Objective: To describe aspects found on HRCT scans of the chest in patients infected with the influenza A (H1N1) virus. Methods: We retrospectively analyzed the HRCT scans of 71 patients (38 females and 33 males) with H1N1 infection, confirmed through laboratory tests, between July and September of 2009. The HRCT scans were interpreted by two thoracic radiologists independently, and in case of disagreement, the decisions were made by consensus. Results: The most common HRCT findings were ground-glass opacities (85%), consolidation (64%), or a combination of ground-glass opacities and consolidation (58%). Other findings were airspace nodules (25%), bronchial wall thickening (25%), interlobular septal thickening (21%), crazy-paving pattern (15%), perilobular pattern (3%), and air trapping (3%). The findings were frequently bilateral (89%), with a random distribution (68%). Pleural effusion, when observed, was typically minimal. No lymphadenopathy was identified. Conclusions: The most common findings were ground-glass opacities and consolidations, or a combination of both. Involvement was commonly bilateral with no axial or craniocaudal predominance in the distribution. Although the major tomographic findings in H1N1 infection are nonspecific, it is important to recognize such findings in order to include infection with the H1N1 virus in the differential diagnosis of respiratory symptoms.

Keywords: Pneumonia, viral; Tomography, X-ray computed; Influenza A virus, H1N1 subtype.

Objective: To determine the frequency of HRCT findings and their distribution in the lung parenchyma of patients with organizing pneumonia. Methods: This was a retrospective review of the HRCT scans of 36 adult patients (26 females and 10 males) with biopsy-proven organizing pneumonia. The patients were between 19 and 82 years of age (mean age, 56.2 years). The HRCT images were evaluated by two independent observers, discordant interpretations being resolved by consensus. Results: The most common HRCT finding was that of ground-glass opacities, which were seen in 88.9% of the cases. The second most common finding was consolidation (in 83.3% of cases), followed by peribronchovascular opacities (in 52.8%), reticulation (in 38.9%), bronchiectasis (in 33.3%), interstitial nodules (in 27.8%), interlobular septal thickening (in 27.8%), perilobular pattern (in 22.2%), the reversed halo sign (in 16.7%), airspace nodules (in 11.1%), and the halo sign (in 8.3%). The lesions were predominantly bilateral, the middle and lower lung fields being the areas most commonly affected. Conclusions: Ground-glass opacities and consolidation were the most common findings, with a predominantly random distribution, although they were more common in the middle and lower thirds of the lungs.

Keywords: Cryptogenic organizing pneumonia; Respiratory tract diseases; Tomography, X-ray computed.

Objective: To describe HRCT findings in patients with bacterial pneumonia following bone marrow transplantation (BMT). Methods: This was a retrospective study involving 30 patients diagnosed with bacterial pneumonia in whom HRCT of the chest was performed within 24 h after the onset of symptoms and the diagnosis was confirmed, based on a positive culture of sputum or bronchial aspirate, together with a positive pleural fluid or blood culture, within one week after symptom onset. There were 20 male patients and 10 female patients. The median age was 21 years (range, 1-41 years). The BMT had been performed for the treatment of the following: chronic myeloid leukemia, in 14 cases; severe aplastic anemia, in 6; acute myeloid leukemia, in 4; Fanconi's anemia, in 3; and acute lymphocytic leukemia, in 3. Two radiologists analyzed the HRCT scans and reached their final decisions by consensus. Results: The most common HRCT findings were air-space consolidation (in 60%), small centrilobular nodules (in 50%), ground-glass opacities (in 40%), bronchial wall thickening (in 20%), large nodules (in 20%), pleural lesions (in 16.7%) and tree-in-bud opacities (in 10%). The pulmonary lesions were distributed in the central and peripheral areas in 15 patients, whereas they were exclusively peripheral in 11. Lesions were located in the lower and middle lobes of the lung in 22 and 20 patients, respectively. Conclusions: The most common HRCT findings in our patient sample were air-space consolidation, small centrilobular nodules and ground-glass opacities, most often in the central and peripheral regions of the middle and lower lung zones.

Keywords: Bone marrow transplantation; Pneumonia, bacterial; Tomography, X-Ray Computed.

