Thrombotic microangiopathy during pregnancy

Schistocyte detection in artificial intelligence age

Schistocytes are fragmented red blood cells produced as a result of mechanical damage to erythrocytes, usually due to microangiopathic thrombotic diseases or mechanical factors. The early laboratory detection of schistocytes has a critical impact on the timely diagnosis, effective treatment, and positive prognosis of diseases such as thrombocytopenic purpura and hemolytic uremic syndrome. Due to the rapid development of science and technology, laboratory hematology has also advanced. The accuracy and efficiency of tests performed by fully automated hematology analyzers and fully automated morphology analyzers have been considerably improved. In recent years, substantial improvements in computing power and machine learning (ML) algorithm development have dramatically extended the limits of the potential of autonomous machines. The rapid development of machine learning and artificial intelligence (AI) has led to the iteration and upgrade of automated detection of schistocytes. However, along with significantly facilitated operation processes, AI has brought challenges. This review summarizes the progress in laboratory schistocyte detection, the relationship between schistocytes and clinical diseases, and the progress of AI in the detection of schistocytes. In addition, current challenges and possible solutions are discussed, as well as the great potential of AI techniques for schistocyte testing in peripheral blood.

Labor and delivery: DIC, HELLP, preeclampsia

Hematologists are often needed to assist with the management of microangiopathic emergencies in pregnancy. A firm understanding of the diagnosis and management of preeclampsia with severe features, hemolysis elevated liver enzyme and low platelet syndrome, and disseminated intravascular coagulation, which are the most common causes of microangiopathic emergencies, is critical. However, being able to consider when other microangiopathic emergencies (acute fatty liver of pregnancy, congenital and acquired thrombotic thrombocytopenic purpura, complement mediated microangiopathy, antiphospholipid syndrome) should be considered is imperative. The hematologist and obstetric team should work together to optimize the care of common as well as rare hematologic emergencies.

HELLP syndrome complicated by ischemic colitis: A case report

Key Clinical Message

HELLP syndrome is a complicated disorder associated with many unknown complications, which ischemic colitis might be one of. Timely diagnosis and prompt management with multidisciplinary approach is the key for a favorable outcome.

Abstract

HELLP syndrome is a triad of hemolysis (H), elevated liver enzymes (EL), and low platelet count (LP) which is considered a rare but serious pregnancy complication. HELLP syndrome is mainly associated with pre-eclampsia, but can also occur individually. It may cause maternal and fetal mortality and some life-threatening morbidity. The best management considered for HELLP syndrome is immediate delivery in most cases. We report a 32-week pregnant woman with pre-eclampsia who developed HELLP syndrome shortly after admission which led to a preterm cesarean section. Rectal bleeding and diarrhea started the day after delivery, and all the workups and imaging suggested ischemic colitis. She received intensive care and supportive management. The patient recovered and was discharged uneventfully. HELLP syndrome may be associated with many unknown complications, and ischemic colitis might be one of them. Timely diagnosis and prompt management with a multidisciplinary approach is the key to a favorable outcome.

Proteinuria in thrombotic microangiopathy is associated with partial podocytopathy

BACKGROUND

Thrombotic microangiopathy (TMA) results in acute kidney injury, but the cause of heavy proteinuria in this disorder is puzzling. The goal of this study was to determine if there were significant effacement of foot processes and CD133-positive hyperplastic podocytes in TMA to explain the proteinuria.

METHODS

The study included 12 negative controls (renal parenchyma removed from renal cell carcinoma) and 28 thrombotic microangiopathy due to different etiologies. The percent of foot process effacement was estimated, and proteinuria level was obtained for each TMA case. Both groups of cases were stained for CD133 by immunohistochemical method, and the number of positive CD133 in hyperplastic podocytes was counted and analyzed.

RESULTS

Nineteen (19) of 28 (68%) TMA cases had nephrotic range proteinuria (urine protein/creatinine >3). Twenty-one (21) of 28 (75%) TMA cases showed positive CD133 staining in scattered hyperplastic podocytes within Bowman's space but was absent in control cases. The percent of foot process effacement (56 ± 4%) correlated with proteinuria (protein/creatinine ratio 4.4 ± 0.6) (r = 0.46, p = .0237) in TMA group.

CONCLUSION

Our data indicate that the proteinuria in TMA can be associated with significant effacement of foot processes. CD133-positive hyperplastic podocytes can be seen in the majority of TMA cases of this cohort, indicating a partial podocytopathy.

Haematological changes from conception to childbirth: An indicator of major pregnancy complications

BACKGROUND

About 800 women die every day worldwide from pregnancy-related complications, including excessive blood loss, infections and high-blood pressure (World Health Organization, 2019). To improve screening for high-risk pregnancies, we set out to identify patterns of maternal hematological changes associated with future pregnancy complications.

