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Kidney Week

Abstract: TH-PO124

Postpartum Complement Mediated Thrombotic Microangiopathy: A Case Report

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Anderson, Christian, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
  • Honkanen, Iiro, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
  • Kuppachi, Sarat C., The University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
Introduction

Complement mediated thrombotic microangiopathy (TMA) can be associated with a high risk of progression to ESRD if it is unrecognized early in its course. Frequently, a trigger in a genetically susceptible individual initiates aberrant activity of the complement cascade causing microangiopathic hemolytic anemia. Herein, we present the case of a 26-year-old who presented with TMA at the time of her delivery and subsequently found to have a mutation in the Wilms’ tumor 1 (WT1) gene.

Case Description

A 26-year-old nulliparous woman was admitted to the hospital on post-partum day (PPD) 1. Delivery was complicated by profuse bleeding requiring transfusion of RBCs, platelets, and FFP. She was referred to the Nephrology service on PPD2 with anuria, acute kidney injury (AKI) with a creatinine of 3.6 mg/dL, thrombocytopenia (nadir 14,000), hemolytic anemia, and low complement levels. Urinalysis showed hematuria, protein creatinine ratio of 1.55, and muddy brown casts. Given progression of her kidney injury depsite plasmapharesis and a normal ADAMTS-13 level, she was started on eculizumab 900 mg every 14 days with improvement in her platelet count. She required three hemodialysis treatments for volume overload, before her kidney function eventually normalized. Her eculizumab was then discontinued. Genetic testing revealed a heterozygous mutation in WT1 variant NM_024426.6:c.662-6C>A, which is a variant of unknown significance.

Discussion

Pregnancy is a well-established trigger for TMA which must be included in the differential diagnosis of peri- and post-partum patients with AKI. Once TMA is identified, it is important to pursue genetic testing to better understand the genetic variants implicated in the disease. This has implications for treatment, prognosis, and further research. To the best of our knowledge there is only one reported case of WT1 mutation presenting as complement mediated hemolytic syndrome. WT1 encoded proteins are necessary to regulate cell growth and maintain normal function of renal podocytes and the glomerular filtration barrier. We hypothesize that reduced WT1 expression, leading to podocytopathy could be one of the pathogenic factors contributing to the occurrence of TMA. Based on this experience, and successful treatment with eculizumab, we want to raise awareness to the to the possibility of WT1 mutations triggering TMA in susceptible patients.