The relationship of antiphospholipid antibodies to thromboembolic events in pediatric patients with systemic lupus erythematosus: a cross-sectional study

Association of Antiphospholipid Antibodies with Clinical Manifestations in Children with Systemic Lupus Erythematosus

BACKGROUND

The aim of the study is to evaluate the effect of the presence of antiphospholipid antibodies on the clinical and laboratory manifestations, disease activity and outcomes of the disease in patients with childhood-onset systemic lupus erythematosus (cSLE).

METHODS

We conducted a 10-year cross-sectional study with a retrospective analysis of clinical and laboratory parameters and outcome of the disease (kidney, nervous system involvement, thrombosis). For the purpose of the study, patients were divided into cohort groups based on the presence of antiphospholipid antibodies (aPLA), named the aPLA positive group, or their absence, named the aPLA negative group. Values of aPLA were defined in reference laboratories. The disease activity was measured by the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, whereas tissue damage degree was measured by Systemic Lupus International Collaborating Clinics/American College of Rheumatology-Damage Index (SLICC/ACR DI; SDI; DI).

RESULTS

Research in our center showed that patients with cSLE often had hematological, cutaneous, and non-thrombotic neurological manifestations. Antiphospholipid antibodies may be present transiently or permanently. A significant change in the titer value was observed in the IgG isotype of aCLA. The presence of higher values of IgM β2GP1 at the beginning indicates that higher disease activity can be expected. Higher disease activity correlates with greater tissue damage. Additionally, it has been shown that aPLA positive patients have two and a half times higher risk of tissue damage than aPLA negative ones.

CONCLUSION

Our study shows that the presence of antiphospholipid antibodies in patients with childhood onset systemic lupus erythematosus may indicate a higher risk of tissue damage, but since it is a rare disease in childhood, prospective and multicenter studies are necessary to assess the importance of the presence of these antibodies.

A significant improvement of thromboses treated by a new oral anticoagulant in an 11-year-old girl with systemic lupus erythematosus associated antiphospholipid syndrome: A case report

Pediatric venous thrombosis is associated with a variety of chronic diseases. Antiphospholipid syndrome (APS) is one of them and is commonly related to systemic lupus erythematosus (SLE). Warfarin is the mainstream of anticoagulation treatment in pediatric APS currently but it needs close monitoring and frequent dose adjustment. New oral anticoagulants (NOAC) is one of the innovative options in recent years but there is a lack of report in secondary prevention of deep vein thrombosis (DVT), especially pediatric APS. Herein we reported the significant therapeutic effect of edoxaban in a 11-year-old girl of newly diagnosed SLE and APS, who had deep vein thrombosis as the initial presentation.

Venous Thromboembolism among Noncritically Ill Hospitalized Children: Key Considerations for the Pediatric Hospital Medicine Specialist

Venous thromboembolism (VTE) is a leading cause of morbidity and preventable harm among noncritically ill hospitalized children. Several clinical factors relevant to the noncritically ill hospitalized child significantly increase the risk of VTE including the presence of central venous catheters, systemic inflammation, and prolonged immobilization. Although risk mitigation strategies have been described, the diagnosis, treatment, and prevention of VTE require standardization of institutional practices combined with multidisciplinary collaboration among pediatric hospitalists, hematologists, and other care providers. In this narrative review, we summarize the epidemiology of VTE, risk models identifying high-risk conditions associated with VTE, and prevention and treatment strategies. We further describe successful quality improvement efforts implementing institutional VTE risk stratification and thromboprophylaxis procedures. Finally, we highlight unique challenges facing pediatric hospital medicine specialists in the era of the COVID-19 pandemic, including caring for adults admitted to pediatric hospital units, and describe future research opportunities for VTE in the noncritically ill hospitalized child.

Pediatric APS: State of the Art

PURPOSE OF REVIEW

The purpose of this report is to review recent research findings on APS in children and neonates.

RECENT FINDINGS

European evidence-based recommendations for diagnosis and treatment of pediatric APS has recently been published by the SHARE Initiative. Recent studies have shown a high prevalence of non-thrombotic manifestations in children with aPL, domains 4/5 specificity of 'innocent' anti-β2GPI antibodies in infants, and a higher risk for developmental delays and learning disabilities, hence, the need for neurodevelopmental monitoring in children born to mothers with APS. An International effort on creating a new diagnostic criteria for APS is underway. Pediatric APS is a rare disease with significant differences from the APS in adults. Majority of the children with persistently positive aPL do not develop thrombotic events; however, relatively higher proportion of thrombosis in children is related to aPL positivity compared to adults; this may partly be due to the absence of common pro-thrombotic "second-hit" risk factors of adults such as atherosclerosis and cigarette smoking. Diagnosis of APS in children may be delayed or missed when adult APS criteria are used, because in pediatric APS, non-thrombotic clinical manifestations such as thrombocytopenia, hemolytic anemia, and neurological disorders such as migraine, epilepsy, and chorea may precede thrombotic manifestations. Around 20% of the children initially diagnosed with primary APS eventually develop SLE. Neonatal APS is rare; however, the offspring of mothers with APS are at a higher risk for developmental delays and learning disabilities; prematurity and IUGR may increase this risk. Regular assessment of neurodevelopmental status of these children should be performed. Thrombosis is a rare event in the offspring of mothers with APS; anticoagulation of such infants is not recommended. An international effort to create a new diagnostic criteria for APS is underway.

