SOFT TISSUE INFECTIONS

Sonographic assessment of musculoskeletal causes of calf pain and swelling

Calf pain or swelling is a common presentation to the emergency department. The differential diagnoses are wide. Deep vein thrombosis (DVT) is often the first diagnosis to be excluded given its potentially fatal complications. Musculoskeletal causes of calf pain or swelling such as Baker's cyst, muscle or tendon tear, soft tissue infection, and inflammation are not uncommon and can often be confidently diagnosed with ultrasonography (US). Familiarity with these conditions and the sonographic findings would be useful in making timely and correct diagnosis.

Are there any reasons to change our behavior in necrotizing fasciitis with the advent of new antibiotics?

PURPOSE OF REVIEW

The treatment of necrotizing fasciitis requires a multifaceted approach, consisting of surgical source control with immediate surgical debridement along with life support, clinical monitoring, and antimicrobial therapy. Many drugs are now available for the treatment of this life-threatening infectious disease, and the purpose of this review is to provide the reader with an updated overview of the newest therapeutic options.

RECENT FINDINGS

Because most necrotizing soft tissue infections are polymicrobial, broad-spectrum coverage is advisable. Acceptable monotherapy regimens include piperacillin-tazobactam or a carbapenem. However, drugs such as ceftolozane-tazobactam, ceftazidime-avibactam in association with an antianaerobic agent (metronidazole or clindamycin) are currently available as valuable alternatives. The new cephalosporins active against methicillin-resistant Staphylococcus aureus (MRSA), ceftaroline, and ceftobiprole share similar antibacterial activity against Gram-positive cocci, and they might be considered as an alternative to nonbetalactam anti-MRSA agents for necrotizing fasciitis management. Two new long-acting lypoglycopeptides - oritavancin and dalbavancin - share the indications for acute bacterial skin and skin structure infections and had similar activity against Gram-positive cocci including MRSA and streptococci.

SUMMARY

Carbapenem-sparing agents are particularly suitable for antimicrobial stewardship strategy. The new long-acting lypoglycopeptides are very effective in treating necrotizing fasciitis and are uttermost attractive for patients requiring short hospital stays and early discharge.

Necrotizing Fasciitis Caused by Group A Streptococcus: Case Report and Therapy Update

Necrotizing fasciitis is a life-threatening infection that affects the fascia and fat tissue underlying the skin. The diagnosis is often difficult because subcutaneous changes may not be readily apparent. Toxin-producing bacteria are usually the cause, with group A streptococcus (GAS) or Streptococcus pyogenes being responsible for a significant portion of the morbidity and mortality associated with this infection. The mortality rate associated with necrotizing fasciitis varies between 30% and 60%. Toxic shock-like syndrome and multisystem organ failure are the usual causes of death. Early diagnosis and surgery have been associated with decreased morbidity and mortality, and appropriate antimicrobial (eg, penicillin plus clindamycin) and supportive therapy is of utmost importance. Intravenous immunoglobulin and hyperbaric oxygen therapy may be beneficial in treating the infection; however, these 2 therapies require further research. Clinicians need to familiarize themselves with the disease and the different treatment modalities to be able to make the appropriate therapeutic decision. The optimal treatment of necrotizing fasciitis still remains a challenge today. This article presents an illustrative case with a brief overview of necrotizing fasciitis, and the current therapeutic modalities used in the management of the disease.

Necrotizing Fasciitis of the First Ray Caused by Group a Streptococcus

Necrotizing fasciitis of the hand is a rare clinical entity, frequently with devastating functional consequences. A case of necrotizing fasciitis of the thumb and thenar eminence caused by Group A Streptococcus is reported and the management of this condition in the upper limb discussed.