Objective: To describe the characteristics of patients with influenza A (H1N1)-associated pneumonia treated at two hospitals in the region of Liguria, Italy, as well as to describe their treatment and outcomes. Methods: This was a prospective observational study including all patients older than 16 years of age with a confirmed diagnosis of influenza A (H1N1) who were admitted to Villa Scassi Hospital, in the city of Genoa, Italy, or to the Sestri Levante General Hospital, in the city of Sestri Levante, Italy, between September of 2009 and January of 2010. The primary outcome measure was mortality within 60 days after diagnosis. Secondary outcome measures were the need for mechanical ventilation and the length of hospital stay. Results: Of the 40 patients with a confirmed diagnosis of influenza A (H1N1), 27 presented pneumonia during the study period. The mean age of the 27 patients was 42.8 ± 14.8 years, and the mean length of hospital stay was 11.6 ± 8.2 days. Of the 27 patients, 20 had respiratory failure, 4 underwent invasive mechanical ventilation, and 5 underwent noninvasive ventilation. One patient had comorbidities, developed multiple organ failure, and died. Conclusions: During the influenza A (H1N1) pandemic, the associated mortality rate was lower in Italy than in other countries, and cases reported in the country typically had a milder course than did those reported elsewhere. Nevertheless, 9 of our cases (33%) rapidly evolved to respiratory failure, requiring mechanical ventilation.

Keywords: Pneumonia; Influenza A virus, H1N1 subtype; Respiratory insufficiency.

Objective: To evaluate HRCT scans of the chest in 22 patients with cocaine-induced pulmonary disease. Methods: We included patients between 19 and 52 years of age. The HRCT scans were evaluated by two radiologists independently, discordant results being resolved by consensus. The inclusion criterion was an HRCT scan showing abnormalities that were temporally related to cocaine use, with no other apparent causal factors. Results: In 8 patients (36.4%), the clinical and tomographic findings were consistent with "crack lung", those cases being studied separately. The major HRCT findings in that subgroup of patients included ground-glass opacities, in 100% of the cases; consolidations, in 50%; and the halo sign, in 25%. In 12.5% of the cases, smooth septal thickening, paraseptal emphysema, centrilobular nodules, and the tree-in-bud pattern were identified. Among the remaining 14 patients (63.6%), barotrauma was identified in 3 cases, presenting as pneumomediastinum, pneumothorax, and hemopneumothorax, respectively. Talcosis, characterized as perihilar conglomerate masses, architectural distortion, and emphysema, was diagnosed in 3 patients. Other patterns were found less frequently: organizing pneumonia and bullous emphysema, in 2 patients each; and pulmonary infarction, septic embolism, eosinophilic pneumonia, and cardiogenic pulmonary edema, in 1 patient each. Conclusions: Pulmonary changes induced by cocaine use are varied and nonspecific. The diagnostic suspicion of cocaine-induced pulmonary disease depends, in most of the cases, on a careful drawing of correlations between clinical and radiological findings.

Keywords: Cocaine, Cocaine-related disorders; Tomography, X-ray computed; Lung diseases.

Objective: To evaluate pandemic influenza A (H1N1) 2009 in hospitalized patients in order to identify risk factors for hospitalization and, consequently, for the worsening of the disease. Methods: This retrospective observational study was conducted between March and December of 2010. The data were collected from the Brazilian Ministry of Health National Case Registry Database. We included only patients (inpatients and outpatients) in whom H1N1 infection was confirmed (via laboratory testing) during the study period. The variables regarding demographic and clinical characteristics were statistically evaluated in order to compare the hospitalization rates in the presence or absence of these factors. Risk factors were identified by logistic regression analysis. Results: We included 4,740 patients with laboratory confirmation of H1N1 infection. Of these, 1,911 individuals were hospitalized, and 258 (13.5%) died. The risk factors for hospitalization were age (20-29 years), African or Indigenous ethnicity, presence of specific comorbidities (heart disease, lung disease, kidney disease, hemoglobinopathy, immunosuppression, diabetes, obesity, puerperium, and smoking), a high number of comorbidities, and specific symptoms (dyspnea, diarrhea, vomiting, chest pain, hemoptysis, pneumonia, and wheezing). Higher levels of education and early use of oseltamivir were found to be protective factors. Hospitalization contributed to an increase in survival. Conclusions: Knowledge of the epidemiological characteristics that can be associated with hospitalization, disease severity, and mortality can be helpful in the adoption of preventive measures, as well as in the early diagnosis and treatment of disease, which might contribute to the reduction in the numbers of hospitalizations and deaths.

