Development of a computed tomography-based scoring system for necrotizing soft-tissue infections

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.

Volumetric computed tomography measurements as predictors for outcomes in a cohort of Fournier's gangrene patients

PURPOSE

This study evaluates the prognostic value of CT findings, including volumetric measurements, in predicting outcomes for patients with Fournier gangrene (FG), focusing on mortality, ICU admission, hospital stay length, and healthcare costs.

METHODS

A retrospective study was conducted on 38 FG patients who underwent CT scans before surgical debridement. We analyzed demographic data, CT volumetric measurements, and clinical outcomes using logistic and linear regression models.

RESULTS

No single CT measurement significantly predicted mortality or ICU admission. The best model for mortality prediction included age, air volume, NSTI score, and male sex, with an AUC of 0.911. Intubation likelihood was modeled with an AUC of 0.913 using age, NSTI score, and visceral to subcutaneous fat ratio. The ICU admission model achieved an AUC of 0.677. Hospital stay was predicted by air volume (β = 0.0002656, p = 0.0505) with an adjusted R-squared of 0.1287. Air volume significantly predicted hospital costs (β = 2.859, p = 0.00558), resulting in an adjusted R-squared of 0.2165.

CONCLUSION

Volumetric CT findings provide valuable prognostic insights for FG patients, suggesting a basis for informed clinical decisions and resource allocation. Further validation in larger, multi-center studies is recommended to develop robust predictive models for FG outcomes.

Progress in Multidisciplinary Treatment of Fournier's Gangrene

Fournier's gangrene (FG) is a life-threatening and special form of necrotizing fasciitis, characterized by occult onset, rapid progress and high mortality, occurring mainly in men over 50 years of age. Risk factors of FG include diabetes, HIV infection, chronic alcoholism and other immunosuppressive state. FG was previously considered as an idiopathic disease, but in fact, three quarters of the infections originated from the skin, urethra and gastrointestinal tract. Initial symptoms of FG are often inconsistent with severity and can progress promptly to fatal infection. Although the treatment measures of FG have been improved in recent years, the mortality does not seem to have decreased significantly and remains at 20% - 30%. The time to identify FG and the waiting period before surgical debridement are directly related to the prognosis. Therefore, in addition to the combination of intensive fluid resuscitation and broad-spectrum antibiotics, treatment of FG should particularly emphasize the importance of early surgical debridement assisted with fecal diversion and skin reconstruction when necessary. This paper is to briefly summarize the progress in the definition, epidemiology, clinical manifestations, diagnosis, treatment and prognosis of Fournier's gangrene in recent years, more importantly, illustrates the importance of multidisciplinary cooperation in the management of FG.

Negative Pressure Wound Therapy for the Treatment of Fournier's Gangrene: A Rare Case with Rectal Fistula and Systematic Review of the Literature

Fournier's gangrene (FG) is a Necrotizing Soft Tissue Infection (NSTI) of the perineal region characterized by high morbidity and mortality even if appropriately treated. The main treatment strategies are surgical debridement, broad-spectrum antibiotics, hyperbaric oxygen therapy, NPWT (Negative Pressure Wound Therapy), and plastic surgery reconstruction. We present the case of a 50-year-old woman with an NSTI of the abdomen, pelvis, and perineal region associated with a rectal fistula referred to our department. After surgical debridement and a diverting blow-out colostomy, an NPWT system composed of two sponges connected by a bridge through a rectal fistula was performed. Our target was to obtain healing in a lateral-to-medial direction instead of depth-to-surface to prevent the enlargement of the rectal fistula, promoting granulation tissue growth towards the rectum. This eso-endo-NPWT technique allowed for the primary suture of the perineal wounds bilaterally, simultaneously treating the rectal fistula and the perineum lesions. A systematic review of the literature underlines the spreading of NPWT and its effects.

