A rare case of Interstitial lung disease complicated by overlapping syndrome with obstructive ventilatory dysfunction as the first symptom

Abstract

Interstitial lung disease is often a serious complication of connective tissue disease（CTD）, representing the first cause of death in CTD. However, there are few reports of SSc-RA overlap-associated interstitial pneumonia. Respiratory dysfunction as the first clinical manifestation is even rarely reported. We herein described a case of a male patient who developed significant respiratory dysfunction as the principal clinical sign for the past 6 months, plus newly developed skin thickening in bilateral upper limbs and pain and swelling of multiple joints for the past 6 weeks. Extensive immunological screening showed high titer of antinuclear antibodies(ANA), rheumatoid factor(RF), anti-cyclic peptide containing citrulline (anti-CCP)，and positive anti-Scl-70 antibody. Chest high resolution computed tomography(HRCT) was performed and hence ILD was confirmed. Pulmonary function test (PFT) revealed obstructive ventilatory dysfunction rather than restrictive ventilatory dysfunction. So bronchodilation test was performed and asthma was considered. Finally, after a multidisciplinary team (MDT) discussion, the diagnosis of asthma and ILD associated with SSc-RA overlap was established. It is important to note that CTD associated pulmonary interstitial fibrosis must be considered as the differential diagnosis of any newly diagnosed interstitial pulmonary disease. In addition, if patient with dyspnea is highly suspicious of pulmonary interstitial fibrosis, bronchodilation test is still needed to exclude asthma in order to avoid misdiagnosis.