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Summary The immunosuppressive treatment of immune‐mediated thrombotic thrombocytopenic purpura (iTTP) in patients with intolerance or refractoriness to the B‐cell depleting monoclonal antibody rituximab remains debated. Daratumumab, a plasma cell‐directed monoclonal antibody targeting CD38, represents a therapeutic option, but data are scarce. The French Thrombotic Microangiopathies Reference Center conducted a nationwide survey on iTTP patients treated with daratumumab. Nine episodes from seven patients were identified. Treatment was administered for A Disintegrin And Metalloproteinase with ThromboSpondin‐1 motifs, 13th member (ADAMTS13) relapses while patients were otherwise in clinical response (N = 8), or during the acute phase of the disease following rituximab intolerance (N = 1). Patients have received a median of three previous therapeutic lines. ADAMTS13 activity improved in eight cases following daratumumab administration, including three cases where ADAMTS13 normalized. ADAMTS13 relapses occurred in three patients; in two cases, retreatment with daratumumab was successful. Median ADAMTS13 relapse‐free survival was not reached; 12‐month ADAMTS13 relapse‐free survival was 56%. Daratumumab‐related adverse events occurred in five cases and were non‐severe infusion‐related reactions in all cases. These results suggest that daratumumab may be an effective treatment option for iTTP patients with intolerance or refractoriness to rituximab. [ABSTRACT FROM AUTHOR]

This article presents a case report of a patient with immune-mediated thrombotic thrombocytopenic purpura (iTTP), a potentially life-threatening blood clotting disorder. The patient experienced a stroke before developing low platelet count and abnormal red blood cell breakdown. The article emphasizes the importance of early diagnosis and treatment to prevent further organ damage. The patient was successfully treated with therapeutic plasma exchange, prednisolone, and caplacizumab, which improved platelet count and resolved the abnormal red blood cell breakdown. The article also discusses how this case challenges the typical presentation of the disorder and suggests a potential mechanism for organ damage in iTTP. The study received funding from the Ministry of Health, Labour and Welfare of Japan. [Extracted from the article]

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening, often immune-mediated disease that affects 2–13 persons per million per year. Hemolytic anemia, thrombocytopenia, and end-organ damage due to the formation of microthrombi are characteristic of TTP. ADAMTS13 is a disintegrin, metalloproteinase, cleaving protein of von Willebrand factor (VWF) that processes the VWF multimers to prevent them from interacting with platelets and, in turn, to microvascular thrombosis. Prompt diagnosis of TTP is critical yet challenging. Thrombotic microangiopathies have similar clinical presentation. Measurement of ADAMTS13 activity helps in the differential diagnosis. Less than 10% ADAMTS13 activity is indicative of TTP. Laboratory ADAMTS13 activity assays include incubating the test plasma with the substrate (full-length VWM multimers) and detection with direct or indirect measurement of the cleavage product. The purpose of this study is to examine the diagnostic potential, advantages, and weaknesses of the ADAMTS13 potency in TTP. [ABSTRACT FROM AUTHOR]

Thrombotic microangiopathy (TMA), characterized by microangiopathic hemolytic anemia, thrombocytopenia, and multisystem organ dysfunction, is a life‐threatening disease. Patients with TMA who do not exhibit a severe ADAMTS‐13 deficiency (defined as a disintegrin‐like and metalloprotease with thrombospondin type 1 motif no. 13 activity ≥10%: TMA‐13n) continue to experience elevated mortality rates. This study explores the prognostic indicators for augmented mortality risk or necessitating chronic renal replacement therapy (composite outcome: CO) in TMA‐13n patients. We included 42 TMA‐13n patients from January 2008 to May 2018. Median age of 41 years and 60% were female. At presentation, 62% required dialysis, and 57% warranted intensive care unit admission. CO was observed in 45% of patients, including a 9‐patient mortality subset. Multivariate logistic regression revealed three independent prognostic factors for CO: early administration of eculizumab (median time from hospitalization to eculizumab initiation: 5 days, range 0–19 days; odds ratio [OR], 0.14; 95% confidence interval [CI], 0.02–0.94), presence of neuroradiological lesions (OR, 6.67; 95% CI, 1.12–39.80), and a PLASMIC score ≤4 (OR, 7.39; 95% CI, 1.18–46.11). In conclusion, TMA‐13n patients exhibit a heightened risk of CO in the presence of low PLASMIC scores and neuroradiological lesions, while early eculizumab therapy was the only protective factor. [ABSTRACT FROM AUTHOR]

