Acquired inhibitors of coagulation in nonhemophiliac children

Lupus Anticoagulant Positivity in Pediatric Patients With Prolonged Activated Partial Thromboplastin Time: A Single-Center Experience and Review of Literature

The presence of lupus anticoagulants (LAs) is an important cause of activated partial thromboplastin time (aPTT) prolongation found in children after an infection or during screening tests before surgical intervention. The authors retrospectively reviewed the charts of 68 patients who have been consulted from surgery departments with prolonged aPTT. These patients were reevaluated with aPTT analysis after 1 week. Thirteen patients had normal aPTTs. Therefore, 55 patients remained with prolonged aPTTs. LA positivity was detected in 39 patients. Sixteen of these had prolonged aPTT prior to surgery (41%). Others with LA positivity had systemic lupus erythematosus (SLE; n = 6), infection (n = 5), leukemia (n = 3), hemolytic uremic syndrome (n = 2), epistaxis (n = 2), antiphospholipid syndrome (APS; n = 1), chronic immune thrombocytopenic purpura (n = 1), acute poststreptococcal glomerulonephritis (n = 1), central nervous system (CNS) thrombosis (n = 1), and congenital heart disease (n = 1). None of the patients had bleeding history. LA positivity rarely leads to bleeding and/or thrombosis. Specific therapy is usually not needed. Further prospective multicenter studies are required to understand clinical outcomes and laboratory correlation in children with positive LA.

Lupus anticoagulants in two children--bleeding due to nonphospholipid-dependent antiprothrombin antibodies

We describe two children with significant bleeding: one with multiple ecchymoses and the other with scrotal bleeding. In both patients, the activated partial thromboplastin time (APTT) was prolonged, with positivity for lupus anticoagulants (LA). However, the Owren prothrombin time (PT), usually insensitive for LA, was also prolonged. The presence of LA is associated with diverse clinical manifestations, with most patients being asymptomatic while others present venous or arterial thrombosis. Bleeding in conjunction with LA is rare and it is unusual to see prolongation of the Owren PT assay due to LA. An extended laboratory investigation of one of the patient's plasma revealed not only LA but also a specific nonphospholipid-dependent antiprothrombin antibody causing an acquired hypoprothrombinemia.

CONCLUSION

It is likely that the low prothrombin activity and not the LA caused the bleeding. The bleeding signs and symptoms in both patients subsided when the PT was normalized, although the prolonged APTT and the LA remained.

Acquired hemophilia in pediatrics: a systematic review

Acquired hemophilia A is a rare but potentially life-threatening hemorrhagic disorder caused by the development of autoantibodies directed mostly against coagulation factor VIII. Acquired hemophilia is frequently associated with several underlying conditions such as malignancy, autoimmune disorders, drug reactions, and pregnancy, although the pathogenesis remains undetermined (idiopathic) in up to 50% of reported cases. The disorder occurs most commonly in the elderly and only rarely affects pediatric patients, who might however experience severe, and sometimes life-threatening, hemorrhage. The maternal transplacental transfer of the autoantibody to the neonate occurs very rarely and also in this circumstance it may be associated with clinically significant bleeding. The management of acute bleeding and the inhibitor eradication are the mainstay of the treatment. The outcome in pediatric patients seems more favorable than in adults because the inhibitors usually resolve more quickly and in a higher rate of patients. The epidemiology, diagnosis, clinical course, and management of this hemorrhagic disorder in children will be addressed in this systematic review.

Venous thrombosis and pulmonary embolism in a child with pneumonia due to Mycoplasma pneumoniae

A 13-year-old boy with Mycoplasma pneumoniae pulmonary infection developed deep vein thrombosis and pulmonary embolism. He was found to have protein S deficiency and transient antiphospholipid antibodies. Though uncommon, it is important to consider venous thromboembolic disease in children whose clinical course is atypically severe.