Keywords: Influenza A virus, H1N1 subtype; Hospitalization; Risk factors; Oseltamivir.

In March of 2009, a flu epidemic began in Mexico. Shortly thereafter, similar cases appeared in other countries, alerting authorities to the risk of a pandemic. This article details the principal signs and symptoms of infection with the swine-origin Influenza A (H1N1) virus. In addition, the measures to be taken in suspected or confirmed cases are addressed, as are the procedures to follow in relation to contacts. Furthermore, the drugs used in the prophylaxis against and the treatment of infection with the H1N1 virus are described.

Keywords: Influenza A virus, H1N1 subtype; Influenza A virus; Disease outbreaks.

In view of the pandemic caused by a new virus, influenza A (H1N1), we report the case of a 56-year-old patient without relevant risk factors and with severe acute respiratory syndrome resulting from infection with this virus. We present the results of laboratory tests and the imaging findings (chest X-ray and CT scans). The evolution was favorable, and the patient was discharged after 14 days.

Keywords: Influenza A virus, H1N1 subtype; Severe acute respiratory syndrome; Patient care.

Objective: The halo sign consists of an area of ground-glass opacity surrounding pulmonary lesions on chest CT scans. We compared immunocompetent and immunosuppressed patients in terms of halo sign features and sought to identify those of greatest diagnostic value. Methods: This was a retrospective study of CT scans performed at any of seven centers between January of 2011 and May of 2015. Patients were classified according to their immune status. Two thoracic radiologists reviewed the scans in order to determine the number of lesions, as well as their distribution, size, and contour, together with halo thickness and any other associated findings. Results: Of the 85 patients evaluated, 53 were immunocompetent and 32 were immunosuppressed. Of the 53 immunocompetent patients, 34 (64%) were diagnosed with primary neoplasm. Of the 32 immunosuppressed patients, 25 (78%) were diagnosed with aspergillosis. Multiple and randomly distributed lesions were more common in the immunosuppressed patients than in the immunocompetent patients (p < 0.001 for both). Halo thickness was found to be greater in the immunosuppressed patients (p < 0.05). Conclusions: Etiologies of the halo sign differ markedly between immunocompetent and immunosuppressed patients. Although thicker halos are more likely to occur in patients with infectious diseases, the number and distribution of lesions should also be taken into account when evaluating patients presenting with the halo sign.

Keywords: Tomography, X-ray computed; Aspergillosis; Lung neoplasms.

In 2010, 96 patients suspected of being infected with the influenza A (H1N1) virus were hospitalized at the Hospital São Paulo, located in the city of São Paulo, Brazil. Of those 96 patients, 4 (4.2%) were found to be infected with influenza A virus-3 with influenza A (H1N1) and 1 with seasonal influenza A-and 2 patients (2.1%) were found to be infected with influenza B virus. Most (63.5%) of the suspected cases occurred in children, as did half of the positive cases. The second wave of influenza A (H1N1) infection was weaker in São Paulo. The decrease in the number of hospitalizations for H1N1 infection in 2010 might be attributable to vaccination.

Keywords: Influenza A virus, H1N1 subtype; Influenza, human; Pneumonia; Pandemics.

The authors report the case of a female patient who developed chronic eosinophilic pneumonia secondary to long-term use of nitrofurantoin for prophylaxis of recurrent urinary tract infections due to urethral stenosis. On high-resolution computed tomography scans, the pulmonary reaction to nitrofurantoin most commonly manifests as an interstitial-alveolar pattern in both lung bases. However, in this case, the alterations were most pronounced in the periphery of the upper lobes. In itself, this tomographic profile is strongly indicative of chronic eosinophilic pneumonia. The patient had previously been submitted to an open lung biopsy. The diagnosis of chronic eosinophilic pneumonia was confirmed through a review of the biopsy.

Keywords: Pneumonia; Pulmonary eosinophilia; Nitrofurantoin/adverse effects; Tomography, X-ray computed.

