Khanuja Kavisha, Levy Ariel T, McLaren Rodney A, Berghella Vincenzo
Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, PA (Dr Khanuja).
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Weill Cornell Medicine at New York Presbyterian Hospital, New York, NY (Dr Levy).
Am J Obstet Gynecol MFM. 2022 May;4(3):100606. doi: 10.1016/j.ajogmf.2022.100606. Epub 2022 Mar 11.
Given the overlapping clinical indicators and lack of diagnostic testing, misdiagnosis of immune thrombocytopenic purpura and gestational thrombocytopenia in pregnancy may be common. Current recommendations suggest utilizing platelet nadir during pregnancy to guide diagnosis.
This study aimed to assess the accuracy of gestational thrombocytopenia and immune thrombocytopenic purpura diagnoses using pre- and postpregnancy platelet counts.
This was a retrospective cohort study of patients diagnosed with gestational thrombocytopenia and immune thrombocytopenic purpura from January 2017 to December 2019. Platelet counts were extracted from charts and evaluated at several time periods, namely prepregnancy (within 5 years), during pregnancy, and postpartum (>6 weeks to 5 years). A diagnosis of gestational thrombocytopenia was considered inaccurate if platelet counts were <150,000/µL pre- or postpregnancy with no other apparent causes or if the platelet nadir dropped below 100,000/µL during pregnancy. A diagnosis of immune thrombocytopenic purpura was deemed inaccurate if pre- or postpregnancy platelet counts were >150,000/µL. The primary outcome was accuracy of gestational thrombocytopenia and immune thrombocytopenic purpura diagnoses in patients. Secondary outcomes included mean platelet counts during pregnancy and difference in mean platelet counts for patients with an accurate vs inaccurate diagnosis of gestational thrombocytopenia. Outcomes were summarized with descriptive statistics and compared using Student t tests.
A total of 116 patients met the inclusion criteria of which 111 (96%) and 5 (4%) had gestational thrombocytopenia and immune thrombocytopenic purpura diagnoses, respectively. Platelet counts outside of pregnancy were available for 91 (82%) of the patients, and 66 (57%) had prepregnancy platelet counts available. Of the 91 patients, the diagnosis was considered accurate in 61 (67%) and 5 (100%) patients with gestational thrombocytopenia and immune thrombocytopenic purpura, respectively. Conversely, 30 of 35 (86%) patients with immune thrombocytopenic purpura were found to be inaccurately diagnosed with gestational thrombocytopenia after application of platelet thresholds. Among these 30 patients, 10 had a prepregnancy platelet count <150,000/µL, 12 had a postpartum platelet count <150,000/µL, 3 had a platelet count nadir <100,000/µL during pregnancy, and 7 met more than 1 criterion. Pre- and postpregnancy platelet counts and platelet count nadir differed significantly for patients with an accurate vs inaccurate diagnosis of gestational thrombocytopenia (P<.001).
When pre- and postpregnancy platelet counts were checked, one-third of cases of gestational thrombocytopenia met the criteria for immune thrombocytopenic purpura and were thus incorrectly diagnosed during pregnancy. Prepregnancy platelet counts, available for most patients, should be considered when diagnosing gestational thrombocytopenia vs immune thrombocytopenic purpura.
鉴于临床指标重叠且缺乏诊断检测手段，孕期免疫性血小板减少性紫癜和妊娠期血小板减少症的误诊可能很常见。当前建议利用孕期血小板最低点来指导诊断。
本研究旨在评估使用孕前和产后血小板计数诊断妊娠期血小板减少症和免疫性血小板减少性紫癜的准确性。
这是一项回顾性队列研究，研究对象为2017年1月至2019年12月期间被诊断为妊娠期血小板减少症和免疫性血小板减少性紫癜的患者。从病历中提取血小板计数，并在几个时间段进行评估，即孕前（5年内）、孕期和产后（>6周至5年）。如果孕前或产后血小板计数<150,000/µL且无其他明显原因，或孕期血小板最低点降至<100,000/µL，则妊娠期血小板减少症的诊断被认为不准确。如果孕前或产后血小板计数>150,000/µL，则免疫性血小板减少性紫癜的诊断被认为不准确。主要结局是患者中妊娠期血小板减少症和免疫性血小板减少性紫癜诊断的准确性。次要结局包括孕期平均血小板计数以及妊娠期血小板减少症诊断准确与不准确的患者之间平均血小板计数的差异。结局用描述性统计进行总结，并使用学生t检验进行比较。
共有116例患者符合纳入标准，其中111例（96%）和5例（4%）分别被诊断为妊娠期血小板减少症和免疫性血小板减少性紫癜。91例（82%）患者有非孕期血小板计数，66例（57%）患者有孕前血小板计数。在这91例患者中，妊娠期血小板减少症和免疫性血小板减少性紫癜患者的诊断分别在61例（67%）和5例（100%）中被认为准确。相反，在应用血小板阈值后，35例免疫性血小板减少性紫癜患者中有30例（86%）被误诊为妊娠期血小板减少症。在这30例患者中，10例孕前血小板计数<150,000/µL，12例产后血小板计数<150,000/µL，3例孕期血小板计数最低点<100,000/µL，7例符合多项标准。妊娠期血小板减少症诊断准确与不准确的患者，其孕前和产后血小板计数以及血小板计数最低点有显著差异（P<.001）。
当检查孕前和产后血小板计数时，三分之一的妊娠期血小板减少症病例符合免疫性血小板减少性紫癜的标准，因此在孕期被错误诊断。在诊断妊娠期血小板减少症与免疫性血小板减少性紫癜时，应考虑大多数患者可获得的孕前血小板计数。
