Diffuse Alveolar Hemorrhage in an Undiagnosed Systemic Lupus Erythematosus Patient.

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by a wide range of clinical manifestations affecting multiple organs. While standardized diagnostic criteria are commonly used, the lack of pathognomonic presenting signs and symptoms often makes the diagnosis challenging. Of the many pulmonary manifestations, diffuse alveolar hemorrhage (DAH) is one of the most severe complications caused by the disruption of the capillary alveolar interface. Although this condition is rarely encountered, it has a rapidly progressive course and can be life-threatening, which warrants a prompt diagnostic workup and an aggressive therapeutic approach. We report a case of a 58-year-old female who presented to the emergency department with dyspnea and multiple episodes of hemoptysis. Further investigations revealed anemia, thrombocytopenia, and diffuse bilateral infiltrates on high-resolution computed tomography, consistent with DAH in a patient with undiagnosed SLE.