Idiopathic pulmonary fibrosis is a severe and progressive chronic fibrosing interstitial lung disease, a definitive diagnosis being established by specific combinations of clinical, radiological, and pathological findings. According to current international guidelines, HRCT plays a key role in establishing a diagnosis of usual interstitial pneumonia (UIP). Current guidelines describe three UIP patterns based on HRCT findings: a typical UIP pattern; a pattern designated "possible UIP"; and a pattern designated "inconsistent with UIP", each pattern having important diagnostic implications. A typical UIP pattern on HRCT is highly accurate for the presence of histopathological UIP, being currently considered to be diagnostic of UIP. The remaining patterns require further diagnostic investigation. Other known causes of a UIP pattern include drug-induced interstitial lung disease, chronic hypersensitivity pneumonitis, occupational diseases (e.g., asbestosis), and connective tissue diseases, all of which should be included in the clinical differential diagnosis. Given the importance of CT studies in establishing a diagnosis and the possibility of interobserver variability, the objective of this pictorial essay was to illustrate all three UIP patterns on HRCT.

Keywords: Tomography, X-ray computed; Lung diseases, interstitial; Pulmonary fibrosis.

Objective: The aim of this study was to examine the parenchymal and extracellular matrix remodeling process in two histologic patterns-nonspecific interstitial pneumonia (NSIP) and usual interstitial pneumonia (UIP)-in cases of idiopathic and sclerosis/systemic sclerosis (SSc)-associated interstitial pneumonia. Methods: We examined 15 cases of idiopathic NSIP, 10 cases of idiopathic UIP, 5 cases of SSc-UIP and 9 cases of SSc-NSIP. In the lung parenchyma, epithelial cells, endothelial cells and myofibroblasts were evaluated by immunohistochemical staining, whereas histochemical staining was used in order to evaluate collagen/elastic fibers in the extracellular matrix. Results: The percentage of surfactant protein A-positive epithelial cells was significantly greater in idiopathic NSIP than in SSc-NSIP, as well as being greater in idiopathic UIP than in SSc-UIP. Idiopathic NSIP and idiopathic UIP presented significantly higher immunoexpression of alpha smooth muscle actin in myofibroblasts than did SSc-NSIP and SSc-UIP. The percentage of CD34 endothelial cells in the pulmonary microvasculature was significant lower in idiopathic UIP than in SSc-UIP. The density of collagen fibers was significantly greater in idiopathic NSIP and idiopathic UIP than in SSc-NSIP and UIP. In contrast, the elastic fiber density was significantly lower in idiopathic UIP than in SSc-UIP. Conclusions: Increased collagen synthesis, destruction of elastic fibers, high myofibroblast proliferation and poor microvascularization might represent a remodeling process found in idiopathic interstitial pneumonia, whereas the reverse might represent a repair process in SSc-associated interstitial pneumonia.

Keywords: Epithelial cells; Neovascularization, pathologic; Collagen; Elastin; Idiopathic interstitial pneumonias; Scleroderma, systemic.

Idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) is a progressive interstitia pulmonary disease of unknown etiology. Since Hamman's and Rich's (1944) reports, many studies have tried to find a histological marker for the correlation between prognosis and response to therapy. However, there are many doubts regarding pathogenesis. In addition, it is generally accepted that response to therapy is related to the relative degree of cellularity and fibrosis. The purpose of this study is to describe the results of inflammatory/exudative changes, fibrotic/reparative changes, and airway alterations, using a semi-quantitative method by independent evaluation of two pathologists, in 24 open lung biopsies with the diagnosis of idiopathic pulmonary fibrosis. Fourteen histological features were analyzed using the 0 to 5 scale for interstitial alterations and the 0 to 2 scale for the airway changes. There was significant interobserver agreement for all histological features with Kw (Kappa) variations between 0.47 and 0.92. There was significant disagreement only for septal inflammatory intensity analysis, suggesting that these features must be discussed by the pathologists. The semi-quantitative method assessment was effective.