Pediatric antiphospholipid syndrome

Despite its potential to cause significant morbidity in children, pediatric antiphospholipid syndrome (APS) is an understudied condition. In this review, we will cover what is known about pediatric APS epidemiology and how the clinician might approach the diagnosis of pediatric APS. We will highlight similarities and differences with the adult disease, both for primary APS and in the context of lupus. Clinical manifestations beyond thrombosis, especially neurologic and hematologic in nature, will be discussed. We will also consider what unique implications antiphospholipid antibody-positivity may have for children with lupus and for neonates born to mothers with APS. The approach to treatment will be covered, including the unique impact of APS medications on children as compared with adults. Finally, the importance of future mechanistic research is emphasized as physicians endeavor to provide the personalized care that children with APS clearly deserve.

European evidence-based recommendations for diagnosis and treatment of paediatric antiphospholipid syndrome: the SHARE initiative

Antiphospholipid syndrome (APS) is rare in children, and evidence-based guidelines are sparse. Consequently, management is mostly based on observational studies and physician's experience, and treatment regimens differ widely. The Single Hub and Access point for paediatric Rheumatology in Europe (SHARE) initiative was launched to develop diagnostic and management regimens for children and young adults with rheumatic diseases. Here, we developed evidence-based recommendations for diagnosis and treatment of paediatric APS. Evidence-based recommendations were developed using the European League Against Rheumatism standard operating procedure. Following a detailed systematic review of the literature, a committee of paediatric rheumatologists and representation of paediatric haematology with expertise in paediatric APS developed recommendations. The literature review yielded 1473 articles, of which 15 were valid and relevant. In total, four recommendations for diagnosis and eight for treatment of paediatric APS (including paediatric Catastrophic Antiphospholipid Syndrome) were accepted. Additionally, two recommendations for children born to mothers with APS were accepted. It was agreed that new classification criteria for paediatric APS are necessary, and APS in association with childhood-onset systemic lupus erythematosus should be identified by performing antiphospholipid antibody screening. Treatment recommendations included prevention of thrombotic events, and treatment recommendations for venous and/or arterial thrombotic events. Notably, due to the paucity of studies on paediatric APS, level of evidence and strength of the recommendations is relatively low. The SHARE initiative provides international, evidence-based recommendations for diagnosis and treatment for paediatric APS, facilitating improvement and uniformity of care.

Pulmonary embolism in an adolescent girl with negative ACLA systemic lupus erythematosus (SLE): a case report

Pulmonary involvement is a common manifestation in systemic lupus erythematosus (SLE), whereas pulmonary thromboembolism (PTE) is rarely seen in SLE. PTE related to anti-phospholipid antibody syndrome (APS) is also a rare disease. We have reported a 13-year-old female diagnosed with SLE Two years ago, who is being treated with hydroxychloroquine and prednisolone. She presented with shortness of breath, dry cough, and fever about two weeks prior to admission. She was initially admitted with the diagnosis of pneumonia, but no clinical improvement was seen she was given antibiotics. Hemoptysis was added to her symptoms, so spiral high resolution computed tomography (HRCT) of the lungs was requested, and it indicated patchy consolidations bilaterally. With suspicion of pulmonary thromboembolism (PTE), spiral computed tomography angiography of pulmonary vessels was done, revealing PTE. After initiation of anti-coagulants, her clinical condition and respiratory status improved significantly. We present a rare case of SLE where only lupus anti-coagulant test was abnormal while other tests, such as anti-cardiolipin antibody and anti-phospholipid antibody were normal. Therefore, we can conclude that clinical suspicion had the main role in diagnosis in our case, as it has in medicine.

Factors associated with thrombosis in pediatric patients with systemic lupus erythematosus

OBJECTIVE

The risk of thrombosis is increased in patients with systemic lupus erythematosus (SLE). Few studies have assessed factors associated with thrombosis within the pediatric SLE (pSLE) population. We sought to better characterize these associated factors in pSLE patients using the Childhood Arthritis & Rheumatology Research Alliance (CARRA) registry.

METHODS

Within the CARRA registry, patients with a history of thrombosis were compared to those without. Univariate logistic regression was used to calculate odds ratios. A multivariable logistic regression model was conducted that included variables from the univariate analysis that had a p value < 0.10 and other variables identified as clinically significant from published literature.

RESULTS

Among the 979 pSLE patients in the CARRA registry, 24 (2.5%) patients had a history of arterial thrombosis and 35 (3.6%) of venous thrombosis. In the univariate analysis, the odds ratio of having a thrombotic event were found to be significantly higher in patients with a history of vasculitis, avascular necrosis (AVN), or antiphospholipid antibody (aPL). Similar results were found for vasculitis, AVN, and aPL in the multivariable analysis.

CONCLUSION

Our study of pSLE patients suggests that vasculitis, positive APL, and AVN are associated with thrombotic events in this population.

Study of audiovestibular dysfunction in children with systemic lupus erythematosus

OBJECTIVE

Inner ear dysfunction in systemic lupus erythematosis patients has been reported but audiovestibular involvement is not well documented especially in pediatrics. This study was designed to evaluate silent audiovestibular dysfunction among SLE children.

METHODS

Case control study examined in allergy and immunology clinic; pediatrics hospital and audiovestibular clinic; Ain Shams University from January 2009 to December 2010. Thirty-five systemic lupus erythematosus children (diagnosed according to American College of Rheumatology); age group 8-16 years, were randomly selected. Five of them were excluded due to one or more exclusion criteria (previous otitis media, stroke, lupus cerebritis, meningitis or encephalitis, audiovestibular symptom). Ten of them refused enrollment or could not complete full battery. Seventeen females and three males, mean age 12.9 ± 2.6 years, completed the study. Control group included 20 normal subjects, age and sex matched. Full clinical assessment, basic audiological evaluation and vestibular testing (videonystagmography VNG and computerized dynamic posturography CDP) were conducted for children included in the study.

