Diffuse alveolar hemorrhage as the initial presentation of systemic lupus erythematosus in a previously healthy female

Diffuse alveolar hemorrhage (DAH) is an uncommon but life-threatening pulmonary manifestation of systemic lupus erythematosus (SLE), associated with high morbidity and mortality. Although it typically occurs in patients with established disease, DAH may rarely represent the initial manifestation of the disease, creating a significant diagnostic challenge. We describe a 35-year-old woman with no known medical history who presented with acute respiratory failure and hemoptysis. She was transferred intubated following cardiac arrest and admitted to the intensive care unit. Initial investigations revealed profound anemia (hemoglobin 3.3 g/dL), bilateral pulmonary infiltrates, respiratory acidosis, and hypoxemia. Bronchoscopy confirmed diffuse alveolar hemorrhage. In the absence of an alternative cause, an immunologic evaluation was undertaken and supported a new diagnosis of SLE, with positive antinuclear antibodies, elevated anti-double-stranded DNA, anti-SmD, and anti-RNP antibodies, along with low complement levels. The patient was treated with high-dose corticosteroids, cyclophosphamide, and plasmapheresis, leading to steady clinical improvement. She was successfully extubated and discharged on a tapering course of corticosteroids. This case illustrates that diffuse alveolar hemorrhage may be the initial manifestation of systemic lupus erythematosus. Early recognition, prompt immunosuppressive therapy, and coordinated multidisciplinary care are essential and may be life-saving in severe presentations.