Keywords: Idiopathic pulmonary fibrosis (IPF). Usual interstitial pneumonia (UIP). Semi-quantitative method assessment.

Objective: To evaluate the differences between surgical biopsies of distinct lung lobes in terms of the histopathological features of usual interstitial pneumonia, using a semiquantitative score. Methods: We selected all of the patients diagnosed with idiopathic pulmonary fibrosis and submitted to surgical biopsy in two distinct lobes between 1995 and 2005 at the Hospital São Paulo and other hospitals operated by the Federal University of São Paulo. In the histological evaluation of the specimens, we used a semiquantitative method based on previous studies, assigning a score to each of the biopsied sites. Results: In this sample of patients, we found no statistically significant differences that would alter the stage of the disease, based on the score used. This finding was independent of the biopsy site (middle lobe or lingular segment). Conclusions: No significant histological differences were found between the lung lobes studied. The definitive histological diagnosis of usual interstitial pneumonia did not alter the stage of the disease.

Keywords: Lung diseases, interstitial; Pulmonary fibrosis; Thoracic surgery; Pathology; Thoracic surgery, ­video-assisted.

Leptospirosis is an infectious disease characterized by multisystemic involvement. The lung involvement is common, usually mild and frequently neglected. When respiratory manifestations are prominent in a patient with leptospirosis, there is the potential for diagnostic confusion. The authors report a severe case of leptospiral pneumonia, with the objective of highlighting this etiological possibility of community pneumonia, especially when there is suspicion of epidemic features.

Chronic eosinophilic pneumonia is a rare disease of unknown cause characterized by eosinophilic alveolar and interstitial infiltration. The authors describe the case of a 49-year-old caucasian woman, presenting dyspnea on minimum effort, with insidious beginning and progressive course in the last six months. The main findings were serum eosinophilia and in the sputum, chest radiographs showing multifocal infiltrations of irregular distribution in both lungs and a restrictive functional impairment. The patient was submitted to an open lung biopsy, which demonstrated a chronic eosinophilic pneumonia. There was a dramatic clinical, radiological, and functional response after corticosteroid therapy.

Objective: Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically occurs in cases of influenza (airborne transmission) or during episodes of bacteremia (blood-borne transmission). Methods: A retrospective and descriptive study was conducted in patients admitted to our hospital between January of 1992 and December of 2003. All of he patients included had been diagnosed with community-acquired pneumonia caused by Staphylococcus aureus. All were older than 14 years of age, and none were intravenous drug users. Results: Community-acquired pneumonia was identified in 332 cases, of which 24 (7.3%) were identified as cases of staphylococcal pneumonia. Age ranged from 14 to 89 years. Fifteen patients were male, and nine were female. Twelve patients met the criteria for severe pneumonia. Chest X-rays showed unilateral consolidation in 14 cases, bilateral consolidation in 10, pleural effusion in 15, rapid radiological progression of pulmonary lesions in 14, cavitation in 6 and pneumothorax in 1. Most of the patients presented comorbidities, of which diabetes mellitus was the most common. Twelve patients presented complications such as empyema and septic shock. Four patients died, translating to a mortality rate of 16.6% in our sample. Conclusions: The clinical presentation of pneumonia caused by S. aureus is similar to that of pneumonia caused by other etiological agents. Radiological findings, epidemiological data and risk factors provide important clues to the diagnosis. These factors are important for clinical suspicion, since S. aureus is not typically addressed in empirical treatment.

Keywords: Staphylococcal pneumonia; Staphylococcal infections; Community-acquired infections.

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.

48 years-old woman, asymptomatic, presented with radiographic findings of patchy airspace consolidation with nodular opacities in the upper right lobe, middle lobe and lingula. The differential diagnoses of neoplasms, sarcoidosis, granulomatous diseases and tuberculosis were considered. Diagnosis of Bronchiolitis obliterans organizing pneumonia was made by means of videothoracoscopy whereupon treatment with corticosteroids was begun. The patient had a positive evolution with resolution of the radiographic finding.

