The pediatric acenocoumarol dosing algorithm: the Children Anticoagulation and Pharmacogenetics Study.

Essentials A pediatric pharmacogenetic dosing algorithm for acenocoumarol has not yet been developed. We conducted a multicenter retrospective follow-up study in children in the Netherlands. Body surface area and indication explained 45.0% of the variability in dose requirement. Adding the genotypes of VKORC1, CYP2C9 and CYP2C18 to the algorithm increased this to 61.8%. SUMMARY: Background The large variability in dose requirement of vitamin K antagonists is well known. For warfarin, pediatric dosing algorithms have been developed to predict the correct dose for a patient; however, this is not the case for acenocoumarol. Objectives To develop dosing algorithms for pediatric patients receiving acenocoumarol with and without genetic information. Methods The Children Anticoagulation and Pharmacogenetics Study was designed as a multicenter retrospective follow-up study in Dutch anticoagulation clinics and children's hospitals. Pediatric patients who used acenocoumarol between 1995 and 2014 were selected for inclusion. Clinical information and saliva samples for genotyping of the genes encoding cytochrome P450 (CYP) 2C9, vitamin K epoxide reductase complex subunit 1 (VKORC1), CYP4F2, CYP2C18 and CYP3A4 were collected. Linear regression was used to analyze their association with the log mean stable dose. A stable period was defined as three or more consecutive International Normalized Ratio measurements within the therapeutic range over a period of ≥ 3 weeks. Results In total, 175 patients were included in the study, of whom 86 had a stable period and no missing clinical information (clinical cohort; median age 8.9 years, and 49% female). For 80 of these 86 patients, genetic information was also available (genetic cohort). The clinical algorithm, containing body surface area and indication, explained 45.0% of the variability in dose requirement of acenocoumarol. After addition of the VKORC1, CYP2C9, and CYP2C18 genotypes to the algorithm, this increased to 61.8%. Conclusions These findings show that clinical factors had the largest impact on the required dose of acenocoumarol in pediatric patients. Nevertheless, genetic factors, and especially VKORC1, also explained a significant part of the variability.

Characteristics and quality of oral anticoagulation treatment in pediatric patients in the Netherlands based on the CAPS cohort.

Essentials The knowledge of quality and safety of acenocoumarol and phenprocoumon use in children is limited. We used data from a multicenter retrospective follow-up study in children in the Netherlands. The quality of anticoagulation control in the first month of use was low, but improved thereafter. No thromboembolic events occurred, however bleeding events occurred in 1-3 out of 10 patients. SUMMARY: Background The use of vitamin-K antagonists in pediatric patients is rare and information on the quality and safety of treatment with acenocoumarol and phenprocoumon is limited. Objectives To assess the quality, safety and effectiveness during the first year of acenocoumarol and phenprocoumon treatment in pediatric patients in the Netherlands. Methods The Children Anticoagulation and Pharmacogenetics Study (CAPS) was designed as a multicenter retrospective follow-up study. Patients who used acenocoumarol or phenprocoumon at an age of ≤ 18 years, were selected from four pediatric hospitals and one anticoagulation clinic in the Netherlands. The quality of treatment was assessed by calculating the percentage of time in therapeutic INR range (TTR) for the first month and for every 3 months of use during the first year of treatment. Effectiveness and safety were assessed by the number of thromboembolic and bleeding events. Results In total, 213 patients participated, of whom 187 (155 acenocoumarol; 32 phenprocoumon) were included in this analysis. The mean TTR was 47.0% and 51.4% in the first month of use for acenocoumarol and phenprocoumon, respectively. After the first 3 months the mean TTR for both VKAs was above 64%. In 14.6% (acenocoumarol) and 31.3% (phenprocoumon) of the patients a bleeding event occurred during the first year of treatment; no thromboembolic events were reported. Conclusions The quality of anticoagulation treatment was low during the first month of use and leaves room for improvement. After the first month it increased to an acceptable level. However, bleeding events occurred frequently during the first year.

Age dependency of coagulation parameters during childhood and puberty.

