Atypical Hemolytic Uremic Syndrome After Traumatic Rectal Injury: A Case Report

Abstract Background: Atypical hemolytic uremic syndrome (aHUS) is a rare, progressive, life-threatening condition of thrombotic microangiopathy (TMA) that is characterized by thrombocytopenia, microangiopathic hemolytic anemia, and renal impairment. The mechanisms of aHUS are still unknown. To our knowledge, there is currently no report establishing aHUS after traumatic injury. We herein present a case of aHUS after traumatic injury.Case presentation: A 55-year-old man with a medical history of percutaneous coronary intervention due to ST elevation myocardial infarction visited the emergency room after a traumatic injury caused by a tree limb. Abdominal computed tomography revealed a rectal wall defect with significant air density in the perirectal space and preperitoneum, implying rectal perforation and, therefore, an emergency operation was performed. As there was an absence of intraperitoneal intestinal perforation, we performed diverting sigmoid loop colostomy. An additional intermittent simple repair was performed due to perianal and anal injuries. One day after the operation, his urine output abruptly decreased and serum creatinine level increased. In addition, his platelet level decreased, and a spiking fever occurred after 2 days. The patient was diagnosed with acute renal failure secondary to aHUS and was treated with fresh frozen plasma replacement. Continuous renal replacement therapy (CRRT) was also started for oliguria and uremic symptoms. The patient received CRRT for 3 days and intermittent hemodialysis thereafter. He received four weekly sessions of hemodialysis for 2 weeks. After hemodialysis and subsequent supportive treatment, his urine output and renal function continuously improved. Similarly, his hemolytic anemia and thrombocytopenia also gradually improved. His dialysis was terminated on day 22 of admission and he was discharged after recovery. His improved state has since been maintained.Conclusions: This case suggests that a traumatic event can be a triggering factor for aHUS, and it should be considered in patients who have thrombocytopenia and acute renal failure with microangiopathic hemolytic anemia after trauma. Early diagnosis and appropriate management can be critical to achieve favorable outcomes in posttraumatic patients with aHUS.