Keywords: bronchiolitis obliterans organizing pneumonia, bronchiolitis obliterans

Pneumocystosis is an opportunistic infection that occurs frequently in immunodeficient patients, mainly in those with the acquired immunological deficiency (AIDS). The authors report the case of a patient with insidious symptoms of fever, cough, and weight loss. Thorax radiography revealed a tumoral image in the right costophrenic angle. Treatment for tuberculosis (therapeutic test) presented no response. An open lung biopsy was performed and the histological examination revealed Pneumocystis carinii pneumonia. The patient presented significant clinical and radiological improvement with specific treatment.

Keywords: pneumocystis carinii pneumonia; AIDS-related opportunistic infections

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.

Most interstitial lung diseases (ILD) are indolent in nature, producing subacute or chronic symptoms that progress at various rates and are usually present for months to years before a diagnosis is established. This report describes a case of a fulminating and life-threatening variant of idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP). Early suspicion, histologic diagnosis, and prompt initiation of corticosteroid therapy is important to prevent mortality.

Keywords: Bronchiolitis obliterans with organizing pneumonia (BOOP). Interstitial lung disease.

The authors report the case of an adolescent with bilateral interstitial bronchopneumonia caused by measles. They discuss this rare presentation and the usefulness of thorax CT scan for the diagnosis of this disease.

Keywords: Measles. Pneumonia. CT scan.

Organized pneumonia secondary to amiodarone use is rare. Only eight cases have been reported in the literature. It is reported on the case of a 75-year-old female who, after a cumulative dose of 43 g of amiodarone, presented coughing, progressive dyspnea and bilateral infiltrates seen at thoracic radiographs. Transbronchial biopsy confirmed the diagnosis. As the drug was discontinued, there was functional and clinical improvement.

Keywords: Bronchiolitis obliterans organizing pneumonia. Amiodarone. Drug therapy. Drug toxicity.

Nosocomial pneumonia, especially ventilator-associated pneumonia, is a common infection in ICUs. The main etiologic factors involve colonizing and opportunistic bacteria from the oral cavity. Oral hygiene measures, including the use of oral antiseptic agents, such as chlorhexidine, have proven useful in reducing its incidence. The objective of this article was to review the literature on the importance of the oral environment in the development of nosocomial pneumonia.

Keywords: Intensive care; Oral hygiene; Cross infection; Pneumonia.

Psittacosis, also known as ornithosis, is a disease caused by Chlamydia psittaci. The most common clinical presentation is insidious onset, mild symptoms resembling a nonspecific viral illness and preference for the lungs. It is rarely a systemic and fatal disease. It is described a rare case of pneumonia due to Chlamydia psittaci that progressively developed into respiratory failure, requiring mechanical ventilation. It is very important to consider psittacosis in cases of atypical pneumonia whose evolution is unsatisfactory, with no response to antimicrobial therapy and epidemiology is positive for exposure to birds. Prompt recognition is vital as the response to appropriate treatment is excellent. Delayed diagnosis may lead to a severe course and fatal outcome.

Keywords: Mycoplasma pneumonia. Ornithosis.

A 50-year-old woman with chagasic esophageal achalasia and megacolon presented with nonproductive cough, chest pain and dyspnea. A chest X-ray showed bilateral opacity suggestive of lobar pneumonia. Open lung biopsy revealed lipoid pneumonia resulting from aspiration of mineral oil from a mineral oil-based laxative that the patient had been taking regularly for the last three years. The authors discuss concomitance of chagasic megacolon and esophageal achalasia with lipoid pneumonia and make recommendations regarding the use of mineral oil-based products by these patients.

Keywords: Pneumonia, aspirtion/etiology. Pneumonia, lipid/etiology. Esophageal achalasia/pathology. Chagas disease/complications.