Four women with a chronic respiratory illness characterized by chronic cough, dyspnea, mild to severe physiologic abnormalities, relatively normal chest radiographs, and lack of response to bronchodilators or prednisone were identified and prospectively evaluated. Constrictive bronchiolitis, defined as concentric narrowing of the bronchiolar lumen, mural scarring, smooth muscle hyperplasia, and mucus stasis, was the major histologic finding on open lung biopsy in all cases. Each presented with an illness clinically distinct from asthma, connective tissue disorders, occupational or environmental lung disease, bronchiectasis, diffuse panbronchiolitis, cystic fibrosis, and emphysema. None of the patients smoked cigarettes. None had clinical evidence of a recent viral lower respiratory tract infection. The physical examinations were normal except for rales heard on chest examination in two patients. Chest radiographs showed increased bronchovascular markings in three patients. Lung function was normal in one patient, two of the patients had a reduced diffusing capacity associated with moderate hypoxemia and an obstructive ventilatory defect, and one patient exhibited a mixture of restrictive and obstructive defects. None have experienced significant progression of their disease over 1 to 5 yr of follow-up. However, complete return to normal function did not occur. We hypothesize that patients with the constellation of findings described represent a distinct and definable clinicopathologic entity and further clarifies the spectrum of "small airways disease." Establishing the diagnosis appears important for prognostic and possibly therapeutic reasons.
The epidemiology of asthma is complex but essential in enhancing the understanding of a disease that affects millions of patients. Asthma is associated with significant morbidity and mortality. Asthma prevalence rates in the United States reached a plateau after 1998 with an estimated overall prevalence of 3.8% in 2003. Racial disparities exist and there are staggering differences in morbidity and mortality. The analysis of data collected from epidemiologic studies continues to be a critical part of enhancing the understanding of the pathophysiology of asthma, which will lead to improved patient outcomes.
Inhaled long-acting beta(2)-agonists improve asthma control when added to inhaled corticosteroid (ICS) therapy.