Complement-Mediated Thrombotic Microangiopathy in Pregnancy: An Educational Case Report

Area of Science:

• Nephrology
• Hematology
• Obstetrics

Background:

• Thrombotic microangiopathy (TMA) encompasses rare diseases like atypical hemolytic uremic syndrome (aHUS).
• Distinguishing aHUS in pregnancy from pre-eclampsia or HELLP syndrome is critical due to differing treatments.
• Pregnancy-associated aHUS (p-aHUS) often involves complement alternative pathway dysregulation, necessitating timely intervention.

Observation:

• A 28-year-old woman developed severe symptoms including vomiting, epigastric pain, and hypertension post-delivery of twins.
• Initial concerns included HELLP syndrome and acute fatty liver of pregnancy, with evidence of acute kidney injury and thrombocytopenia.
• Despite initial conservative management, the patient required dialysis for anuric acute kidney injury, with a final diagnosis of p-aHUS confirmed by TMA work-up showing low C3 levels.

Findings:

• Treatment with a C5 inhibitor was initiated on day 8 post-delivery.
• Rapid normalization of platelet count occurred within 2 days of the first C5 inhibitor dose.
• Dialysis was discontinued after 3 months, but the patient maintained reduced kidney function with an eGFR of 23 mL/min/1.73 m² at 6 months.

Implications:

• Delayed diagnosis of p-aHUS can negatively impact patient outcomes.
• Postpartum TMA unresponsive to other treatments, with negative ADAMTS13 and APLAS serologies, suggests p-aHUS.
• Early C5 inhibitor therapy is recommended for p-aHUS, requiring multidisciplinary care at specialized centers for prompt diagnosis and treatment.