Antiphospholipid antibodies: laboratory and pathogenetic aspects

Antiphospholipid antibodies (aPL) constitute a heterogeneous group of autoantibodies that share the ability to bind phospholipids (PL) alone, protein-PL complexes, or PL-binding proteins. They have been detected in isolation, in association with autoimmune diseases such as systemic lupus erythematosus (SLE), and during the course of different infections. aPL have been associated with an array of clinical manifestations in virtually every organ, although deep vein and arterial thrombosis as well as pregnancy morbidity are predominant. The co-occurrence of these clinical findings with aPL constitutes the so-called antiphospholipid syndrome (APS). aPL can be detected by immunological methods [e.g., anticardiolipin antibodies (aCL)] or by functional methods that exploit the effect of aPL on blood coagulation [lupus anticoagulant (LA)]. Since aPL are heterogeneous, numerous immunological and coagulation assays have been developed. These assays have not been fully standardized, and, therefore, problems such as high interlaboratory variation are relatively frequent. Recently, recommendations have been published regarding LA and aCL testing. Not all aPL are pathogenic. However, when they are not associated with infections, they have a role in the pathogenesis of APS. Clinical and experimental data have shown that aPL exert their pathogenic activity by interfering with the function of coagulation factors, such as thrombin and factors X, XI and XII, and with the function of anticoagulant proteins of the protein C system. In addition, aPL interaction with platelets and endothelial cells induces a pro-adhesive activated phenotype.

Bruising: when it is spontaneous and not idiopathic thrombocytopenia purpura

Bruising is a presentation that often causes concern. There are many causes of bruising in children, including non-accidental injury, which must be excluded. We report a case of a 22-month-old boy where all the common diagnoses were excluded. We highlight the need to be aware of transient acquired inhibitors of coagulation that can cause spontaneous bleeding.

Transient lupus anticoagulant and prolonged activated partial thromboplastin time secondary to Epstein-Barr virus infection

We describe the case of a previously well 19-month-old boy who presented with an acute Epstein-Barr virus infection and a prolonged activated partial thromboplastin time (APTT) associated with the presence of a transient lupus anticoagulant (LA). The boy had an excellent outcome, with gradual normalization of the APTT and disappearance of the LA.

Acquired anti-FVIII inhibitors in children

Acquired inhibitors to FVIII (anti-FVIII) are uncommon in children. An acquired anti-FVIII developed in a previously healthy 4-year-old boy treated with penicillin for streptococcal pharyngitis. Aspirin prophylaxis begun for suspected rheumatic fever led to compartment syndromes of all four extremities, which resolved with high-dose FVIII and surgical decompression. Anti-FVIII in this patient, and the five additional cases identified in a survey of 160 haemophilia treatment centres, occurred at a median age of 8 years, with median initial and peak titres of 4.6 and 6.9 Bethesda Units (BU), respectively. All six presented with bleeding, including haematomas (three intramuscular, one intracranial), and ecchymoses in three. The median baseline FVIII was 0.05 U mL(-1), and the median baseline activated partial thromboplastin time (APTT) was 79.8 s. The inhibitor resolved completely in five patients (83%) within a median 5 months, after treatment with FVIII concentrate, steroids, cytoxan, methotrexate, and no treatment. The inhibitor persisted in the patient with Goodpasture's disease, despite steroids, cytoxan, cyclosporin, and intravenous gamma globulin. Aspirin therapy, in two, worsened ongoing bleeding. The association of penicillin-like drugs in this and three other cases in the literature suggest that to avoid potential catastrophic bleeding, it is prudent to obtain an APTT prior to initiating aspirin for suspected rheumatic fever. In conclusion, acquired anti-FVIII inhibitors in children may cause severe bleeding, and remit in the majority after FVIII and/or immunosuppressive therapy.

Clinical significance of lupus anticoagulants in children

OBJECTIVES

To determine the spectrum of associated clinical manifestations and time course of lupus anticoagulants (LA) in children.

STUDY DESIGN

Retrospective study of 95 consecutive children (46 boys and 47 girls), with a median age of 5.3 years (range, 1.7 to 17.1 years), diagnosed with presence of LA at a hemostasis referral center; 83 were followed up over a median of 2.9 years (range, 6 weeks to 21.6 years).

