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BackgroundCoccidioidomycosis (cocci) is an endemic fungal disease that can cause asymptomatic or post-symptomatic lung nodules which are visible on chest CT scanning. Lung nodules are common and can represent early lung cancer. Differentiating lung nodules due to cocci from those due to lung cancer can be difficult and lead to invasive and expensive evaluations.Materials and methodsWe identified 302 patients with biopsy-proven cocci or bronchogenic carcinoma seen in our multidisciplinary nodule clinic. Two experienced radiologists who were blinded to the diagnosis read the chest CT scans and identified radiographic characteristics to determine their utility in differentiating lung cancer nodules from those due to cocci.ResultsUsing univariate analysis, we identified several radiographic findings that differed between lung cancer and cocci infection. We then entered these variables along with age and gender into a multivariate model and found that age, nodule diameter, nodule cavitation, presence of satellite nodules and radiographic presence of chronic lung disease differed significantly between the two diagnoses. Three findings, cavitary nodules, satellite nodules and chronic lung disease, have sufficient discrimination to potentially be useful in clinical decision-making.ConclusionsCareful evaluation of the three obtained radiographic findings can significantly improve our ability to differentiate benign coccidioidomycosis infection from lung cancer in an endemic region for the fungal disease. Using these data may significantly reduce the cost and risk associated with distinguishing the cause of lung nodules in these patients by preventing unnecessary invasive studies.

Asthma-COPD overlap (ACO) is a common clinical syndrome, yet there is no single objective definition. We hypothesized that immunoglobulin E (IgE) measurements could be used to refine the definition of ACO. In baseline plasma samples from 2870 participants in the COPD Genetic Epidemiology (COPDGene®) study, we measured total IgE levels and specific IgE levels to 6 common allergens. Compared to usual chronic obstructive pulmonary disease (COPD), participants with ACO (based on self-report of asthma) had higher total IgE levels (median 67.0 versus 42.2 IU/ml) and more frequently had at least one positive specific IgE (43.5% versus 24.5%). We previously used a strict definition of ACO in participants with COPD, based on self-report of a doctor's diagnosis of asthma before age 40. This strict ACO definition was refined by the presence of atopy, determined by total IgE > 100 IU/ml or at least one positive specific IgE, as was the broader definition of ACO based on self-reported asthma history. Participants with all 3 ACO definitions were younger (mean age 60.0-61.3 years), were more commonly African American (36.8%-44.2%), had a higher exacerbation frequency (1.0-1.2 in the past year), and had more airway wall thickening on quantitative analysis of chest computed tomography (CT) scans. Among participants with ACO, 37%-46% did not have atopy; these individuals had more emphysema on chest CT scan. Based on associations with exacerbations and CT airway disease, IgE did not clearly improve the clinical definition of ACO. However, IgE measurements could be used to subdivide individuals with atopic and non-atopic ACO, who might have different biologic mechanisms and potential treatments.

[Pulmonary alveolar proteinosis]. Pulmonary alveolar proteinosis (PAP) is a rare, diffuse infiltrative lung disease of unknown etiology characterized by accumulation of abnormal lung surfactant in the alveoli and distal airways. Although it was first described in 1958, few large scale studies have been published. The diagnosis is conventionally based on lung biopsy and the value of less invasive procedures such as bronchoalveolar lavage (BAL) remains controversial. A multi-center retrospective study was conducted in an attempt to update epidemiological, clinical and long term outcome and to assess the usefulness of chest CT scan and BAL in the management of a large homogeneous series of 41 patients. Inclusion criteria required a clinical picture compatible with PAP and either histological confirmation, or a BAL with a milky macroscopic appearance coupled with positive staining to PAS. Mean age was 48.8 years with a 4: 1 male predominance. The prevalence of smokers (80%) and occupational exposure to various inhaled dusts (39%) was high. The clinical, roentgenographic and functional features were in keeping with previous series. Worsening dyspnea was the most common symptom. Other common manifestations were dry cough, recurrent lung infections, weight loss, finger clubbing, crackles and cyanosis. LDH serum levels were increased in 51% of cases. Lung function tests usually showed a mild restrictive ventilatory defect with hypoxemia and reduced DLCO. Chest X ray revealed bilateral ground glass opacities with consolidation or air bronchogram involving peri-hilar or lower lobes. Chest CT scan, performed in 38 patients, revealed a similar pattern in most of them with diffuse intra-alveolar ground glass opacities (33/38) and interlobular thickening (35/38), resulting in a crazy paving appearance in the typical geographic pattern (32/38). This latter aspect was highly suggestive of the diagnosis. Segmental BAL led to a definitive diagnosis in 62% and lung biopsy was only req