Ultrasound Examination of Pediatric Musculoskeletal Diseases and Neonatal Spine

Ultrasound (US) is a simple, non-invasive imaging modality which allows high-resolution imaging of the musculoskeletal (MSK) system. Its increasing popularity in pediatrics is due to the fact that it does not involve radiation, has an ability to visualize non-ossified cartilaginous and vascular structures, allows dynamic imaging and quick contralateral comparison. US is the primary imaging modality in some pediatric MSK conditions like infant hip in developmental dysplasia (DDH), hip joint effusion, epiphyseal trauma and evaluation of the neonatal spine. US is the modality of choice in infants with DDH, both in the initial evaluation and post-treatment follow-up. US has a sensitivity equivalent to MRI in evaluation of the neonatal spine in experienced hands and is a good screening modality in neonates with suspected occult neural tube defects. In other MSK applications, it is often used for the initial diagnosis or in addition to other imaging modalities. In trauma and infections, US can often detect early and subtle soft tissue abnormalities and a quick comparison with the contralateral side aids in diagnoses. Dynamic imaging is crucial in evaluating congenital instabilities and dislocations, soft tissue and ligamentous injuries, epiphyseal injuries and fracture separations. High-resolution imaging along with color Doppler (CD) is useful in the characterization of soft tissue masses. This article reviews the applications of US in pediatric MSK with emphasis on conditions where it is a primary modality. Limitations of US include inability to penetrate bone, hence, limited diagnosis of intraosseous pathology and operator dependency.

Magnetic resonance imaging of musculoskeletal infections: systematic diagnostic assessment and key points

Prompt diagnosis and treatment are essential in preventing the complications of musculoskeletal infection. In this context, imaging is often used to confirm clinically suspected diagnoses, define the extent of infection, and ensure appropriate management. Because of its superior soft-tissue contrast resolution, magnetic resonance imaging (MRI) is the modality of choice for evaluating musculoskeletal infections. This article describes the MRI features along the full spectrum of musculoskeletal infections and provides several illustrative case examples.

Musculoskeletal gene therapy and its potential use in the treatment of complicated musculoskeletal infection

Tissue repair is a major issue in orthopedics. Many musculoskeletal tissues, including cartilage, meniscus, and the anterior cruciate ligament, heal poorly after injury. Recent studies have led to the identification of numerous growth factors and other gene products that can promote the regeneration of damaged musculoskeletal tissues. In the last century, the discovery and evolving use of antibiotics has significantly decreased the prevalence and severity of infectious diseases. In many orthopedic scenarios, however, treatment of infections can be difficult, and often involves a prolonged course of antibiotics with concomitant surgical interventions and loss of tissue. Although studies have demonstrated the successful transfer of target genes and the associated manipulation of the musculoskeletal tissue environment, researchers have made few attempts designed to use gene therapy to treat infectious musculoskeletal diseases in animal models. Before it is possible to use gene-based approaches to treat such diseases effectively, researchers must perform more studies to investigate the potential problems that may arise when using gene therapy in an infectious environment.

Necrotizing fasciitis: analysis of 48 cases in South Auckland, New Zealand

BACKGROUND

To assess the presentation, management and risk factors for mortality in necrotizing fasciitis at Middlemore Hospital in South Auckland, New Zealand.

METHODS

A retrospective review of the medical records of patients presenting to Middlemore Hospital over a 6-year period (1997-2002) with a diagnosis of necrotizing fasciitis.

RESULTS

Forty eight patients were identified. There were 27 men and 21 women whose age ranged from 19 to 80 years (median 51 years) at presentation. Maori and Pacific Islanders accounted for 64% of total admissions despite making up only 31% of the referral population. Streptococcus Pyogenes was the most common bacterial isolate (54%). 31% of patients had polymicrobial infections. Sixty-two per cent of cases involved extremities. The median number of operations and length of stay were 4 and 31 days, respectively. Overall mortality was 29%. In multivariate analysis, delay in surgical intervention (P = 0.015) and diabetes mellitus (P = 0.023) were found to be associated with increased mortality. Ethnicity, sex, type of pathogen, site of infection and increasing age did not affect mortality.

CONCLUSION

Necrotizing fasciitis remains a significant problem in our community especially in the Maori and Pacific population. Early surgical debridement decreases mortality rates.

Musculoskeletal infections: ultrasound appearances

Musculoskeletal infections are commonly encountered in clinical practice. This review will discuss the ultrasound appearances of a variety of musculoskeletal infections such as cellulitis, infective tenosynovitis, pyomyositis, soft-tissue abscesses, septic arthritis, acute and chronic osteomyelitis, and post-operative infection. The peculiar sonographic features of less common musculoskeletal infections, such as necrotizing fasciitis, and rice body formation in atypical mycobacterial tenosynovitis, and bursitis will also be presented.

[Necrotizing soft tissue infections: nomenclature and classification]

Terminology used to refer to necrotizing infections is extensive because of the absence of clear definitions and the use of classification systems based on a variety of criteria, including etiologic, microbiologic, anatomic, and clinical aspects. This situation has led to some confusion. In the attempt to unify terminology, it might be more appropriate to use only the terms necrotizing fasciitis and myonecrosis, in which differentiation is mainly anatomical. Another option would be to use only the expression necrotizing soft tissue infections, a non-specific term, since these constitute a group of clinical processes having similar pathophysiologic characteristics and therapeutic principles.

