Thromboembolism in paediatric lupus patients

Long-term treatment of thrombosis with enoxaparin in pediatric and adolescent patients

Thrombosis is a rare event in childhood and adolescence. Nevertheless, increasing numbers of invasive diagnostic and therapeutic procedures also result in increasing numbers of thromboses in pediatric cases, necessitating effective antithrombotic treatment regimens. In recent years, low-molecular-weight heparins (LMWH) in particular have been proved to be a safe and effective alternative to unfractioned heparins. However, the application of LMWH in pediatric patients has not been supported by a single controlled study so far. Furthermore, there is no official approval of these drugs for children. In this pilot study 27 children with deep venous thromboses (DVT) were treated with the LMWH enoxaparin at a dosage of 1.5 mg/kg body weight b.i.d. in neonates and infants and 1 mg/kg body weight b.i.d. in children. This dosage was lowered for prophylaxis if therapeutic success was achieved. The aim of the study was to investigate both, efficacy with respect to patency rates and safety during acute and long-term follow-up. Sufficient therapeutic success required a rapid production of anti-Xa target activity and was reached in 85% of the treated patients, who showed patency of the affected vessel at last follow-up. The mean duration of treatment with full dosage was 16.5 days, followed by prophylaxis over a mean duration of 9.8 months. Rethrombosis or adverse events including heparin-induced thrombocytopenia were not observed in any patient. In conclusion, enoxaparin provides an effective and safe alternative to unfractioned heparins in the treatment of thrombosis in infancy, childhood and adolescence.

Acute pulmonary embolism in childhood

Pulmonary embolism is an uncommon, but potentially fatal disease in children. Most children with pulmonary embolism have underlying clinical conditions, of which the presence of a central venous catheter is the most frequent. The clinical presentation is often subtle, or masked by the underlying clinical condition. Diagnostic as well as therapeutic strategies for pulmonary embolism in children are mostly extrapolated from studies in adults. Pulmonary angiography is still the gold standard in diagnosing pulmonary embolism, but several other radiographic tests can be used to diagnose pulmonary embolism, including ventilation-perfusion lung scanning, helical computed tomography, magnetic resonance imaging and echocardiography. The choice of treatment depends on the clinical presentation of the patient. Anticoagulation is the mainstay of therapy for children with pulmonary embolism. However, thrombolytic therapy can be considered for patients with hemodynamic instability. The outcome of pediatric pulmonary embolism is uncertain and needs to be studied.

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.

Lupus eritematoso sistémico pediátrico

Pediatric systemic lupus erythematosus (pSLE) is a chronic mutisystemic autoimmune disease with complex clinical manifestations. Although the presentation, clinical manifestations, immunological findings and treatment issues of pSLE are similar to those of adult SLE patients, there are special issues which need to be considered when dealing with SLE in children. During the last decade survival has improved remarkably as a result of earlier diagnosis, recognition of milder disease and better approaches to therapy. However, pSLE remains a potentially serious condition. Although the pathogenesis of SLE remains poorly understood, susceptibility involves a combination of environmental, hormonal and genetic factors. Better understanding of SLE pathogenesis will hopefully lead to more specific and less toxic therapies for this disease.

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.

Incidence and risk factors of thromboembolism in systemic lupus erythematosus: A comparison of three ethnic groups

OBJECTIVE

To compare the incidence and risk factors for thromboembolic events in systemic lupus erythematosus (SLE) patients of different ethnic backgrounds.

METHODS

SLE patients who were newly diagnosed or were referred within 6 months of diagnosis between 1996 and 2002 were prospectively followed up for the occurrence of thromboembolic events. Cumulative hazard and risk factors for thromboembolism were evaluated and compared among patients of different ethnic origins.

