Nonpulmonary Infections of the Thorax
Introduction
Nonpulmonary infections of the thorax can be broadly divided into the following categories based on site of involvement: Heart, cardiac devices and vascular grafts, mediastinum, chest wall and soft tissues, pleura, and spine. Etiologies include primary infection via direct spread from adjacent structures, hematogenous spread, or postsurgical. In this article, we will discuss the imaging appearance of various forms of nonpulmonary intrathoracic infections. Radiologists must be familiar with these entities to ensure quick diagnosis so that treatment, which in some instances can be lifesaving, can promptly be initiated.
Section snippets
Cardiac Infections
Cardiac infections can be classified as infections that primarily involve the valves, myocardium, pericardium, or a combination of these structures. Endocarditis is an infection of the valve apparatus and adjacent structures often caused by bacteria or fungi. Although infectious endocarditis is somewhat rare, the mortality rate is high and ranges from 10%-25%.1 Diagnosis of infectious endocarditis (IE) is made with a combination of history, lab findings, and imaging. A history of intrinsic
Infection of Left Ventricular Assist Devices
Left ventricular assist devices (LVADs) are used in clinical practice for temporary hemodynamic support, as a bridge to transplantation, as a bridge to recovery, or as chronic support for patients who are ineligible for transplantation.21 Many types of LVADs exist and the details of their indications, components, function, and imaging evaluation are beyond the scope of this article. However, as with any surgical hardware, there is a risk of infection, and radiologists should be familiar with
Vascular Graft Infections
Infections related to grafts are rare but can be a serious complication of vascular surgery, with mortality rates reported in the range of 25%-75%.22 The incidence of graft infection ranges from 1.5%-6%.22 and several variables play a role in outcomes including: graft site, host immune status, pathogen, and time to diagnosis. Imaging is important for highlighting the following in cases of suspected graft infection: (1) graft position (2) graft structural integrity (3) perigraft inflammatory
Mediastinitis
Mediastinal infection is a serious condition that can occur as a sequela of surgery, esophageal perforation, extension of lower cervical infection, or from hematogenous spread of infection, with the first two causes being the most common.29 Chest radiography has a limited role in the imaging of suspected mediastinal infection, and contrast-enhanced CT is the main modality for assessment of the mediastinal structures. Common findings seen in acute mediastinal infection include increased
Chest Wall Infections
Chest wall infections are uncommon but can be a significant source of morbidity and mortality in susceptible populations such as immunocompromised patients. Organisms that are usually responsible include bacteria such as Staphylococcus, Streptococcus, Klebsiella, and Pseudomonas. Nonpyogenic organisms such as tuberculosis, Aspergillus, and Actinomyces can also be seen.38 In drug users, pseudomonas tends to be more common while Staphylococcal species are more often seen in the general
Spinal Infections – Discitis/Osteomyelitis/Epidural Abscess
Spinal infections represent approximately 2%-4% of all cases of osteomyelitis.46 Patients may present with back pain and fever, or symptoms may be nonspecific, which may lead to delay in diagnosis. Unless advanced disease is present, chest radiographs may be normal in many cases. On CT, paraspinal soft tissue stranding with edema and a mass-like appearance are typical, along with narrowing of the disc space (Fig. 19). MRI is the examination of choice and may demonstrate abnormal marrow signal
Conclusion
Nonpulmonary infections can be a serious cause of morbidity and mortality. In addition to the lungs, radiologists should direct careful attention to the mediastinum, chest wall, spine and soft tissues, particularly in immunocompromised patients, to assess for extrapulmonary infections. Prompt reporting of such infections is critical to beginning appropriate therapy.
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Cited by (1)
Vascular Infections in the Thorax
2022, Seminars in RoentgenologyCitation Excerpt :Perigraft fluid and/or soft tissue present more than 3 months after surgery should raise suspicion for infection.20 Other findings concerning for graft infection include new gas (Fig. 6), rim enhancement, lymphadenopathy, and rapidly increasing aneurysm sac size.22 Septic (or suppurative) thrombophlebitis is characterized by the combination of endovascular thrombus with associated infection and can involve both superficial and deep veins throughout the body.