Incidence of obstetrical thrombotic thrombocytopenic purpura in a retrospective study within thrombocytopenic pregnant women. A difficult diagnosis and a treatable disease

Abstract

BackgroundThrombotic thrombocytopenic Purpura (TTP) defined as ADAMTS-13 (A Disintegrin And Metalloprotease with ThromboSpondin type 1 domain 13) activity <10 % is a rare aetiology of thrombocytopenia during pregnancy, although the precise incidence is unknown. During pregnancy, the diagnosis of TTP is crucial as it has high feto-maternal morbidity-mortality and requires urgent plasma exchange. The purpose of this study was to assess the incidence of TTP retrospectively and to describe case presentations and follow-up.MethodsA monocentric retrospective study (2008–2009) was conducted among pregnant women followed in a tertiary care obstetrical unit who experienced at least one episode of severe thrombocytopenia (platelets ≤75 G/L) during 2008 and 2009. In cases of uncertain aetiology of thrombocytopenia, ADAMTS-13 activity was assessed by the full length technique.ResultsAmong 8,908 deliveries over the 2 year period, 79 women had a platelet count nadir ≤75 G/L. Eighteen had a known aetiology of thrombocytopenia and 11 were lost to follow-up. Among 50 remaining patients, ADAMTS-13 activity was undetectable (<5 %) in 4, consistent with the diagnosis of TTP. Platelet count spontaneously normalized in 3 patients after delivery. None presented focal cerebral involvement. Three of the four, who were primipara patients, had a sustained severe deficiency in the absence of anti-ADAMTS-13 antibodies, and ADAMTS-13 gene sequencing indicated a constitutive deficiency. The fourth, a multipara patient, had an acquired, auto-immune TTP. Placental pathology in the three primipara patients showed severe and non-specific ischemic lesions. Two patients lost their babies shortly after birth. In subsequent pregnancies in these two patients, prophylactic plasma infusion initiated early with increasing volume throughout pregnancy prevented TTP relapse, improved placental pathology, and led to normal delivery.ConclusionsThe prevalence of TTP among thrombocytopenic pregnant women is high, up to 5 % in a tertiary unit. Platelet count normalization after delivery does not eliminate TTP. Clinicians should be aware of TTP during pregnancy, and, even if assessed retrospectively, ADAMTS-13 assessment is of particular importance for identifying patients with congenital TTP. In these patients, preventive plasma infusion and/or exchange can dramatically improve foetal prognosis, resulting in successful childbirth.

How I treat thrombotic thrombocytopenic purpura in pregnancy

“…In practice, we advise for CBC serial monitoring in any pregnant woman with thrombocytopenia ,100 000/mL, adding a blood film and LDH in case of platelets ,75 000/mL, given the high prevalence of cTTP (as high as 5%) reported in a large obstetric population with such a low platelet count. 16 In clinical practice, it is much more likely to face preeclampsia (PE) or hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome rather than pregnancy-associated TTP, given their reported incidences of 3% to 5%, 0.1% to 0.8%, and probably ,0.00004%, respectively. 15 However, the high fetomaternal mortality rate if unrecognized and untreated requires a high index of suspicion for TTP.…”

A Case of Idiopathic Thrombocytopenic Purpura during Pregnancy

“…Most women with ITP have mild to moderate thrombocytopenia and approximately 30-35% of the cases require intervention during pregnancy (3). The disorder can be associated with both fetal and maternal morbidity and mortality (5). In a study in England, the prevalence of thrombocytopenia was found to be 3.6%, but the mothers in this study had no sign of bleeding (6).…”

Thrombotic microangiopathies during pregnancy: The obstetrical and neonatal perspective

“…Overall, the estimated incidence of TTP associated with pregnancy is less than 1 per 100,000 pregnancies [15], even if a retrospective study on 8908 deliveries in a tertiary unit reported that the prevalence of TTP among thrombocytopenic pregnant women was up to 5% [16].…”