Case report: Timing of eculizumab treatment in catastrophic antiphospholipid syndrome.

Catastrophic antiphospholipid syndrome (CAPS) is a life-threatening condition of small-vessel thrombosis with acute multiple-organ involvement and visceral damage. In this report, we present a case of a patient with CAPS who is refractory to conventional therapy. For the first time in a patient with CAPS, marked C5b-9 formation was demonstrated on microvascular endothelial cells, suggesting the usefulness of therapeutic complement inhibition in this setting. Eculizumab, a C5-blocking monoclonal antibody, is remarkably effective in the treatment of different forms of thrombotic microangiopathy by controlling complement system hyperactivation. It halted the "thrombotic storm" and promptly achieved full recovery of thrombocytopenia. However, kidney function did not recover, possibly because eculizumab was administered too late. Conceivably, the timing of treatment is crucial to achieving disease remission before irreversible structural damage occurs in target organs, thereby preventing their complete functional recovery.

[Clinical characteristics and genetic profile of complement system in renal thrombotic microangiopathy in patients with severe forms of arterial hypertension].

BACKGROUND: The spectrum of diseases characterized by the development of renal thrombotic microangiopathy (TMA) encompasses the malignant hypertension (MHT). TMA in MHT has conventionally been regarded as a variation of secondary TMA, the treatment of which is restricted to the stabilization of blood pressure levels, a measure that frequently fails to prevent the rapid progression to end-stage renal disease in patients. Nevertheless, there exists a rationale to suggest that, in certain instances, endothelial damage in MHT might be rooted in the dysregulation of the complement system (CS), thereby presenting potential opportunities for the implementation of complement-blocking therapy. AIM: To study clinical manifestations and genetic profile of CS in patients with morphologically confirmed renal TMA combined with severe AH. MATERIALS AND METHODS: 28 patients with morphologically verified renal TMA and severe AH were enrolled to the study. Patients with signs of microangiopathic hemolysis and thrombocytopenia were not included in the study due to possible compliance with the criteria for atypical hemolytic uremic syndrome (aHUS). The prevalence of rare genetic defects (GD) of the CS was assessed by molecular genetic analysis (search for mutations in the clinically significant part of the human genome - exome) by next-generation sequencing technology (NGS). RESULTS: GD of CS were detected in a quarter of patients. Rare genetic variants classified as "likely pathogenic" including defects in CFI, C3, CD46, CFHR4, CFHR5 genes were detected in five cases. Two patients were found to have chromosomal deletions containing CFH-related proteins genes (CFHR1, CFHR3). CONCLUSION: Rare variants of CS genes linked to aHUS were found in 25% of patients with renal TMA, the genesis of which was originally thought to be secondary and attributed to MHT, with partial or complete absence of hematological manifestations of microangiopathic pathology. The key to confirming TMA associated with MHT, particularly in the absence of microangiopathic hemolysis and thrombocytopenia, elucidating its nature, and potentially effective complement-blocking therapy in patients with GD of CS, appears to be a genetic study of CS combined with a morphological study of a renal biopsy.

[Lupus nephritis and thrombotic microangiopathy: A review].

Lupus nephritis (LN) is one of the most common organ-specific manifestations of systemic lupus erythematosus (SLE). Various clinical signs of LN develop in at least 50% of patients with SLE. In addition to LN, the spectrum of renal lesions associated with SLE also includes vascular pathology. One of the variants of renal microvascular injury is thrombotic microangiopathy (TMA), the mechanisms of which are diverse. The review focuses on the main forms of TMA, including antiphospholipid syndrome and nephropathy associated with antiphospholipid syndrome, TMA caused by complement system regulation disorders and deficiency of ADAMTS13. In most cases, these forms of TMA are combined with LN. However, they may also exist as a single form of kidney damage. This article discusses the TMA pathogenesis, the impact on kidney prognosis, and treatment options.

Thrombotic Microangiopathies and the Kidney.

Thrombotic microangiopathy (TMA) is a pathological lesion that occurs due to endothelial injury. It can be seen in a heterogenous group of disorders, typically characterized by microangiopathic hemolytic anemia, thrombocytopenia, and end-organ ischemia. TMA can also be renal limited with no systemic manifestations. There are multiple etiologies of a TMA with complement activation being a core underlying mechanism, although the nature and extent of complement involvement can vary. A further complicated factor is the cross talk between complement, neutrophils, and coagulation pathways in the pathophysiology of TMAs. Therefore, a thorough and systematic clinical history and laboratory evaluation are critical to establish the cause and pathophysiology of a TMA. Furthermore, TMAs are associated with significant morbidity and mortality, and timely diagnosis is key for appropriate management and to prevent end-stage kidney disease and other associated complications. In this review, we focus on the pathology, mechanisms, diagnostic work up and treatment of TMAs associated with various etiologies. We also define the complement evaluations that should be conducted in these patients and further highlight the currently approved complement therapies as well as others in the pipeline.