RESULTS

Five systemic lupus erythematosus patients had sensorineural hearing loss strongly associated with +ve antiphospholipid antibody and two had conductive hearing loss. Two children in control group had conductive hearing loss (p=0.05). Abnormal VNG findings was significantly higher among systemic lupus erythematosus children (40%) compared to controls (0%) and associated with +ve antiphospholipid antibodies (χ(2)=10, p=0.002, Fisher exact test=0.003). Twenty-five percentage of systemic lupus erythematosus children had abnormal CDP findings reflecting impaired balance function associated with positive antiphospholipid antibodies showing significant statistical difference compared to controls (0% affection) (χ(2)=5.7, p=0.017, Fisher exact test=0.047).

CONCLUSION

Silent audiovestibular dysfunction is prevalent among systemic lupus erythematosus children especially those positive for antiphospholipid antibodies necessitating routine regular evaluation.

Common acquired causes of thrombosis in children

Compared to adults, venous thromboembolism in the pediatric population is a rare event. Cancer, cardiac disease, antiphospholipid antibodies, and indwelling catheters are established risk factors for thromboembolism in children. We examined the literature related to thrombophilia in children, childhood cancer and thrombosis, cardiac disease and thrombosis, and antiphospholipid antibody syndrome in children. Citations in identified articles yielded additional articles for review. We found that studies of acquired thrombophilia in children are limited. Current treatment for thromboembolism in children is based on adult data therefore optimal treatment in this population remains unclear.

Annexin A5 anticoagulant activity in children with systemic lupus erythematosus and the association with antibodies to domain I of β2-glycoprotein I

Children with systemic lupus erythematosus (SLE) have a high prevalence of antiphospholipid (aPL) antibodies and are at increased risk for aPL-related thrombosis. We investigated the association between annexin A5 anticoagulant activity and antibodies to the domain I portion of β2-glycoprotein I (anti-DI antibodies), and propose a potential mechanism for the pathogenesis of aPL-related thrombosis. Using samples from 183 children with SLE collected during the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we examined resistance to the anticoagulant effects of annexin A5, using the annexin A5 resistance (A5R) assay, and evaluated for anti-DI IgG antibodies. Children with SLE had higher frequency of anti-D1 antibodies (p = 0.014) and significantly reduced A5R compared to pediatric controls: mean A5R = 172 ± 30% versus 242 ± 32% (p < 0.0001). Children with SLE and positive anti-DI antibodies had significantly lower mean A5R levels compared to those with negative anti-DI antibodies: mean A5R = 155 ± 24% versus 177 ± 30% (p < 0.0001). In multivariate analysis, anti-DI antibodies (p = 0.013) and lupus anticoagulant (LA) (p = 0.036) were both independently associated with reduced A5R. Children with SLE have significantly reduced annexin A5 anticoagulant activity that is associated with the presence of LA and anti-DI antibodies.

Antiphospholipid antibodies in children with systemic lupus erythematosus: a long-term clinical and laboratory follow-up status study from northwest India

We have previously shown that children with pediatric systemic lupus erythematosus (pSLE) have high incidence of anti-phospholipid antibodies (APLA) and reports suggest that presence of APLA can modify disease expression. While the frequency of APLA has been studied previously in adults with SLE, there is paucity of literature in children especially with regard to long-term follow-up. In the earlier study, we analyzed 27 pSLE patients for the prevalence of APLA; in the present study, we further reviewed the APLA status and its relation with clinical outcome of this cohort of patients over a further 7 year follow-up period. Out of the initial cohort of 27 patients, follow-up APLA testing was available in 21 patients who were tested for APLA at least once during this time. Seven (33.3 %) of these 21 patients were never positive for any of the APLA; 1 (4.8 %) was persistently positive; and 13 (61.9 %) were positive for APLA intermittently or at least once. Overall, APLA positivity for IgG, IgM anticardiolipin antibodies (ACA) and lupus anticoagulant (LA) was comparable, with positivity seen in 10 (47.6 %), 9 (42.9 %) and 9 (42.9 %) cases, respectively. Anti-β2 GP1 antibodies were tested in 11 patients on follow-up, of which 3 (27.3 %) showed positivity. In all, 10 (47.6 %) patients showed positivity for more than 1 APLA. Two (9.5 %) patients showed varying degrees of positivity for LA, ACA, and anti-β2 GP1 antibodies at different times, thereby showing the importance of checking for all APLAs at each time of testing. Out of these 21 patients, 3 (14.3 %) patients had thrombosis, and all 3 patients were positive for APLA. There were 2 (9.5 %) fatalities-both of these had thrombosis and were positive for APLA. Our study shows that pSLE patients on treatment frequently test positive for APLA. Thrombosis was infrequent in this cohort. However, when present it was associated with APLA positivity and high fatality in our experience. On the other hand, presence or persistence of these antibodies was not always associated with thrombosis. Our study suggests that pSLE children should be tested routinely for APLA, as this would identify patients with an increased risk of thrombotic complications. However, the frequency of repeat testing for APLA in those who test negative initially needs to be determined on a case-to-case basis.

Venous thromboembolism in the paediatric patient

Venous thromboembolism is a concern in the paediatric population and its incidence seems to be increasing. Symptoms and signs may be subtle so a high degree of suspicion is needed. Paediatric patients represent a unique challenge in the provision of anticoagulation due to their unique physiology.