Necrotizing Fasciitis of the Upper Extremity - A Review

Necrotizing fasciitis is a soft tissue infection that habitually originates from the fascial sheaths, expands at a volant pace, leads to extensive necrosis of the subcutaneous tissues, and eventually ends up in a life-threatening condition with notably elevated amputation and mortality rates. Factors that induce interruption of skin integrity, such as trauma or intravenous drug use, are the most common inciting events. Specific clinical signs heralding its presence are usually absent in the early stages, often resulting in misdiagnosis. Early recognition, prompt and aggressive surgical debridement, antibiotic use, and supportive care constitute the fundamental principles to lean on for a better prognosis. Necrotizing fasciitis of the upper extremity is relatively rare and consequently holds a limited place in the literature. Only a few studies assess it as a separate entity, with most of them being case reports or small case series. We, therefore, performed a review of the current literature, to assemble the dispersed results of different studies and clarify the various aspects of upper limb necrotizing fasciitis. In this systematic review, we present the epidemiological data, the causative events, the most frequent underlying diseases, the risk factors, the amputation and mortality rates, the pathogenic microorganisms, the clinical characteristics, the diagnostic tools, the medical and surgical management concerning necrotizing fasciitis of the upper limb. Finally, the results indicating its differentiation compared to necrotizing fasciitis of other anatomic sites are remarkably highlighted.

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.

Infective endocarditis: Role of molecular techniques in early diagnosis

Infective endocarditis (IE), a heart valve infection primarily caused by bacteria such as streptococci or staphylococci, causes significant morbidity and mortality. Despite the long-term use of broad-spectrum antimicrobials, the infection is often difficult to manage. The latest diagnostic modalities for IE are discussed in this study. Blood culture use in pathogen identification can lead to loss of precious time as well as generation of false negative reports. The first steps in diagnosis are blood cultures and echocardiography, but molecular techniques can be extremely useful and may be used for an accurate and early diagnosis.

CT in necrotizing soft tissue infection: diagnostic criteria and comparison with LRINEC score

OBJECTIVE

To investigate which computed tomography (CT) criteria are most useful in diagnosing necrotizing soft tissue infection (NSTI) and how CT performs with respect to the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score.

METHODS

Patients who underwent CT for suspected NSTI were eligible for inclusion. LRINEC score was assessed. CT scans were evaluated for subcutaneous edema, fluid along superficial fascia, fluid along deep fascia, blurring of intermuscular fat planes, fluid collection, and air in the soft tissues. Surgical findings or clinical follow-up served as reference standard.

RESULTS

Fourteen patients with NSTI and 34 patients with non-NSTI were included. LRINEC score was significantly higher in patients with NSTI (median of 7.5 vs. 6, p = 0.039). Fluid along the deep fascia was significantly more frequently present in patients with NSTI (46.2% vs. 5.9%, p = 0.001). In multiple logistic regression analysis, presence of fluid along the deep fascia was significantly associated with NSTI (odds ratio [OR] = 10.28, 95% CI: 1.57 to 67.18, p = 0.015), whereas the LRINEC score was not significantly associated with NSTI (OR = 1.27, 95% CI: 0.92 to 1.74, p = 0.146). Using presence of fluid along the deep fascia as diagnostic criterion for NSTI, sensitivity was 46.2% (95% CI, 23.2 to 70.9%) and specificity was 94.1% (95% CI, 80.9 to 98.4%).

CONCLUSION

Fluid along the deep fascia was the only CT criterion which was significantly associated with NSTI and appeared more useful than the LRINEC score. In the right clinical setting, presence of this CT finding is highly suggestive for NSTI. Its absence, however, does not rule out NSTI.

KEY POINTS

• The presence of fluid along the deep fascia at CT is highly suggestive for NSTI in suspected patients. Its absence, however, does not rule out NSTI. `• The use of fluid along the deep fascia as a criterion appears to be more useful than the LRINEC score in diagnosing NSTI.