Real-World Application of Recently Proposed ASTCT/CIBMTR/EBMT/APBMT Consensus Risk Stratification for Transplantation-Associated Thrombotic Microangiopathy in Children.

Consensus diagnostic and risk stratification of transplantation-associated thrombotic microangiopathy (TA-TMA) was recently achieved from international transplantation groups. Although the proposed diagnostic criteria have been applied to multiple pediatric cohorts, there are scant data applying the novel risk stratification approach in children with TA-TMA. In this retrospective cohort study, all children undergoing an allogeneic HCT or autologous HCT for neuroblastoma were prospectively screened for TA-TMA, diagnosed, and risk-stratified using the Jodele criteria from August 2019 to October 2023. Our institutional practice during the study period was treat all Jodele intermediate-risk (IR) and high-risk (HR) patients with eculizumab. Harmonization risk stratification criteria were applied retrospectively. All survival analyses were calculated from the day of TA-TMA diagnosis. To identify which specific harmonization high-risk features were the most important predictors for nonrelapse mortality (NRM), full and reduced logistical regression models were tested. The lowest Bayes information criterion and optimal Mallows CP statistic were used to identify the best subset. The analysis was performed with SAS 9.4 (SAS Institute, Cary, NC). Fifty-two children were diagnosed with TA-TMA during the study period, at a median of 37.5 days post-HCT (range, 3 to 735 days). Using Jodele risk stratification, 11 (21%) were SR, 21 (40%) were IR, and 20 (39%) were HR. Forty (77%) were treated with eculizumab. There were no statistically significant differences in NRM among Jodele risk groups, although overall survival (OS) differed significantly. Using the harmonized stratification, 49 children (94%) were stratified as HR and 3 as standard risk (SR), there were no statistically significant differences in NRM or OS between groups. Eight children (15.4%) were classified as SR using Jodele risk stratification but restratified as HR using the harmonization criteria. One child (12.5%) died in the setting of severe GVHD, and the remaining 7 were alive at the last follow-up. In a best subset model, lactate dehydrogenase (LDH) level >2 times the upper limit of normal (ULN) (odds ratio [OR], 6.52, 95% confidence interval [CI], .96 to 44.3; P = .05), grade II-IV acute graft-versus-host disease (GVHD) at the time of TA-TMA diagnosis (OR, 15.4; 95% CI, 2.14 to 110.68; P = .01), and organ dysfunction at the time of TA-TMA (OR, 21.5; 95% CI, 2.96 to 156.37; P = .002) were significantly associated with NRM; elevated sC5b-9, urine protein/creatinine ratio, and viral infections were not significantly associated with NRM. Using these best-fit criteria, 14 patients were classified as SR and 38 were classified as HR, NRM was significantly higher, and OS was significantly lower. In this cohort of children with TA-TMA, retrospective application of the harmonization criteria resulted in more patients stratified as HR compared to use of the previously described Jodele criteria. The intention of the harmonization criteria was to identify those at greatest risk of poor outcomes; while all harmonization SR patients survived, this risk stratification was very sensitive. Previous criticisms of harmonization risk stratification include limited access to sC5b-9 testing. These data suggest that organ dysfuncion, acute GVHD, and LDH >2 times ULN are the most important predictors of NRM in this cohort, allowing risk stratification even in the absence of available sC5b-9 testing. Additional studies are needed to validate these findings.

Pulmonary tumor thrombotic microangiopathy: Two case reports and literature review.

RATIONALE: Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare but serious complication in patients with malignancy; its main manifestation includes acute pulmonary hypertension with severe respiratory distress. More than 200 cases have been reported since it was first identified in 1990. PTTM accounts for approximately 0.9% to 3.3% of deaths due to malignancy, but only a minority of patients are diagnosed ante-mortem, with most patients having a definitive diagnosis after autopsy. PATIENT CONCERNS: Two middle-aged women both died within a short period of time due to progressive dyspnea and severe pulmonary hypertension. DIAGNOSES: One patient was definitively confirmed as a gastrointestinal malignant tumor by liver puncture biopsy pathology. Ultimately, the clinical diagnosis was pulmonary tumor thrombotic microangiopathy. INTERVENTIONS: The patient was treated symptomatically with oxygen, diuresis, and anticoagulation, while a liver puncture was perfected to clarify the cause. OUTCOMES: Two cases of middle-aged female patients with rapidly progressive pulmonary hypertension and respiratory failure resulted in death with malignant neoplasm. LESSONS: PTTM has a rapid onset and a high morbidity and mortality rate. Our clinicians need to be more aware of the need for timely diagnosis through a targeted clinical approach, leading to more targeted treatment and a better prognosis.