BACKGROUND: Use of age-adjusted reference values is crucial for correct diagnosis and management of thrombotic and hemorrhagic disease in children. They vary with utilized reagents and analyzers. OBJECTIVES: We established reference values with the Sysmex CA-1500 System and in parallel with the Behring BCS System using reagents from Siemens Healthcare Diagnostics Products GmbH. METHODS: After informed consent, blood samples were obtained from 218 healthy children and 52 healthy adults, grouped as 1-6 months (n = 29), 7-12 months (n = 25), 1-5 years (n = 57), 6-10 years (n = 57), 11-18 years (n = 50) and > 19 years (n = 52). RESULTS: Most coagulation parameters demonstrate good comparability between analyzers with the exception of PT and APTT. Single coagulation factors fibrinogen, factor (F) II, FIX, FXI and XII were significantly decreased in the youngest children; the strongest age dependency was found for coagulation inhibitors Protein C and S, both significantly decreased in infancy and young childhood. We confirmed that high levels of von Willebrand factor are found in the youngest children without increased levels of FVIII followed by decreased von Willebrand levels in the subsequent age group. In children with blood group O a less distinct increase in time was found, compared with individuals with one of the other blood groups. CONCLUSIONS: The correlation between the CA-1500 and the BCS system was remarkable. Differences were most pronounced between children < 12 months and older children and adults, confirming the phenomenon of developmental hemostasis. The rationale for age-related changes in the hemostatic system remains unraveled. Our results underline the need for age-specific reference ranges.

Subglottic stenosis in Shwachman-Diamond syndrome - is there a link?

Clinically relevant cartilaginous subglottic stenosis was found in 2 patients with Shwachman-Diamond syndrome (SDS) for which tracheotomy was required in one case. Considering the pathogenesis of SDS, including deficient chondrogenesis, we hypothesise that subglottic stenosis may be a rare symptom of SDS. Otorhinolaryngologist and paediatricians should be aware of the risk of airway pathology in patients with SDS.

Etiology and treatment of perinatal stroke; a role for prothrombotic coagulation factors?

The detection rate of perinatal stroke is rising due to improved neuroradiological imaging techniques, increased survival of neonates with severe underlying diseases and an increased awareness of the diagnosis by pediatricians. Its pathogenesis is multifactorial and includes a large variety of maternal and neonatal risk factors as well as prothrombotic coagulation factors. Although the relative risk of prothrombotic coagulation factors is still unknown, testing is recommended to design large studies in the near future. This article is an overview of studies of prothrombotic risk factors in both neonatal arterial ischemic stroke and cerebral sinovenous thrombosis. Although prothrombotic coagulation factors are present in more than half of the cases, we conclude that they most likely play a minor role in the pathogenesis of perinatal stroke. Current therapeutic guidelines focusing on thrombosis are based on expert opinion and recommend low molecular weight or unfractionated heparin for cardioembolic arterial ischemic stroke, antiplatelet or anticoagulant therapy for recurrent arterial ischemic stroke, and low molecular weight heparin or unfractionated heparin for sinovenous thrombosis without hemorrhage and/or when extension of the thrombotic process occurs.

Pharmacokinetic, pharmacodynamic and intracellular effects of PEG-asparaginase in newly diagnosed childhood acute lymphoblastic leukemia: results from a single agent window study.

L-asparaginase is an effective drug for treatment of children with acute lymphoblastic leukemia (ALL). The effectiveness is thought to result from depletion of asparagine in serum and cells. We investigated the clinical response in vivo of 1000 IU/m(2) pegylated (PEG)-asparaginase and its pharmacokinetic, pharmacodynamic and intracellular effects in children with newly diagnosed ALL before start of combination chemotherapy. The in vivo window response was significantly related to immunophenotype and genotype: 26/38 common/pre B-ALL cases, especially those with hyperdiploidy and TELAML1 rearrangement, demonstrated a good clinical response compared to 8/17 T-ALL (P=0.01) and BCRABL-positive ALL (P=0.04). A poor in vivo clinical window response was related to in vitro resistance to L-asparaginase (P=0.02) and both were prognostic factors for long-term event-free survival (hazard ratio 6.4, P=0.004; hazard ratio 3.7, P=0.01). After administration of one in vivo dose of PEG-asparaginase no changes in apoptotic parameters or in intracellular levels of twenty amino acids in leukemic cells could be measured, in contradiction to the changes found after in vitro exposure. This may be explained by the rapid removal of apoptotic cells from the circulation in vivo. One additional dose of PEG-asparaginase upfront ALL treatment did not lead to other severe toxicities.

