In 1979, Hunninghake and Fauci in their review entitled “Pulmonary Involvement in the Collagen Vascular Disorders,” suggested that this involvement is frequent in Sjögren s syndrome and can be manifested as pleurisy, interstitial fibrosis, desiccation of the tracheobronchial tree, and lymphoid interstitial disease. They also stated that the first two could be manifestations of the concomitant rheumatic disorder and that only desiccation of the tracheobronchial tree and lymphoid interstitial fibrosis are “specific” for Sjogren’s syndrome.
There have been several articles on the lungs and Sjogren’s syndrome since then. Only two deal with large populations of patients with primary Sjogren’s syndrome. Oxholm et al reported in their large series of 46 such patients that the most common functional abnormality was reduced pulmonary diffusing capacity. We have reported in a previous study of 22 patients with primary Sjogren’s syndrome that there are two distinct forms of respiratory involvement, ie, (1) “xerotrachea” manifested only by dry cough without any roentgenologic or functional abnormality, and (2) diffuse interstitial pulmonary disease. Pulmonary function in that study was evaluated only with spirometry and arterial blood gas levels. Three other studies deal with small numbers of patients with both primary and secondary Sjogren’s syndrome and stress airways obstruction as the most common abnormality. In this study, based on clinical, roentgenologic, functional, and histologic data, we suggest that primary Sjogren’s syndrome can frequently (75 percent) involve the respiratory system from the trachea and large airways to the small airways, pulmonary parenchyma, and pulmonary interstitium.
Involvement of the trachea and large airways results in their desiccation and presents with dry cough that can, at times, be very annoying. We had patients treated for “asthma,” “chronic bronchitis,” or even “tuberculosis” because of this cough before Sjogren’s syndrome was diagnosed. We can attribute this isolated symptom of dry cough that was the only abnormal respiratory manifestation in six of our patients (17 percent) to desiccation of the tracheobronchial tree (“xerotrachea”), since no other cause for the cough was found, and the desiccation of the airways was documented bronchoscopically. This has also been documented by other investigators in the past who have shown bronchial mucosal infiltration with mononuclear cells in similar patients. It is interesting that this group of patients cannot be detected with functional criteria, and therefore clinical evaluation is very valuable in their case.
Peripheral airways can be involved, and the result is frequent respiratory tract infections and obstructive ventilatory defects (three patients; 8 percent). In one such patient (patient 13), transbronchial lung biopsy revealed parabronchial chronic inflammation, probably secondary to repeated previous pulmonary infections. The medical history was suggestive, and the pulmonary function studies revealed obstruction of large airways.
Small airways (<2mm in diameter) can also be involved (22 percent of our patients; 8/36). This can be part of the interstitial pulmonary disease, as is well known for interstitial pulmonary disease of different etiology, but it can also occur alone. Thus, eight of our patients (22 percent) had isolated small airways disease, manifested by significantly diminished MEF25 (<65 percent of predicted) and suggestive flow-volume curves (Fig 1). Three patients had diminished MEF25 combined with impaired diffusion. This was considered part of the interstitial pulmonary involvement. Three more had diminished MEF25 combined with impaired FEVi. This was considered part of an obstructive ventilatory defect. Newball and Brahim have documented the abnormality of small airways in Sjogren’s syndrome histologically by showing “mononuclear cell infiltration around narrowed small airways” in two patients. Nowadays the medical science is ready to treat almost all diseases or even find the treatment to sustain the health condition on the level.
Diffuse pulmonary interstitial pulmonary disease was common in our patients (25 percent; 9/36). This is in agreement with the large series of Strimlan et al and Oxholm et al but not with smaller series showing obstruction as the main abnormality. The lung biopsies that we performed on four such patients showed a spectrum of interstitial pathologic findings ranging from “active” lymphocytic infiltrates to interstitial fibrosis (Fig 2). Bronchoalveolar lavage should be very helpful for additional information of this involvement. It could also help to clarify if small airways disease is part of the interstitial pathologic abnormality or an isolated manifestation.
The correlation of respiratory manifestations with the clinical and serologic characteristics of Sjögrens syndrome showed that extraglandular manifestations and serologic markers, like antibodies to Ro(SSA) or La(SSB) antigens (or both), had similar frequency in patients with and patients without respiratory involvement. Finally, this correlation showed that respiratory symptoms occur often before or concomitantly with the first classic symptoms of Sjögrens syndrome. Thus, questions to detect dry cough should be included in the initial evaluation of patients with Sjögrens syndrome.
Our results indicate that respiratory involvement is frequent in patients with primary Sjogrens syndrome. The most common manifestations of this are diffuse interstitial pulmonary disease, small airways disease, and xerotrachea. Further studies are required, eg, with bronchoalveolar lavage. These studies should include only patients with primary Sjogrens syndrome, thus avoiding the confusion of respiratory manifestations of the concomitant rheumatic disorder.