B43-38 Out of Breath and Out of Sync: A Case of Autoimmune Crossfire

Abstract Polymyositis-associated interstitial lung disease (PM-ILD) represents a severe extra-muscular manifestation of idiopathic inflammatory myopathies and remains a leading cause of morbidity and mortality. The coexistence of autoimmune hepatitis-induced cirrhosis and pulmonary hypertension is exceptionally uncommon and may reflect either connective tissue disease related to pulmonary vascular involvement or porto-pulmonary hypertension. We report a case of acute ILD exacerbation in a patient with polymyositis and autoimmune hepatitis complicated by pulmonary hypertension and chronic aspiration. Mr. M, a 40-year-old male with polymyositis, cirrhosis from autoimmune hepatitis, OSA, SVT, and colitis, was on long-term immunosuppressive therapy (prednisone 20 mg daily, azathioprine, mycophenolate, and Bactrim prophylaxis). He previously received rituximab, discontinued after a 2022 hospitalization for esophageal varices and right groin cellulitis requiring wound VAC. He had been stable off oxygen until October 2025, when he developed progressive dyspnea and hypoxia. Examination revealed decreased breath sounds bilaterally and O2 saturation 89% on room air. CTA chest ruled out pulmonary embolism, and echocardiogram showed RVSP 53 mmHg, consistent with pulmonary hypertension. The patient was diagnosed with an acute ILD exacerbation in the setting of polymyositis and autoimmune hepatitis, with chronic aspiration pneumonitis as a likely contributor. Treatment included high-dose corticosteroids, continuation of mycophenolate and azathioprine, supplemental oxygen, and pulmonary rehabilitation. He improved clinically and was weaned to low-flow oxygen. Right-heart catheterization was planned for further evaluation. Overlap of polymyositis and autoimmune hepatitis may promote chronic lung inflammation through T-cell-mediated alveolitis and cytokine dysregulation. Aspiration and portal hypertension further aggravate endothelial injury, triggering ILD flares and pulmonary vascular remodeling. Early recognition of these processes is crucial since management differs: connective tissue disease-related ILD may benefit from antifibrotic or vasodilator therapy, whereas portopulmonary hypertension requires treatment of portal hypertension. Coordinated care between pulmonology, rheumatology, and hepatology was vital for this patient’s management. This case highlights the intersection of autoimmune myopathy, hepatic autoimmunity, and interstitial lung disease with pulmonary hypertension. Recognition of aspiration as a precipitant and timely evaluation for portopulmonary hypertension can guide therapy and improve outcomes in complex autoimmune-related ILD. This abstract is funded by: None