C41-40 Two Organs, One Culprit: Lupus Masquerading as Pneumonia and Medullary Infarct

Abstract Introduction Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder with diverse organ involvement, often posing a diagnostic challenge due to its heterogeneous presentation. Pulmonary manifestations occur in approximately 3-9% of patients and encompass acute lupus pneumonitis, diffuse alveolar hemorrhage, nonspecific interstitial pneumonia (NSIP), and organizing pneumonia (OP). Among these, OP and NSIP are distinctly uncommon but clinically significant due to their potential reversibility with early immunosuppression. Central nervous system (CNS) vasculitis represents another rare and severe complication of SLE, occurring in less than 1% of cases and frequently presenting with stroke-like deficits. Prompt recognition and initiation of corticosteroids or cytotoxic therapy are critical to prevent irreversible injury. We describe an unusual case of newly diagnosed SLE presenting with both pulmonary organizing pneumonia and CNS vasculitis, which responded favorably to early corticosteroid therapy. Case A 48-year-old woman with a history of right-sided breast cancer, previously treated with mastectomy, chemotherapy, and discontinued tamoxifen due to drug-induced vasculitis, presented with diffuse rash, left breast swelling, and paresthesias. One month prior, she had undergone pleural biopsy for a large effusion, which revealed inflammatory but nonmalignant changes. On admission, she was hypertensive with laboratory evidence of hyponatremia, elevated alkaline phosphatase, and high CRP. CT chest demonstrated bilateral multifocal consolidations with pleural effusions. Initial antibiotic therapy for presumed pneumonia was ineffective. Skin biopsy revealed acute vasculitis, while autoimmune studies showed low C4, ANA titer 1:1280, and positivity for anti-Sm and anti-SSA antibodies. Given persistent fevers and worsening effusion, she was started on corticosteroids for suspected SLE-associated organizing pneumonia. Four days later, she developed left-sided ptosis, dysarthria, and hemiparesis. MRI revealed a dorsal medullary infarct, and work-up excluded embolic, infectious, and paraneoplastic etiologies. CNS vasculitis secondary to SLE was diagnosed, and she received intravenous methylprednisolone 1 g daily for five days, resulting in marked neurological and radiographic improvement. She was discharged on a steroid taper with rheumatology and neurology follow-up. Discussion This case highlights a rare dual presentation of SLE with pulmonary organizing pneumonia and CNS vasculitis. Literature review underscores that both entities carry high morbidity but are potentially reversible with timely corticosteroid therapy. Clinicians should maintain vigilance for autoimmune etiologies when infection-like pulmonary infiltrates and multifocal neurological deficits coexist. References PalmucciS etal. Clinical and radiological features of lung disorders related to connective-tissue diseases: a pictorial essay. Insights Imaging. 2022;13(1):108.doi:10.1186/s13244-022-01243-2. SchwartzN etal. Neuropsychiatric lupus: new mechanistic insights and future treatment directions. Nat Rev Rheumatol. 2019;15(3):137-52. doi:10.1038/s41584-018-0156-8. This abstract is funded by: none