Acute Lupus Pneumonitis and Severe Multisystem Complications: A Complex Inpatient Course.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with diverse systemic manifestations. Pulmonary involvement is common, but acute lupus pneumonitis (ALP) is rare, occurring in fewer than 5% of patients, and is associated with poor outcomes. We describe a 60-year-old woman with longstanding SLE/Sjögren's overlap who presented with progressive dyspnea, pleuritic chest pain, and productive cough. Radiology revealed bilateral ground-glass opacities consistent with ALP. Her clinical course was complicated by superimposed infection, severe left ventricular dysfunction with decompensated heart failure, stage 2 acute kidney injury, and chronic small vessel cerebrovascular disease. She required intensive immunosuppression, antimicrobial therapy, and advanced cardiac support, with eventual stabilization and discharge. This case illustrates the diagnostic challenges of distinguishing ALP from infection and cardiogenic pulmonary oedema, the interplay of multisystem disease in SLE, and the importance of early multidisciplinary involvement in critically ill patients.