Kidney Week

Abstract: FR-PO0992

Complement-Mediated Thrombotic Microangiopathy in Pregnancy: Diagnostic Challenges and the Role of Early Eculizumab Therapy

Session Information

• Women's Health and Kidney Diseases
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Women's Health and Kidney Diseases

• 2100 Women's Health and Kidney Diseases

Authors

• Vazquez Morales, Emily, Universidad de Puerto Rico Escuela de Medicina, San Juan, Puerto Rico

Emily Vazquez Morales, MD

• Pico-Ramirez, Alexandra C., Universidad de Puerto Rico Escuela de Medicina, San Juan, Puerto Rico

Alexandra C. Pico-Ramirez, MD

• Ocasio Melendez, Ileana E., Universidad de Puerto Rico Escuela de Medicina, San Juan, Puerto Rico

Ileana E. Ocasio Melendez, MD, FASN

• Rivera-Bermudez, Carlos G., Universidad de Puerto Rico Escuela de Medicina, San Juan, Puerto Rico

Carlos G. Rivera-Bermudez, MD

• Rivera Rios, Jeaneishka Marie, Universidad de Puerto Rico Escuela de Medicina, San Juan, Puerto Rico

Jeaneishka Marie Rivera Rios, MD

Introduction

Pregnancy-associated thrombotic microangiopathy (TMA) is diagnostically challenging due to overlap among HELLP syndrome, thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation, and complement-mediated TMA (CM-TMA/aHUS). Delayed recognition may result in irreversible kidney injury. Early complement inhibition is increasingly considered when diagnostic confirmation is delayed.

Case Description

A 32-year-old G1P0 at 36 weeks gestation with class II obesity presented with headache, blurry vision, hypertension, and proteinuria (0.4 g/day), concerning for preeclampsia. Labor was induced and initial postpartum course was uncomplicated. Seventy-two hours later, she developed severe hypertension, thrombocytopenia, hemoglobin decline from 10.3 to 6.8 g/dL, transaminitis, hypofibrinogenemia, and severe acute kidney injury. Nephrology was consulted.

Renal failure progressed with oliguria and creatinine rising from 0.66 to 8.44 mg/dL. Workup revealed schistocytes, low haptoglobin, LDH 2090 U/L, and worsening proteinuria to 2.6 g/day. Hemodialysis was initiated. Differential diagnosis included HELLP syndrome, TTP, and complement-mediated TMA (CM-TMA). Given ongoing microangiopathic hemolysis and dialysis-dependent renal failure, empiric eculizumab was started after meningococcal vaccination and antibiotic prophylaxis while ADAMTS13 testing was pending.

Subsequent ADAMTS13 activity was preserved, lowering suspicion for TTP. Following complement inhibition, renal function and urine output improved rapidly, allowing discontinuation of dialysis within one week. She completed six doses of eculizumab. At follow-up, renal function normalized, proteinuria improved to <300 mg/g, and rheumatologic and genetic testing were negative. Eculizumab was discontinued without relapse.

Discussion

This case highlights diagnostic uncertainty in postpartum TMA and limitations of delayed confirmatory testing. Persistent hemolysis and severe kidney injury despite improving coagulopathy raised concern for complement-mediated disease. Rapid recovery after eculizumab supports complement activation in pregnancy-associated TMA and emphasizes the importance of early empiric complement blockade. Further studies are needed to define optimal diagnostic pathways and treatment duration in CM-TMA.