Modification of biological parameters after treatment with recombinant factor VIIa in a patient with thrombocytopathy due to storage pool disease.

Patients with thrombocytopathy due to storage pool disease mostly suffer from mild bleeding diathesis. However surgical interventions can lead to excess bleeding. We describe how treatment with recombinant factor VIIa (Novoseven) during a surgical procedure in a boy with SPD leads to an immediate rise in PF-4, thereby activating factor Xa on the platelet surface, leading to active thrombin generation.

Gender and age-related differences in Burkitt lymphoma--epidemiological and clinical data from The Netherlands.

Although Burkitt's lymphoma (BL) is classified as one entity in the World Health Organisation (WHO) classification, we wondered whether BL should not be considered as a different disease in children compared with adults. Netherlands Cancer Registry (NCR) data were obtained from 1994 to 1998 (n=203). Detailed clinical data from two treatment protocols were compared: one for adults up to the age of 65 years (n=27) and one for children (n=80). All slides of the two clinical studies were centrally reviewed which included immunophenotyping and when necessary breakpoint analysis of MYC/8q24. Only cases with an unambiguous diagnosis of BL (classical and atypical BL) were accepted. The age distribution of BL-patients showed a bimodal distribution with a peak at the paediatric age and a steady increase after approximately 60 years of age. Most of the patients were males (89% for children and 78% for adults) and only male patients showed this bimodality. Children more often had extranodal disease (81% vs. 59%), whereas adults more often had nodal disease (89% vs. 53%). Based on epidemiology and clinical presentation, the concept that BL is one disease should be re-challenged.

Early prognostic indicators of outcome in ischemic childhood stroke.

The aim of this study was to identify early prognostic factors in children with ischemic arterial stroke. Presenting symptoms, patterns of infarction on magnetic resonance imaging and computed tomography scans, and etiologic findings were compared with clinical outcome in a consecutive series of 31 children with ischemic arterial stroke. Presentation with an altered level of consciousness, seizures, or both and a completed or cortical completed stroke of the middle cerebral artery were found to be significant risk factors for poor outcome. No significant correlation was found between prognosis of childhood stroke and etiology, age at presentation, or gender.

SIOP treatment guidelines for renal tumours in small infants: fact or fantasy?

AIMS: Since as far back as 1980, SIOP (Société Internationale d>>Oncologie Pédiatrique) have advocated primary nephrectomy (PN) only for unilateral renal tumours in patients > tumour (WT). Fourteen of the 25 patients (56%) were treated with PN, including four patients with CMN. In group B there was one patient (2%) with CMN and 40 patients with WT. Thirteen of the patients (31%) were treated with PN. A total of 15 patients were treated before 1980 and 26 after 1980. Eight of 15 (53%) patients were treated with PN before 1980 and 21/26 (81%) were pre-treated after 1980, according to the protocol. CONCLUSION: Despite the SIOP recommendations, only 56% of patients

Diclofenac sodium, 0.1% (Voltaren Ophtha), versus sodium chloride, 5%, in the treatment of filamentary keratitis.

PURPOSE: To compare the efficacy and short-term safety of diclofenac sodium, 0.1% (Voltaren Ophtha; Ciba-Vision) and of sodium chloride, 5% ophthalmic solution, in the treatment of filamentary keratitis (FK) in patients with dry-eye syndrome due to secondary Sjögren's syndrome. METHODS: Thirty-two patients (64 eyes) with dry-eye syndrome due to secondary Sjögren' syndrome were enrolled in a randomized study (patients and authors were aware of which medication was being used). All patients had FK. Sixteen patients were treated with sodium chloride, 5% drops, and 16 patients received diclofenac sodium, 0.1% eyedrops. Treatment regimen included instillation of 1 drop, 4 times a day for 28 days, for both groups. Clinical assessment was performed once a week during the study period. Data on the efficacy and safety of the different therapeutic regimens were collected and compared. RESULTS: Both medications achieved disappearance of filaments at the end of the study. Treatment with diclofenac sodium, 0.1%, revealed a significantly more rapid improvement of the clinical symptoms as compared with sodium chloride, 5%. No significant adverse effects were observed in both groups. CONCLUSION: Diclofenac sodium, 0.1%, may be an effective and safe topical therapy in patients with FK caused by secondary Sjögren's disease.

Nucleolar organizer regions in conjunctival nevi and melanomata.

