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Kidney Week

Abstract: FR-PO139

Navigating Atypical Hemolytic Uremic Syndrome (aHUS) in Pregnancy

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Hoteit, Mayssaa, Bridgeport Hospital Internal Medicine, Bridgeport, Connecticut, United States
  • KFoury, Hala M., American University of Beirut, Beirut, Lebanon
  • Abu-Alfa, Ali K., American University of Beirut, Beirut, Lebanon
Introduction

AKI during pregnancy can stem from various causes. Notably, conditions like preeclampsia, HELLP syndrome, TTP, and aHUS present diagnostic challenges due to overlapping symptoms. Understanding these diverse etiologies is crucial for accurate diagnosis and appropriate management strategies. We describe a case of AKI during pregnancy, diagnosed as aHUS.

Case Description

A 21-year-old female with a history of CKD presented during pregnancy with worsening Cr. At age 5, her kidney biopsy showed MPGN with C3 deposition on IF. Her Cr remained stable over the years, around 1.2-1.5 mg/dl, but increased during her pregnancy to 1.6-1.7 with worsening proteinuria. At 36 weeks GA, she was admitted for elevated BP. Laboratory investigations showed Hb of 10.7 g/dl, Plt of 221,000/mcL, Cr of 2.1 mg/dl, LDH of 425 IU/L, and haptoglobin of 0.25 g/L. She was started on magnesium, and labor was induced. Six weeks postpartum, she presented with tonic-clonic seizures, diffuse body edema, elevated Cr, and hemolytic anemia. Further investigations, including CT chest-abdomen-pelvis and CT brain, revealed fluid overload and no acute changes in the brain. An echocardiogram showed a hyperdynamic LV. Initially diagnosed with postpartum eclampsia, she received magnesium but developed severe hypermagnesemia, requiring urgent dialysis. Subsequently, her Cr continued to rise with associated anemia and thrombocytopenia.

Discussion

A suspicion for TMA was raised, leading to further investigations: ADAMTS13 activity returned as 67%, and kidney biopsy showed swelling of the endothelial cells, extensive double contour formation, and one glomerulus showed a thrombus, with non-specific fibrinogen staining on IF. Despite treatment with 10 plasma exchange sessions, her Cr continued to rise, necessitating the initiation of chronic dialysis. The possibility of aHUS was raised, but unfortunately, eculizumab was unavailable. It was eventually secured four months later, but its intermittent administration failed to improve her condition, and she remained dialysis-dependent. As part of her pre-transplantation workup, genetic testing for aHUS revealed a class 3 variant in the C3 gene and another variant of unknown significance in the CFHR5 gene.

Kidney biopsy