Severe HELLP syndrome masquerading as thrombocytopenic thrombotic purpura: a case report

Abstract

Background: Thrombotic microangiopathies (TMAs) occurring in the postpartum period may be difficult to manage. They present as the combination of mechanical hemolytic anemia and consumption thrombocytopenia due to endothelial dysfunction. The cause of this endothelial aggression can be multiple: thrombocytopenic thrombotic purpura (TTP), HELLP syndrome, antiphospholipid syndrome, atypical hemolytic and uremic syndrome or acute fatty liver of pregnancy. TTP results from a severe deficiency of ADAMTS13, which is a protease cleaving specifically von Willebrand factor chiefly produced by liver cells. There are two main causes, the production of anti-ADAMTS13 auto-antibodies and, more rarely, a genetic deficiency in ADAMTS13. First-line treatment is based on plasma exchange. HELLP syndrome occurs in the third trimester of pregnancy usually in association with preeclampsia and represents a form of TMA characterized by damage to the sinusoidal capillaries of the liver. Prompt delivery is the main treatment. We present a case illustrating the challenges in discriminating between different postpartum TMAs, with a focus on the distinction between TTP and HELLP syndrome. Specifically, we highlight how acute liver failure (ALF) stemming from HELLP may lead to TTP with a spectacular response to plasma exchanges.

Case: A 28-year-old, 33 + 4 weeks pregnant woman presented with severe preeclampsia complicated by ALF in the setting of partial liver necrosis, disseminated intravascular coagulation, microangiopathic hemolytic anemia and acute kidney injury. Greatly diminished levels of ADAMTS13 (< 5%) activity and neurological impairment suggested an initial diagnosis of thrombotic thrombocytopenic purpura (TTP). Therapeutic plasma exchange (TPE) was initiated and complete renal, neurological, hematological and hepatic recovery was observed. Secondary TTP induced by ALF due to HELLP syndrome was the final diagnosis.

Conclusion: Our case addresses the overlapping nature of postpartum TMAs and raises the possibility that HELLP-induced ALF may constitute an additional mechanism resulting in TTP, thereby opening a possible indication for TPE.

Keywords: Acute liver failure; Case report; HELLP syndrome; Therapeutic plasma exchange; Thrombotic microangiopathy; Thrombotic thrombocytopenic purpura.

Fig. 1

Imaging and temporal trends of lactate dehydrogenase (LDH) levels and platelets following delivery. Computerized Tomography scan (a) with axial reconstruction shows lack of perfusion of the posterior sector of the liver (black arrow). Magnetic Resonance Imaging with T2 sequence (b) and T1 sequence with gadolinium injection (c) show high signal T2 of the posterior sector of the liver related to necrosis (white arrows) and lack of enhancement after gadolinium injection (white arrows) related to the infarction of the hepatic parenchyma. Therapeutic plasma exchange (TPE, red arrows) was initiated at day 5 following delivery and renal replacement therapy (RRT, green arrows) at day 1. Serum lactate dehydrogenase (LDH, black line), platelet count (red line) and serum creatinine (green line, mg/L) are given on the ordinate. Day 1 is the day of delivery. The dotted line is the standard for platelets