The objective of this study was to compare the argyrophil nucleolar organizer region (Ag-NOR) counts of conjunctival nevi and melanomata and to compare the efficacy of this method in their differential diagnosis. Nine histologically diagnosed conjunctival nevi and three conjunctival malignant melanomas were studied. Representative sections were stained using the AgNOR technique. Fifty cells of each melanocytic lesion were randomly selected without knowing their histologic diagnosis. The AgNORs were visualized at a magnification of x1000. They consisted of clusters >1 micron in diameter and of satellites <1 micron in diameter, which were counted and recorded for each cell separately. The mean AgNOR count for the nevi was 1.12 clusters and 1.72 satellites per cell, while the count for the melanomas was 1.6 clusters and 6.8 satellites per cell. These results are statistically significant. There was no overlap between the number of AgNOR clusters and satellites in conjunctival nevi and melanomas, indicating that the AgNOR count might be a useful tool in distinguishing benign from malignant conjunctival melanocytic lesions.

Phenotype variability of the dominant beta-thalassemia induced in four Dutch families by the rare cd121 (G-->T) mutation.

Eight patients who were carriers of beta-thalassemia induced by the cd121 (G-->T) mutation are described in four nonrelated Dutch families. This mutant, which is considered rare and inherited in a dominant manner, is expressed in a different way among each of the four families and even among carriers of the same family. The symptoms vary from an hemolytic anemia of intermediate gravity with hepatosplenomegaly, inclusion bodies and erythroblastosis, to a mild anemia with minor hematological abnormalities. We report the analytical procedures used for the detection of the mutant, the hematological and clinical data of the four families and discuss the variable physiopathology of this molecular defect. We also compare the variation in fetal hemoglobin expression in relation to the haplotypes of the beta-gene cluster and to the different hematological conditions. The presence of this rare mutant in four nonrelated Dutch families could derive from a single mutation or from multiple events. The existence of the four mutations in three different haplotypes suggests the occurrence of at least two independent events. The presence of five abnormal hemoglobins and the beta-thalassemia defect on different haplotypes at cd121 also suggests a relatively increased rate of mutations at this particular site.

Age-related differences in outcome and severity of DIC in children with septic shock and purpura.

We studied the influence of age on mortality and severity of clotting abnormalities in 79 children (median age: 3.1 years) with meningococcal sepsis. Parameters of coagulation and fibrinolysis and plasma levels of cytokines were prospectively measured on admission. The mortality rate was 27%. The age of survivors was significantly different from that of non-survivors (p = 0.013). With the exception of FVII, vWF and t-PA, parameters of coagulation and fibrinolysis, as well as plasma cytokine levels were related to outcome. Patients were divided in two groups: younger and older than median age. The mortality in children < or = 3.1 years was 40% versus 13% in children > 3.1 years (p = 0.006). In contrast to cytokine levels, which were not different between the two age groups, fibrinogen, prothrombin, factors V, VII, VIII, vWF, protein C, antithrombin, FDP, and the ratio PA1-1/t-PA were related to age, indicating a more severe coagulopathy in children < or = 3.1 years despite a similar degree of inflammatory response. A relative deficiency of coagulation factors due to an immature state of the clotting system, as well as an inadequate fibrinolytic response, both related to age may have caused this more severe coagulative response in younger children, and may have contributed to the higher mortality rate.

The relationship between plasminogen activator inhibitor-1 and proinflammatory and counterinflammatory mediators in children with meningococcal septic shock.

Proinflammatory cytokines (tumor necrosis factor [TNF]-alpha and interleukin [IL]-6 and -8), counterinflammatory compounds (IL-10 and soluble TNF receptors p55 and p75 [sTNFR-55 and -75]), and hemostatic parameters were determined in 38 patients with meningococcal septic shock. Eleven patients (29%) died. Serum levels of pro- and counterinflammatory compounds and plasma levels of plasminogen activator inhibitor (PAI)-1 were significantly higher in nonsurvivors. The interval between appearance of petechiae and blood sampling was shorter in nonsurvivors than in survivors (3.6 +/- 2.4 vs. 6.1 +/- 3.3 h; P = 0.4). This interval correlated strongly with the levels of TNF-alpha, IL-6, -8, and -10, sTNFR-55 and -75, and PAI-1. However, with the exception of PAI-1, differences between concentrations of these mediators disappeared after adjustment for the interval. PAI-1 levels correlated with TNF-alpha concentrations (r = .75; P < .001) and were 1.9 (P = .01) times higher in nonsurvivors at a similar TNF-alpha concentration. Thus, an increased PAI-1 response to TNF-alpha may be associated with fatality, probably because of polymorphism of the PAI-1 gene.

