The prevalence and type of pulmonary involvement in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic and inflammatory disease that affects the spinal column and peripheral joints. Pulmonary manifestations in patients with ankylosing spondylitis are rare and usually asymptomatic and include restrictions from fibrobullous apical disease, chest wall disease, spontaneous pneumothorax, and obstructive sleep apnea. This cross-sectional study was performed on 60 patients with AS. All patients fulfilled the modified New York criteria, 1984. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI), CRP, and ESR were measured in all patients. All patients were visited by a rheumatologist and a pulmonologist, and pulmonary function test (PFT) and chest x-ray (CXR) were performed. High-resolution computed tomography (HRCT) was performed only in patients who had abnormal results in clinical examination, PFT, or CXR. Overall, 50 patients had normal CXR (83.3%) and 10 patients (16.7%) had abnormal CXR, including reticulonodular (3.3%), atelectasis (3.3%), and lucency (3.3%). Of the 14 cases that were HRCT, only 8 (57.1%) had abnormal lung CT scans. The Pulmonary Function Test (PFT) was taken from all patients, and 15 (25%) patients had abnormal results, 11 (18.3%) had a restrictive pattern, and 4 (6.7%) had an obstructive pattern. The incidence of lung involvement in patients with AS in this study is similar to that of other studies (16%); in most cases, the lung involvement is of the restrictive pattern. Lung involvement in these patients may be asymptomatic.