Laboratory testing in pediatric rheumatology

In children, laboratory evaluations can assist in the screening of patients for inflammatory disorders, confirm diagnoses, allow for monitoring of disease activity and response to therapy, and suggest prognoses and risk of morbidities associated with rheumatic diseases. This review provides an overview of the usefulness and interpretation of both the commonly ordered tests ordered by the general pediatrician as well as those frequently used in the pediatric rheumatology clinic for diagnosis and disease monitoring. Studies discussed include the complete blood count, acute phase reactants, autoantibodies, serum complement, urinalysis, streptococcal antibody tests, and commonly used genetic studies.

Prevalence of annexin A5 resistance in children and adolescents with rheumatic diseases

OBJECTIVE

The underlying mechanism(s) by which antiphospholipid antibodies (aPL) result in thrombosis remains poorly understood. A significant body of evidence has evolved to support the hypothesis that antibody-mediated disruption of an annexin A5 anticoagulant shield may play a role in the pathogenesis; this proposed mechanism has not been previously studied in children.

METHODS

We investigated the association between aPL and resistance to annexin A5 anticoagulant activity in 90 children with a variety of rheumatic diseases using a novel mechanistic assay, the annexin A5 resistance assay (A5R).

RESULTS

Patients with a diagnosis of primary aPL syndrome, systemic lupus erythematosus, and mixed connective tissue disease demonstrated lower mean A5R levels (p = 0.030), higher prevalence of positive aPL (p < 0.001), and more thrombotic events (p = 0.014) compared to those with other diagnoses. Patients with persistently positive aPL had significantly lower mean A5R compared to patients with no aPL (mean A5R = 203% ± 44% vs 247% ± 35%; p < 0.001), whereas patients with transient aPL did not. Patients with thrombosis had lower A5R levels compared to those without thrombosis (mean A5R = 207% ± 36% vs 237% ± 46%; p = 0.048).

CONCLUSION

Children and adolescents with rheumatic diseases and persistent aPL have reduced annexin A5 anticoagulant activity, whereas transient, nonpathogenic aPL have less effect on annexin A5 activity.

Pediatric lupus--are there differences in presentation, genetics, response to therapy, and damage accrual compared with adult lupus?

Some complement deficiencies predispose to systemic lupus erythematosus (SLE) early in life. Currently, there are no known unique physiologic or genetic pathways that can explain the variability in disease phenotypes. Children present with more acute illness and have more frequent renal, hematologic, and central nervous system involvement compared to adults with SLE. Almost all children require corticosteroids during the course of their disease; many are treated with immunosuppressive drugs. Mortality rates remain higher with pediatric SLE. Children and adolescents accrue more damage, especially in the renal, ocular and musculoskeletal organ systems. Conversely, cardiovascular mortality is more prevalent in adults with SLE.

Venous thrombosis in children

The advances in pediatric tertiary care have resulted in a decrease in the mortality of children with serious underlying conditions. Consequently, there has been an increase in previously rare complications of therapy in children, including venous thrombosis. Although there is a paucity of properly designed trials in the field of pediatric thrombosis, many advances have been made over the past 15 years. Venous thrombosis in children has been the subject of many reviews. This review is an update of the available evidence in the management of venous thrombosis in children, excluding thrombosis of the CNS.

Venous thromboembolism in children

With improved pediatric survival from serious underlying illnesses, greater use of invasive vascular procedures and devices, and a growing awareness that vascular events occur among the young, venous thromboembolism (VTE) increasingly is recognized as a critical pediatric concern. This review provides background on etiology and epidemiology in this disorder, followed by an in-depth discussion of approaches to the clinical characterization, diagnostic evaluation, and management of pediatric VTE. Prognostic indicators and long-term outcomes are considered, with emphasis on available evidence underlying current knowledge and key questions for further investigation.

Antiphospholipid antibodies in pediatric systemic lupus erythematosus and the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is recognized increasingly as the most common acquired hypercoagulation state of autoimmune etiology and may occur as an isolated clinical entity (primary APS) or in association with an underlying systemic disease, particularly systemic lupus erythematosus (SLE). The major differences between pediatric and adult APS include absence of common acquired risk factors for thrombosis, absence of pregnancy-related morbidity, increased incidence of infection-induced antibodies, differences in cut-off values for determination of aPL and specific factors regarding long-term therapy in children. APS in children has been largely reported in patients with arterial or venous thromboses and less frequently in association with neurological or hematological manifestations. The presence of aPL in pediatric SLE can modify the disease expression and may be an important predictor of the development of irreversible organ damage. Two recently established international registries of neonates and children with APS provide a good opportunity to conduct large, prospective studies on the clinical significance of aPL and long-term outcome of pediatric APS.

Antiphospholipid syndrome in pediatrics

APS is recognized increasingly as a leading cause of vascular thrombosis in the pediatric population. With the obvious exception of pregnancy morbidity, most of the clinical features that may occur in adults with APS have been described also in children. Because the coincident prothrombotic factors that are common in adults have little or no impact in children, pediatric patients with APS constitute a suitable sample to investigate the relationship of aPL with the associated clinical manifestations, such as thrombocytopenia, hemolytic anemia, chorea, and livedo reticularis, and the specificities of aPL that are more linked to thrombosis. On the other hand, because of the high frequency of infectious processes in early life, children may have a greater prevalence of nonpathogenic and transient aPL. For these reasons, the diagnostic and therapeutic approach to APS in childhood may be different from that for adults. Because of the rarity of aPL-related thrombosis in children, the natural history and optimal management can be defined only through large, multicenter, controlled studies. A internet-based registry for pediatric patients with APS (Ped-APS Register) has been recently established as part of the activities of the Euro-aPL Forum and the Lupus Working Group of the Pediatric Rheumatology European Society. This registry is aimed to obtain information on APS in childhood, particularly regarding association of aPL with clinical manifestations, specificity of aPL, impact of treatment and long-term outcome (http://www.med.ub.es/MIMMUN/FORUM/PEDIATRIC.HTM).

