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ZusammenfassungAngeborene Thrombozytopathien sind komplexe Erkrankungen. Zur optimalen Blutungsprophylaxe und -behandlung empfehlen wir eine Abklärung und Diagnose der zugrunde liegenden Funktionsstörung. Dazu steht eine interdisziplinäre Leitlinie zur Verfügung (AWMF # 86–003 S2K; Hämostaseologie 2014; 34: 201–212).Die Behandlung ist auf den Defekt, die Thrombozytenzahl, das Lebensalter und die klinischen Umstände abzustimmen. Die Transfusion von Thrombozyten allein kann wegen der damit verbundenen Risiken unangemessen sein. Empfohlen wird ein stufenweiser und individualisierter Behandlungsplan. Antifibrinolytika sind generell anwendbar, besonders bei der Quebec-Erkrankung. Desmopressin ist älteren Kindern vor behalten und vor allem zur Behandlung der Storage- Pool-Erkrankungen und nicht klassifizierter Defekte geeignet. Rekombinanter FVIIa ist zwar nur für die Behandlung der Thrombasthenie Glanzmann mit Alloantikörpern zugelassen, wird jedoch in der klinischen Praxis auch bei Thrombozytendefekten mit schwerer Blutungsneigung eingesetzt. Das Ziel dieser Leitlinie ist die Behandlung von Patienten mit angeborenen Thrombozytenfunktionsstörungen bestmöglich zu unterstützen.

SummaryThe development of neutralizing alloanti-bodies (inhibitors) to factor VIII (FVIII) is one of the most serious complications in the treatment of haemophiliacs. Inhibitors occur in approximately 20 to 30% of previously untreated patients (PUPs), predominantly children, with severe haemophilia A within the first 50 exposure days (ED). Immune tolerance induction (ITI) leads to complete elimination of the inhibitor in up to 80% of the patients and offers the possibility to restore regular FVIII prophylaxis. However, patients with high titre inhibitors, in whom standard ITI fails, usually impose with high morbidity and mortality and therefore prompting physicians to alternate therapy regimens. Rituximab, an anti-CD 20 monoclonal antibody has been successfully used in children and adults for the management of B-cell mediated disorders. We report on the use of a new protocol including rituximab in two adolescents with severe haemophilia A and high titre inhibitors, severe bleeding tendency and high clotting factor consumption after failing standard ITI. Both patients received a concomitant treatment with FVIII according to the Bonn protocol, cyclosporine A and immunoglobulin. Treatment with rituximab resulted in a temporary B-cell depletion leading to the disappearance of the inhibitor. FVIII recovery and half-life turned towards normal ranges. In patient 1 the inhibitor reappeared 14 months after the last rituximab administration. In patient 2 complete immune tolerance could be achieved for 60 months. Bleeding frequency diminished significantly and clinical joint status improved in both patients. In patient 1 the treatment course was complicated by aspergillosis and hepatitis B infection. Conclusion: Rituximab may be favourable for patients with congenital haemophilia, high-titre inhibitors and a severe clinical course in whom standard ITI has failed. Prospective studies are required to determine safety, efficacy and predictors of success.

BACKGROUND AND OBJECTIVE Resistance against activated protein C (APC), caused by factor V R506Q mutation (factor V Leiden mutation), is among the most important hereditary clotting defects that are associated with an increased risk of venous thrombosis. As there are hardly any data for Germany regarding APC resistance that have been validated by genetic analysis, this study was undertaken to determine the prevalence of factor V Leiden (fVL) mutations in a sizeable group of patients in Germany with venous thromboembolism (VTE) and a control group of healthy persons. PATIENTS AND METHODS 1200 consecutive patients (689 females, 511 males) from various regions of Germany were examined who, at an age between 0.1 and 45 years, had developed primary deep vein thrombosis (DVT) and/or pulmonary embolism (PE), as confirmed by imaging tests. The control group consisted of 740 healthy persons (332 females and 408 males; median age 33 years) for whom there was no evidence in their personal or family history of TE. Analysis of the fV-1691 genotype was by Mnll-restriction analysis of genomic fV DNA fragments, amplified by polymerase chain reaction. RESULTS The prevalence in the control group was 7.5% the for heterozygotic fV:Q506 mutant (25 females, 30 males). For the patients the prevalence of the fV R506Q mutation was 27.2% (32.1% heterozygotes [165 females, 112 males]; 4.1% homozygotes [33 females, 16 males], i.e. significantly higher than in the healthy controls (P < 0.0001). In 81.3% of the patients with fV:Q506 DVT in the leg-pelvic vein region was found as the first manifestation, thrombosis in an atypical site in 14.4% and isolated PE in 4.3%. The first manifestation had occurred spontaneously in 36% of patients with the fV:Q506 mutant (44 females, 75 males), in 53.1% of homozygotes and in 33.5% of heterozygotic carriers of the mutation. CONCLUSION The fV Leiden mutation due to APC resistance is the most common cause of venous thrombosis and apparently one of the most common inherited diseases.