The objective of this study was to review the literature related to avian influenza A (H5N1). The bibliographic research was conducted using the Medline, MD Consult, HighWire, Medscape and Literatura Latinoamericana y del Caribe en Ciencias de la Salud (LILACS, Latin American and Caribbean Health Sciences Literature) databases, as well as through direct research, limiting the scope to articles published within the past 10 years. We selected 31 original articles addressing the recent outbreaks of infection with the H5N1 subtype of avian influenza A in domesticated birds in Asia, which have resulted in significant economic losses and repercussions for public health, as well as some cases of human infection presenting high lethality. In most cases, infection has been associated with direct exposure to infected birds or contact with surfaces infected with bird excrement. However, cases of human-to-human transmission have been confirmed. In those cases, the incubation period varied from 2 to 4 days. The clinical manifestations range from asymptomatic infection to mild upper airway disease, pneumonia and multiple organ failure. Chest X-rays may reveal bilateral interstitial infiltrate, lobar collapse, focal consolidation and air bronchogram without pleural effusion. Lymphopenia is indicative of a poor prognosis. Supportive care appears to be the only acceptable treatment. Risk factors for poor prognosis include advanced age, delayed hospitalization, lower airway involvement, low white blood cell count or lymphopenia upon admission. Controlling outbreaks in domestic fowl and limiting contact between humans and infected birds must be the priorities in the management of this disease at the public health level. In addition, techniques and knowledge regarding the disease should be widely disseminated.

Keywords: Influenza A virus, avian /pathogenicity; Influenza; Disease outbreaks; Disease vectors; Clinical trials

Objective: The aim of this study was to analyze chest CT scans of patients with thoracic textiloma. Methods: This was a retrospective study of 16 patients (11 men and 5 women) with surgically confirmed thoracic textiloma. The chest CT scans of those patients were evaluated by two independent observers, and discordant results were resolved by consensus. Results: The majority (62.5%) of the textilomas were caused by previous heart surgery. The most common symptoms were chest pain (in 68.75%) and cough (in 56.25%). In all cases, the main tomographic finding was a mass with regular contours and borders that were well-defined or partially defined. Half of the textilomas occurred in the right hemithorax and half occurred in the left. The majority (56.25%) were located in the lower third of the lung. The diameter of the mass was ≤ 10 cm in 10 cases (62.5%) and > 10 cm in the remaining 6 cases (37.5%). Most (81.25%) of the textilomas were heterogeneous in density, with signs of calcification, gas, radiopaque marker, or sponge-like material. Peripheral expansion of the mass was observed in 12 (92.3%) of the 13 patients in whom a contrast agent was used. Intraoperatively, pleural involvement was observed in 14 cases (87.5%) and pericardial involvement was observed in 2 (12.5%). Conclusions: It is important to recognize the main tomographic aspects of thoracic textilomas in order to include this possibility in the differential diagnosis of chest pain and cough in patients with a history of heart or thoracic surgery, thus promoting the early identification and treatment of this postoperative complication.

Keywords: Foreign-body reaction; Tomography, spiral computed; Thoracic surgery.

This study aimed to review the literature on infection with the H5N1 subtype of avian influenza A virus, taking into consideration the fact that, in the event of a pandemic, children might become a major risk group. Searches were limited to the past ten years and were carried out using the following electronic databases: Medline, MD Consult, HighWire and Medscape. Children and young adults account for a significant proportion of the susceptible population. We found that more than half of the individuals infected were under 20 years of age and that one quarter were under the age of 10. The incubation period ranged from 2 to 5 days. Initial clinical manifestations are nonspecific, which hinders the diagnosis. Most of the infected individuals presented severe pneumonia, which evolved to respiratory insufficiency within an average of 4 days. Chest X-rays can reveal diffuse multifocal/interstitial infiltrates or segmental/lobar consolidation with air bronchogram. The pathogenic potential is high, with mortality rates up to 63%, indicating that the pandemic virus might present high pathogenicity and high mortality. Knowledge of the risk of a pandemic and of the measures to be taken in suspect cases constitutes an important step toward controlling a potential pandemic.

Keywords: Influenza A virus; Disease vectors; Disease outbreaks; Influenza A virus, H5N1 subtype.