Necrotizing Soft Tissue Infections (NSTI): Pearls and Pitfalls for the Emergency Clinician

Imaging of MSK infections in the ER

Musculoskeletal infections in the ER are not an uncommon presentation. The clinical context is critical in determining the suspicion for infection and degree of tissue involvement which can involve all layers from the skin to bones. The location, extent, and severity of clinically suspected infection directly relate to the type of imaging performed. Uncomplicated cellulitis typically does not require any imaging. Localized and superficial infections can mostly be evaluated with ultrasound. If there is a diffuse site (an entire extremity) or suspected deeper involvement (muscle/deep fascia), then CT is accurate in diagnosing, widely available, and performed quickly. With potential osseous involvement, MRI is the gold standard for diagnosing acute osteomyelitis; however, it has the drawbacks of longer scan times, artifacts including patient motion, and limited availability.

Pyomyositis in the sternocleidomastoid muscle in a previously healthy 36-year-old woman

Pyomyositis is a bacterial infection of striated muscle, usually located to muscles in the extremities or pelvis. We present a microbiologically unique case report of pyomyositis in the sternocleidomastoid muscle (the first of its kind in Denmark) caused by Staphylococcus epidermidis, S. capitis and possibly Streptococcus pneumoniae. Pyomyositis is very rare but can lead to critical complications such as endocarditis and sepsis. It is therefore important to know the condition when evaluating an infected patient with muscle pain. Treatment consists of antibiotics and - if relevant - surgical abscess drainage.

High risk and low prevalence diseases: Acute limb ischemia

INTRODUCTION

Acute limb ischemia is a rare but serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of acute limb ischemia, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Acute limb ischemia is defined as a sudden decrease in limb perfusion resulting in cessation of blood flow and nutrient and oxygen delivery to the tissues. This leads to cellular injury and necrosis, ultimately resulting in limb loss and potentially systemic symptoms with significant morbidity and mortality. There are several etiologies including native arterial thrombosis, arterial thrombosis after an intervention, arterial embolus, and arterial injury. Patients with acute limb ischemia most commonly present with severe pain and sensory changes in the initial stages, with prolonged ischemia resulting in weakness, sensory loss, and color changes to the affected limb. The emergency clinician should consult the vascular specialist as soon as ischemia is suspected, as the diagnosis should be based on the history and examination. Computed tomography angiography is the first line imaging modality, as it provides valuable information concerning the vasculature and surrounding tissues. Doppler ultrasound of the distal pulses may also be obtained to evaluate for arterial and venous flow. Once identified, management includes intravenous unfractionated heparin and vascular specialist consultation for revascularization.

CONCLUSIONS

An understanding of acute limb ischemia can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Diagnosis and Management of Severe Water-Related Skin and Soft Tissue Sepsis: A Summative Review of the Literature

BACKGROUND

Skin and soft tissue infections (SSTIs) are common presentations in the emergency department. However, this is less common after contact with contaminated saltwater or freshwater. This review presents the diagnosis and management of water-related soft tissue sepsis in this vulnerable and difficult-to-treat subgroup of necrotizing soft tissue sepsis.

METHODS

A summative literature overview is presented regarding bacterial and fungal SSTI after contact with contaminated water, with practical diagnostic and management aspects.

RESULTS

The literature indicates that these wounds and infections remain difficult to treat. An approach using appropriate diagnostic tools with both medical and surgical management strategies is provided.

CONCLUSIONS

SSTIs due to water contamination of wounds involve unusual organisms with unusual resistance patterns, and require a nuanced and directed diagnostic approach with an adaptation of the usual antibiotic or antifungal selection to achieve a successful cure, along with aggressive debridement and wound care.

Ultrasound for the diagnosis of necrotizing fasciitis: A systematic review of the literature

BACKGROUND

Necrotizing fasciitis (NF) is a deadly disorder that can be challenging to diagnose on history and examination alone. Point-of-care ultrasound (POCUS) is widely available and has been increasingly used for diagnosing skin and soft tissue infections. We performed a systematic review to determine the accuracy of POCUS for diagnosing NF with subgroup analyses of the accuracy of specific POCUS examination components.

METHODS

PubMed, Scopus, CINAHL, LILACS, the Cochrane databases, Google Scholar, and bibliographies of selected articles were assessed for all retrospective, prospective, and randomized control trials evaluating the accuracy of POCUS for diagnosing NF. Data were dual extracted into a predefined worksheet and quality analysis was performed with the QUADAS-2 tool. Data were summarized and an overall summary was completed.

RESULTS

We identified three papers (n = 221 patients; 33% NF) that met our inclusion criteria. The overall sensitivity ranged from 85.4%-100% while the specificity ranged from 44.7% to 98.2%. Fluid accumulation along the fascial plane was the most sensitive (85.4%; 95% CI 72.2% - 93.9%), while subcutaneous emphysema was the most specific (100%; 95% CI 92.5% - 100%).

CONCLUSIONS

POCUS has good sensitivity and specificity for the diagnosis of NF. POCUS should be considered as an adjunct to the initial clinical decision making for the diagnosis of NF.

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.

Rational Use of Ceftriaxone in Necrotizing Fasciitis and Mortality Associated with Bloodstream Infection and Hemorrhagic Bullous Lesions

Necrotizing fasciitis (NF) is an uncommon life-threatening necrotizing skin and soft tissue infection. The formation of hemorrhagic bullae is a special skin sign of NF. The purposes of this study were to investigate the incidence of hemorrhagic bullae formation and bacteremia associated with different organisms, to appraise the appropriate use of ceftriaxone, and to compare the clinical and laboratory risk indicators of NF patients with Gram-positive and Gram-negative infections on the initial examination. Methods: From March 2018 to December 2020, there were seventy-four NF patients with positive monomicrobial bacterial cultures enrolled based on surgical confirmation, and were categorized into two groups: the Gram-positive group and the Gram-negative group. Ceftriaxone susceptibility tests were carried out using the standard disk diffusion technique. Data, such as demographics, clinical outcomes, microbiological results, presentations of hemorrhagic bullae, and laboratory findings, were compared among these two groups. Results: The Gram-negative group included 52 patients, of whom 6 patients died, resulting in a mortality rate of 11.5%. The Gram-positive group included 22 patients and none died. Patients with bacteremia, hemorrhagic bullae, shock, fever, higher segmented forms and banded forms, and lower platelet counts constituted higher proportions in the Gram-negative group than in the Gram-positive group. The multivariate analysis identified six variables for the differentiation of Gram-negative and Gram-positive NF: the presentation of bacteremia, hemorrhagic bullae, shock at first consultation, fever with body temperature > 38.5 °C, band forms > 0%, and segmented forms ≦ 74%. A total of 66 isolates (89.2%) was susceptible to ceftriaxone. Conclusions: Gram-negative NF patients were significantly associated with hemorrhagic bullae presentation, blood stream infection, and mortality. Physicians should be alert to NF patients with the appearance of bacteremia, shock, fever, higher WBC banded and segmented forms, and lower platelet counts at the emergency department, with patients revealed to more likely have Gram-negative infections. Ceftriaxone with/without other appropriate antibiotics under the supervision of infectious doctors appeared to be clinically effective for the treatment of NF and blood stream infections.