Inherited factor VII (FVII) deficiency is a rare autosomal recessive disorder. Mutations and polymorphisms of the FVII gene were characterized in more than 40 unrelated patients with FVII deficiency. Among the 29 different mutations, the most frequent were Ala294 Val, Ala294Val;404delC, IVS7+7, and Val281 Phe. Four novel mutations (IVS2+1G>C, Arg247 Cys, Glu265 Lys, Asp343 His) were detected. The relationships between genotypes of mutations and polymorphisms of the FVII gene, FVII deficiency, and clinical phenotype were investigated. Homozygosity of the Phe4 Leu, IVS4+1G>A, Cys135 Arg, Ala244 Val, and Ala294 Val;404delC and the double heterozygosity of Tyr68 Cys / IVS3-1G>A, Val252 Met / IVS2+5G>T, Val281 Phe / Cys135 Arg, Ala294 Val / Val281 Phe, Ala294 Val;404delC / Val281Phe, Ala294 Val;404delC / Arg152 stop, Ala294Val;404delC / Gln(-35) stop, Ala294 Val / Val252 Met, Ala294 Val / Gly156 Asp, and Thr359 Met / Asp242 His were related to clinical symptoms. Double heterozygotes for Arg247 Cys / IVS2+1G>C, Ala206 Thr / Pro303 Arg, Leu(-20) Pro / Val252 Met as well as IVS7+7 /Ala294 Val, IVS7+7 /Ala206 Thr, and IVS7+7 / Met298 Ile were asymptomatic. The clinical symptomatology is rather poor in correlation with the FVII activity. Concerning the clinical phanotype, a correlation seems to exist between specific mutations and clinical symptoms.

SummaryThis review analyses literature reports from 1970 to 1998 assessing the use of streptokinase (SK), urokinase (UK) or recombinant tissuetype plasminogen activator (rt-PA) for thrombolytic therapy in neonates and infants. From 1970 to 1998 182 infants were reported to have received SK (n = 54; 29.5%), UK (n = 41; 22.5%) or rt-PA (n = 87; 48%). During thrombolytic therapy no concomitant heparin administration or low dose heparin therapy (5 U/kg/h) were recorded. To perform reocclusion prophylactics heparin was reinitiated at the end of thrombolytic therapy usually in the recommended dosage of 20 U/kg/h. The overall thrombolytic patency rate in neonates varied from 39% to 86%. Besides bleeding from local puncture sites or recent catheterisation sites (10.4%), pulmonary embolism was reported in 1.1% of the 182 infants. Major bleeding complications, i.e. pulmonary bleeding (0.6%), gastrointestinal bleeding (0.6%) or intraventricular haemorrhage (IVH 2.7%) are rarely reported side effects and only 2 thrombolysis related deaths due to haemorrhage were mentioned. Bleedings reported in the central nervous system (n = 4) mainly occurred in preterm infants (n = 3). In conclusion, data of this preliminary analysis suggest that there is no big difference (p = 0.09; χ2-test) in the efficacy rate between the 3 thrombolytic agents used in the first year of life. In each case an assessment must be made with respect to the relative benefit conferred by thrombolytic therapy in preventing organ or limb damage versus the potential side effects, costs and inconvenience for the childhood patient. Controlled prospective multicentre studies on thrombolytic therapy in neonates and infants are recommended to evaluate patency rates and adverse effects for the different thrombolytic agents used.

ZusammenfassungDie steigende Anzahl von thrombotischen Ereignissen im Kindesalter, auch bedingt durch die zunehmenden Katheterisierungen in Neonatologie, Kardiologie und Onkologie, zeigen die Bedeutung und Notwendigkeit thrombolytischer Therapien im Kindesalter. Die Indikationsstellung zu einer thrombolytischen Therapie hängt ab von der Lokalisation des Verschlusses sowie den Zielen und möglichen Folgen einer Thrombolyse. Für die Anwendung der Thrombolytika Streptokinase und Urokinase bei Erwachsenen liegen Richtlinien vor, aus denen die Indikationen eindeutig hervorgehen. Im Kindesalter existieren inzwischen zahlreiche Erfahrungen mit der Lysetherapie, jedoch gibt es keine offiziell erstellten Indikationen für diese Therapie. Daher muß bei Kindern auf bisher publizierte Erfahrungen bei der Indikationsstellung zurückgegriffen werden und der zu erwartende Nutzen einer thrombolytischen Therapie gegenüber möglichen Folgeschäden abgewogen werden.Durch die Entwicklung des Thrombolytikums rt-PA haben sich neue Aspekte für die Lysetherapie bei Kindern ergeben. Eine fibrinolytische Behandlung mit rt-PA bietet den großen Vorteil einer weitgehend fibrinspezifischen Wirkung im Gegensatz zu Streptokinase und Urokinase. Ein weiterer Vorteil liegt in der guten Steuerbarkeit der fibrinolytischen Therapie mit rt-PA aufgrund der kurzen Halbwertszeit.Generell sollte die Indikation zur Thrombolyse im Kindesalter gestellt werden, wenn von dem thrombotischen Verschluß unmittelbar eine Lebensbedrohung ausgeht oder wenn eine lebensbedrohliche Krankheitsprogredienz durch eine erfolgreiche Lyse abgewendet werden kann. Außerdem ist die Indikation zur Lyse dann gegeben, wenn ein sicherer oder möglicher Dauerschaden aus dem Thromboseereignis erwächst. Eine Lyse kann auch indiziert sein, wenn dadurch Beschwerden des Patienten bekämpft werden oder ein thromboembolisches Ereignis beziehungsweise ein Thromboserezidiv verhindert werden kann. Vor jeder Indikationsstellung müssen eventuelle Kontraindikationen beachtet werden. Eine Relativierung der Kontraindikationen ist bei vitaler Indikation beziehungsweise bei zu erwartenden schweren Folgeschäden zu erwägen.