Utility of the Laboratory Risk Indicator for Necrotizing Fasciitis Score: Comorbid Conditions Do Matter

Background: The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) has been proposed as a diagnostic tool for necrotizing soft tissue infection (NSTI). However, its utility remains underreported, particularly in patients with comorbid conditions. The purpose of this study was to identify the test characteristics of LRINEC for patients with various comorbid conditions. Patients and Methods: We conducted a retrospective study including patients with suspected NSTI. Our study patients were then relegated into the subgroups; intravenous drug use (IVDU), end-stage liver disease (ESLD), and diabetes mellitus (DM). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a positive LRINEC score (≥ 6 or 8) were calculated in reference to intra-operative findings or results of the pathologic examination. Area under the curve (AUC) using receiver operating characteristic (ROC) plots were compared between each subgroup and the overall study population using DeLong test. Results: A total of 220 patients were included for the analysis. Overall, the sensitivity was 76%, specificity of 52%, PPV of 32%, and NPV of 88%. The subgroup analysis showed low PPVs in all subgroups. The DM and ESLD groups had a high NPV (90.5% and 88.0%, respectively), whereas NPV in the IVDU group was 70.6%. The AUC and DeLong test for the subgroups were 0.649 (p = 0.902) for ESLD, 0.699 (p = 0.683) for DM, and 0.565 (p = 0.034) for IVDU. Conclusions: The LRINEC can be a useful adjunct to rule out the diagnosis of NSTI with exception of IVDU. In contrast, further diagnostic workup might be still required in those patients with positive LRINEC.

Pediatric necrotizing soft tissue infection after elective surgery: A case report and literature review

INTRODUCTION

Necrotizing soft tissue infections (NSTIs) are rare but often lethal. Early diagnosis and aggressive surgical debridement are essential to achieve the best possible outcome.

CASE PRESENTATION

A 12-year old boy was diagnosed with a necrotizing soft tissue infection following elective revision surgery for functional impairment resulting from scar tissue of the neck. Fever and inflammation of the surgical wound manifested 24-36 hours postoperatively. Antibiotic therapy with amoxicillin-clavulanic acid was initiated, but the patient was unresponsive. Ultrasonography, a wound culture and surgical exploration confirmed the diagnosis. The culture was positive for a Streptococcus pyogenes infection and antibiotic treatment was switched to penicillin and clindamycin. Following the diagnosis, surgical debridement was performed subcutaneously, and only necrotic tissue was removed to preserve as much skin tissue as possible. After eradication of the infection, vacuum-assisted closure of the wound was used to close the subcutaneous space. The patient was discharged after 40 days.

CONCLUSION

In this patient, we treated a necrotizing soft tissue infection with antibiotics, skin sparing surgeries and negative pressure wound therapy (NPWT). We used ultrasonography as imaging technique to help with the diagnosis. The extensiveness of surgical debridement was rather limited. We focused on opening all affected fascial layers. The surgical debridement was subcutaneous, and only necrotic tissue was removed. Because of the location in the neck, we tried to avoid an aggressive skin debridement to preserve as much skin tissue as possible. Negative pressure wound therapy is not frequently used in this context but it contributed to an enhanced wound healing. Ultrasonography for diagnosing NSTIs is useful, but the clinical findings and an explorative surgery will remain most important.

Fulminant necrotizing fasciitis to the hand in a patient on high-dose steroids: A case report of successful limb salvage

Glucocorticoids are commonly used in the management of patients with brain Tumour for reducing peritumoral and vasogenic edema. However, they may lead to development of limb and life-threatening conditions such as necrotizing fasciitis (NF). NF is a rare but potentially lethal condition. Early detection and aggressive treatment may lead to decreased mortality and limb salvage. The diagnosis is predominately clinical but may be supported by laboratory and radiological investigations. Chronic steroid use not only predisposes to the development of NF but also may mask early features delaying presentation and diagnosis. Clinicians should have a high index of suspicion especially in patients on chronic steroid therapy as this may aid in early detection and treatment. We present a case report of a successful limb salvage that exemplifies these points.

