Notfall-Neuropädiatrie – Der arteriell ischämische Schlaganfall als einer der zeitkritischsten Notfälle bei Kindern und Jugendlichen

Der arteriell ischämische Schlaganfall im Kindes- und Jugendalter gehört zu den zeitkritischsten Notfällen in der Pädiatrie. Dennoch wird er häufig mit einer oft prognostisch relevanten Zeitverzögerung diagnostiziert. Gründe dafür liegen neben der geringen Awareness auch in der zuweilen unspezifischen klinischen Präsentation mit einer herausfordernden Breite kritischer Differenzialdiagnosen sowie in der Fläche noch wenig verzahnter Akutversorgungsstrukturen. Gleichwohl zeigen grundsätzlich die beim Erwachsenen etablierten Revaskularisationsstrategien auch beim Kind ihre möglichen, zum Teil spektakulären Erfolge. Es gilt also, diese nach Möglichkeit auch den betroffenen Kindern zur Verfügung zu stellen, auch wenn hier derzeit ein nicht annähernd vergleichbarer Grad an Evidenz erreicht ist. Postakut ist die ätiologische Aufarbeitung durch die größere Bandbreite zu bedenkender Risikofaktoren besonders komplex, muss aber in der Lage sein, das individuelle Risikoprofil mit Sekundärprophylaxe, Rezidivrisiko und Outcome präzise zu identifizieren. Die Langzeitbetreuung im multiprofessionellen, interdisziplinären Team muss die biopsychosozialen Aspekte des Kindes in seiner jeweiligen Entwicklungsphase berücksichtigen und damit eine bestmögliche Integration des Kindes in sein soziales und schulisches, später berufliches Umfeld realisieren.

Prospects for research in haemophilia with real-world data-An analysis of German registry and secondary data

INTRODUCTION AND AIM

Open questions in haemophilia, such as effectiveness of innovative therapies, clinical and patient-reported outcomes (PROs), epidemiology and cost, await answers. The aim was to identify data attributes required and investigate the availability, appropriateness and accessibility of real-world data (RWD) from German registries and secondary databases to answer the aforementioned questions.

METHODS

Systematic searches were conducted in BIOSIS, EMBASE and MEDLINE to identify non-commercial secondary healthcare databases and registries of patients with haemophilia (PWH). Inclusion of German patients, type of patients, data elements-stratified by use in epidemiology, safety, outcomes and health economics research-and accessibility were investigated by desk research.

RESULTS

Screening of 676 hits, identification of four registries [national PWH (DHR), national/international paediatric (GEPARD, PEDNET), international safety monitoring (EUHASS)] and seven national secondary databases. Access was limited to participants in three registries and to employees in one secondary database. One registry asks for PROs. Limitations of secondary databases originate from the ICD-coding system (missing: severity of haemophilia, presence of inhibitory antibodies), data protection laws and need to monitor reliability.

CONCLUSION

Rigorous observational analysis of German haemophilia RWD shows that there is potential to supplement current knowledge and begin to address selected policy goals. To improve the value of existing RWD, the following efforts are proposed: ethical, legal and methodological discussions on data linkage across different sources, formulation of transparent governance rules for data access, redefinition of the ICD-coding, standardized collection of outcome data and implementation of incentives for treatment centres to improve data collection.

Haemostatic testing prior to elective surgery in children? Not always!

In Germany, preoperative coagulation tests are commonly used, based on the belief that these tests should identify patients with an increased bleeding risk. However, published evidence does not longer support this approach for both traditional screening tests and novel techniques of global assessment of haemostasis. Unselected screening yields many false positive results and detects irrelevant disorders. It leads to postponement of surgery, anxiety in parents and patients, and is not cost effective. Even worse, it does not reliably detect relevant bleeding disorders such as the most common coagulopathy, von Willebrand disease. The bleeding history of patients and their relatives is a more effective tool to detect patients at risk. According to international guidelines and a joint statement of different German medical societies, a standardized questionnaire should be mandatory in preoperative screening. A diagnostic pathway should be employed to identify patients in whom specific tests are helpful. Because neither laboratory tests nor questionnaires can infallibly predict or exclude perioperative bleeding, guidelines for the management of these unexpected situations have to be established.

Inhibitor-Immunology-Study

The development of inhibitors is one of the most important complications of replacement therapy in haemophilia, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors. Cytokines and their receptors, T-cell receptors, and the Major Histocompatibility Complex may play important roles in the development of inhibitors. Earlier studies showed non significant associations between HLA class and inhibitor development. Later studies found an increased risk of inhibitor development if there was a combination between certain factor VIII mutations and HLA antigens. We performed HLA typing in 50 patients with haemophilia A in an effort to find associations with inhibitor development. Results: 25 patients had developed an inhibitor (11 low titre, 14 high titre), and 25 never had. In logistic regression analysis, HLA-A 34, DRB1 0405, DRB1 1301 seemed to be involved in inhibitor development and HLA-A 30, B 13, B15, B 57, Cw 12, DQB1 0303, DPB1 0201 protection against inhibitor development. In our patients, the HLA-associations with inhibitor development were different from those in previous publications.

