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A3423 - A Critically Ill Postpartum Woman with Thrombotic Thrombocytopenic Purpura (TTP) Vs Hemolysis, Elevated Liver Enzymes, and Low Platelets Syndrome (HELLP)
Author Block: R. Johnson-Paben1, N. Lin2, R. Vandivier2; 1Internal Medicine Residency Training Program, University of Colorado, Aurora, CO, United States, 2Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Aurora, CO, United States.
Introduction
Thrombotic thrombocytopenic purpura (TTP) is a well-recognized hematologic emergency. One-third of all cases of TTP occur during the peri-partum period, as pregnancy is known to reduce ADAMTS-13 activity and therefore significantly increase risk of TTP. Due to significant overlap in clinical and laboratory findings, TTP can easily be misdiagnosed as other disorders including hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome, hemolytic-uremic syndrome, idiopathic thrombocytopenic purpura, antiphospholipid syndrome, or disseminated intravascular coagulation. As mortality and treatment options are vastly different for each disease state, it is paramount to establish an accurate diagnosis.
Case Report
A 36 year-old female with a history of gestational thrombocytopenia presented in active labor and was found to have 61,000 platelets/µl with otherwise normal hematologic labs, renal function, and intracranial imaging. On postpartum day one her platelet count dropped to 9,000 platelets/µl with a relatively preserved hemoglobin of 11.6 grams/dl, raising concern for idiopathic thrombocytopenic purpura. Corticosteroids and intravenous immunoglobulin were initiated with no improvement. On postpartum day three she developed worsening microangiopathic hemolytic anemia with schistocytes visualized on a peripheral blood smear along with elevated liver enzymes concerning for HELLP syndrome. The following day she acutely decompensated with hemoptysis, was intubated for airway protection, and was transferred to the intensive care unit. Ultrasound showed no evidence of retained products of conception. She was treated with platelet and cryoprecipitate transfusion, magnesium infusion as prophylaxis against hypertension and seizure, corticosteroids, and furosemide for concurrent pulmonary edema. Acute kidney injury developed on postpartum day five. On postpartum day six she clinically stabilized and was extubated. Her ADAMTS-13 level resulted as undetectable and she was started on therapeutic plasma exchange for confirmed diagnosis of TTP. Treatment was continued for nine days until her platelets recovered to >100 platelets/µl.
Discussion
Thrombotic microangiopathies in the peri-partum period are diagnostically difficult to distinguish. This patient’s clinical course was initially strongly suggestive of HELLP as the etiology. Determination of ADAMTS-13 level is the only method for definitive diagnosis of TTP, but often takes many days to result. A lactate dehydrogenase (LDH) to aspartate aminotransferase (AST) ratio >22.12 has been proposed as a more readily available laboratory indication of TTP compared to severe HELLP. Failure to definitively rule out TTP should lead to urgent plasma exchange.