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Kidney Week

Abstract: TH-PO129

An Unusual Case of Atypical Hemolytic Uremic Syndrome Triggered by Acute Infectious Mononucleosis Infection Presenting Without Thrombocytopenia

Session Information

Category: Trainee Case Report

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Jain, Rishabh Kumar, University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Duncan, Virginia E., University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Narasimha Krishna, Vinay, University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Bell, Emmy Klip, University of Alabama at Birmingham, Birmingham, Alabama, United States
Introduction

Atypical hemolytic uremic syndrome (aHUS) is characterized by abnormal clotting with features of intravascular hemolysis, thrombocytopenia, and acute kidney injury. Athrombocytopenia has rarely been associated with aHUS. Approximately one half of patients with aHUS have pathogenic gene variants of the complement pathway and gene variants in the coagulation pathway of unclear pathogenicity have also been identified. We describe a patient with acute Epstein Barr virus (EBV) infection who developed aHUS without thrombocytopenia in the setting of gene mutations of both the complement and coagulation pathways.

Case Description

A 26-year-old female with acute infectious mononucleosis diagnosed a week before, presented with malaise, hypertension (148/98 mm) and oliguria. Laboratory data revealed hemoglobin 7.9 gm/dl, BUN 123 mg/dl, creatinine 11.3 mg/dl, UPCR of 5.6 mg/mg with a nephritic sediment. Moderate schistocytes were seen in the peripheral smear but platelets were normal. ADAMS13 was normal. Renal biopsy showed acute and subacute thrombotic microangiopathy. Other than a recent positive IgM Monospot, autoimmune and other infectious studies were unremarkable. She had elevated Ba fragment, Bb fragment and soluble level sMAC/C5b-9. Genetic panel found a likely pathogenic variant in the CFH gene and a novel variant of unknown significance in the PLG (plasminogen) gene. Treatment with eculizumab resulted in discontinuation of dialysis after 4 weeks. Follow up at 6 months showed improved UPCR to 1.5 mg/mg.

Discussion

aHUS is characterized by uncontrolled activation of the alternate pathway of complement at the cell surface. Mutations of the complement pathway are implicated in disease pathogenesis and coagulation pathway genetic variants have been associated. Our patient’s finding of EBV-triggered aHUS has been rarely reported and even less commonly in association with athrombocytopenia. The patient has a rarely described combination of a likely pathogenic variant in the complement pathway CFH gene and a variant in the coagulation pathway PLG gene. Due to absence of causal relationships, these findings may be coincidental in this patient with EBV-triggered aHUS. Further research is needed to elucidate the pathophysiology of aHUS