RESULTS

At diagnosis, 80 of 95 (84%) children were free of symptoms, and presence of LA was found incidentally. Nine children (10%) had bleeding symptoms, 5 (5%) had thrombotic events, and 1 had systemic lupus erythematosus. Among the patients with bleeding, 5 had transient severe hypoprothrombinemia after adenovirus infections, and 3 had thrombocytopenia. None of the children who were initially free of symptoms had bleeding, thrombotic complications, or autoimmune disease subsequently. At follow-up, 48 of 83 (58%) patients had normal activated partial thromboplastin time values after 1.9 years (5 weeks to 19.1 years). Thirty-two (38%) still had activated partial thromboplastin time elevations but did not fulfill all criteria for presence of LA after 3.2 years (7.4 months to 9.3 years). Three (4%) patients, who had presented with thrombosis, had persistent positive LA, anti-cardiolipin, and antinuclear antibodies after 1.4, 2.8, and 7.5 years, respectively. One of these had recurrent thrombosis.

CONCLUSIONS

In most children the presence of LA did not lead to clinical complications and was transient. Bleeding occurred with additional hypoprothrombinemia or thrombocytopenia. Thrombosis was rare and strongly associated with persistently positive LA.

Detection of antiphospholipid antibodies in children and adolescents

The prevalence of antiphospholipid antibodies (APAs) has not yet been studied in children and adolescents with various diseases. We assayed plasma samples of 203 children and adolescents, aged 0.1 to 21 years (median 6 years), by enzyme-linked immunosorbent assay detecting immunoglobulin G (IgG) and IgM antibodies directed against cardiolipin, phosphatidylserine, and phosphatidic acid. According to their diagnosis children were divided into five groups: 10 patients with autoimmune and autoimmune-like diseases (group I); 88 patients with infections (group II); 20 patients with metabolic diseases (group III); 65 children with various other diseases (group IV); 20 healthy children without physical illnes (group V). Results were compared for statistical significance using Fisher's exact test. APAs were found in 65 of 203 patients. In all groups of patients the prevalence of APAs was increased compared with healthy children. The highest prevalence of APAs was found in patients with autoimmune or autoimmune-like diseases or infections. Thrombosis did not occur in children with increased APA levels. In 4 of 65 patients with detectable APAs bleeding was observed. However, three of these four children had additional coagulation abnormalities. We conclude that in children and adolescents increased APA titers may occur in a variety of diseases. The frequency of APA-related symptoms is low.

Transient hemorrhagic diathesis associated with an inhibitor of prothrombin with lupus anticoagulant in a 1 1/2-year-old girl: report of a case and review of the literature

Acquired inhibitors of coagulation causing bleeding manifestations are rare in children, particularly without an associated underlying disorder such as autoimmune disease. We describe an otherwise healthy 1 1/2-year-old girl who had extensive spontaneous bruising and prolonged bleeding from venipuncture sites. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged, with evidence of an immediate-acting inhibitor. Thrombin clotting time, fibrinogen, and platelets were normal. Biologic assay of factors II, V, VII, and X were all low, with increasing values at higher dilutions. However, by immunoassay and/or chromogenic assays, only factor II was reduced. An antibody which failed to neutralize prothrombin activity in vitro was detected against radiolabeled prothrombin. Coagulation studies normalized in parallel with clinical recovery and disappearance of the antibody. This case demonstrates acute hypoprothrombinemia-lupus anticoagulant syndrome as a rare presentation of bleeding diathesis in a healthy young child.

Severe intracranial hemorrhage in a newborn infant with transplacental transfer of an acquired factor VII:C inhibitor

We describe a woman in whom inhibitors to factor VIII:C developed in her first pregnancy. The neonate had a factor VIII:C level of 1% and an inhibitor titer of 5.2 Bethesda units. After an uneventful vaginal delivery, the boy had an intracranial hemorrhage at 5 days of age. To our knowledge, this is the first report of a bleeding complication in a newborn infant with transplacental transfer of an acquired factor VIII:C inhibitor.

Spectrum of clinical manifestations of antiphospholipid antibodies in childhood and adolescence

Nineteen children with circulating anticoagulants or anticardiolipin antibodies and negative or only weakly positive antinuclear factors were reviewed for their clinical manifestations. The relationship between these antibodies and the morbidity in the pediatric age group will be discussed.