Coagulation testing in the evaluation of suspected child abuse

Every year in Germany nearly 3000 cases of child abuse were reported. When children are presented at emergency units with suspicious injuries and bruises a detailed documentation an evaluation is necessary after emergency treatment. As differential diagnosis inherited or acquired bleeding disorders should be excluded. In addition to a detailed evaluation of personal and family history and a physical evaluation different coagulation test to exclude defects of primary and secondary hemostasis should be performed. Clinician must know the limitations of these tests and keep in mind that an abnormal coagulation test does not exclude child abuse. Coagulation defects may be the consequence of child abuse and neglect or the two conditions may coexist.

Repeated coagulation testing in children

Background Mild bleeding disorders (BD) such as von Willebrand disease (VWD) type I are often difficult to diagnose because of inconclusive laboratory results. Our study examines the diagnostic value of repeated testing.

Patients, methods Prospective study on 200 children. Extensive laboratory testing was done twice and a standardized history was taken.

Results 165 patients completed the study (median age 5.6 years). Main reason for referral was aPTT prolongation (n = 109). The initial diagnosis was upheld in 74/165 (44.8%) children. Of 18 patients rated normal, 8 had to be reclassified as possible VWD later. Ten patients were diagnosed VWD I. In 36 patients possible VWD was found, 13 of these had normal results at the second visit while in 6 VWD became more likely. The main diagnosis was lupus-anticoagulant (n=79), normalizing in 24. A total of 88 children underwent surgery during the study period.

Conclusion Our study shows frequent changes in the diagnosis and highlights the limitations of single laboratory tests in detecting mild BD. Clinical and laboratory abnormalities have to be followed and tests must be repeated in unclear cases. Normal values at one point do not exclude a BD.

Arterial thrombosis in homozygous antithrombin deficiency

Antithrombin (AT), a serin protease inhibitor (serpin) produced in the liver, inhibits mainly thrombin and factor Xa. Antithrombin deficiency (AD) is associated with a higher incidence of thrombosis. Case report: We report a newborn with uncomplicated birth in the 40+5 week of gestation and postnatal appearance of a reticular, livide haematoma on the right upper arm and a tonic clonic epileptic seizure. Clinical examination revealed weak pulses in the A. radialis and ulnaris. MRI scan showed a large thrombus in the A. carotis interna and externa with large cerebral infarction and a thrombus in the A. subclavia. Laboratory work up showed elevated D-dimers and antithrombin levels < 20% (lowest 15%), age-related values for protein C, protein S, plasminogen, and no other inherited thrombophilia. Therapy: We started anticoagulation with unfractionated heparin intravenously (aPTT: 50–60 s) and under suspicion of an AD the substitution of AT (70 U/kg body weight). In course of time we changed anticoagulation to low molecular weight heparin (Anti Xa 0.6–0.8 U/ml) and substitution of 250 E/kg AT every second day. In the molecular work up we found a homozygous missense mutation in exon 2 of SERPINC1 gene (type „Budapest 3”). Molecular analysis showed also heterozygous mutations in both parents and a homozygous mutation in the asymptomatic brother aged three years. At age of six months we changed the anticoagulation to coumadin (INR 2.5–3.5). Anticoagulation with coumadin was also started in the brother. Discussion: Hereditary AD is associated with an increased risk of thrombosis. The homozygous status mainly leads to intrauterine fetal loss or the occurrence of peri- and postnatal thrombosis. Therapy consists in the substitution of AT and a lifelong anticoagulation with vitamin K antagonists also in asymptomatic patients.

Postoperative bleeding in paediatric ENT surgery

Bleeding after ear-nose-and throat surgery in children is a serious complication. With the help of the German Surveillance Unit for Rare Paediatric Disorders (Erhebungseinheit für seltene pädiatrische Erkrankungen in Deutschland; ESPED) a two year survey was performed to record the incidence, severity, reasons and treatment of haemorrhages. During the study period, 1069 bleeds were reported from 720 paediatric hospitals and departments of otorhinolaryngology after adenoidectomy and tonsillectomy. 713 reports could be analyzed. Two deaths occurred after adenoidectomy. Although laboratory screening was performed in more than 70% of all cases, bleeding complications were neither foreseeable nor preventable. Inherited coagulopathies were rare and in most cases not detected, neither by laboratory screening nor by taking a history. Since preoperative measures cannot help much to improve the situation, all efforts have to be taken to improve the postoperative period, especially since more than 20% of the hemorrhages occurred during weekends. Guidelines on postoperative care and behaviour should therefore be implemented and parents and patients must be informed on bleeding risks and on what to do in case of emergency. If bleeding occurs, extensive coagulation testing is mandatory.