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The complement system, an important part of the innate system, is known to play a central role in many immune mediated kidney diseases. All parts of the complement system including the classical, alternative, and mannose-binding lectin pathways have been implicated in complement-mediated kidney injury. Although complement components are thought to be mainly synthesized in the liver and activated in the circulation, emerging data suggest that complement is synthesized and activated inside the kidney leading to direct injury. Urinary complement biomarkers are likely a better reflection of inflammation within the kidneys as compared to traditional serum complement biomarkers which may be influenced by systemic inflammation. In addition, urinary complement biomarkers have the advantage of being non-invasive and easily accessible. With the rise of therapies targeting the complement pathways, there is a critical need to better understand the role of complement in kidney diseases and to develop reliable and non-invasive biomarkers to assess disease activity, predict treatment response and guide therapeutic interventions. In this review, we summarized the current knowledge on urinary complement biomarkers of kidney diseases due to immune complex deposition (lupus nephritis, primary membranous nephropathy, IgA nephropathy) and due to activation of the alternative pathway (C3 glomerulopathy, thrombotic microangiography, ANCA-associated vasculitis). We also address the limitations of current research and propose future directions for the discovery of urinary complement biomarkers. [ABSTRACT FROM AUTHOR]

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Intensive care physicians may assume the primary care of patients with transplant-associated thrombotic microangiopathy (TA-TMA), an uncommon but potentially critical complication of hematopoietic stem cell transplants (HSCTs) and solid organ transplants. TA-TMA can have a dramatic presentation with multiple organ dysfunction syndrome (MODS) associated with high morbidity and mortality. The typical presenting clinical features are hemolytic anemia, thrombocytopenia, refractory hypertension, proteinuria and worsening renal failure. Intestinal involvement, with abdominal pain, nausea and vomiting, gastrointestinal bleeding, and ascites are also common. Cardiopulmonary involvement may develop from various causes including pulmonary arteriolar hypertension, pleural and pericardial effusions, and diffuse alveolar hemorrhage. Due to other often concurrent complications after HSCT, early diagnosis and effective management of TA-TMA may be challenging. Close collaboration between ICU and transplant physicians, along with other relevant specialists, is needed to best manage these patients. There are currently no approved therapies for the treatment of TA-TMA. Plasma exchange and rituximab are not recommended unless circulating factor H (CFH) antibodies or thrombotic thrombocytopenic purpura (TTP; ADAMTS activity < 10%) are diagnosed or highly suspected. The role of the complement pathway activation in the pathophysiology of TA-TMA has led to the successful use of targeted complement inhibitors, such as eculizumab. However, the relatively larger studies using eculizumab have been mostly conducted in the pediatric population with limited data on the adult population. This review is focused on the role of intensive care physicians to emphasize the clinical approach to patients with suspected TA-TMA and to discuss diagnosis and treatment strategies. [ABSTRACT FROM AUTHOR]

The study examined the mortality risk for patients with hematological malignancies and febrile neutropenia who were hospitalized on weekends and holidays. The researchers used data from Danish national health registers and found that hospitalizations during weekends and holidays were associated with a higher 30-day mortality rate compared to regular weekdays. However, the cause of this association is unknown and further research with more detailed data is needed to fully understand it. [Extracted from the article]

Catastrophic antiphospholipid syndrome (CAPS) is a rare clinical form of antiphospholipid syndrome (APS) associated with life-threatening complications due to simultaneous thrombosis that may affect small and large vessels. It may be localized to the venous and/or arteries at the same time, and there are not available guidelines based on randomized clinical trials or large series. We here report a clinical case of CAPS with onset after resolution of oligo-symptomatic infection SARS-CoV-2, that had transient improvement with warfarin after recurrent thromboses occurred despite treatment off-label with low doses of low molecular weight heparin. Furthermore, we tried to trace a line by which a multidisciplinary team may set specific timing to have follow-up because of the high morbidity, mortality, and prolonged time of hospitalization.