Pediatric antiphospholipid syndrome

APS is rare in the pediatric age, but it represents an interesting phenomenon because most of the known "second hit" risk factors such as atherosclerosis, smoking, hypertension, contraceptive hormonal treatment, and pregnancy are not present in childhood. This could also be the reason for the prevalence of some clinical manifestations rather than others in PAPS. On the other hand, the increased frequency of infectious processes in the childhood age is likely responsible for the relatively high prevalence of non-pathogenic and transient aPL. Such points raise the problem of a different diagnosis or monitoring approach in pediatric APS. Of particular interest is the special entity of neonatal APS, which represents an in vivo model of acquired autoimmune disease, in which transplacentally acquired aPL cause thrombosis in the newborn. International registries for pediatric and neonatal APS are currently in place; epidemiologic, clinical, and laboratory re-search will help to shed light on all the still obscure aspects of this fascinating but rare disorder in the very young. Finally, treatment is less aggressive overall in pediatric APS, given the reluctance to anticoagulate children over the long term. Studies on the outcome of pediatric APS and the relative risks of prolonged anticoagulation in children are necessary to determine the type and duration of anticoagulation therapy.

Iliofemoral Deep Vein Thrombosis in Childhood; Developing a Management Protocol

OBJECTIVE

To develop an evidence-based protocol for the management of iliofemoral deep vein thrombosis (IDVT) in childhood.

METHODS

A search of the literature was undertaken. All publications pertaining to IDVT in childhood were analysed and then categorised according to their level of evidence. Recommendations were then made on the basis of this.

RESULTS

The commonest presenting symptoms were pain and swelling in the affected limb (evidence level II). Predisposing risk factors of special significance in children included the recent use of a venous access device, malignancy, prothrombotic disorders, infection, surgery and congenital venous anomalies (evidence level II). The most frequently described imaging modalities were B-mode ultrasonography, duplex, venography, and helical CT (evidence level III). The mainstay of treatment was anticoagulation with LMWH alone or followed by warfarin (evidence level I). Early clot removal through catheter-directed thrombolysis or surgical thrombectomy has been shown to be beneficial (evidence level II/III). There is little evidence for the benefit of early mobilisation and compression therapy in childhood.

CONCLUSION

Level I evidence relating to IDVT in childhood is sparse. The possibility of IDVT should be considered when examining a child with a swollen and painful limb. Imaging should be with duplex ultrasound, followed by spiral CT to include assessment of the IVC. A thrombophilia screen should be taken prior to anticoagulation with LMWH (and warfarin). Thrombolysis should be considered in cases of extensive IDVT.

Thrombophilia in children with venous thromboembolic disease

Venous thromboembolic events (VTEs) in children are usually associated with underlying clinical conditions such as central venous line, cancer and cardiac diseases. The objective of this review is to present the importance of thrombophilia to the occurrence of childhood VTE. The reported prevalence of thrombophilia in children with VTE varies extremely between 10% and 78% in different registries. The variation in the reported prevalence most probably reflects differences in the clinical characteristics of the children studied and differences in study designs. The initial management of children with thrombophilia and VTE is similar to those individuals who do not have a specific inherited thrombophilic risk factor, except in the rare events of homozygous deficiencies of prothrombotic coagulation proteins. The impact of thrombophilic markers on long-term therapy and outcome of children with VTE has not been completely clarified. According to the current guidelines for thrombophilia, all children with VTE should be tested for a full panel of genetic and acquired prothrombotic traits. However, re-evaluation of co-morbid risk factors other than thrombophilic markers and careful consideration of the prognostic value of thrombophilic markers might help to change future attitude from the rigidity of current guidelines to more rational schemes.

Predictive value of persistent versus transient antiphospholipid antibody subtypes for the risk of thrombotic events in pediatric patients with systemic lupus erythematosus

Study objectives were to determine, in children with systemic lupus erythematosus (SLE), (1) the association of antiphosholipid antibody (APLA) subtypes with thrombotic events (TEs) and (2) the predictive value of persistent versus transient antibodies for TEs. This is a cohort study of 58 SLE children in whom lupus anticoagulants (LAs), anticardiolipin antibodies (ACLAs), anti–β2-glycoprotein-I (anti–β2-GPI), and antiprothrombin (anti-PT) were assessed on at least 2 occasions (more than 3 months apart). Antibodies were classified as persistent (positive on at least 2 occasions) or transient (positive once). Outcomes were symptomatic TEs confirmed by objective radiographic tests identified retrospectively and prospectively. Seven of the 58 patients (12%) had 10 TEs; 5 patients had TEs during prospective follow-up. Persistent LAs showed the strongest association with TEs (P < .001). Persistent ACLAs (P = .003) and anti–β2-GPI (P = .002) were significantly associated with TEs; anti-PT (P = .063) showed a trend. Persistent or transient LAs and anti–β2-GPI showed similar strength of association, while ACLAs and anti-PT were no longer associated with TEs. Positivity for multiple APLA subtypes showed stronger associations with TEs than for individual APLA subtypes because of improved specificity. Lupus anticoagulant is the strongest predictor of the risk of TEs; other APLA subtypes provide no additional diagnostic value. Anticardiolipin antibodies and anti-PT require serial testing because only persistent antibodies are associated with TEs.

