Regional differences in bronchoalveolar lavage and thoracic high-resolution computed tomography results in dyspneic patients with systemic sclerosis

Objective. Interstitial lung disease (ILD) is the leading cause of death in systemic sclerosis (SSc). Although early identification and treatment of alveolitis may prevent deterioration of lung function, the best approach for diagnosing active alveolitis remains controversial. This study was undertaken to investigate the utility of high-resolution computed tomography (HRCT) of the chest, in comparison with bronchoalveolar lavage (BAL), in the diagnosis of alveolitis in these patients. Methods. Eighteen patients with SSc and dyspnea were evaluated for ILD by pulmonary function testing and bronchoalveolar lavage (BAL), and 15 of these patients underwent chest HRCT. BAL was performed in either the middle lobe or the lingula, and also in a lower lung segment. Differential cell counts were determined by clinical cytopathology, with retrospective recounting in a blinded manner by a single technician. Active alveolitis was defined as the presence of greater than or equal to3.0% polymorphonuclear cells and/or greater than or equal to2% eosinophils in BAL fluid. BAL fluids were cultured for bacteria, mycobacteria, and fungi. HRCT scans were evaluated in a blinded manner for ground-glass opacification and fibrosis in the lavaged lobes. Results. Nine of the 18 patients had active alveolitis recorded in both lavaged segments, while in 4 patients it was recorded in only I segment (lower lobe in 3). Following repeat differential cell counting, 3 patients were reclassified as having active alveolitis and I as having no alveolitis. Culture of BAIL fluid identified clinically unsuspected infection in 3 patients. For the right middle lung lobe or lingula there was excellent agreement between ground-glass opacification and the finding of alveolitis on BAL from segments in the same lung regions, but this was not observed for the lower lobes. The correlation between fibrosis on HRCT and the presence of alveolitis on BAIL was significant for the lower lobes but not the middle lung fields. Conclusion. BAL of the middle lobe or lingula may underestimate the presence of active alveolitis. Similarly, while ground-glass opacification on HRCT accurately predicted alveolitis in the middle lung fields, HRCT did not detect all sites of inflammation and did not, identify infectious etiologies. These data suggest that, in addition to HRCT, BAL with lavage, differential cell counting, and culture from at least 2 segments of lung be performed for diagnosing SSc alveolitis.