Getting it Right the First Time: Frozen Sections for Diagnosing Necrotizing Soft Tissue Infections

Background

The aim of this study was to investigate which histopathologic findings are most indicative for necrotizing soft tissue infections (NSTIs) in ambivalent cases.

Methods

Patients undergoing surgical exploration for suspected NSTIs with obtainment of incisional biopsies for histopathological assessment were included from January 2013 until August 2019. The frozen sections and formalin-fixed paraffin-embedded (FFPE) samples were retrospectively re-assessed. The primary outcome was the discharge diagnosis.

Results

Twenty-seven (69%) biopsies of the 39 included samples were from patients with NSTIs. Microscopic bullae (p = 0.043), severe fascial inflammation (p < 0.001) and fascial necrosis (p < 0.001) were significantly more often present in the NSTI group compared to the non-NSTI group. Muscle edema (n = 5), severe muscle inflammation (n = 5), muscle necrosis (n = 8), thrombosis (n = 10) and vasculitis (n = 5) were most frequently only seen in the NSTI group. In thirteen tissues samples, there were some discrepancies between the severity of findings in the frozen section and the FFPE samples. None of these discrepancies resulted in a different diagnosis or treatment strategy.

Conclusion

Microscopic bullae, severe fascial or muscle inflammation, fascial or muscle necrosis, muscle edema, thrombosis and vasculitis upon histopathological evaluation all indicate a high probability of a NSTI. At our institution, diagnosing NSTIs is aided by using intra-operative frozen section as part of triple diagnostics in ambivalent cases. Based on the relation between histopathologic findings and final presence of NSTI, we recommend frozen section for diagnosing NSTIs in ambivalent cases.

Fournier Gangrene in Men and Women: Appearance on CT, Ultrasound, and MRI and What the Surgeon Wants to Know

Fournier gangrene (FG) is a genitourinary necrotizing fasciitis that can be lethal if not promptly diagnosed and surgically debrided. The diagnosis is often made by physical examination paired with an appropriate clinical suspicion and supporting laboratory values. Imaging, particularly computed tomography (CT), plays a role in delineating involved fascial planes for operative debridement and occasionally in diagnosing FG. Less commonly, the imaging manifestations of FG may also be seen on ultrasound, radiographs, and magnetic resonance imaging. With the ubiquitous use and availability of CT, radiologists have a growing role in recognizing FG. This can be challenging in the absence of fascial gas, but a CT scoring system for necrotizing fasciitis can be helpful in making the diagnosis. Recent series suggest that this predominantly male disease has a rising incidence in women. Women with FG are more likely to be morbidly obese and have vulvar or labial involvement compared to men. Imaging mimics include ulcerative and necrotic tumors, traumatic or iatrogenic fascial gas, and vaginitis emphysematosa. The purpose of this pictorial review is to illustrate the imaging manifestations of FG and its mimics, with emphases on necrotizing fasciitis CT scoring systems and FG in women.

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 fasciitis of the hand: a case report

Necrotizing Fasciitis is a rare life-threatening infection, usually polymicrobial, that frequently affects the extremities in as many as two thirds of the cases. It typically involves primarily the muscular fascia, and then spreads through muscular and subcutaneous tissues. The early diagnosis may be challenging, and appears to be crucial in the management of this condition. We report a case of a 45-year-old man, former drug abuser, diabetic, HCV+, who developed a necrotizing fasciitis of the hand following a minor trauma. Early diagnosis based on clinical, laboratory (LRINEC score) and radiological findings, together with an accurate debridement of the affected site, allowed us to limitate the amputation to the third ray only. The reconstruction with the capitate osteotomy and the coverage with the posterior interosseous flap helped us in further reduction of the functional impairment of the hand. (www.actabiomedica.it)

The Role of Computed Tomography in the Diagnosis of Necrotizing Soft Tissue Infections

BACKGROUND

The exact role of IV contrast-enhanced computed tomography (CT) in the diagnosis of necrotizing soft tissue infections (NSTIs) has not yet been established. We aimed to explore the role of CT in patients with clinical suspicion of NSTI and assess its sensitivity and specificity for NSTI.

