C62-30 Hemoptysis as the Herald: A Rare Pediatric Presentation of Takayasu Arteritis and Systemic Lupus Erythematosus

Background Takayasu arteritis (TA) is a granulomatous large-vessel vasculitis predominantly affecting young females, characterized by inflammation of the aorta and its major branches. Systemic lupus erythematosus (SLE) is a chronic, multisystem autoimmune disease involving immune-complex deposition and small- to medium-vessel inflammation. While both represent autoimmune vasculitides, they differ in vessel caliber and pathophysiology. Overlap between TA and SLE is exceedingly rare, particularly in pediatric or adolescent patients, and pathogenesis remains uncertain but may involve shared B-cell and cytokine-mediated pathways. Case Presentation We describe a 17-year-old female with history of hypertension and chronic iron-deficiency anemia who presented with pericardial effusion, later found to have large-vessel vasculitis consistent with TA. Her course was complicated by diffuse alveolar hemorrhage requiring mechanical ventilation and plasma exchange. Serologic testing subsequently confirmed new-onset SLE, and renal biopsy demonstrated class II glomerulonephritis. She responded to corticosteroids, intravenous immunoglobulin, plasmapheresis, and cyclophosphamide, with stabilization of renal and respiratory function. Discussion DAH is a life-threatening but rare manifestation of SLE and is extremely rare in TA, which primarily affects large vessels and typically spares pulmonary capillaries. The patient’s clinical course suggests sequential autoimmune activation, in which large-vessel vasculitis preceded lupus seroconversion and multi-organ involvement. Recognition of this pattern is essential, as new pulmonary or renal findings in TA should prompt evaluation for overlapping autoimmunity. Conclusion This case underscores the importance of maintaining a high index of suspicion for autoimmune overlap syndromes when clinical features extend beyond the typical presentation of a single disease. Recognizing atypical manifestations- such as pulmonary hemorrhage in Takayasu arteritis- is crucial for timely diagnosis and early initiation of aggressive immunosuppressive therapy to prevent irreversible organ damage. This abstract is funded by: None