Introduction: Connective tissue disease-associated interstitial lung disease (CTD-ILD) is an important contributor to the burden of diffuse parenchymal lung disease in India. In tuberculosis-endemic regions, overlapping clinical and radiological features frequently result in misdiagnosis as pulmonary tuberculosis and exposure to empirical anti-tubercular therapy (ATT), leading to delayed initiation of appropriate treatment. Methods: We conducted a retrospective observational study of 17 patients diagnosed with CTD-ILD between July 2024 and July 2025 at a tertiary care center in Central India. Data collected included demographic characteristics, connective tissue disease subtype, high-resolution CT (HRCT) pattern, autoantibody profile, spirometry findings, prior exposure to anti-tubercular therapy, and treatment received. Results: The mean age was 52.7 years, with female predominance. Connective tissue disease subtypes included Sjögren syndrome (4/17, 24%), systemic lupus erythematosus (3/17, 18%), inflammatory myositis (3/17, 18%), systemic sclerosis (2/17, 12%), mixed connective tissue disease (3/17, 18%), and overlap syndromes (2/17, 12%). The HRCT patterns showed nonspecific interstitial pneumonia (NSIP) in 11/17 (65%), usual interstitial pneumonia (UIP) in 5/17 (29%), and lymphocytic interstitial pneumonia (LIP) in 1/17 (6%). All patients were positive for antinuclear antibodies, with disease-specific extractable nuclear antigen antibodies including Ro52, Jo-1, and Scl-70. Nine patients (9/17, 53%) had received empirical anti-tubercular therapy prior to diagnosis. Spirometry was available in 7/17 patients (41%); the median forced vital capacity was 75% of predicted, and the mean forced expiratory volume in one second to forced vital capacity ratio was 66%. Treatment included mycophenolate mofetil (9/17, 53%) and nintedanib (7/17, 41%), and one patient each received cyclophosphamide and rituximab, respectively. Conclusions: In this central Indian cohort, CTD-ILD most commonly presented with an NSIP pattern and was frequently misdiagnosed as tuberculosis, resulting in exposure to empirical anti-tubercular therapy. Early evaluation with HRCT and autoimmune serological testing is essential to ensure accurate diagnosis and timely initiation of appropriate immunosuppressive and antifibrotic therapy.
Sahu et al. (Fri,) studied this question.