[Study of bullous fibrosis of the upper lobes in ankylosing spondylitis with high-resolution computerized tomography]

The fibrobullous disease of the upper lobes is an uncommon extraspinal complication of ankylosing spondylitis. We report the conventional radiographic and High Resolution Computed Tomographic (HRCT) findings in the fibrobullous disease of the upper lobes in ankylosing spondylitis. From 1988 to 1994, four patients affected with ankylosing spondylitis, with radiographic involvement of the upper lobes, came to our observation. All patients underwent a chest X-ray exam and the previous chest X-rays carried out 2-25 years earlier were reviewed. Within 15 days, HRCT was performed, during inspiratory apnea. In all cases, repeated bronchoscopies were available, showing bronchial inflammation, together with cytologic tests and bronchial fluid cultures, which revealed no development of mycobacterium tuberculosis. The most frequent CT findings were pleural thickening, fibrotic consolidation and thickening of interlobular septa. Bullae, nodules and ground-glass areas were less frequent findings. The standard chest X-ray exam demonstrated, with the same sensitivity as HRCT, pleural thickening, bullae, nodules and volume loss in the involved lung. However, interlobular septa thickening was depicted only in one case, while bronchiectases and ground-glass areas were not recognized at all. Three temporally distinct patterns of apical involvement (infiltrative, interstitial and fibrobullous) were identified. In conclusion, HRCT was more sensitive and more specific than chest X-rays in the study of the fibrobullous disease of the upper lobes in ankylosing spondylitis.