizing Soft Tissue Infections

Despite advances in antibiotic and surgical management and supportive care for necrotizing soft tissue infections, morbidity and mortality remain substantial. Although there are clinical practice guidelines in place, there still remains much variability in choice and duration of antibiotic therapy, time to initial surgical debridement, and use of adjuvant medical therapies. This article offers an overview of necrotizing soft tissue infections with a focus on current diagnostic and treatment modalities.

Necrotizing fasciitis: treatment concepts and clinical results

BACKGROUND

Necrotizing fasciitis is a life-threatening soft tissue infection characterized by a rapid spreading infection of the subcutaneous tissue and in particular the fascia. The management of infected tissues requires a rapid diagnosis, immediate aggressive surgical management and an extended debridement. In some cases early amputations of the affected tissues and maximum intensive care treatment, in case of sepsis, are required. Due to a rising number of cases we aimed to evaluate our patients in a retrospective review.

METHOD

All patients diagnosed with necrotizing fasciitis from 2014 to 2016 (21 months) in our level one trauma center were identified. Their charts were reviewed and data were analyzed in terms of demographic and social information, microbiological results, therapeutic course, socio-economic outcome and mortality.

RESULTS

We found 15 patients with necrotizing fasciitis. None of these died in the observation period. The mean number of surgical interventions was seven. Two patients underwent limb amputation; diabetes mellitus was assigned with a significant higher risk for amputation. The mean hospitalization was 32 days, including 8 days on intensive care unit. Of the discovered bacteria 93% were sensitive to the initial antibiotic treatment with Ampicillin, Clindamycin and Clont.

CONCLUSION

Surgical therapy is indicated if necrotizing fasciitis is suspected. Diabetes mellitus was a clinical predictor of limb amputation in patients with necrotizing fasciitis in our cohort. Aminopenicillin ± sulbactam in combination with clindamycin and/or metronidazole is recommended as initial calculated antibiotic treatment.