Pregnancy and delivery in the context of hemolytic uremic syndrome: A surrogacy case report

Abstract

Pregnancy complicated by hemolytic uremic syndrome (HUS) and its variants presents significant challenges in obstetric care. Thrombotic microangiopathy (TMA), a key feature of HUS, involves microvascular thrombosis that can affect any organ, leading to thrombocytopenia, Coombs-negative hemolytic anemia, and organ dysfunction. The most common forms of thrombotic microangiopathies encountered in pregnant patients include hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, thrombotic thrombocytopenic purpura, HUS and acute fatty liver of pregnancy. TMAs are classified into inherited or acquired primary, secondary, or infection-associated TMAs. Current classifications define primary TMAs as hereditary (mutations in ADAMTS13, MMACHC [cb1c deficiency], or genes encoding complement proteins) or acquired (autoantibodies to ADAMTS13, or autoantibodies to complement Factor H (FH), which is associated with homozygous CFHR3/1 deletion). TMA is associated with various infections, including Shiga toxin-producing Escherichia coli-induced HUS (STEC-HUS) and pneumococcal HUS, as well as other bacterial and viral infections. Secondary TMAs occur in a spectrum of conditions, and in many cases the pathogenic mechanisms are multifactorial or unknown. The classification presented here is not unequivocal: in some secondary TMAs, for example pregnancy-associated TMA or de novo TMA after transplantation, a significant proportion of individuals will have a genetic predisposition to a primary TMA. Atypical HUS is particularly concerning during pregnancy as it results from genetic and acquired mutations in complement regulatory proteins, those involved in the alternative pathway of the immune system. We report the case of an Armenian surrogate mother who developed Escherichia coli-mediated HUS complicated by septicemia, acute kidney injury and clinical features of TMA, including neurological alterations. Despite these severe complications, the patient only began to show improvement after undergoing plasma exchange therapy following a cesarean delivery. This case underscores the critical need for heightened suspicion of HUS during pregnancy when TMA features are present. Prompt diagnosis is essential to ensure timely and effective treatment, as delays can lead to significant maternal and fetal morbidity.

Keywords: hemolytic uremic syndrome; microvascular thrombosis; pregnancy complications; thrombotic microangiopathy.