Catastrophic antiphospholipid syndrome (CAPS) is a rare clinical form of antiphospholipid syndrome (APS) associated with life-threatening complications due to simultaneous thrombosis that may affect small and large vessels. It may be localized to the venous and/or arteries at the same time, and there are not available guidelines based on randomized clinical trials or large series. We here report a clinical case of CAPS with onset after resolution of oligo-symptomatic infection SARS-CoV-2, that had transient improvement with warfarin after recurrent thromboses occurred despite treatment off-label with low doses of low molecular weight heparin. Furthermore, we tried to trace a line by which a multidisciplinary team may set specific timing to have follow-up because of the high morbidity, mortality, and prolonged time of hospitalization. [ABSTRACT FROM AUTHOR]

Thrombotic microangiopathies (TMAs) comprise a distinct group of diseases with different manifestations that can occur in both pediatric and adult patients. They can be hereditary or acquired, with subtle onset or a rapidly progressive course, and they are particularly known for their morbidity and mortality. Pregnancy is a high-risk time for the development of several types of thrombotic microangiopathies. The three major syndromes are hemolysis, elevated liver function tests, and low platelets (HELLP); hemolytic uremic syndrome (HUS); and thrombotic thrombocytopenic purpura (TTP). Because of their rarity, clinical information and therapeutic results related to these conditions are often obtained from case reports, small series, registries, and reviews. The collection of individual observations, the evolution of diagnostic laboratories that have identified autoimmune and/or genetic abnormalities using von Willebrand factor post-secretion processing or genetic–functional alterations in the regulation of alternative complement pathways in some of these TMAs, and, most importantly, the introduction of advanced treatments, have enabled the preservation of affected organs and improved survival rates. Although TMAs may show different etiopathogenesis routes, they all show the presence of pathological lesions, which are characterized by endothelial damage and the formation of thrombi rich in platelets at the microvascular level, as a common denominator, and thrombotic damage to microcirculation pathways induces "mechanical" (microangiopathic) hemolytic anemia, the consumption of platelets, and ischemic organ damage. In this review, we highlight the current knowledge about the diagnosis and management of these complications during pregnancy. [ABSTRACT FROM AUTHOR]

This article discusses immune-mediated thrombotic thrombocytopenic purpura (iTTP), a rare but serious disorder characterized by microvascular thrombosis and potentially life-threatening complications. iTTP is caused by a deficiency in the von Willebrand factor (VWF)-cleaving protease ADAMTS13, which leads to the accumulation of ultralarge VWF multimers and triggers platelet clumping and microvascular thrombosis. Early diagnosis and comprehensive therapy are crucial for optimal patient outcomes. The article provides guidance for diagnosing iTTP, sorting TMA etiologies, assessing severity, and initiating appropriate treatment. It emphasizes the importance of avoiding platelet transfusions and highlights the need for a personalized approach to diagnosis and treatment. [Extracted from the article]

Background: Secondary atypical hemolytic uremic syndrome (secondary aHUS) is a heterogeneous group of thrombotic microangiopathies (TMA) associated with various underlying conditions. Unlike primary aHUS, there is still no hard evidence on the efficacy of complement blockade in secondary aHUS, since the two main series that investigated this subject showed discrepant results. Our work aims to reassess the efficacy of eculizumab in treating secondary aHUS. Methods: Observational, retrospective, single-center study, in which we analyzed the hematological and renal evolution of 23 patients diagnosed with secondary aHUS who received treatment with eculizumab and compared them with a control cohort of 14 patients. Complete renal response was defined as the recovery of renal function before the event, partial renal response as a recovery of 50% of lost glomerular filtration rate, and hematological response as normalization of hemoglobin and platelets. Results: We found no statistically significant differences in baseline characteristics or disease severity between both groups. After a median of 5 doses of eculizumab, the group of patients who received complement blockade presented a significant difference in renal response (complete in 52.3% of patients and partial in 23.8%) compared to the control cohort (complete response 14.3% and partial of 14.3%). Rates of hematological remission were similar in both groups (90.9% in the eculizumab cohort and 85.7% in the control cohort). Conclusion: Early and short-term use of eculizumab in patients with secondary aHUS could be an effective and safe therapeutic option, assuring better renal recovery compared to patients who do not receive complement blockade. [ABSTRACT FROM AUTHOR]

