Comparison of early and late pleuropulmonary findings of ankylosing spondylitis by high-resolution computed tomography and effects on patients' daily life.

Ankylosing spondylitis (AS) is a multisystemic disease and extra-articular features may develop as pleuropulmonary involvement. We aimed to show and compare the early and late pleuropulmonary findings of AS and its effects on patients' daily life by causing dyspnea. The study consisted of 38 patients (33 male, 5 female). All patients met the New York criteria for AS. Patients were divided into two groups for comparison of early (disease duration <10 years and normal chest X-ray, 18 patients) and late (disease duration >/=10 years and normal or abnormal chest X-ray, 20 patients) manifestations. All patients underwent high-resolution computed tomography (HRCT) and pulmonary function tests. A questionnaire was completed to measure perceived shortness of breath (dyspnea score) with activities of daily living such as dressing, shaving or walking. HRCT findings were abnormal in 27 of the 38 patients (73%). Pulmonary involvement was high in early AS (61.1%). The number of findings in early and late AS found were as follows: mosaic pattern (9/10), parenchymal micronodules (2/3), parenchymal bands (5/9), bronchial wall thickening (2/10), ground-glass opacity (7/7), and interlobular septal thickening (6/10). A moderate correlation was obtained between presence of mosaic pattern and forced midexpiratory flow rate (FEF(25-75)) values indicating small airway obstruction (r=0.346, p=0.019). The dyspnea score was statistically higher in patients with AS having pulmonary involvement than those without involvement. Pulmonary involvement is common in early AS compared to late AS. The involvement of small airways was found frequently as interstitial lung disease in early and late AS. This study also suggests that AS with pulmonary involvement may affect patients' daily life by causing dyspnea, which is why early detection of pulmonary lesions may have clinical importance and should be studied in a large cohort.