HELLP Syndrome, Thrombotic Thrombocytopenic Purpura or Both: Appraising the Complex Association and Proposing a Stepwise Practical Plan for Differential Diagnosis.

Both thrombocytopenia and microangiopathic hemolytic anemia (TMA) are seen in thrombotic thrombocytopenic purpura (TTP) and HELLP syndrome among other disorders during pregnancy. Although both share backgrounds of endothelial injury and microvascular thrombi and some clinical features, yet, they have different etiologies and courses. In late pregnancy, differentiating between these two pathologies can be extremely difficult due to the immense overlap in clinical and laboratory manifestations and this becomes only possible with the use of specific markers as ADAMTS-13, when available. Hereby, we describe three cases that may exemplify the complex association between PE/HELLP syndrome and TTP. The first case presented with PE/HELLP syndrome and deteriorated postpartum to improve on plasmapheresis. The second case was a known TTP patient who developed superimposed PE/HELLP at 27 weeks gestation which necessitated emergent delivery. The third was a case of preeclampsia that progressed to HELLP syndrome on day 2 postpartum but 3 days later was complicated by TTP. HELLP syndrome and TTP can co-exist, but can also complicate one another. In the absence of instantaneous results of ADAMTS-13 and when diagnosis with clinical judgement alone cannot be done with certainty, a short trial-plasmapheresis could be attempted with close observation of the immediate response. This stepwise approach might prove to be a valuable tool when integrated in the usual workup of clinical and laboratory evaluation both before and after delivery.