Systemic lupus erythematosus

Systemic lupus erythematosus in children and adolescents is a multisystem autoimmune disease with a great variability in disease presentation and course. This article summarizes available epidemiologic data, clinical patterns, approaches to investigation and treatment, and recent outcome data.

Antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by a combination of arterial or venous thrombosis and recurrent fetal loss, accompanied by elevated titers of antiphospholipid antibodies (aPL). APS has been recognized as the leading cause of vascular thrombosis in children. The diagnostic and therapeutic approach to APS in childhood may be different from that for adults and because of the rarity of aPL-related thrombosis in children, the natural history and optimal management of APS can be defined only through large, multicenter, controlled studies.

Pulmonary thromboembolism in children

Pulmonary thromboembolism (PTE) is uncommonly diagnosed in the pediatric patient, and indeed often only discovered on autopsy. The incidence of pediatric PTE depends upon the associated underlying disease, diagnostic tests used, and index of suspicion. Multiple risk factors can be found including: peripartum asphyxia, dyspnea, haemoptysis, chest pain, dehydration, septicemia, central venous lines (CVLs), trauma, surgery, ongoing hemolysis, vascular lesions, malignancy, renal disease, foreign bodies or, uncommonly, intracranial venous sinus thrombosis, burns, or nonbacterial thrombotic endocarditis. Other types of embolism can occur uncommonly in childhood and need to be recognized, as the required treatment will vary. These include pulmonary cytolytic thrombi, foreign bodies, tumor and septic emboli, and post-traumatic fat emboli. No single noninvasive test for pulmonary embolism is both sensitive and specific. A combination of diagnostic procedures must be used to identify suspect or confirmed cases of PTE. This article reviews the risk factors, clinical presentation and treatment of pulmonary embolism in children. It also highlights the current diagnostic tools and protocols used to evaluate pulmonary embolism in pediatric patients.

Thromboembolism in paediatric lupus patients

Paediatric patients with systemic lupus erythematosus (SLE) and antiphospholipid antibodies (aPL), specifically lupus anticoagulants (LAC) are at high risk of developing thromboembolic events (TE). Our objectives were to determine the prevalence of TE in paediatric SLE patients with LAC and to determine if anticoagulation was effective to decrease morbidity, and prevent recurrent TE. We reviewed data on 149 paediatric SLE patients treated over 10 years. In all, 24 patients (16%) were LAC positive, and 21 TE occurred in 13 of these LAC positive patients (54% incidence of TE in LAC positive patients). The events were cerebral venous thrombosis (9), arterial stroke (3), deep venous thrombosis (4), pulmonary embolism (2), other venous event (1) and other arterial events (2). The median duration between SLE diagnosis and first TE was 15.2 months (range 0-62), and the median age at first TE was 15.1 years (range 11.4-18.4). Long-term anticoagulation was prescribed, and eight patients (62%) were transferred to adult care on lifelong oral warfarin; four (31%) remain under our care on lifelong warfarin, and one patient died of causes unrelated to her TE. No patient has been identified with deficiencies of protein C, protein S or antithrombin III. One patient is heterozygous for Factor V Leiden, and one is heterozygous for both the Prothrombin 20210A mutation and the MTHFR (methylene tetrahydrofolate reductase) mutation. Four patients had recurrent TE (31%), and three were not anticoagulated at the time of their second event. One patient had two recurrences on therapeutic anticoagulation. Thromboembolic events are prevalent in the LAC positive paediatric SLE population, and consideration for lifelong anticoagulation must occur after an initial TE.

Morbidity of lupus anticoagulants in children: a single institution experience

INTRODUCTION

The lupus anticoagulant (LA) and the anticardiolipin antibodies (ACA) are the antiphospholipid antibodies more relevant clinically. Their clinical manifestations are diverse with most patients being asymptomatic while others present venous or arterial thrombosis, and more rarely, bleeding. Our objectives were to evaluate clinical presentation of LA in children and to correlate it to LA behavior.

PATIENTS AND METHODS

A retrospective cohort of patients (under 18 years old) who had a positive determination of LA followed by at least another determination of LA at a variable period was evaluated. Personal and family history, including infectious diseases temporally related to the event, were recorded. The screening of other coagulation disorders was performed according to symptoms, family history or laboratory results.

RESULTS

Thirty-six patients were evaluated, median age was 10.8 years old, and 52.8% were female. Asymptomatic patients were 19.4% (7/36) of study population. Bleeding and thrombosis were found in 52.8% and 27.8%, respectively. Median LA determinations per patient were 3. von Willebrand disease was diagnosed in 66.7% of patients consulting for bleeding. A concomitant hemostatic defect was found in 8/10 patients with thrombosis (p = 0.003). LA behavior was not uniform and not correlated to symptoms.

CONCLUSIONS

Most LA found in children is incidental and asymptomatic. In children with bleeding, LA might be a fortuitous finding associated with VWD. The persistence of LA does not imply a higher risk of thrombosis.