Transient lupus anticoagulant associated with hypoprothrombinemia and factor XII deficiency following adenovirus infection

A potent lupus anticoagulant (LA) was detected in four children, 1 week after the clinical onset of an adenovirus infection. The adenovirus infection was documented by direct virus detection in the stool of one patient and serologically in the others. None of the children had elevated titers of IgM- and only one of IgG-anticardiolipin antibodies (ACA). All patients had a marked reduction of prothrombin activity as well as antigen. Prothrombin-antibody complexes were demonstrated in the patients' plasma or mixtures of patient and normal plasma. Factor XII activity was moderately reduced in three of the patients. All coagulation abnormalities returned to normal within 4-12 weeks. Localized bleeding was observed in two cases, but there was no generalized bleeding tendency or evidence of thrombosis.

Venous thrombosis associated with lupus anticoagulant and anticardiolipin antibodies

We describe deep vein thrombosis associated with lupus anticoagulant and anticardiolipin antibodies in three children aged 10 to 14 years. One of them also had arterial thromboses. None of the patients had systemic lupus erythematosus when the thrombosis first occurred, but one fulfilled the criteria for systemic lupus erythematosus 3 years later. At presentation all had symptoms suggestive of pulmonary embolism and evidence of an autoimmune disease: Addison's disease in one, anti-DNA or antinuclear antibodies in all three, and a positive Coombs' test in two. Two of the three gave a false-positive test for syphilis. In the patient with systemic lupus erythematosus recurrent thrombocytopenia and severe haemolytic anaemia necessitated splenectomy. A child should be tested for lupus anticoagulant or anticardiolipin antibody if venous or arterial occlusion occurs without a known predisposing cause, or if there is pulmonary embolism or symptoms or laboratory findings suggestive of a connective tissue disease.

Acquired coagulation inhibitor in association with Rocky Mountain spotted fever. With a review of other acquired coagulation inhibitors

An acutely ill 4-year-old girl with Rocky Mountain spotted fever (RMSF) was found to have a coagulation inhibitor. This child had no serious bleeding manifestations and minimal hemorrhagic skin manifestations despite severe RMSF, concurrent thrombocytopenia, as well as the coagulation inhibitor. Hemostatic abnormalities that occur with RMSF as well as other infectious illnesses associated with coagulation inhibitors are reviewed.

Inhibitors of coagulation in children

Acquired inhibitors of coagulation factor interaction in nonhemophilic children are usually nonspecific, transient, and unassociated with clinical bleeding. They occur with some frequency and are the most common cause for a prolonged APTT found by routine testing. In children, some association with viral infections and treatment with penicillin has been noted, but their interrelationship with the development of antibodies remains unclear. The exact nature of these antibodies, usually directed against coagulant factor phospholipid, is not clear and multiple antibodies both specific as well as nonspecific may occur. No therapy is generally required. Rarely has the acute development of antibodies directed against specific coagulation factors occurred. The laboratory evaluation of the type of inhibitor is, therefore, most important as specific inhibitors may be associated with life-threatening bleeding situations. Their therapy should probably include attempts at eradication of the inhibitor by immunosuppressive agents or other newer modalities. Unfortunately, little information is available regarding the nature and outcome of specific inhibitors in children. Acquired inhibitors in hemophilic patients occur in about 6 to 10% of patients. Newer approaches to their therapy include activated PCC which have generally improved the outlook for such patients. Treatment regimens involve a knowledge of inhibitor response and the concomitant use of plasmapheresis, high-dose or continuous i.v. Factor VIII, and porcine Factor VIII, followed by activated PCC. The role of immunosuppressive agents and other newer modalities appears promising, however, prospective controlled studies are necessary to evaluate their role in the overall management of such patients.

Acquired factor VIII deficiency in an elderly woman on tamoxifen

A case is presented and acquired factor VIII deficiency is discussed. The studied patient was elderly and had cancer of left breast, cancer of the head of the pancreas, history of blood transfusions, and was on tamoxifencitrate therapy for breast cancer. Any one of the above factors could have been responsible for production of factor VIII deficiency.

Spontaneously acquired factor VIII inhibitor in a non-haemophiliac child

A three-year-old girl who had for two months suffered bruising after minimal injury was admitted because of diffuse ecchymoses and a large haematoma hindering elbow movement. These symptoms were attributable to the development of antifactor VIII inhibitor. No definite etiology was evident despite repeated immunological investigation. Although the inhibitor still persisted at high levels after two years, no further haemorrhage occurred, excepted haematomas three months after the onset of symptoms, in association with mumps.