Nationwide Analysis of Adult-Onset Still Disease With and Without Hemophagocytic Lymphohistiocytosis.

INTRODUCTION: Adult-onset Still disease (AOSD) is a rare inflammatory condition with a monophasic, intermittent, or chronic clinical course, and a subset may experience life-threatening complications such as hemophagocytic lymphohistiocytosis (HLH). This study aims to characterize concurrent AOSD and HLH and identify variables independently associated with in-hospital death. METHODS: We performed a medical records review of AOSD with and without HLH from the 2016-2019 National Inpatient Sample database. We performed a multivariable logistic regression analysis for in-hospital death. Results were reported as adjusted odds ratios (OR adj ). RESULTS: There were 5495 hospitalizations with AOSD, of which 340 (6.2%) had HLH. Thirty (9.0%) of the combined AOSD and HLH group died in the hospital compared with 75 (1.5%) of those without HLH. Multivariable analysis in AOSD inpatients showed that disseminated intravascular coagulation (OR adj 6.13), hepatic failure (OR adj 7.16), infection (OR adj 3.72), respiratory failure (OR adj 6.89), and thrombotic microangiopathy (OR adj 14.05) were associated with higher odds of death. However, HLH itself was not an independent predictor of mortality in AOSD population. CONCLUSIONS: HLH occurred in a small minority of inpatients with AOSD. HLH itself was not an independent risk factor for in-hospital death. Disseminated intravascular coagulation, hepatic failure, infection, respiratory failure, and thrombotic microangiopathy were associated with higher odds of in-hospital death in AOSD. Better awareness of these life-threatening complications may improve hospital outcomes.

Neurological involvement in hematopoietic stem cell transplantation-associated thrombotic microangiopathy.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a well-recognized serious complication of hematopoietic stem cell transplantation (HSCT). The understanding of TA-TMA pathophysiology has expanded in recent years. Dysregulation of the complement system is thought to cause endothelial injury and, consequently, microvascular thrombosis and tissue damage. TA-TMA can affect multiple organs, and each organ exhibits specific features of injury. Central nervous system (CNS) manifestations of TA-TMA include posterior reversible encephalopathy syndrome, seizures, and encephalopathy. The development of neurological dysfunction is associated with a significantly lower overall survival in patients with TA-TMA. However, there are currently no established histopathological or radiological criteria for the diagnosis of CNS TMA. Patients who receive total body irradiation (TBI), calcineurin inhibitors (CNI), and severe acute and chronic graft-versus-host disease (GVHD) are at a high risk of experiencing neurological complications related to TA-TMA and should be considered for directed TA-TMA therapy. However, the incidence and clinical manifestations of TA-TMA neurotoxicity remain unclear. Studies specifically examining the involvement of CNS in TMA syndromes are limited. In this review, we discuss clinical manifestations and imaging abnormalities in patients with nervous system involvement in TA-TMA. We summarize the mechanisms underlying TA-TMA and its neurological complications, including endothelial injury, evidence of complement activation, and treatment options for TA-TMA.

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

Platelets play an important role in hemostasis, and a low platelet count usually increases the risk of bleeding. Conditions in which thrombosis occurs despite low platelet counts are referred to as thrombosis with thrombocytopenia syndrome, including heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, thrombotic microangiopathy (TMA), and disseminated intravascular coagulation. TMA includes thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (HUS), and atypical HUS. Patients with these pathologies present with thrombosis and consumptive thrombocytopenia associated with the activation of platelets and the coagulation system. Treatment varies from disease to disease, and many diseases have direct impacts on mortality and organ prognosis if therapeutic interventions are not promptly implemented. Underlying diseases and the results of physical examinations and general laboratory tests as part of a thorough workup for patients should promptly lead to therapeutic intervention before definitive diagnosis. For some diseases, the diagnosis and initial treatment must proceed in parallel. Utilization of not only laboratory tests but also various scoring systems is important for validating therapeutic interventions based on clinical information.

Thrombotic microangiopathy in patients with sickle cell disease.

OBJECTIVE: To describe two cases of patients who had thrombotic microangiopathy (TMA) associated with sickle cell disease (SCD). CASE DESCRIPTION: Both patients started with a painful crisis and had acute chest syndrome during hospitalization. They showed significant worsening of hemolytic anemia, with very high levels of lactate dehydrogenase, thrombocytopenia, lowered level of consciousness, organ damage and the presence of schistocytes in peripheral blood. Due to the possibility of TMA, despite the very rare association with SCD, they were treated with fresh frozen plasma replacement and plasmapheresis, with good response. COMMENTS: TMA is a serious, life-threatening disease, characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ damage. The association of SCD and TMA is difficult to diagnose, since they can share a similar clinical presentation. Recognizing this association and promptly instituting treatment may impact the survival of these patients.

