A Case of Hemolysis, Elevated Liver Enzyme, and Low Platelet Count (HELLP) Syndrome-Precipitated Acute Thrombotic Thrombocytopenia Purpura.

Hemolysis, elevated liver enzyme, and low platelet count (HELLP) syndrome and thrombotic thrombocytopenic purpura (TTP) are both thrombotic microangiopathies that share overlapping clinical and laboratory features, making differentiation during pregnancy particularly challenging. We present a case of a 27-year-old woman at 21 weeks gestation who initially presented with hypertensive emergency and right middle cerebral artery (MCA) ischemic stroke requiring embolectomy and whose subsequent intensive care unit (ICU) course was complicated by fever, severe thrombocytopenia, microangiopathic hemolytic anemia (MAHA), and transaminitis raising concern for concurrent HELLP syndrome and TTP. Further workup revealed undetectably low ADAMTS-13 activity with negative inhibitor and identification of two heterozygous pathogenic ADAMTS-13 gene variants, confirming a diagnosis of hereditary TTP superimposed on HELLP syndrome. Management was complicated by the need for platelet transfusion prior to delivery despite its contraindication in TTP, which required multidisciplinary collaboration between Ob/Gyn perinatology and hematology. The decision was made to manage concurrent HELLP and TTP with emergent delivery followed by plasma exchange (PLEX). This unique case demonstrates the challenges of diagnosing and starting appropriate management when there is concern for both HELLP and TTP due to the significant clinical and laboratory overlap. Additionally, a high index of suspicion should be maintained for the possibility of pregnancy precipitating acute-on-chronic hereditary TTP events in patients presenting with severe thrombocytopenia and prior unexplained pregnancy loss.