Evaluation of the utility of the ISTH-BAT in haemophilia carriers: a multinational study

INTRODUCTION

There has been increasing recognition in recent years that female carriers of haemophilia manifest abnormal bleeding; however, data on the use of bleeding assessment tools in this population are lacking.

AIM

Our objective was to validate the ISTH-BAT in haemophilia carriers to describe bleeding symptoms and allow for comparisons with factor levels and other patient groups.

METHODS

This was a prospective, observational, cross-sectional study performed by members of Global Emerging HEmostasis Panel (GEHEP). Unselected consecutive haemophilia carriers were recruited and a CRF and the ISTH-BAT were completed by study personnel.

RESULTS

A total of 168 haemophilia carriers were enrolled: 155 haemophilia A and 13 haemophilia B. The mean age was 40 years (range: 20-82). Carriers had higher mean bleeding scores (BS) compared with age-matched controls (n = 46; 5.7 vs. 1.43; P < 0.0001) and Type 3 VWD OC (n = 32; 3.0; P = 0.009), but lower BS compared with women with Type 1 VWD (n = 83; 8.7; P < 0.0001). Fifteen carriers reported haemarthrosis, and of those six had normal FVIII/FIX levels. There was a significant but weak negative correlation between BS and factor level (Spearman's r²  = -0.36, P < 0.001).

CONCLUSION

Our results show that haemophilia carriers experience abnormal bleeding, including haemarthrosis. Overall, BS in women with Type 1 VWD > haemophilia carriers > Type 3 VWD OC > controls. Understanding the performance of the ISTH-BAT in this population is a critical step in future research aimed at investigating the underlying pathophysiology of abnormal bleeding, with the ultimate goal of optimizing treatment.

Prospective evaluation of a pediatric bleeding questionnaire and the ISTH bleeding assessment tool in children and parents in routine clinical practice

BACKGROUND

Diagnosing mild bleeding disorders (BDs) in children is difficult. Bleeding scores (BSs) have been proposed for obtaining standardized quantitative histories.

OBJECTIVES

To compare the Canadian pediatric bleeding questionnaire (PBQ) with the new ISTH bleeding assessment tool (ISTH BAT) for the determination of BS in a routine pediatric outpatient setting.

METHODS

One hundred children with a suspected BD were enrolled in this cross-sectional study. Bleeding scores were calculated for all children and their natural parents. For all children, extensive laboratory investigations were performed.

RESULTS

Based on laboratory tests, 56 children were diagnosed as having no BD, 11 were diagnosed with possible VWD, 12 with VWD 1, 11 with VWD 2, five with possible platelet defects, and five with mild factor deficiencies. Both questionnaires were able to discriminate between no BD and VWD (P = 0.0001), but the area under the receiver characteristics curve to detect any mild BD was only 0.76. Despite the inherited nature of the BD, a family score did not increase the ability to discriminate between no BD and VWD (P = 0.2052). There was no significant difference between the two tools used (P = 0.3253) or simple qualitative criteria, such as yes/no questions regarding bleeding (P = 0.3477).

CONCLUSIONS

The two tools translated into German did not differ substantially. Both were able to discriminate between no BD and a possible BD with acceptable accuracy. A BS of < 2 makes a BD unlikely. Simple qualitative criteria were similar; however, to allow comparison of studies and follow-up in patients over time, we recommend the ISTH BAT.

Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders

BACKGROUND

The European Network of Rare Bleeding Disorders (EN-RBD) was established to bridge the gap between knowledge and practise in the care of patients with RBDs.

OBJECTIVES

To explore the relationship between coagulation factor activity level and bleeding severity in patients with RBDs.

PATIENTS/METHODS

Cross-sectional study using data from 489 patients registered in the EN-RBD. Coagulation factor activity levels were retrieved. Clinical bleeding episodes were classified into four categories according to severity.

RESULTS

The mean age of patients at data collection was 31 years (range, 7 months to 95 years), with an equal sex distribution. On linear regression analysis, there was a strong association between coagulation factor activity level and clinical bleeding severity for fibrinogen, factor (F) X, FXIII, and combined FV and FVIII deficiencies. A weaker association was present for FV and FVII deficiencies. There was no association between coagulation factor activity level and clinical bleeding severity for FXI. The coagulation factor activity levels that were necessary for patients to remain asymptomatic were: fibrinogen, > 100 mg dL(-1); FV, 12 U dL(-1); combined FV + VIII, 43 U dL(-1); FVII, 25 U dL(-1); FX, 56 U dL(-1) ; FXI, 26 U dL(-1); FXIII, 31 U dL(-1). Moreover, coagulation factor activity levels that corresponded with Grade III bleeding were: undetectable levels for fibrinogen, FV and FXIII, < 15 U dL(-1) for combined FV + VIII; < 8 U dL(-1) for FVI; < 10 U dL(-1) for FX; and < 25 U dL(-1) for FXI.