Soft tissue disease

In the assessment of patients with soft tissue complaints, it is important to consider infectious etiologies in the differential diagnosis, especially in immunocompromised hosts. The exact categorization of some bacterial infections of the soft tissues may be difficult. The structures potentially involved include the skin, subcutaneous tissue, fascia, and skeletal muscle. Classification is usually based upon the anatomic structure involved, the infecting organism, and the clinical picture. The categorization is complicated by the fact that some infections may involve several soft tissue components and multiple bacterial species. In this review, we will cover cutaneous and subcutaneous tissue infections, fasciitis, septic bursitis, tendonitis, and pyomyositis.

Massive infectious soft-tissue injury: diagnosis and management of necrotizing fasciitis and purpura fulminans

LEARNING OBJECTIVES

After studying the article, the participant should be able to: 1. Describe the most common bacteriology of necrotizing fasciitis and purpura fulminans. 2. Describe the "finger test" in the diagnosis of necrotizing fasciitis. 3. Discuss the three presentation patterns of necrotizing fasciitis. 4. Discuss the pathophysiology of acute infectious purpura fulminans. 5. Discuss the treatment strategies for necrotizing fasciitis and purpura fulminans, including the use of artificial skin substitutes. Necrotizing fasciitis and purpura fulminans are two destructive processes that involve skin and soft tissues. The plastic and reconstructive surgeon may frequently be called on for assistance in the diagnosis, treatment, and/or reconstruction of patients with these conditions. Understanding the natural history and unique characteristics of these processes is essential for effective surgical management and favorable patient outcome. A comprehensive review of the literature pertaining to these two conditions is presented, outlining the different pathophysiologies, the patterns of presentation, and the treatment strategies necessary for successful management of these massive infectious soft-tissue diseases.

Role of ultrasound in musculoskeletal infections

Ultrasound is able to play a key role in the management of musculoskeletal soft tissue infections. It is an easily accessible imaging modality that can be used immediately after plain radiographs have been obtained. Quick diagnosis is essential in the clinical setting of musculoskeletal infection because delay can lead to significant morbidity. In addition to its diagnostic capabilities, US offers a safe, real-time, and convenient technique to perform immediately a guided-needle aspiration of any suspicious fluid collection. US provides the most efficient way to document quickly an infection of the musculoskeletal soft tissues and to identify the offending micro-organism.

Musculoskeletal infections: US manifestations

One of the most important prognostic factors in patients with musculoskeletal infections is the delay in establishing therapy. Early diagnosis of septic arthritis requires analysis of joint fluid. Ultrasonography (US) is a rapid, portable, sensitive technique for confirming the presence of joint effusions. The study can be easily repeated for follow-up of lesions. US allows real-time guidance of fluid aspiration and can reduce the risk of contaminating other anatomic compartments, especially in the hands, wrists, and feet. Radiography provides complementary information and should be performed in conjunction with US. US is the imaging modality of choice for diagnosis of superficial abscesses. Dynamic compression with the US probe and color Doppler imaging can facilitate detection of superficial abscesses. US may help in the early diagnosis of osteomyelitis by demonstrating subperiosteal or juxtacortical fluid collections and by providing guidance for aspiration of these collections. Evaluation of osseous involvement requires additional imaging; a US examination with normal results does not allow exclusion of bone infection. US is not degraded by metallic artifact and may be useful in cases of osteomyelitis complicating metallic fixation in an extremity. After initial radiography, US can play an important role in the management of musculoskeletal infections.

Systemic lupus erythematosus complicated by necrotizing fasciitis

A case of necrotizing fasciitis (NF) is described in a 46-year-old woman with recent onset systemic lupus erythematosus (SLE). Deep-tissue infections are more common in SLE patients on high-dose corticosteroids, but, to our knowledge, this is the second case described in association with SLE. Although NF may initially be difficult to diagnose, the presence of marked systemic symptoms out of proportion to the local findings should suggest the correct diagnosis. NF diagnostic criteria, treatment and prognosis are discussed.

Miliary tuberculosis presenting as tenosynovitis in a case of rheumatoid arthritis

A 77-year-old woman with a seropositive nodular rheumatoid arthritis and vasculitis, who was treated with high doses of corticosteroids and intravenous cyclophosphamide, developed miliary tuberculosis that was heralded by a tenosynovitis in her right wrist. A 1-year course of anti-tuberculous therapy resulted in complete resolution of the tenosynovitis and disseminated infection.

