Atypical hemolytic uremic syndrome (aHUS), also known as complement-mediated thrombotic microangiopathy (CM-TMA), is an extremely rare but potentially life-threatening disorder that presents with the triad of thrombocytopenia, hemolytic anemia, and acute renal failure. aHUS is attributed to genetic mutations in the complement regulation system and is typically triggered by events such as pregnancy, vaccination, or surgery. This case report describes a patient initially admitted for acute pancreatitis secondary to alcohol abuse who developed aHUS within 48 hours of admission. The diagnosis of aHUS was confirmed via a full diagnostic workup. Hematology recommended supportive care. The case was further complicated by acute hypoxic respiratory failure secondary to community-acquired pneumonia, which developed simultaneously with the aHUS. The patient’s aHUS resolved as the acute pancreatitis resolved with supportive care, and the pneumonia resolved with antibiotics and inhaled corticosteroids, which likely helped improve the aHUS. When patients present with acute pancreatitis and hematologic abnormalities, clinicians should suspect aHUS and perform a thorough workup to distinguish between aHUS and other autoimmune hematologic conditions, such as typical hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), or drug-induced complement-mediated anemia (CMA). While most reported cases have been treated with plasma exchange therapy or eculizumab, we present one of the few cases where the patient was treated with supportive care.
Prakash et al. (2026) studied this question.