In 34 perinatally HIV infected children time of manifestation, type and treatability of neurologic disorders were investigated for a period of 7 years (1987-1994). Neurological investigations were done every 6 months; EEG and MRI/CT were examined initially in the asymptomatic stage and were repeated when neurologic Symptoms occurred. Zidovudine therapy was started after onset of symptoms, dosage was raised, when treatment with Zidovudine had already begun (600-720 mg/m2/day). Various neurological manifestations were seen in 4 of 12 patients in stage B (33%) and in 11 of 14 children in AIDS (80%). 7 of the 14 AIDS-patients (50%) developed a subacute progressive course or progressive plateau course and 4 of 14 (30%) a static course of encephalopathy. Pathological changes in EEG were seen in 54% of investigated patients with neurological deficits. Neuroimaging revealed pathological findings in all symptomatic subjects, 6 of 11 patients in AIDS (55%) has a severe general cerebral atrophy and multifocal white matter lesions. Zidovudine had a positive temporary effect from 6 to 12 months in 5 of 11 treated patients (45%). At present a thorough neurological examination is the most sensitive method to detect neurological impairment in HIV infected children. In most cases CT/MRI scan provides information about the course of the encephalopathy. Antiretroviral therapy has a limited benefit, if neurologic symptoms start after the second year of life.

Consumption coagulopathy in childhood is still a serious problem. Besides treatment of the underlying diseases therapy of consumption coagulopathy was performed with heparin and nowadays with substitution of coagulation factors, especially antithrombin III concentrate, alone or in combination with heparin. We performed administration of AT III concentrates only, without additional heparin treatment in children with proven septicaemia (preterm infants n = 21, children beyond the newborn period n = 18). Antithrombin III, platelet count, fibrinogen, PT, aPTT and TT were assayed. These coagulation parameters turned to be normal 48 hours after normalisation of the antithrombin III plasma level-AT III increased to normal values within 24 hours after the initial substitution in all children. Lethal outcome was not observed after sole administration of AT III as well as no other side effects have been seen. In summary, these data indicate that consumption coagulopathy in childhood can be managed successfully with early substitution of AT III concentrate.

In order to establish an univariate nonparametric pediatric tolerance region platelet function has been investigated in 105 healthy children and adolescents. In comparison to adult normal values, the bleeding time is shortened, spontaneous platelet aggregation is enhanced as well as collagen-induced platelet aggregation. 30% of the children showed an increased disaggregation in ADP-induced aggregation. A slight delay was found in the spreading of thrombocytes. Platelet volume shifted to the left. Values of beta-thromboglobulin were raised. Compared to adult values no alterations could be found in platelet shape-change. Changes of platelet functions were more apparent in the younger children.

Thrombolytic therapy usually used for thrombosis in the adult has been administered as a therapeutic regiment in pediatric patients (parental consent was sought prior to the treatment with rt-PA). We report our experience with rt-PA in 17 children and adolescents suffering from arterial (n = 4) or venous thrombosis (n = 13) due to local rhabdomyosarcoma, acute lymphoblastic leukemia, chronic myeloblastosis, sickle cell anaemia, parenteral nutrition, haemolytic uremic syndrome, central arterial and venous catheters and septicemia Thrombotic diseases have been diagnosed by Doppler ultrasound, computed tomography, angiography and phlebography. Rt-PA therapy was started immediately after diagnostic procedures had been performed. Rt-PA dose varied from 0.2 mg as a single dose to 0.8 mg/kg bw/d over a three day period in children local thrombolysis was performed. In patients requiring systemic thrombolytic therapy rt-PA was administered from 0.8 mg/kg bw/d in three days to 2.0 mg/kg bw/d over a whole period of three weeks in both groups during thrombolysis low dose heparin was added. When rt-PA infusion was terminated heparin (70 IU - 400 IU/kg bw/d) was administered for 7 to 14 days in order to prevent reocclusion. Later prophylaxis with coumarin derivatives in venous thrombosis and antiplatelet agents in arterial occlusive diseases was performed. In no patient did we see a decrease of fibrinogen and plasminogen during rt-PA therapy.(ABSTRACT TRUNCATED AT 250 WORDS)