Catastrophic antiphospholipid syndrome (CAPS) is a multi-organ systemic thrombotic condition precipitated due to various secondary conditions such as infection, surgery, and estrogen use. The subsequent formation of various autoantibodies and various organ involvement such as the brain, heart, and kidneys cause rapid progression of the disease. The acute features of thrombosis and the predominant involvement of kidneys and the brain make the differentiation of this condition with other thrombotic microangiopathies difficult. However, early suspicion of CAPS with prompt management is key to favorable prognosis in such patients. Multidisciplinary approach to diagnosis and medical management plays an important role in the successful outcome of CAPS patients. The three pillars of management are therapeutic plasma exchange (TPE), steroids, and anticoagulants. TPE plays a major role in eliminating incriminating antibodies, cytokines, tumor necrosis factor, and complement. We present a case of 34-year-old female with definite CAPS, managed successfully with the triple regimen comprising a total of seven TPE sessions, pulse therapy with steroids, and anticoagulants. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Atypical hemolytic uremic syndrome, a rare thrombotic microangiopathy, necessitates early diagnosis and comprehensive care due to its potential severity, emphasizing the importance of a multidisciplinary approach to improve outcomes. [ABSTRACT FROM AUTHOR]

Objective: To report a pediatric case of drug-induced thrombotic microangiopathy caused by cocaine Case description: We report a nine-month-old patient who developed thrombotic microangiopathies after extreme cocaine intoxication, multiple organ dysfunction syndrome with hemodynamic dysfunction, anuric renal failure, liver failure, encephalopathy, and myocardial injury, corresponding phenotypically to thrombocytopenia-associated multiple organ failure. The patient received continuous venous hemofiltration and therapeutic plasma exchange, recovering satisfactorily. She was discharged after 30 days of hospitalization under the guidance of the childcare service, and was healthy after one year of follow-up. Toxicological samples confirmed high levels of cocaine and derivatives in blood, urine and hair. Comments: To our knowledge, this is the first reported pediatric case. There are particularities of cocaine intoxication pathophysiology that can trigger thrombotic microangiopathies because of vasoconstriction, direct endothelial injury, platelet activation, and increasing von Willebrand factor and fibrinogen levels. All of which results in a prothrombotic state, inflammatory dysregulation, and microvascular thrombi. The increasing use of cocaine, especially among young adults, puts children at high risk of toxicity, either by passive unintentional exposure, or abuse due to the increased availability in homes. [ABSTRACT FROM AUTHOR]

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Background: Thrombotic microangiopathy (TMA) is a rare side effect of interferon-beta (IFN-β) therapy. The clinical characteristics of IFN-β-induced TMA are unknown. Objectives: To explore the clinical characteristics of IFN-β-induced TMA and provide reference for the prevention of TMA. Design: Articles on IFN-β-induced TMA were collected by searching the literature in relevant Chinese and English databases from inception to 31 July 2023. Methods: Data in the articles were extracted and analyzed retrospectively. Results: Forty-seven patients, with a median age of 41 years (range 22, 66), were included in the analysis. The median time to the diagnosis of IFN-β-induced TMA was 8 years (range 0.1–30) after administration. The main clinical symptoms were neurological symptoms (51.1%), hypertension (78.7%), dyspnea (19.1%), edema (19.1%), asthenia/fatigue (19.1%), and digestive symptoms (17.0%). Most patients presented with hemolytic anemia (76.6%), thrombocytopenia (63.8%), and acute kidney injury (70.2%). All patients stopped IFN-β and received plasma exchange therapy (53.2%), systemic steroids (46.8%), antihypertensive therapy (46.8%), eculizumab (12.8%), and rituximab (12.8%). Kidney damage was not completely reversible; 40.4% of patients achieved renal function and hematology remission, 27.7% developed chronic kidney disease, 25.5% developed end-stage renal disease, and 2.1% died. Conclusion: IFN-β-induced TMA is a rare but serious complication that can be life-threatening. It may occur after many years of IFN-β therapy, and patients taking IFN-β should be monitored for symptoms such as headache and hypertension. [ABSTRACT FROM AUTHOR]

