Pulmonary involvement in ankylosing spondylitis

Anti-tumor necrosis factor-alpha agents have recently been approved and recommended as effective and relatively safe drug therapy for ankylosing spondylitis. In light of this major advance in the management of these patients, recent observations on the pulmonary manifestations of ankylosing spondylitis are reviewed.

High-resolution computed tomography abnormalities were found to be prevalent (range 50-85%) in ankylosing spondylitis even in patients with early disease, and in those with normal chest radiographs and without respiratory symptoms. The high-resolution computed tomography changes included apical fibrosis, interstitial lung disease, emphysema, bronchietasis and pleural thickening. In general, the high-resolution computed tomography changes were of mild degree, and no correlation was observed between high-resolution computed tomography abnormalities, pulmonary function test variables and indices of ankylosing spondylitis symptoms and disease structural severity. Spontaneous pneumothorax was reported to be a rare complication, but tended to occur in those patients with fibrobullous disease.

The clinical significance of the high-resolution computed tomography abnormalities remains to be determined. Most of the published studies are cross-sectional, and are limited by lack of control subjects matched for age, gender and tobacco use. Studies to correlate high-resolution computed tomography changes with bronchoalveolar lavage and lung biopsies as well as prospective studies on long-term evolution of these findings including those patients receiving anti-tumor necrosis factor-alpha agents are needed.