Clinical Year in Review II: Mechanical Ventilation, Acute Respiratory Distress Syndrome, Critical Care, and Lung Cancer

In his review, Dr. Schwartz summarized the idiopathic and familial forms of pulmonary fibrosis, as well as chronic hypersensitivity pneumonitis (CHP) and nonspecific interstitial pneumonitis. Pulmonary fibrosis remains a significant health problem whose true incidence and prevalence has been believed to be increasing in recent years. Using a database from the National Center for Health Statistics, Olson and colleagues (1) clearly show for the first time that the mortality rates have increased from 1992 to 2003. Although these data do not confirm that the prevalence is increasing, they do suggest that there have been improvements in reporting and identification of fibrotic lung diseases. Of note, two-thirds of deaths in all patients reported were due to fibrotic lung disease. The trends increased for both men and women. The age-adjusted mortality increased for both sexes, and the authors of this report suggest that this trend will continue. One of the variants of idiopathic pulmonary fibrosis (IPF) is the accelerated form of this disease. The genetics that characterize the differences between slow progression of IPF and the rapidly progressive form of this disease were previously unknown. To address this question, Dr. Selman and associates examined gene expression profiles in 88 patients with histologically proven, slowly progressing IPF and 26 patients with the rapid variant (2). To be included in the ‘‘slow’’ group, symptoms had to present for more than 2 years, whereas the ‘‘rapid’’ group was symptomatic for less than 6 months. Surgical lung biopsy was performed in 31% of the patients studied. There were more men than women in the rapid group, but there were no differences between the groups in terms of age, physiologic profiles, or bronchoalveolar lavage (BAL) differential cell counts. The data showed multiple differences in gene expression profiles in the two groups. Two genes, adenosine 2B receptor and prominin-1/CD133, were expressed more strongly in the rapid group. In addition, expression of matrix metalloproteinases and markers of fibroblast activation was more pronounced in the rapid group. This report raises the question that certain gene profiles may be associated with differential responses to treatments, and reveals potential targets for therapeutic intervention in each form of this disease. Historical studies have shown that smoking is associated with the onset of IPF. However, the relationship to smoking status relative to outcome in IPF remains unclear. A retrospective review of 249 patients with IPF, 39 of whom had biopsy-proven disease (3), reported that, when current smokers were compared with former smokers (n 5 166), a better outcome was noted in the current smoking group. However, when the authors compared nonsmokers with either former smokers or the combined group of current and former smokers, there was increased survival in the nonsmoking group (n 5 63). Collectively, these data show that smoking negatively impacts survival in patients with IPF. Although the familial form of pulmonary fibrosis is rare (occurs in 5% in all patients with IPF), the clinical characteristics of this illness are not well defined. In a report from Rosas and colleagues (4), clinical summaries of 164 subjects from 18 families with familial pulmonary fibrosis were reported. Notably, occult interstitial lung disease was detected by highresolution chest computed tomography (HRCT) in 31 of 143 persons studied. These individuals were younger than their cohorts and were less likely to be smokers. However, open lung biopsies that were conducted in asymptomatic persons revealed several histologic subtypes, which include IPF and nonspecific interstitial pneumonia (NSIP). Finally, this reports highlights that smoking increases the risk of developing lung disease in familial pulmonary fibrosis. Radiologic imaging is used increasingly to distinguish various forms of lung disease. However, there are limited reports using HRCT to discern the differences between CHP from other forms of fibrotic disease, such as IPF and NSIP. Silva and colleagues (5) conducted a retrospective analysis of 66 patients, 18 of whom had CHP, 23 of whom had IPF, and 25 of whom had a diagnosis of NSIP. In this report, it was not clear if NSIP was idiopathic or associated with a connective tissue disease (see below). The radiologic features that distinguished CHP were decreased attenuation and vascularity, the presence of centrilobular nodules, and the absence of lower zone–predominant infiltrates. In contrast, IPF and NSIP are lower zone predominant. On the basis of these findings, the authors were able to correctly diagnose 70 of 132 readings (53%), and they were able to differentiate NSIP from IPF. Although these results are intriguing, it is interesting to speculate what the data would have revealed if surgical lung biopsy were reported from each group relative to the radiologic pattern observed. Another finding from this study confirmed that CHP has a better prognosis than IPF. The lesion of NSIP may occur in a variety of settings, but its relationship to connective tissue diseases has not been established. To address this question, Kinder and coworkers (6) examined 28 consecutive patients with idiopathic interstitial pneumonia (IIP) who met the following criteria for undifferentiated connective tissue disease (UCTD): one clinical manifestation of connective tissue disease, serologic evidence of systemic inflammation in the absence of clinical infection, and absence of sufficient American College of Rheumatology criteria for another connective tissue disease. Compared with the control group (i.e., patients with IIP without UCTD [n 5 47]), the patients with UCTD were more likely to be women, (Received in original form June 18, 2008; accepted in final form June 23, 2008)

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.