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Kidney Week

Abstract: PO2603

Proteinuria in Early Pregnancy: Role of sFLT-1:PlGF Ratio

Session Information

Category: Trainee Case Report

  • 2000 Women’s Health and Kidney Diseases

Authors

  • Seif, Nay, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Ellis, Carla L., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Wadhwani, Shikha, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
Introduction

A 32-year-old nulliparous woman at 205/7 weeks gestation by in vitro fertilization was admitted for hypertension (HTN), proteinuria, and acute kidney injury.

Case Description

She reported no home medications other than prenatal vitamins. Exam was notable only for trace leg edema. Given nephrotic syndrome early in pregnancy and unremarkable hemolysis work-up (Figure 1A), there was concern for acute glomerulonephritis (GN). Renal biopsy showed signs of thrombotic microangiopathy (TMA) (Figure 1B) without evidence of immune-complex mediated GN. As Atypical hemolytic uremic syndrome (aHUS) and Preeclampsia (PEC) were both on the differential, serum was tested for sFLT-1 and PlGF. Based on emerging evidence of alternative complement pathway activation in PEC, Eculizumab use was discussed but not pursued due to uncertain fetal viability, even with pregnancy prolongation. Ultimately, patient chose to terminate the pregnancy and subsequent pathology review revealed maternal vascular malperfusion and early intrauterine fetal demise. Levels of sFLT-1 (95,228 pg/ml), PlGF (139.3 pg/ml), and sFLt-1: PlGF ratio (683.6) were all consistent with severe PEC (Figure 1C). At 2-month follow-up, proteinuria had resolved and HTN was controlled with Nifedipine.

Discussion

Patients presenting with nephrotic syndrome and hypertension ≦ 20 weeks gestation pose a diagnostic dilemma. Renal biopsy is necessary to distinguish PEC from GN but pathological diagnosis of TMA can lead to persistent diagnostic uncertainty. Measurement of circulating angiogenic factors can be useful, with sFLT-1:PlGF ratio > 38 supporting a diagnosis of PEC. Further validation and widespread availability of such testing is needed to assist in management of early pregnancy complications.

Figure 1: Clinical data & Jones stain showing glomerular basement membrane duplication, characteristic of TMA.