C41-38 Lupus Lurking in the Lungs

Abstract Introduction Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder predominantly affecting women aged 15-45 with a female to male ratio 9:1. Interstitial lung disease (ILD) occurs in approximately 2-3% of SLE cases, typically presenting with dyspnea and nonproductive cough, often accompanied by cutaneous manifestations like vitiligo and Raynaud’s phenomenon. Older age and elevated anti-U1 RNP antibodies have been associated with increased risk of SLE-ILD. This report describes a presentation of SLE as ILD in an elderly male. Case A 62-year-old male with a history of hypertension, hyperlipidemia, type 2 diabetes, and prior tobacco use presented with progressive exertional dyspnea and hypoxia requiring high-flow nasal cannula. Examination revealed respiratory distress and diminished breath sounds, without peripheral edema or jugular venous distension. Cardiac workup showed elevated troponins, ECG changes, and echocardiographic findings consistent with heart failure (EF 30%, regional wall motion abnormalities, mild mitral and tricuspid regurgitation) and cardiac catheterization showed multi-vessel disease. CT chest revealed bilateral infiltrates in a nonspecific interstitial pneumonia (NSIP) pattern. Despite diuresis, hypoxia persisted. Bronchoscopy with lavage excluded acute diffuse alveolar hemorrhage as the patient was on a heparin drip and infectious etiology. Further evaluation uncovered vitiligo and Raynaud’s phenomenon, previously attributed to cervical stenosis. Initial autoimmune serologies were negative, including myositis panel and mixed connective tissue disorders. Empiric corticosteroid therapy (prednisone 60 mg daily) led to rapid clinical improvement, and he was discharged on supplemental oxygen with a steroid taper. Subsequent rheumatologic evaluation revealed low ANA titers, low complement C4, and positive beta-2 glycoprotein and cardiolipin antibodies. RNA polymerase III was minimally elevated; anti-RNP and myositis panels remained negative. A diagnosis of SLE was established, and the patient was started on hydroxychloroquine and azathioprine, resulting in resolution of pulmonary infiltrates and discontinuation of supplemental oxygen. Conclusion This case highlights the importance of maintaining a broad differential when evaluating ILD, particularly in atypical presentations. Collaboration between pulmonology and rheumatology is essential. Repeated serologic testing may be necessary when clinical suspicion remains high. Management typically involves corticosteroids and immunosuppressive agents tailored to patient tolerance, including hydroxychloroquine, mycophenolate mofetil, cyclophosphamide, azathioprine, rituximab, calcineurin inhibitors, or methotrexate. This abstract is funded by: none