Extreme Hyperhemolysis Syndrome in a Patient With Sickle Cell Disease Successfully Managed With Eculizumab: A Case of Survival at 1.2 g/dL Hemoglobin.

This case presents a 26-year-old male with sickle cell disease (SCD) who experienced a catastrophic hyperhemolysis syndrome (HHS) triggered by red blood cell (RBC) transfusion. The patient was initially hospitalized for a vaso-occlusive crisis and fever; the patient's clinical status deteriorated rapidly as his hemoglobin (Hb) plummeted from 7.5 g/dL to a nadir of 1.2 g/dL. Despite treatment with corticosteroid and intravenous immunoglobulin (IVIG) therapy, the hemolytic process persisted. To manage the critical imbalance between oxygen delivery and demand, invasive mechanical ventilation was initiated as a supportive metabolic measure. Due to the failure of conventional therapies, eculizumab was administered on the third day of intensive care unit (ICU) admission. This intervention resulted in the cessation of hyperhemolysis, followed by gradual hematological stabilization and recovery. This report underscores the severity of HHS and demonstrates the successful use of terminal complement inhibition as a life-saving rescue strategy in extreme cases.