Pulmonary Infections in Immunocompromised Hosts: The Importance of Correlating the Conventional Radiologic Appearance with the Clinical Setting

Abstract

The lung is one of the most frequently involved organs in a variety of complications in the immunocompromised host. Among the pulmonary complications that occur in this kind of patient, infection is the most common and is associated with high morbidity and mortality. Although chest radiography and computed tomography (CT) are essential diagnostic tools, radiologists often have difficulty in establishing the correct diagnosis on the basis of radiologic findings alone. The reasons are that the immunocompromised host is potentially susceptible to infection from many different microorganisms and that radiologic findings are seldom specific for the detection of a particular pathogen. Experience has shown that a particular clinical setting predisposes patients to infection by particular pathogens. The setting comprises (a) the specific epidemiologic or environmental exposure, (b) the type of underlying immune defect, (c) the duration and severity of immune compromise, and (d) the progression rate and pattern of the radiologic abnormality. Correlating the radiologic appearance with the clinical setting can expedite diagnosis and appropriate therapy. In this review, the authors describe the clinical settings that are helpful in choosing the radiologic approach to treatment of the immunocompromised host who presents with suspected pulmonary infection.

Candidiasis in pediatric patients with cancer interned in a university hospital

“…Fungal infection is an important cause of morbidity and mortality in immunocompromised pediatric cancer patients (19). The underlying disease, neutropenia and other risk factors, substantially alter the epidemiology of infection allowing the development of opportunistic infectious processes at some point during the immunosuppressive therapy (5,24).…”

Angioinvasive pulmonary aspergillosis after allogeneic bone marrow transplantation: clinical and high-resolution computed tomography findings in 12 cases

“…The HRCT scan is superior to plain radiographic films in the detection and characterization of pulmonary complications after BMT. This exam is indicated in the presence of clinical manifestations of pulmonary disease with normal or unspecific radiographic findings, and for those patients who do not present clinical improvement despite adequate therapy [9,[14][15][16][17]. Therefore, the HRCT scan allows more effective investigation for patients in the period after BMT, which is of high importance in such patients whose clinical deterioration is fast and lethal.…”

“…In severe neutropenic patients the halo sign is highly suggestive of APA. However, other diseases associated or not to the BMT, such as candida infection, CMV pneumonia, herpes simplex infection, Wegener's granulomatosis, Kaposi's sarcoma and hemorrhagic metastasis can also present with this finding [16,17]. If there is a separation between necrotic lung fragments and the adjacent parenchyma, the air crescent sign can be seen.…”

High-resolution computed tomography (HRCT) of lung infections in non-AIDS immunocompromised patients

“…Imaging plays a crucial role in the detection and management of pulmonary infection in these individuals [10][11][12][13][14][15]. However, the development of pulmonary infiltrates in these patients remains a difficult diagnostic challenge [12,15,16].…”

“…However, the development of pulmonary infiltrates in these patients remains a difficult diagnostic challenge [12,15,16]. The differential diagnosis is broad and includes both infectious and noninfectious causes such as hemorrhage, drug-induced lung disease, pulmonary edema, and pulmonary embolism [10].…”