Complement-mediated thrombotic microangiopathy on a background of Alport syndrome: A case report.

Here we present a case of complement-mediated thrombotic microangiopathy (TMA) in a patient who has a background of Stage 5 chronic kidney disease secondary to Alport syndrome. We explain our approach to the diagnosis of TMA, especially the reliance on non-renal manifestations of TMA and the role of kidney biopsy given there was a background of advanced kidney impairment at baseline.

Severe hemolysis, elevated liver enzymes, and low platelet syndrome requiring differentiation of thrombotic microangiopathy: Four cases from a nationwide survey in Japan.

Severe cases of hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome requiring plasma exchange or dialysis should be differentiated from other thrombotic microangiopathy (TMA) and treated appropriately. To evaluate the prevalence and clinical characteristics of such cases in Japan, a questionnaire-based survey was conducted among obstetricians who are members of the Perinatal Research Network Group in Japan. There were a total of 335 cases of HELLP syndrome over a 3-year period in the 48 facilities that responded to the survey. Four patients required plasma exchange or dialysis, of which two were diagnosed with atypical hemolytic uremic syndrome and two with TMA secondary to systemic lupus erythematosus. Although such severe HELLP syndrome is rare, identifying the clinical features and making accurate differential diagnosis are critical for optimal clinical outcomes for mothers and neonates.

The kidney histopathological spectrum of patients with kidney injury following snakebite envenomation in India: scoping review of five decades.

INTRODUCTION: Snakebite is a public health problem leading to about 58,000 deaths every year in India. Kidney injury subsequent to snakebite envenomation is common with a reported prevalence of up to 32%. The current study aims to elucidate the spectrum of kidney histopathology in acute kidney injury (AKI) cases associated with snake bites. METHODS: We searched seven electronic database studies to identify studies describing the histopathological findings in the kidney with snakebite envenomation. Two reviewers independently conducted titles and abstract screening as well as full-text evaluation for the final inclusion decision. Data were extracted as per the standardized form. We conducted narrative synthesis. Studies done exclusively on autopsy findings, in vitro studies, and case reports were excluded. RESULTS: We retrieved 1464 studies and finally included 28 studies which met the eligibility criteria in the analysis. Most studies were single-centre and the majority were cross-sectional. Overall we included a total of 534 renal biopsies. Russell's viper bite was the most common cause related to AKI. Acute tubular necrosis was the most common finding followed by acute interstitial nephritis, acute cortical necrosis (ACN), and thrombotic microangiopathy (TMA). Vasculitis changes in vessels were rarely reported. Lesions such as ACN and TMA were associated with poor outcomes. CONCLUSION: This analysis supports the notion that renal biopsies are important to guide prognosis and increase our knowledge about post-snake bite AKI pathophysiology.

A case-based narrative review of pregnancy-associated atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy.

Atypical hemolytic uremic syndrome is a complement-mediated thrombotic microangiopathy caused by uncontrolled activation of the alternative complement pathway in the setting of autoantibodies to or rare pathogenic genetic variants in complement proteins. Pregnancy may serve as a trigger and unmask atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy (aHUS/CM-TMA), which has severe, life-threatening consequences. It can be difficult to diagnose aHUS/CM-TMA in pregnancy due to overlapping clinical features with other thrombotic microangiopathy syndromes including hypertensive disorders of pregnancy. However, the distinction among thrombotic microangiopathy etiologies in pregnancy is important because each syndrome has specific disease management and treatment. In this narrative review, we discuss 2 cases to illustrate the diagnostic challenges and evolving approach in the management of pregnancy-associated aHUS/CM-TMA. The first case involves a 30-year-old woman presenting in the first trimester who was diagnosed with aHUS/CM-TMA and treated with eculizumab from 19 weeks' gestation. Genetic testing revealed a likely pathogenic variant in CFI. She successfully delivered a healthy infant at 30 weeks' gestation. In the second case, a 22-year-old woman developed severe postpartum HELLP syndrome, requiring hemodialysis. Her condition improved with supportive management, yet investigations assessing for aHUS/CM-TMA remained abnormal 6 months postpartum consistent with persistent complement activation but negative genetic testing. Through detailed case discussion describing tests assessing for placental health, fetal anatomy, complement activation, autoantibodies to complement regulatory proteins, and genetic testing for aHUS/CM-TMA, we describe how these results aided in the clinical diagnosis of pregnancy-associated aHUS/CM-TMA and assisted in guiding patient management, including the use of anticomplement therapy.