Unraveling the Cause of Hemolytic Anemia in the Emergency Department: A Destructive Path.

Hemolytic anemia is a rare but potentially life-threatening condition in the emergency department (ED) that requires timely recognition and early intervention. Hemolytic anemia results from either the intravascular or extravascular breakdown of red blood cells. The most common causes of secondary hemolytic anemia include lymphoproliferative disorders, autoimmune disorders, and infections. This case will demonstrate how an urgent diagnosis of hemolytic anemia can lead to the underlying cause: diffuse large B-cell lymphoma. This case illustrates how laboratory evaluation, early subspecialty involvement, and maintenance of a broad differential are integral in a patient whose initial presentation is indistinguishable from other causes of hemolytic crisis. A 61-year-old man presented to the ED complaining of worsening dyspnea on exertion and fatigue for two weeks. He arrived at the ED with stable vital signs. His vitals were as follows: blood pressure 118/66 mmHg, heart rate 72 beats per minute (bpm), respiratory rate 16 breaths per minute, temperature 97.8°F, and oxygen saturation 100% on room air. Laboratory evaluation revealed a hemoglobin of 7.6 g/dL, hematocrit of 21.4%, lactate dehydrogenase at 416 U/L, indirect hyperbilirubinemia of 2.8 mg/dL, and haptoglobin at <5 mg/dL. The patient was admitted to the hospital where he experienced multiple episodes of acute hemodynamic decompensation and underwent further diagnostic evaluation, ultimately resulting in a diagnosis of diffuse large B-cell lymphoma. This case highlights how hemolytic anemia can mimic more common presentations such as acute blood loss, viral hepatitis, sepsis, autoimmune disorders, or malignancies. Awareness of its hallmark laboratory pattern and initiation of therapy are critical for optimal patient outcomes in the ED setting. The laboratory findings and clinical presentation of hemolytic anemia require early detection, as they may reflect life-threatening conditions such as autoimmune hemolytic anemia, glucose-6-phosphate dehydrogenase deficiency, or thrombotic microangiopathies including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome. This case is notable for three distinct features: the diagnostic workup spanned two continents and was complicated by incomplete prior investigations; bilateral deep vein thromboses provided an early but underappreciated clue to an underlying hypercoagulable lymphoproliferative process; and autoimmune hemolytic anemia preceded and ultimately led to the diagnosis of diffuse large B-cell lymphoma, highlighting a diagnostic sequence with significant implications for emergency physicians.