METHODS

The medical records of patients admitted between 2009 and 2016, who received IV contrast-enhanced CT to rule out NSTI, were reviewed. CT was considered positive in case of: (a) gas in soft tissues, (b) multiple fluid collections, (c) absence or heterogeneity of tissue enhancement by the IV contrast, and (d) significant inflammatory changes under the fascia. NSTI was confirmed only by the presence of necrotic tissue during surgical exploration. NSTI was considered absent if surgical exploration failed to identify necrosis, or if the patient was successfully treated non-operatively.

RESULTS

Of the 184 patients, 17 had a positive CT and hence underwent surgical exploration with NSTI being confirmed in 13 of them (76%). Of the 167 patients that had a negative CT, 38 (23%) underwent surgical exploration due to the high clinical suspicion for NSTI and were all found to have non-necrotizing infections; the remaining 129 (77%) were managed non-operatively with successful resolution of symptoms. The sensitivity of CT in identifying NSTI was 100%, the specificity 98%, the positive predictive value 76%, and the negative predictive value 100%.

CONCLUSIONS

A negative IV contrast-enhanced CT scan can reliably rule out the need for surgical intervention in patients with initial suspicion of NSTI.

Preoperative CT Findings and Interobserver Reliability of Fournier Gangrene

OBJECTIVE

The objective of our study was to delineate CT findings and anatomic areas of involvement of surgically proven Fournier gangrene (FG) and determine interobserver reliability.

MATERIALS AND METHODS

This study was a single-center retrospective study of patients with FG who underwent CT before surgical débridement of FG during a 9-year period. Thirty-eight patients with FG, 17 male and 21 female patients, underwent preoperative CT. Two radiologists reviewed the CT studies and recorded findings and anatomic areas of involvement. CT findings were categorized according to a previously described CT scoring system for necrotizing fasciitis and included the presence or absence of fascial air, muscle or fascial edema, fluid tracking, lymphadenopathy, and subcutaneous edema. Cohen kappa was calculated for interobserver reliability.

RESULTS

Mean body mass index (BMI [weight in kilograms divided by height in meters squared]) was 42, and 22 of 38 (58%) patients had diabetes. Mean BMI and proportion of patients with diabetes were significantly higher in female patients (mean BMI = 46; 16/21 with diabetes) than male patients (mean BMI = 36; 6/17 with diabetes). CT studies of most patients showed fascial air (36/38 [95%], both readers 1 and 2). Interobserver reliability was substantial to almost perfect for all CT findings except lymphadenopathy, for which it was fair (κ = 0.37). Genital, perineal, and ischiorectal involvement were seen in 87% (33/38), 87% (33/38), and 32% (12/38) of patients for reader 1 and 84% (32/38), 84% (32/38), and 26% (10/38) of patients for reader 2 (κ = 0.29, penis; κ = 0.65, scrotum; κ = 0.91, vulva and labia; κ = 0.68, perineal involvement; κ = 0.80, ischiorectal involvement).

CONCLUSION

Most CT findings of FG and anatomic areas of involvement showed good interobserver reliability. A high proportion of female patients with FG were observed in this study compared with prior series.

Necrotizing infection of the heart

A case of necrotizing infection of the heart is presented. A 70-year-old woman presented with vague chest and abdominal pain. CT of the abdomen and pelvis was initially obtained, which demonstrated gas in the myocardium of the left ventricle. Subsequent chest CT, endoscopy, and abdominal surgical exploration did not reveal perforated viscus or diaphragm compromise. At median sternotomy, the inferior wall of the heart was found to be necrotic. Culture of the excised tissue grew E. coli. The patient expired shortly after surgical exploration.