RESULTS

We studied 625 patients who fulfilled the American College of Rheumatology criteria for SLE (89% women): 258 Chinese, 140 African Americans, and 227 Caucasians. The mean +/- SD age at SLE diagnosis was 35.7 +/- 14 years. After a followup of 3,094 patient-years, 48 arterial events and 40 venous events occurred in 83 patients. The overall incidence of arterial and venous thromboembolism was 16/1,000 patient-years and 13/1,000 patient-years, respectively. The cumulative hazard of arterial events at 60 months after the diagnosis of SLE was 8.5%, 8.1%, and 5.1% for the Chinese, African Americans, and Caucasians, respectively. The corresponding cumulative risk of venous events was 3.7%, 6.6%, and 10.3%, respectively (P = 0.008 for Chinese versus Caucasians, by log rank test). Smoking, obesity, antiphospholipid antibodies, and use of antimalarial agents and exogenous estrogens were less frequent in the Chinese patients. In Cox regression models, low levels of high-density lipoprotein (HDL) cholesterol, Chinese ethnicity, oral ulcers, and serositis predicted arterial events, whereas male sex, low levels of HDL cholesterol, antiphospholipid antibodies, non-Chinese ethnicity, obesity, renal disease, and hemolytic anemia predicted venous events.

CONCLUSION

There are ethnic differences in the incidence of arterial and venous thromboembolism in patients with SLE that cannot be fully explained by the clinical factors studied. Further evaluation of other genetic and immunologic factors is warranted.

Update on pediatric systemic lupus erythematosus

PURPOSE OF REVIEW

The purpose of this review is to provide an update on the clinical manifestations of SLE in children. Emerging clues on the pathogenesis of the disease based on recent human studies conducted both in children and adults, will also be summarized.

RECENT FINDINGS

Pediatric Rheumatologists caring for children with SLE face many challenges. As the life expectancy of these patients improves, new recognized complications such as accelerated atherosclerosis and hypertension emerge as major causes of morbidity. However, few longitudinal studies describing the long term outcome of these children, including the impact of disease and treatment on their physical and psychological development are available. Few prospective interventional studies have been carried out to assess the efficacy of established and novel treatments in the pediatric population. Recently, basic studies aimed at understanding the immune alterations underlying this disease have been performed in children. These studies indicate an important role for interferon-alpha (IFN-alpha) in the pathogenesis of this disease and reveal an overall striking homogeneity of leukocyte gene expression profiles in children and adults with SLE. The contribution of novel gene polymorphisms to disease susceptibility and the sequential breakdown of tolerance to nuclear antigens that precedes clinical manifestations in patients with SLE are among the recent studies that are helping us understand the complex SLE puzzle.

SUMMARY

SLE continues to cause significant morbidity in the pediatric age group. A better recognition of the age-specific manifestations and long-term complications of this disease is required to improve its outcome. Understanding its unique pathogenesis will hopefully lead to the development of better, more targeted and less toxic therapies.

Are phospholipid-binding antibodies implicated in the pathogenesis of diabetic microangiopathy?

Diabetic retinopathy (DR) is a major cause of blindness in the working population of the Western world and there is no doubt that its prevalence is strongly related to the duration of diabetes and the glycemic control. However, although intensive diabetes management, with the goal of achieving near-normal glycemia, has been shown to prevent and/or delay the onset of DR, there is now ample of evidence that the development of this microangiopathy is a multifactorial process in which genetic, metabolic, haemostatic and growth factors play an important role. Moreover, given the suggestions that immunological mechanisms might have a role in the pathogenesis of diabetic microangiopathy via immune complex deposition, it has been hypothesized that antiphospholipid antibodies (A-Ab) directed against endothelial antigens could be responsible for initiating vascular injury. In particular, not only A-Ab production was found to be increased in patients with overt nephropathy or macroangiopathy but also Lupus Anticoagulant positivity, representing an intersection point between immune and haemostatic alterations, has been highlighted as a potential and additional risk factor in the pathogenesis of microangiopathy in type 1 diabetics. Moreover, given the high levels of activated protein C, endothelin-1 and thrombo-modulin that have been observed in normo-albuminuric and uncomplicated patients, it has been concluded that the vascular endothelium shifts pathologically from an antithrombotic to a prothrombotic state even in the early phases of the disease. This condition was found to be more pronounced in subjects with anticardiolipin positivity and/or high circulating immune complexes concentrations, since they possess the ability not only to induce platelet activation and aggregation but also to activate the complement system via the classical pathway. Therefore, a potential synergism between generation of autoantibodies, haemostatic alterations and endothelial stress has been suggested, a stimulating hypothesis that needs further studies to be clarified in its complexity.