Acquired Von Willebrand disease in children with a Wilms' tumor.

The association between acquired von Willebrand disease and Wilms' tumor has been reported in eight cases: four cases reports and one prospective study of Coppes et al. (J. Clin Oncol 10:422-427, 1992) who found this in four out of 50 patients. We retrospectively studied 73 children who were diagnosed with a Wilms' tumor between 1970 and 1993. All patients were treated according to the running international SIOP protocol. According to our local diagnostic workup protocol, blood samples for screening coagulation tests were obtained at diagnosis and during preoperative chemotherapy. Since 1984, factor VIII analysis was added. In four patients, no coagulation screen was done. Bleeding time and screening tests apart from APTT were normal in all 69 children tested before or within 2 days after starting therapy. In 47 out of 73 patients, an APTT was performed before starting therapy. In 19 patients (40%), it was prolonged (>33 sec). In 8 of them (17%), the prolongation was severe (> or = 40 sec). In 11 out of the 19 patients, factor VIIIc, factor VIIIag, and factor VIII RcoF determinations were done. In two children, all three factors were decreased suggestive for von Willebrand disease. One of the 19 patients with a prolonged APTT had hematuria. The others had no increased bleeding tendency or signs of bleeding in the tumor. In all patients, the prolonged APTT normalised during preoperative chemotherapy within 6 weeks. Frequent blood samples were obtained of the two children with acquired von Willebrand disease and showed normalisation of the coagulation disorder after 1 and 2 weeks, respectively. No specific therapy to correct the coagulation abnormalities was given to any patient.

Minimal effects of E. coli and Erwinia asparaginase on the coagulation system in childhood acute lymphoblastic leukemia: a randomized study.

A randomized study was done in twenty newly diagnosed children with acute lymphoblastic leukemia. Ten children were treated with Escherichia coli L-asparaginase, and ten with Erwinia chrysanthemi L-asparaginase. L-asparaginase (ASP) treatment started halfway during ALL-induction treatment with vincristine, prednisone, daunorubicin and intrathecal methotrexate. The mean activated partial thromboplastin time (APTT) level in all children demonstrated a significant fall (P < 0.001) from 28.25 sec at diagnosis to 23.0 sec at the start of ASP treatment. In this same time interval, the mean fibrinogen level declined markedly from 3 g/l to 1.2 g/l (P < 0.001), probably due to prednisone therapy. The APTT stayed shortened during ASP therapy, whereas the hypofibrinogenemia recovered significantly faster in the Erwinia group (P < or = 0.01). Factors (F) II, V, VII and X stayed within the normal range, while F VIII and F IX were elevated. During the entire period of induction therapy, the ATIII activity remained within the normal range in both treatment groups. The protein C values, however, demonstrated a steady decline from 140% at start of ASP treatment to a mean of 81% and 93%, respectively, at the end of the ASP therapy in the E. coli and Erwinia group. Five of the ten children treated with E. coli ASP demonstrated protein C levels below 70% at the end of ASP therapy, opposed to none of the Erwinia treated patients (P = 0.03). We suggest that the effect of ASP resulting in decreased coagulation factor synthesis is in part counterbalanced by the effect of prednisone on the coagulation system, when ASP is administered at the end of ALL induction treatment. The overall effect of ASP either of E. coli or of Erwinia on the hemorrhagic system reveals a slight imbalance towards thrombosis, mainly because of a gradual decrease in protein C activity. This imbalance is less pronounced in the Erwinia group.

Late-onset papilledema following spinal injury. Case report.

Papilledema, is a known complication of various spinal pathologies. It has, however, been only infrequently reported following spinal injury, and may be overlooked in these cases. Presented herein is a 27 year old male who suffered thoracic and lumbar spinal injuries. Papilledema following mild increase in intracranial pressure (IICP) developed 3 weeks following trauma, and subsided within 8 weeks. The importance of routine repeat ophthalmoscopic examinations following spinal injury to detect changes characteristic of IICP is emphasized.