Not Your Typical Hemolytic Uremic Syndrome: A Diagnostically Challenging Case Study

• Published in: Blood 2024-11, Vol.144 (Supplement 1), p.5534-5534
• Main Authors: Qu, Dan C., Moalem, Kamilia N., Beshah, Fireneh N., Cohen, Jonathan J.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2024-196399

Introduction Hemolytic uremic syndrome (HUS) is a disease group characterized by microangiopathic hemolytic anemia, thrombocytopenia, and kidney injury caused by thrombotic microangiopathy (TMA), a pathology involving endothelial damage in microvessels causing microthrombi. Although often caused by Shiga toxin-producing E. coli (STEC), HUS also has rarer causes including drug-induced, cobalamin C deficiency-mediated, and complement-mediated (CM). We present a case of HUS with difficult diagnostic work-up due to complex patient history and hospital course. Case Description A 65-year-old man with multiple myeloma on carfilzomib/pomalidomide/dexamethasone was hospitalized for one day history of fatigue, nausea, vomiting, abdominal pain, diarrhea, and low urine output. Initial laboratory values showed platelets 8,000/uL, hemoglobin 12.5 g/dL, WBC 24,800/uL, creatinine 3.2 mg/dL, BUN 44 mg/dL, and total bilirubin 4.4 mg/dL. Urine studies showed microscopic hematuria and albuminuria (>1313 ug/mg). Blood smear showed reactive leukocytosis, rare platelets, and marked schistocytes. Hemolysis studies showed indirect bilirubin 3.4 mg/dL, haptoglobin