METHODS

Using mixed effects models, we established changes in 14 complete blood count (CBC) parameters for 1710 healthy pregnancies and compared them to measurements from 98 pregnancy-induced hypertension, 106 gestational diabetes and 339 postpartum hemorrhage cases.

RESULTS

Results show interindividual variations, but good individual repeatability in CBC values during physiological pregnancies, allowing the identification of specific alterations in women with obstetric complications. For example, in women with uncomplicated pregnancies, haemoglobin count decreases of 0.12 g/L (95% CI -0.16, -0.09) significantly per gestation week (p value <.001). Interestingly, this decrease is three times more pronounced in women who will develop pregnancy-induced hypertension, with an additional decrease of 0.39 g/L (95% CI -0.51, -0.26). We also confirm that obstetric complications and white CBC predict the likelihood of giving birth earlier during pregnancy.

CONCLUSION

We provide a comprehensive description of the associations between haematological changes through pregnancy and three major obstetric complications to support strategies for prevention, early-diagnosis and maternal care.

Histopathologically TMA-like distribution of multiple organ thromboses following the initial dose of the BNT162b2 mRNA vaccine (Comirnaty, Pfizer/BioNTech): an autopsy case report

Background

Coronavirus disease 2019 (COVID-19) has spread worldwide. Vaccination is now recommended as one of the effective countermeasures to control the pandemic or prevent the worsening of symptoms. However, its adverse effects have been attracting attention. Here, we report an autopsy case of multiple thromboses after receiving the first dose of the BNT162b2 mRNA vaccine (Comirnaty, Pfizer/BioNTech) in an elderly woman.

Case presentation

A 72-year-old woman with a history of diffuse large B-cell lymphoma in the stomach and hyperthyroidism received the first dose of the BNT162b2 mRNA vaccine and died 2 days later. The autopsy revealed multiple microthrombi in the heart, brain, liver, kidneys, and adrenal glands. The thrombi were CD61 and CD42b positive and were located in the blood vessels primarily in the pericardial aspect of the myocardium and subcapsular region of the adrenal glands; their diameters were approximately 5–40 μm. Macroscopically, a characteristic myocardial haemorrhage was observed, and the histopathology of the characteristic thrombus distribution, which differed from that of haemolytic uraemic syndrome and disseminated intravascular coagulation, suggested that the underlying pathophysiology may have been similar to that of thrombotic microangiopathy (TMA).

Conclusion

This is the first report on a post-mortem case of multiple thromboses after the BNT162b2 mRNA vaccine. The component thrombus and characteristic distribution of the thrombi were similar to those of TMA, which differs completely from haemolytic uraemic syndrome or disseminated intravascular coagulation, after vaccination. Although rare, it is important to consider that fatal adverse reactions may occur after vaccination and that it is vital to conduct careful follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00418-7.

Incidence of thrombotic microangiopathies in Quebec: insight from a laboratory centralizing ADAMTS-13 testing

BACKGROUND

Thrombotic microangiopathies (TMA) are serious medical conditions requiring a prompt diagnosis to adapt treatment. The determination of ADAMTS-13 activity enables discriminating thrombotic thrombocytopenic purpura (TTP) from other forms of TMA. The purpose of this study was to provide an estimate of the incidence of TTP and TMA in the Canadian Quebec province using data collected from a laboratory centralizing ADAMTS-13 testing for the whole province.

RESULTS

From 2012 to 2019, 846 patients were evaluated for plasma ADAMTS-13 activity due to a suspicion of TMA. TTP was identified in 147 patients. Of these, 118 patients with a median age of 51.5 years and a male-female ratio of 1:1.4 had their first episode of TTP during the study period. The number of ADAMTS-13 tests performed and the number of patients with suspected TMA increased annually by 19% and 21% respectively. While the incidence of non-TTP TMA increased annually, that for TTP remained unchanged. This averaged 10.2 (95% CI 5.9-14.4) per million persons per year for suspected non-TTP TMA and 1.8 (95% CI 1.3-2.4) for confirmed TTP. The incidence rate of TMA other than TTP was higher in the age group 70-79 years (21.8; 95% CI 5.4-38.1) for females and in the age group 80-89 years (24.4; 95% CI 7.2-41.7) for males compared to other age groups. The incidence rate of TTP was higher in the age group 40-49 years (4.0; 95% CI 2.0-5.9) for women and in the age group 60-69 years (3.4; 95% CI 1.1-5.6) for men compared to other age groups.

CONCLUSION

The analysis of centralized data measuring ADAMTS-13 activity allowed us to adequately establish the incidence rate and demographic characteristics of TMA, particularly TTP, in Quebec. TTP incidence remained stable while suspected non-TTP TMA steadily increased from 2012 to 2019.

The Glomerular Endothelium Restricts Albumin Filtration

Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.