CONCLUSIONS

There is a heterogeneous association between coagulation factor activity level and clinical bleeding severity in different RBDs. A strong association is only observed in fibrinogen, FX and FXIII deficiencies.

Arterial thrombosis in homozygous antithrombin deficiency

Antithrombin (AT), a serin protease inhibitor (serpin) produced in the liver, inhibits mainly thrombin and factor Xa. Antithrombin deficiency (AD) is associated with a higher incidence of thrombosis.

CASE REPORT

We report a newborn with uncomplicated birth in the 40+5 week of gestation and postnatal appearance of a reticular, livide haematoma on the right upper arm and a tonic clonic epileptic seizure. Clinical examination revealed weak pulses in the A. radialis and ulnaris. MRI scan showed a large thrombus in the A. carotis interna and externa with large cerebral infarction and a thrombus in the A. subclavia. Laboratory work up showed elevated D-dimers and antithrombin levels <20% (lowest 15%), age-related values for protein C, protein S, plasminogen, and no other inherited thrombophilia.

THERAPY

We started anticoagulation with unfractionated heparin intravenously (aPTT: 50-60 s) and under suspicion of an AD the substitution of AT (70 U/kg body weight). In course of time we changed anticoagulation to low molecular weight heparin (Anti Xa 0.6-0.8 U/ml) and substitution of 250 E/kg AT every second day. In the molecular work up we found a homozygous missense mutation in exon 2 of SERPINC1 gene (type "Budapest 3"). Molecular analysis showed also heterozygous mutations in both parents and a homozygous mutation in the asymptomatic brother aged three years. At age of six months we changed the anticoagulation to coumadin (INR 2.5-3.5). Anticoagulation with coumadin was also started in the brother.

DISCUSSION

Hereditary AD is associated with an increased risk of thrombosis. The homozygous status mainly leads to intrauterine fetal loss or the occurrence of peri- and postnatal thrombosis. Therapy consists in the substitution of AT and a lifelong anticoagulation with vitamin K antagonists also in asymptomatic patients.

Repeated coagulation testing in children. Does it improve the diagnostic value?

BACKGROUND

Mild bleeding disorders (BD) such as von Willebrand disease (VWD) type I are often difficult to diagnose because of inconclusive laboratory results. Our study examines the diagnostic value of repeated testing.

PATIENTS, METHODS

Prospective study on 200 children. Extensive laboratory testing was done twice and a standardized history was taken.

RESULTS

165 patients completed the study (median age 5.6 years). Main reason for referral was aPTT prolongation (n = 109). The initial diagnosis was upheld in 74/165 (44.8%) children. Of 18 patients rated normal, 8 had to be reclassified as possible VWD later. Ten patients were diagnosed VWD I. In 36 patients possible VWD was found, 13 of these had normal results at the second visit while in 6 VWD became more likely. The main diagnosis was lupus-anticoagulant (n=79), normalizing in 24. A total of 88 children underwent surgery during the study period.

CONCLUSION

Our study shows frequent changes in the diagnosis and highlights the limitations of single laboratory tests in detecting mild BD. Clinical and laboratory abnormalities have to be followed and tests must be repeated in unclear cases. Normal values at one point do not exclude a BD.

Inhibitor-immunology-study. Evaluation of inhibitor development in haemophilia B

The development of inhibitors in haemophilia B is one of the most important complications of replacement therapy, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors, and to date, only little is known about its underlying mechanisms. Here, we present first results of the haemophilia B group of our Inhibitor-Immunology study.

PATIENTS, METHODS

So far we have analysed 15 patients with haemophilia B. Four of them developed a high titre inhibitor; the remaining 11 had no inhibitor. We evaluated 9 SNPs in 8 genes (CD40, CTLA-4 , IL-1β, IL-10, TLR2 , TLR4, TLR9, TNF-α). We compared the distribution of these alleles between inhibitor and non-inhibitor haemophilia B patients and between haemophilia B patients and a normal male control population. HLA typing was performed in all patients. Results, discussion: There appears to be a trend towards a skewed distribution of TLR 9, IL-10 and CTLA4 alleles in haemophilia B patients. Due to the limited number these differences are, however, not statistically significant. The t-test of all patients with inhibitor versus without inhibitor was significant for HLA-A*03 and DPB1*0401 and borderline for DRB1*0201.