Diagnosis and Treatment of Gout in the Intensive Care Unit

Gout is a common cause of arthritis resulting from formation of monosodium urate crystals in synovial tissues. The incidence of this condition in the critically ill population is unknown, but gout can result in short-term morbidity and it can occasionally complicate management of a patient's primary condition. The diagnosis of gout should be considered in any patient in whom acute arthritis or bursitis develops. Aspiration of the involved joint or bursa and identification of crystals using either polarized or light microscopy are mandatory. Treatment options in critically ill patients differ from the usual treatment of gout because most critically ill patients have or are at risk for renal dysfunction and gastrointestinal bleeding, thus making use of nonsteroidal anti-inflammatory agents and colchicine hazardous. Intravenous colchicine in critically ill patients should be used with extreme caution, if at all, because the risk of bone marrow toxicity and other complications are well described in this patient population. Initial regimens should include use of adrenocorticotropic hormone, intra-articular corticosteroids, or systemic steroids. Analgesics may be beneficial as primary therapy in minor cases of acute gout, and they may be useful as adjunctive therapy in more severe cases. The role of colchicine as a prophylactic agent is discussed, as are treatment options in the allograft transplant population, in which rapidly progressive gout is increasingly common.

Necrotizing fasciitis

Necrotizing fasciitis is an uncommon soft-tissue infection, usually caused by toxin-producing, virulent bacteria, which is characterized by widespread fascial necrosis with relative sparing of skin and underlying muscle. It is accompanied by local pain, fever, and systemic toxicity and is often fatal unless promptly recognized and aggressively treated. The disease occurs more frequently in diabetics, alcoholics, immunosuppressed patients, i.v. drug users, and patients with peripheral vascular disease, although it also occurs in young, previously healthy individuals. Although it can occur in any region of the body, the abdominal wall, perineum, and extremities are the most common sites of infection. Introduction of the pathogen into the subcutaneous space occurs via disruption of the overlying skin or by hematogenous spread from a distant site of infection. Polymicrobial necrotizing fasciitis is usually caused by enteric pathogens, whereas monomicrobial necrotizing fasciitis is usually due to skin flora. Tissue damage and systemic toxicity are believed to result from the release of endogenous cytokines and bacterial toxins. Due to the paucity of skin findings early in the disease, diagnosis is often extremely difficult and relies on a high index of suspicion. Definitive diagnosis is made at surgery by demonstration of a lack of resistance of normally adherent fascia to blunt dissection. Treatment modalities include surgery, antibiotics, supportive care, and hyperbaric oxygen. Early and adequate surgical debridement and fasciotomy have been associated with improved survival. Initial antibiotic therapy should include broad aerobic and anaerobic coverage. If available, hyperbaric oxygen therapy should be considered, although to our knowledge, there are no prospective, randomized clinical trials to support this. Mortality rates are as high as 76%. Delays in diagnosis and/or treatment correlate with poor outcome, with the cause of death being overwhelming sepsis syndrome and/or multiple organ system failure.

Septic bursitis

Nine cases of septic bursitis are presented, and the literature on the subject comprehensively reviewed, with an emphasis on the clinical manifestations of septic bursitis in various anatomic locations. Physical activities associated with increased susceptibility to septic bursitis and systemic conditions that increase the severity of septic bursitis are catalogued. Analysis of the microbiology of cases reported in the literature demonstrates that greater than 80% of cases of septic bursitis are caused by Staphylococcus aureus and other gram-positive organisms. However, a wide variety of gram-negative microorganisms, fungi, and other infectious agents have been reported to cause septic bursitis and may lead to complications in diagnosis and treatment. The nine cases reported here demonstrate the potential severity of septic bursitis and emphasize that significant systemic complications may result from this common musculoskeletal infection. Indications for hospitalization and/or intravenous antibiotic therapy for septic bursitis include the presence of fulminant local infection, evidence for systemic toxicity, or infection in an immunocompromised patient. Patients who fail to respond to intravenous antibiotics and percutaneous aspiration of the bursa may require surgical drainage or bursectomy by one of several methods that have been proposed. There is some recent evidence that intrabursal corticosteroid injection for therapy of nonseptic subcutaneous bursitis may be more effective than systemic antiinflammatory medication or simple bursa aspiration.