Atypical Hemolytic Uremic Syndrome and Chronic Ulcerative Colitis Treated with Eculizumab
Tennille N. Webb *
Department of Pediatric Nephrology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA.
Heidi Griffiths
Department of Pediatrics, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA.
Yosuke Miyashita
Department of Pediatric Nephrology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA.
Riha Bhatt
Department of Gastroenterology, Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania
Ronald Jaffe
Department of Pathology, Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Michael Moritz
Department of Pediatric Nephrology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA.
Johannes Hofer
Department of Pediatrics, Innsbruck Medical University, Austria.
Agnieszka Swiatecka-Urban *
Department of Pediatric Nephrology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA and Department of Clinical Biology and Physiology, University of Pittsburgh School of Medicine, One Children’s Hospital Drive, 4401 Penn Avenue, Pittsburgh, Pennsylvania, USA.
*Author to whom correspondence should be addressed.
Abstract
Background: Hemolytic-uremic syndrome (HUS) presents with hemolytic anemia, thrombo-cytopenia, and thrombotic microangiopathy of the kidney and usually results from Shiga-toxin induced activation of the alternative complement pathway. Gastroenteritis is a common feature of the Shiga-toxin producing Escherichia coli HUS, referred to as STEC-HUS. An inherited or acquired complement dysregulation may lead to HUS referred to as non-STEC or atypical (a)HUS. Although gastroenteritis is not a common presentation of aHUS, some patients develop ischemic colitis and may be misdiagnosed as acute appendicitis or acute ulcerative colitis (UC).
Case Diagnosis –Treatment: We present a patient with low circulating complement (C) 3 levels who developed aHUS in the course of chronic active UC. Resolution of renal and gastrointestinal manifestations in response to treatment with eculizumab, a humanized monoclonal antibody against terminal C5 protein suggests the role of alternative complement in the pathogenesis of both, aHUS and UC.
Conclusion: This case illustrates that dysregulation of the alternative complement pathway may manifest in other organs besides the kidney and that the circulating C3 levels do not correlate with the disease activity or the clinical response to eculizumab.
Keywords: Hemolytic–uremic syndrome (HUS), thrombotic microangiopathy (TMA), ulcerative colitis (UC), inflammatory bowel disease (IBD), acute kidney injury (AKI), membrane attack complex (MAC).