Thrombocytopenia and thromboembolism in pediatric systemic lupus erythematosus

To define in children with systemic lupus erythematosus (SLE) the incidence, outcome, and association of thrombocytopenia with other SLE manifestations, specifically thromboembolic events (TEs), we retrospectively reviewed 106 pediatric patients with SLE diagnosed between 1992 and 2001. Thrombocytopenia was found in 50%, which was of a moderate or severe degree in 34%. The thrombocytopenia was sustained in 29% of all patients. Twelve patients were diagnosed with autoimmune thrombocytopenic purpura 2 to 69 months before the diagnosis of SLE. Of them, 10 children required treatment, and three patients underwent splenectomy. TEs occurred in 10.4% of the total cohort of 106. Lupus anticoagulant, but not anticardiolipin antibodies and sustained thrombocytopenia, were associated with a higher risk for TEs.

Venous thrombosis in children

Venous thromboembolic (VTE) events are being increasingly diagnosed in systemic and cerebral vessels in children. Systemic VTE are increasing in children as a result of therapeutic advances and improved clinical acumen in primary illnesses that previously caused mortality. The epidemiology of systemic VTE has been studied in international registries. In children older than 3 months, teenagers are the largest group developing VTE. The most common etiologic factor is the presence of central venous lines. Clinical studies have determined the most sensitive diagnostic method for diagnosing upper system VTE are ultrasound for jugular venous thrombosis and venography for intrathoracic vessels. However, the most sensitive diagnostic methods for lower system VTE and pulmonary embolism (PE) have not been established. Treatment studies for VTE consist of inadequately powered randomized controlled trials or prospective cohort studies. The long-term outcome of systemic VTE, post-thrombotic syndrome, has been reported in children. Cerebral sinovenous thrombosis (CSVT) is becoming increasingly diagnosed in children due to the recognition of the associated subtle clinical symptoms and improved cerebrovascular imaging. The etiology of CSVT includes thrombophilia, head and neck infections, and systemic illness. Estimates of the incidence and outcome of childhood CSVT have recently become available through the Canadian Pediatric Ischaemic Stroke Registry. Clinical studies have not yet been carried out in children to determine the best method of diagnosis or treatment. There have only been case-series studies carried out in the treatment of CSVT. Properly designed clinical trials are urgently required in children with systemic VTE/PE and CSVT to define the best methods of diagnosis, treatment and long-term management.

Thromboembolic diseases of childhood

Over the last decade, pediatric thrombophilia programs have emerged around the world as a new discipline in pediatric hematology. These programs specialize in the diagnosis, prevention and treatment of children with thromboembolic events (TEs) in both the venous and arterial systems. The need for separate pediatric programs has been discussed previously. (J Pediatr Hematol Oncol 1997; 19: 7-22.) The following article will update previous reviews (Hematol Oncol Clin North Am 1998; 12: 1283-1312; Thromb Haemost 1997; 78: 715-725) and will concentrate on three aspects: (1) The risk factors for acquiring TEs; (2) The confirmatory diagnostic tests used in children with TEs; and (3) The different antithrombotic agents used for prevention and treatment. The current knowledge in respect to the above points is only the "tip of the iceberg". Well-designed prospective trials are required to establish the contribution of congenital prothrombotic disorders, appropriate diagnostic strategies, and optimal therapy for children with TEs.

[Childhood-onset systemic lupus erythematosus]

Systemic Lupus Erythematosus (SLE) remains a challenging autoimmune disease in term of etiology, pathogenesis and treatment. It is estimated that 10-17% of lupus patients present before the age of 16. SLE in children appears to have more severe organ involvement than in adults. The outcome of childhood SLE has improved during the last decade, but the morbidity remains high.

A prospective cohort study determining the prevalence of thrombotic events in children with acute lymphoblastic leukemia and a central venous line who are treated with L-asparaginase: results of the Prophylactic Antithrombin Replacement in Kids with Acute Lymphoblastic Leukemia Treated with Asparaginase (PARKAA) Study

BACKGROUND

Thrombotic events (TEs) are serious secondary complications in children with acute lymphoblastic leukemia (ALL) who receive L-asparaginase (ASP) therapy; however, the prevalence of TEs has not been established. The primary objective of the Prophylactic Antithrombin Replacement in Kids with Acute Lymphoblastic Leukemia Treated with Asparaginase (PARKAA) Study was to determine the prevalence of TEs. The secondary objective was to detect any association of TEs with the presence of congenital or acquired prothrombotic disorders.

METHODS

Children with ALL were screened for TEs at the end of ASP treatment using bilateral venograms, ultrasound, magnetic resonance imaging, and echocardiography. Symptomatic TEs were confirmed by appropriate radiographic tests. All tests were read by a blinded central adjudication committee.

RESULTS

Twenty-two of 60 children had TEs, a prevalence of 36.7% (95% confidence interval, 24.4-48.8%). TEs were located in the sinovenous system of the brain in 1 patient, the right atrium in 3 patients, and the upper central venous system in 19 patients. TEs detected by venography resulted in 1) 25-100% occlusion, with 1 in 3 patients showing occlusion of > 75% of the greatest vessel dimension, and 2) the presence of collaterals in 60% of patients, with 40% categorized as major. No children with TEs were positive for factor V Leiden or prothrombin gene 20201A, and four of eight children with antiphospholipid antibodies had a TE.

CONCLUSIONS

The prevalence of TEs is exceedingly high in this population, and it is likely that the extent of occlusion is likely clinically significant. No trend was seen toward an association between TEs and the presence of congenital prothrombotic disorders. A trend was seen toward an association between TEs and antiphospholipid antibodies. Carefully designed clinical trials of primary prophylaxis for the prevention of TEs are required in this patient population.