Aim: Although perinatal thrombotic microangiopathy has become increasingly understood, the racial characteristics of patients with this condition remain unclear. Herein, we report the characteristics of patients with perinatal thrombotic microangiopathy at a single institution in Japan. Methods: We conducted a retrospective study over a 5‐year period from January 1, 2017, to December 31, 2021, using the electronic medical records of pregnant women who delivered at the perinatal center of our hospital. We extracted the data of those who developed perinatal thrombotic microangiopathy and evaluated their characteristics at the time of disease onset, final diagnosis, and maternal and fetal outcomes. Results: Of the 10 224 deliveries that occurred during the 5‐year period, only seven patients (0.06%) had perinatal thrombotic microangiopathy. The median pre‐pregnant body mass index was 18.65 kg/m2 (minimum 17.3 kg/m2, maximum 20.7 kg/m2). More than half of the patients were conceived by in‐vitro fertilization, and 42% these had twin deliveries. Four patients had a history of rheumatic disease. The other three patients without underlying diseases developed thrombotic microangiopathy with HELLP syndrome, and one patient transitioned to atypical hemolytic uremic syndrome. Conclusions: Based on low body mass index and in‐vitro fertilization, which are characteristic of Japanese women, medical complications and twin pregnancies may be a risk for thrombotic microangiopathy. Additionally, depending on the cause of thrombotic microangiopathy, its timing and onset differed. [ABSTRACT FROM AUTHOR]

Summary: The objective of this guideline is to provide healthcare professionals with clear, up‐to‐date and practical guidance on the management of thrombotic thrombocytopenic purpura (TTP) and related thrombotic microangiopathies (TMAs), including complement‐mediated haemolytic uraemic syndrome (CM HUS); these are defined by thrombocytopenia, microangiopathic haemolytic anaemia (MAHA) and small vessel thrombosis. Within England, all TTP cases should be managed within designated regional centres as per NHSE commissioning for highly specialised services. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Thrombotic microangiopathies are a side effect of anti‐VEGF therapies, which are often limited to the kidneys but can also occur systemically and be life‐threatening. Screening for increasing proteinuria is essential. We present the case of a 65‐year‐old male patient with a multifocal HCC, Barcelona clinic liver cancer (BCLC) classification B at the time of diagnosis. The HCC was treated with nine sessions of transarterial chemoembolization (TACE), and after a progress, the therapy was switched to a combination of atezolizumab and bevacizumab. Five months after therapy change, he presented with an acute kidney injury. The histopathology of the renal biopsy showed findings of a thrombotic microangiopathy (TMA), which we treated with 12 sessions of therapeutic plasma exchange in combination with steroids, resulting in a decreased TMA activity and later in a remission of the TMA. This case suggests the importance of monitoring the kidney function and proteinuria in patients under anti‐vascular endothelial growth factor (VEGF) therapy and shows a rare differential diagnosis for a worsening of kidney function in these patients. Furthermore, it shows that therapeutic plasma exchange might be a valuable therapeutic option for patients with TMA due to anti‐VEGF therapy. [ABSTRACT FROM AUTHOR]

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare medical emergency for which a correct and early diagnosis is essential. As a severe deficiency in A Disintegrin And Metalloproteinase with ThromboSpondin type 1 repeats, member 13 (ADAMTS13) is the underlying pathophysiology, diagnostic strategies require timely monitoring of ADAMTS13 parameters to differentiate TTP from alternative thrombotic microangiopathies (TMAs) and to guide initial patient management. Assays for conventional ADAMTS13 testing focus on the enzyme activity and presence of (inhibitory) anti-ADAMTS13 antibodies to discriminate immune-mediated TTP (iTTP) from congenital TTP and guide patient management. However, diagnosis of iTTP remains challenging when patients present borderline ADAMTS13 activity. Therefore, additional biomarkers would be helpful to support correct clinical judgment. Over the last few years, the evaluation of ADAMTS13 conformation has proven to be a valuable tool to confirm the diagnosis of acute iTTP when ADAMST13 activity is between 10 and 20%. Screening of ADAMTS13 conformation during long-term patient follow-up suggests it is a surrogate marker for undetectable antibodies. Moreover, some non-ADAMTS13 parameters gained notable interest in predicting disease outcome, proposing meticulous follow-up of iTTP patients. This review summarizes non-ADAMTS13 biomarkers for which inclusion in routine clinical testing could largely benefit differential diagnosis and follow-up of iTTP patients. [ABSTRACT FROM AUTHOR]