Identification and long-term observation of early joint damage by magnetic resonance imaging in clinically asymptomatic joints in patients with haemophilia A or B despite prophylaxis

Severe haemophilia is associated with recurrent joint bleeds, which can lead to haemophilic arthropathy. Subclinical joint bleeds have also been associated with joint damage detected using magnetic resonance imaging (MRI). We investigated the development of early changes in clinically asymptomatic joints using MRI in haemophilia A or B patients receiving prophylactic therapy. In this single-centre retrospective cohort study, patients with clinical evidence of joint damage in one ankle and one clinically asymptomatic ankle, in which we performed an MRI scan of both ankles in one session, were enrolled. MRI findings were graded using a 4-point scoring system (0 = normal findings and III = severe joint damage). Since 2000, 38 MRIs in 26 patients have been performed. Starting at a median age of 4 years, 23 patients received prophylaxis 2-3 times weekly. On-demand treatment was performed in three patients. Eight patients (31%) presented with an MRI score of 0, 12 (46%) had a score of I, four (15%) had a score of II, and two (8%) had a score of III in the clinically unaffected ankle. The six patients with MRI scores of II and III had started regular prophylaxis between the ages of 2 years and 15 years; none had developed an inhibitor or experienced a clinically evident bleed in the asymptomatic ankle. During our study, five of 26 patients had a worsening of MRI findings without experiencing a joint bleed. Early morphological changes in clinically asymptomatic ankles can be detected using MRI, despite adequate prophylaxis.

Inhibitor-Immunology-Study

The development of inhibitors in haemophilia B is one of the most important complications of replacement therapy, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors, and to date, only little is known about its underlying mechanisms. Here, we present first results of the haemophilia B group of our Inhibitor-Immunology study.

Patients, methods So far we have analysed 15 patients with haemophilia B. Four of them developed a high titre inhibitor; the remaining 11 had no inhibitor. We evaluated 9 SNPs in 8 genes (CD40, CTLA-4, IL-1β, IL-10, TLR2, TLR4, TLR9, TNF-α). We compared the distribution of these alleles between inhibitor and non-inhibitor haemophilia B patients and between haemophilia B patients and a normal male control population. HLA typing was performed in all patients.

Results, discussion There appears to be a trend towards a skewed distribution of TLR 9, IL-10 and CTLA4 alleles in haemophilia B patients. Due to the limited number these differences are, however, not statistically significant.The t-test of all patients with inhibitor versus without inhibitor was significant for HLA-A*03 and DPB1*0401 and borderline for DRB1*0201.

Postoperative bleeding in paediatric ENT surgery. First results of the German ESPED trial

Bleeding after ear-nose-and throat surgery in children is a serious complication. With the help of the German Surveillance Unit for Rare Paediatric Disorders (Erhebungseinheit für seltene pädiatrische Erkrankungen in Deutschland; ESPED) a two year survey was performed to record the incidence, severity, reasons and treatment of haemorrhages. During the study period, 1069 bleeds were reported from 720 paediatric hospitals and departments of otorhinolaryngology after adenoidectomy and tonsillectomy. 713 reports could be analyzed. Two deaths occurred after adenoidectomy. Although laboratory screening was performed in more than 70% of all cases, bleeding complications were neither foreseeable nor preventable. Inherited coagulopathies were rare and in most cases not detected, neither by laboratory screening nor by taking a history. Since preoperative measures cannot help much to improve the situation, all efforts have to be taken to improve the postoperative period, especially since more than 20% of the hemorrhages occurred during weekends. Guidelines on postoperative care and behaviour should therefore be implemented and parents and patients must be informed on bleeding risks and on what to do in case of emergency. If bleeding occurs, extensive coagulation testing is mandatory.

Rate of inhibitor development in previously untreated hemophilia A patients treated with plasma-derived or recombinant factor VIII concentrates: a systematic review

BACKGROUND

Different rates of inhibitor development after either plasma-derived (pdFVIII) or recombinant (rFVIII) FVIII have been suggested. However, conflicting results are reported in the literature.

OBJECTIVES

To systematically review the incidence rates of inhibitor development in previously untreated patients (PUPs) with hemophilia A treated with either pdFVIII or rFVIII and to explore the influence of both study and patient characteristics.

METHODS

Summary incidence rates (95% confidence interval) from all included studies for both pdFVIII and rFVIII results were recalculated and pooled. Sensitivity analysis was used to investigate the effect of study design, severity of disease and inhibitor characteristics. Meta-regression and analysis-of-variance were used to investigate the effect of covariates (testing frequency, follow-up duration and intensity of treatment).

RESULTS

Two thousand and ninety-four patients (1965 treated with pdFVIII, 887 with rFVIII; median age, 9.6 months) from 24 studies were investigated and 420 patients were observed to develop inhibitors. Pooled incidence rate was 14.3% (10.4-19.4) for pdFVIII and 27.4% (23.6-31.5) for rFVIII; high responding inhibitor incidence rate was 9.3% (6.2-13.7) for pdFVIII and 17.4% (14.2-21.2) for rFVIII. In the multi-way anova study design, study period, testing frequency and median follow-up explained most of the variability, while the source of concentrate lost statistical significance. It was not possible to analyse the effect of intensity of treatment or trigger events such as surgery, and to completely exclude multiple reports of the same patient or changes of concentrate.

