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Kidney Week

Abstract: PO0179

Catch 22: The Vicious Cycle of Malignant Hypertension and Worsening Renal Thrombotic Microangiopathy

Session Information

  • AKI Mechanisms - 2
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Report

  • 103 AKI: Mechanisms

Authors

  • Lakshman, Sneha, North Shore Medical Center, Salem, Massachusetts, United States
  • Kruger gomes, Larissa, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
  • William, Jeffrey H., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
Introduction

Renal Thrombotic microangiopathy (TMA) may arise from multiple distinct etiologies. Malignant hypertension is one of these conditions that can precipitate and worsen Renal TMA. The detection of C5B-9 on endothelial cells may help determine the timing and selection of treatment to break the vicious cycle of malignant hypertension and worsening renal TMA.

Case Description

34-year-old woman with a history of gestational hypertension, presented to the ED with complaints of a viral URI and was found to be in hypertensive emergency with an SBP in the 260’s. She was a non-smoker and did not use drugs or alcohol. She denied having any other symptoms or any recent medication use.

Her labs were notable for hemolytic anemia and acute kidney injury with a creatinine of 4.0 mg/dL. A peripheral smear confirmed schistocytes, along with a normal serum ADAMTS 13 activity at 89. Extensive work-up for atypical hemolytic uremic syndrome was negative and complement levels were normal. Renal ultrasound showed diffusely increased renal cortical echogenicity. Renal biopsy confirmed the diagnosis of acute on chronic thrombotic microangiopathy with severe endothelial swelling and onion-skin lesions of the arterioles and small arteries.

Her creatinine peaked at 5.49 mg/dL, but urine output was stable, and she never required dialysis. She was treated with aggressive antihypertensives with consideration of eculizumab therapy.

Discussion

Eculizumab was approved to inhibit complement-mediated TMA in atypical HUS in 2011. The literature describes complement-amplifying conditions including malignant hypertension, complications of pregnancy, and autoimmune diseases being associated with the onset of TMA as they activate the alternative complement pathway in up to 69% of cases with atypical HUS. Standard therapies for malignant hypertension do not address underlying complement dysregulation and TMA may persist despite blood pressure management.

The ‘domino effect’ created by this inflammatory cascade is difficult to reverse and may benefit from eculizumab therapy, whether they have a genetic predisposition or not. The detection of C5B-9 formation on the endothelial cells may reflect complement defects among patients with TMA and severe hypertension, which can be a valuable tool in sub-stratifying whether these patients may benefit from terminal complement inhibitor therapy.