Can necrotizing soft tissue infection be reliably diagnosed in the emergency department?

Necrotizing soft tissue infections (NSTIs) are associated with a high mortality and require prompt recognition and treatment, consisting of aggressive surgical debridement and critical care support. Diagnosis is a key step, which is generally made in the operating room (OR), but the decision to debride requires guidance. This is frequently made on clinical grounds, but NSTI can be occult in presentation and several other infective processes can mimic NSTI. It is unknown whether the various scoring systems described in the literature can enable clinicians to reliably diagnose NSTI in the emergency department, rather than the OR. The topic was debated at the 36thAnnual Point/Counterpoint Acute Care Surgery Conference and the following article summarizes the discussants points of view along with a summary of the evidence.

Statistical medicine: An emerging medical specialty

A large number of statistical tools are now used for medical decision in the core activities of diagnosis, treatment and prognosis. These tools provide undeniable help in improving medical outcomes. Prominent among them are uncertainty measurement by probability, medical indicators and indexes, reference ranges, and scoring systems. In addition are tools such as odds ratio, sensitivity, specificity and predictivities, area under the ROC curve, likelihood ratios, and cost-benefit analysis that are commonly applied in medical research but have implications for day-to-day clinical activities. These tools have so completely integrated into medical practice that statistical medicine by itself can stand alone as a medical specialty. Time has arrived to recognize statistical medicine as a medical specialty.

Management of necrotizing skin and soft tissue infections

Although rare, necrotizing skin and soft tissue infections can be devastating infections that are difficult to diagnose and challenging to manage. Clinical presentation is often insidious, and a low index of suspicion is critical. Various diagnostic tools, such as scoring systems or imaging techniques, have been introduced, but none is convincingly superior to sound clinical judgment. Early diagnosis allows early adequate therapy that includes antibiotic therapy, critical care support, specific interventions such as intravenous immunoglobulin in selected patients and, most importantly, early source control. Empirical antibiotic therapy should cover a broad range of both Gram-negative and Gram-positive aerobic and anaerobic microorganisms, and clindamycin is recommended when group A Streptococcus is a suspected pathogen.

Point-of-care ultrasound diagnosis of necrotizing fasciitis missed by computed tomography and magnetic resonance imaging

BACKGROUND

Necrotizing fasciitis (NF) is a rare but deadly disease. Diagnosis of necrotizing soft tissue infections can be challenging for a variety of reasons. Point-of-care (POC) ultrasound (US) has been described as a diagnostic tool to help the acute care clinician make the early diagnosis that is imperative to optimize outcomes.

OBJECTIVE

To report a case of Group A Streptococcus NF recognized with POC US, and subsequent negative findings on computed tomography (CT) and magnetic resonance imaging (MRI).

CASE REPORT

A 54-year-old diabetic woman presented to the Emergency Department with atraumatic right foot and lower leg pain associated with fever. Examination was concerning for NF, and a POC US was performed, which showed thickened deep fascia and fluid tracking along the deep fascial plane, with fluid pockets measuring 6 mm in depth, consistent with NF. Surgical consultation was obtained. Per request, CT and MRI of the patient's lower extremity were performed; both were interpreted by the radiologist as showing changes consistent with cellulitis. Septic shock and multisystem organ failure ensued; the patient was eventually taken to the operating room, where operative findings were consistent with NF. Operative cultures grew Streptococcus pyogenes.

CONCLUSION

NF is a surgical emergency. Early and accurate diagnosis is critical to ensure the necessary aggressive management needed to optimize outcomes. This case illustrates the utility of POC US to make the prompt diagnosis of NF, particularly in light of subsequently negative CT and MRI.