CONCLUSIONS

These findings underscore the need for randomized controlled trials to address whether or not the risk of inhibitor in PUPs with hemophilia A differs between rFVIII and pdFVIII.

Coagulation testing in the evaluation of suspected child abuse

Every year in Germany nearly 3000 cases of child abuse were reported. When children are presented at emergency units with suspicious injuries and bruises a detailed documentation an evaluation is necessary after emergency treatment. As differential diagnosis inherited or acquired bleeding disorders should be excluded. In addition to a detailed evaluation of personal and family history and a physical evaluation different coagulation test to exclude defects of primary and secondary hemostasis should be performed. Clinician must know the limitations of these tests and keep in mind that an abnormal coagulation test does not exclude child abuse. Coagulation defects may be the consequence of child abuse and neglect or the two conditions may coexist.

Haemostatic testing prior to elective surgery in children? Not always!

In Germany, preoperative coagulation tests are commonly used, based on the belief that these tests should identify patients with an increased bleeding risk. However, published evidence does not longer support this approach for both traditional screening tests and novel techniques of global assessment of haemostasis. Unselected screening yields many false positive results and detects irrelevant disorders. It leads to postponement of surgery, anxiety in parents and patients, and is not cost effective. Even worse, it does not reliably detect relevant bleeding disorders such as the most common coagulopathy, von Willebrand disease. The bleeding history of patients and their relatives is a more effective tool to detect patients at risk. According to international guidelines and a joint statement of different German medical societies, a standardized questionnaire should be mandatory in preoperative screening. A diagnostic pathway should be employed to identify patients in whom specific tests are helpful. Because neither laboratory tests nor questionnaires can infallibly predict or exclude perioperative bleeding, guidelines for the management of these unexpected situations have to be established.

Inhibitor-Immunology-Study. Different HLA-types seem to be involved in the inhibitor development in haemophilia A

The development of inhibitors is one of the most important complications of replacement therapy in haemophilia, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors. Cytokines and their receptors, T-cell receptors, and the Major Histocompatibility Complex may play important roles in the development of inhibitors. Earlier studies showed non significant associations between HLA class and inhibitor development. Later studies found an increased risk of inhibitor development if there was a combination between certain factor VIII mutations and HLA antigens. We performed HLA typing in 50 patients with haemophilia A in an effort to find associations with inhibitor development.

RESULTS

25 patients had developed an inhibitor (11 low titre, 14 high titre), and 25 never had. In logistic regression analysis, HLA-A 34, DRB1 0405, DRB1 1301 seemed to be involved in inhibitor development and HLA-A 30, B 13, B15, B 57, Cw 12, DQB1 0303, DPB1 0201 protection against inhibitor development. In our patients, the HLA-associations with inhibitor development were different from those in previous publications.

Pharmacokinetics, efficacy, and safety of LMWHs in venous thrombosis and stroke in neonates, infants and children

Since the early nineties it has been shown that low molecular weight heparin (LMWH) has significant advantages over unfractionated heparin and oral anticoagulants for both the treatment and the prevention of thrombosis, not only in adults, but also in children. The present review was based on an 'EMBASE', 'Medline' and 'PubMed' search including literature published in any language since 1980 on LMWH in neonates, infants and children. It included paediatric pharmacokinetic studies, the use of LMWH in children with venous thrombosis, LMWH administration in paediatric patients with ischaemic stroke, and its use in order to prevent symptomatic thromboembolism in children at risk. An increasing rate of off-label use of LMWH in children has been reported, showing that LMWHs offer important benefits to children with symptomatic thromboembolic events and poor venous access. Two well-conducted pharmacokinetic studies in this age group showed that neonates and younger infants require higher LMWH doses than older children to achieve the targeted anti-Xa levels, due to an increased extra vascular clearance. Recurrent symptomatic thromboses under LMWH occur in approximately 4% of children treated for venous thrombosis, and in 7% of children treated for stroke; major bleed was documented in 3% of children with therapeutic target LMWH anti-Xa levels, whereas minor bleeding was reported in approximately 23% of children receiving either therapeutic or prophylactic doses, respectively. Further randomized controlled trials are recommended to evaluate the optimum duration and application for different LMWH indications in children.