Atypical hemolytic uremic syndrome (aHUS) is a rare disease caused by a genetic dysregulation of the alternative complement pathway, characterized by thrombocytopenia, hemolytic anemia, and acute kidney injury, and included in the group of thrombotic microangiopathies. With the introduction of humanized monoclonal antibodies that inhibit C5 activation, the natural history of aHUS completely changed, with a better prognosis, a quick recovery of renal function, and a significant reduction of end-stage renal disease incidence. Nowadays, there is an increasing interest in the molecular and genetic bases of this severe disease. The aim of this narrative review is to provide readers with a practical guide about different possible involved genes, elucidating the specific role of each transcribed protein in the pathogenesis of aHUS. Moreover, we analyzed the main current evidence about the relationship among genetic mutations, outcomes, and the risk of recurrence of this manifold disease. [ABSTRACT FROM AUTHOR]

Hereditary thrombotic thrombocytopenic purpura (hTTP), also known as Upshaw–Schulman syndrome, is a rare genetic disorder caused by mutations in the ADAMTS13 gene that leads to decreased or absent production of the plasma von Willebrand factor (VWF)-cleaving metalloprotease ADAMTS13. The result is circulating ultra-large multimers of VWF that can cause microthrombi, intravascular occlusion and organ damage, especially at times of turbulent circulation. Patients with hTTP may have many overt or clinically silent manifestations, and a high index of suspicion is required for diagnosis. For the treatment of hTTP, the goal is simply replacement of ADAMTS13. The primary treatment is prophylaxis with plasma infusions or plasma-derived factor VIII products, providing sufficient ADAMTS13 to prevent acute episodes. When acute episodes occur, prophylaxis is intensified. Recombinant ADAMTS13, which is near to approval, will immediately be the most effective and also the most convenient treatment. In this review, we discuss the possible clinical manifestations of this rare disease and the relevant differential diagnoses in different age groups. An extensive discussion on prophylaxis and treatment strategies is also presented. Unique real patient cases have been added to highlight critical aspects of hTTP manifestations, diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Thrombotische Mikroangiopathien sind seltene, potenziell lebensbedrohliche Erkrankungen mit vielfältiger Ätiologie. Sie präsentieren sich klinisch als Trias aus mikroangiopathischer hämolytischer Anämie, Thrombozytopenie sowie variablen Organdysfunktionen, typischerweise in Form von akutem Nierenversagen oder neurologischen Defiziten, bedingt durch thrombotische Verschlüsse der Mikrozirkulation. In den letzten Jahren wurden bedeutende Fortschritte erzielt, die zur Entdeckung wichtiger zugrunde liegender Pathomechanismen geführt und somit die Entwicklung gezielter therapeutischer Ansätze ermöglicht haben. [ABSTRACT FROM AUTHOR]

Pregnancy and the postpartum period represent phases of heightened vulnerability to thrombotic microangiopathies (TMAs), as evidenced by distinct patterns of pregnancy-specific TMAs (e.g., preeclampsia, HELLP syndrome), as well as a higher incidence of nonspecific TMAs, such as thrombotic thrombocytopenic purpura or hemolytic uremic syndrome, during pregnancy. Significant strides have been taken in understanding the underlying mechanisms of these disorders in the past 40 years. This progress has involved the identification of pivotal factors contributing to TMAs, such as the complement system, ADAMTS13, and the soluble VEGF receptor Flt1. Regardless of the specific causal factor (which is not generally unique in relation to the usual multifactorial origin of TMAs), the endothelial cell stands as a central player in the pathophysiology of TMAs. Pregnancy has a major impact on the physiology of the endothelium. Besides to the development of placenta and its vascular consequences, pregnancy modifies the characteristics of the women’s microvascular endothelium and tends to render it more prone to thrombosis. This review aims to delineate the distinct features of pregnancy-related TMAs and explore the contributing mechanisms that lead to this increased susceptibility, particularly influenced by the “gravid endothelium.” Furthermore, we will discuss the potential contribution of histopathological studies in facilitating the etiological diagnosis of pregnancy-related TMAs.

Key Clinical Message Atypical hemolytic uremic syndrome, a rare thrombotic microangiopathy, necessitates early diagnosis and comprehensive care due to its potential severity, emphasizing the importance of a multidisciplinary approach to improve outcomes.