Anti-beta2-glycoprotein I antibodies in pediatric systemic lupus erythematosus and antiphospholipid syndrome

OBJECTIVE

To determine whether serum beta2-glycoprotein I antibody (anti-beta2GPI) detection improves identification of pediatric subjects at risk for antiphospholipid syndrome (APS).

METHODS

Serum antiphospholipid antibodies (aPL) were identified by anticardiolipin enzyme-linked immunosorbent assay (ELISA), lupus anticoagulant assays, and syphilis screening in children with primary APS, systemic lupus erythematosus (SLE), or SLE plus APS. Anti-beta2GPI level and isotype were determined by beta2GPI ELISA and correlated with clinical manifestations and other aPL assays.

RESULTS

One hundred-ten subjects under 22 years of age and of mixed ethnicity were evaluated. Fifty-seven had SLE (including 14 with APS), 25 had primary APS, 16 had SLE-like APS, 6 were healthy children with aPL detected incidentally, 4 had other rheumatic diseases and 2 had other conditions. Anti-beta2GPI were detected in 48% of SLE subjects and did not improve aPL detection over standard tests. Anti-beta2GPI were associated with stroke (P = 0.014), but not with other APS manifestations, and were rarely detected in primary APS. Among subjects with APS manifesting as chronic thrombocytopenia, anti-beta(2)GPI distinguished subjects with SLE from those with primary APS.

CONCLUSIONS

With the exception of stroke, anti-beta2GPI detection does not improve identification of pediatric APS over that of traditional aPL assays. Anti-beta2GPI are rare in pediatric primary APS, but may predict evolution of chronic thrombocytopenia to SLE.

Accidental detection of lupus anticoagulants in children

During routine pre-operative evaluation, a 6-month-old infant and an 11-year-old girl were found to have prolonged activated partial thromboplastin time with positive lupus anticoagulants. Both children underwent successful cardiac surgery and had no thrombotic or bleeding complications. A literature search revealed that positive lupus anticoagulants can follow minor infections in otherwise asymptomatic children and are benign and self-limiting. A minority, however, can develop bleeding, thrombosis or an auto-immune disorder.

Systemic lupus erythematosus and antiphospholipid syndrome in children and adolescents

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) can be associated with significant morbidity in children and adolescents. Renal involvement in SLE appears to be more severe and more frequent in the pediatric age group, with the major predictors for poor outcome being the severity of histopathologic lesions, severity of renal impairment at diagnosis, and hypertension. In addition to currently recognized cardiovascular and pulmonary involvement, accelerated atherosclerosis is of increasing concern in young individuals with SLE, because of both disease effects and medication usage. Neuropsychiatric SLE seen in childhood ranges from subtle cognitive dysfunction to severe central nervous system involvement; however, there is controversy over the value of different diagnostic studies. APS in children may be associated with SLE, idiopathic, or associated with viral infections. Systemic anticoagulation is recommended for patients with thrombotic events, but long-term management has not been well studied in children.

Thrombosis in the intensive care unit: etiology, diagnosis, management, and prevention in adults and children

Venous thromboembolism, a well-recognized complication in postoperative patients, is emerging as a frequent complication in critically ill patients in intensive care units. Diagnosis can be particularly difficult in such patients because underlying systemic illnesses may mask common presenting signs and symptoms. Although numerous independent risk factors have been identified, the critical role of both central venous catheters and prothrombotic disorders as significant risk factors is a common theme in the pediatric and adult literature. Various diagnostic tests exist, with venography remaining the gold standard and newer, less invasive methods such as ultrasonography and impedance plethysmography becoming increasingly popular. Standard unfractionated heparin remains the mainstay of therapy and prophylaxis, although the use of low molecular weight heparins is becoming more commonplace. Thrombolytic therapy continues to be reserved for severe, life-threatening, acute thrombosis. In this article, we review the common risk factors, diagnostic modalities, and treatment options for venous thromboembolism in critically ill adult and pediatric patients.

Acquired activated protein C resistance is associated with lupus anticoagulants and thrombotic events in pediatric patients with systemic lupus erythematosus

Acquired activated protein C resistance (APCR) has been hypothesized as a possible mechanism by which antiphospholipid antibodies (APLAs) cause thrombotic events (TEs). However, available evidence for an association of acquired APCR with APLAs is limited. More importantly, an association of acquired APCR with TEs has not been demonstrated. The objective of the study was to determine, in pediatric patients with systemic lupus erythematosus (SLE), whether (1) acquired APCR is associated with the presence of APLAs, (2) APCR is associated with TEs, and (3) there is an interaction between APCR and APLAs in association with TEs. A cross-sectional cohort study of 59 consecutive, nonselected children with SLE was conducted. Primary clinical outcomes were symptomatic TEs, confirmed by objective radiographic tests. Laboratory testing included lupus anticoagulants (LAs), anticardiolipin antibodies (ACLAs), APC ratio, protein S, protein C, and factor V Leiden. The results revealed that TEs occurred in 10 (17%) of 59 patients. Acquired APCR was present in 18 (31%) of 58 patients. Acquired APCR was significantly associated with the presence of LAs but not ACLAs. Acquired APCR was also significantly associated with TEs. There was significant interaction between APCR and LAs in the association with TEs. Presence of both APCR and LAs was associated with the highest risk of a TE. Protein S and protein C concentrations were not associated with the presence of APLAs, APCR, or TEs. Presence of acquired APCR is a marker identifying LA-positive patients at high risk of TEs. Acquired APCR may reflect interference of LAs with the protein C pathway that may represent a mechanism of LA-associated TEs. (Blood. 2001;97:844-849)