Reconstituting factor concentrates: Defining Evidence of Coaching Non-Experts (DEVICE) in haemophilia--a prospective randomized feasibility study

The introduction of new needleless devices as demanded by the US Department of Labor Occupational Safety and Health Administration (OSHA) has caused problems with the reconstitution of antihaemophilic factor in emergency situations. Our aim therefore was to evaluate the feasibility of a needleless device for reconstitution of antihaemophilic factor for non-haemophilia experts and to define evidence of the need for coaching these physicians via providing two additional photographs illustrating the two key points of the factor reconstitution process. Twenty-eight physicians of a tertiary care university children's hospital were randomized into two groups, either with no further explanation of the reconstitution device or with two additional photographs, showing the two key steps of the procedure. Reconstitution of dummy-factor concentrate was video-taped and evaluated by a blinded helper. Main outcome measure was the successful reconstitution of dummy-factor concentrate and procedure failure respectively. Of the group without explanation of the reconstitution device, only two of 14 physicians were able to reconstitute the dummy-factor concentrate. Of the group receiving two photographs, nine of 14 completed the task successfully (P = 0.0068). The needleless device is not self explaining to non-haemophilia physicians involved in emergency services. Coaching via short to the point instructions as provided by simple visual educational material therefore is crucial to enable these physicians to resolve the expensive emergency drug quickly and correctly. Companies concerned with the production of any devices to dissolve drugs, especially for treatment of rare diseases as haemophilia, therefore should take measures to simplify therapy.

Continuous infusion of factor concentrates in children with haemophilia A in comparison with bolus injections

Although the concept of continuous infusion (CI) of factor concentrates is well known, prospective paediatric data are rare. We present a prospective open-labelled non-randomized study focusing on safety, efficacy and factor VIII (FVIII) usage compared with bolus injections (BI) in children. In 43 consecutive patients (0.5-17 years; median: 9.6) undergoing different operations, CI was started with an initial FVIII-bolus of 70 IU kg(-1) bodyweight, followed by a median infusion rate of 4.4 IU kg(-1) h(-1) (range: 2.8-9.5) dose adjusted for daily FVIII levels (target: 60-80%). No direct serious adverse events occurred; however, two out of 43 patients, both from the group of four patients with less than 20 exposure days (ED) before starting CI, developed a high-responding inhibitor. Two CI patients showed mild thrombophlebitis or rash. Infusion rates needed to achieve adequate FVIII levels were highly predictable and could be reduced because of decreasing FVIII clearance. Bleeding, requiring additional boli, was observed in eight out of 43 patients. Therapy duration and factor usage of CI were influenced by the procedure, but not by the product used or thrombophilia. Twelve of these CI patients were compared with 12 contemporary consecutive age- and procedure-matched BI patients. Compared with BI patients, CI patients saved 30% FVIII (812.9 vs. 563.2 IU kg(-1), P < 0.006). We conclude that CI forms a safe and effective method for perioperative care in children and reduces factor usage. Because of the unknown risk of inhibitor development, we will use CI only in patients beyond 20 ED.

Adenosine kinase inhibitor GP515 improves experimental colitis in mice

Adenosine is a potent anti-inflammatory mediator. Through elevation of endogenous adenosine concentrations the adenosine kinase inhibitor GP515 might serve to down-regulate local inflammatory responses. In the present study we investigated the effect of systemic GP515 in the nonacute model of dextran sulfate sodium (DSS)-induced colitis. The clinical score, colon length, histologic score, colon cytokine production, and spleen weight from mice with DSS-induced colitis (3.5% DSS in drinking water for 11 days) receiving GP515 treatment were determined and compared with untreated control mice. Splenocytes were analyzed for phenotype, interferon-gamma (IFNgamma) production, and CD69 expression. First, GP515 treatment resulted in a significant improvement of clinical score (weight loss, stool consistency, and bleeding) and of histologic score. Second, colon shortening, an indirect parameter for the degree of inflammation, was decreased, consistent with a decreased IFNgamma concentration in the colonic tissue. Third, spleen weight was reduced in GP515-treated DSS mice. And fourth, IFNgamma synthesis and CD69 expression, as a marker for early cell activation, of ex vivo-stimulated splenocytes were suppressed in the GP515-treated DSS mice. These studies show that GP515 is effective in the therapy of DSS-induced colitis. One potential mechanism of action is the suppression of IFNgamma synthesis and CD69 expression. Adenosine kinase inhibition forms a pharmacologic target that should be further investigated for chronic inflammatory bowel disease.

High altitude increases circulating interleukin-6, interleukin-1 receptor antagonist and C-reactive protein

