Small airways disease

COPD is a progressive obstruction of the airways as a consequence of small airway disease and emphysema.It is the fourth leading cause of death in developed countries. Chronic inflammation and regulated air supply in the airway are amplified in case of COPD. Decreased activity of histone deacetylase is observed in chronic obstructive pulmonary disease. ... 

Diminished expiratory flows suggestive of small airway disease. 

Small airways disease on CT can be categorized into visible and indirect patterns of the disease. The tree-in-bud sign reflects the presence of dilated centrilobular bronchioles with lumina that are impacted with mucus, fluid, or pus it is often associated with peribronchiolar inflammation (Webb 2006). Cicatricial scarring of many bronchioles results in the indirect sign of patchy density differences of the lung parenchyma, reflecting areas of hypoventilation and air trapping, as well as subsequent hypoperfusion (mosaic perfusion). 

Hansell DM (2001) Small airways diseases detection and insights with computed tomography. Eur Respir J 17 1294-1313... 

Zompatori M, Poletti V, Rimondi MR, Battaglia M, Carvelli P, Maraldi F (1997) Imaging of small airways disease, with emphasis on high resolution computed tomography. Mon-aldi Arch Chest Dis 52 242-248... 

Gueny-Foice ML, Muller NL, Wright JL, et al. A comparison of bronchiolitis obliterans with organizing pneumonia, usual interstitial pneumonia, and small airways disease. Am Rev Respir Dis 1987 135 705-712. 

Radiographic manifestations of diseases affecting the small airways are polymorphous. The chest radiograph can be often normal in patients with documented bronchiolitis, and its sensitivity to detect small airways disease is... 

Hansell DM, Ruhens MB, Padley SP, et al. Obliterative bronchiolitis individual CT signs of small airways disease and functional correlation. Radiology 1997 203 721-726. 

Areas of decreased attenuation reflecting small airways disease... 

Churg A, Wright JL, Wiggs B, Pare PD, Lazar N (1985) Small airways disease and mineral dust exposure prevalence, structure, and function. Am Rev Respir Dis 131 139-143... 

Fig. 7.11. Prone inspiratory thin-section computed tomography of an asbestos miner showing areas of differing attenuation with regions of pulmonary parenchyma which appear blacker than adjacent areas (arrows), an indirect sign of small airways disease. The difference may be accentuated on end-expiratory sections (not shown)...

Desai SR, Hansell DM (1997) Small airways disease expiratory computed tomography comes of age. Clin Radiol... 

Recent studies in healthy subjects have suggested that a sizeable If action of particles deposited in the bronchiolar region is retained for more than 72-96 hr, and that these particles clear more similarly to alveolarly deposited particles. An increased deposition with retentions in the smallest ciliated airways is supported by the similarity in the clearance patterns from these airways, by healthy subjects, for particles inhaled by bolus and particles inhaled expemely slowly (0.05 L/sec), with an intermediate phase of continued clearance between 24 and 96 hr (17,54). From these studies, clearance in the smallest ciliated airways seems to be incomplete, with retentions of about 40% of the particles assumed to have been deposited in the tracheobronchial region, probably because of ineffective mucociliary transport and cough clearance in small airways. Clearance from the bronchiolar region may have features in common with alveolar clearance (65). This region may thus eonstitute a vulnerable zone in which small airway diseases eventually may arise after repeated exposures to noxious agents. 

Acinar enlargement Alveolar capillary destruction Increased lung compliance Small airways disease Inflammation Fibrosis... 

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