Hypoxic pulmonary vasoconstriction is associated with but may not be sufficient for the development of high-altitude pulmonary oedema (HAPO). Hypoxia is known to induce an inflammatory response in immune cells and endothelial cells. It has been speculated that hypoxia-induced inflammatory cytokines at high altitude may contribute to the development of HAPO by causing capillary leakage in the lung. We were interested if such an inflammatory response, possibly involved in a later development of HAPO, is detectable at high altitude in individuals without HAPO. We examined the plasma levels of interleukin 6 (IL-6), interleukin 1 receptor antagonist (IL-1ra) and C-reactive protein (CRP) in two independent studies: study A, Jungfraujoch, Switzerland, three overnight stays at 3458 m, n=12; study B: Capanna Regina Margherita, Italy, 3 overnight stays at 3647 m and one overnight stay at 4559 m, n=10. In both studies, probands showed symptoms of acute mountain sickness but no signs of HAPO. At the Jungfraujoch, IL-6 increased from 0.1+/-0.03 pg/ml to 2. 0+/-0.5 pg/ml (day 2, P=0.03), IL-1ra from 101+/-21 to 284+/-73 pg/ml (day 2, P=0.01), and CRP from 1.0+/-0.4 to 5.8+/-1.5 micrograms/ml (day 4, P=0.01). At the Capanna Margherita, IL-6 increased from 0. 5+/-0.2 pg/ml to 2.0+/-0.8 pg/ml (P=0.02), IL-1ra from 118+/-25 to 213+/-28 pg/ml (P=0.02), and CRP from 0.4+/-0.03 to 3.5+/-1.1 micrograms/ml (P=0.03). IL-8 was below the detection limit of the ELISA (<25 pg/ml) in both studies. The increase of IL-6 and IL-1ra in response to high altitude was delayed and preceded the increase of CRP. We conclude that: (1) circulating IL-6, IL-1ra and CRP are upregulated in response to hypobaric hypoxic conditions at high altitude, and (2) the moderate systemic increase of these inflammatory markers may reflect considerable local inflammation. The existence and the kinetics of high altitude-induced cytokines found in this study support the hypothesis that inflammation is involved in the development of HAPO.

Specific type IV phosphodiesterase inhibitor rolipram mitigates experimental colitis in mice

The specific type IV phosphodiesterase inhibitor rolipram is a potent suppressor of tumor necrosis factor-alpha (TNF) synthesis. We examined the efficacy of rolipram for the prevention and treatment of experimental colitis. To induce colitis, BALB/c mice received 5% dextran sulfate sodium in their drinking water continuously for up to 11 days. Colitis was quantified by a clinical activity score assessing weight loss, stool consistency, and rectal bleeding (range from 0 to 4); by colon length; by a semiquantitative histologic score (range from 0 to 6); and by detecting TNF concentration in colonic tissue by enzyme-linked immunosorbent assay. In a first protocol, rolipram (10 mg/kg b.wt./day i.p.) was started on the same day as dextran sulfate sodium. Rolipram reduced the clinical activity of colitis (score 1.1 +/- 0.3) compared with mice that did not receive rolipram (2.4 +/- 0.4; P =.041). Rolipram also partially reversed the reduction of colon length (without rolipram, 12.4 +/- 0. 3 cm; with rolipram, 15.4 +/- 0.7 cm; P =.004) and improved the histologic score (1.5 +/- 0.6 in rolipram-treated mice versus 4.6 +/- 0.5; P =.020). Rolipram suppressed colonic tissue TNF concentrations. The beneficial effect of rolipram was confirmed in a second protocol in which dextran sulfate sodium exposure was discontinued on day 7 and rolipram was administered from day 8 through day 15. These three series of experiments on a total of 153 mice documented the efficacy of rolipram in both the prevention and treatment of experimental colitis.

Inflammatory bowel disease: no association between allele combinations of the interleukin (IL) I beta and IL-I receptor antagonist gene polymorphisms

BACKGROUND

Interleukin 1 (IL-1) and its physiological antagonist interleukin-1 receptor antagonist (IL-1 ra) play a crucial role in the pathogenesis of inflammatory bowel disease. Polymorphisms in the genes coding for these cytokines, the restriction enzyme TaqI polymorphism for IL-1 beta and the variable number of tandem repeats (VNTR) polymorphism for IL-1 ra, have been shown to influence cytokine synthesis in vitro. Recently, an association has been described for distinct allele combinations of these two polymorphisms in patients with ulcerative colitis and with Crohn's disease but not in healthy control subjects.

METHODS

We studied 56 patients with ulcerative colitis, 64 patients with Crohn's disease and 196 healthy control subjects. All were unrelated Caucasians of European ancestry. After polymerase chain reaction (PCR) the amplification products were analysed on agarose gels. For the IL-1 beta polymorphism the PCR product was additionally digested using the restriction enzyme TaqI.

RESULTS

The allele and genotype frequencies as well as the carriage rates of the IL-1 beta TaqI polymorphism in healthy control subjects were in agreement with previous findings in other populations. Allele and genotype frequencies of the IL-1 beta polymorphism were not different in inflammatory bowel disease patients compared with healthy control subjects. Comparing allele combinations of both polymorphisms no association could be identified either within healthy control subjects or in the groups of patients with ulcerative colitis or Crohn's disease.

CONCLUSION

Thus, we could not confirm the results of a previous study reporting an association between the IL-1ra and IL-1 beta gene polymorphisms in patients with inflammatory bowel disease.