Sites of initial bleeding episodes, mode of delivery and age of diagnosis in babies with haemophilia diagnosed before the age of 2 years: A report from The Centers for Disease Control and Prevention's (CDC) Universal Data Collection (UDC) project
Lack of detailed natural history and outcomes data for neonates and toddlers with haemophilia hampers the provision of optimal management of the disorder. We report an analysis of prospective data collected from 580 neonates and toddlers aged 0-2 years with haemophilia enrolled in the Universal Data Collection (UDC) surveillance project of the Centers for Disease Control and Prevention (CDC). This study focuses on a cohort of babies with haemophilia whose diagnosis was established before the age of two. The mode of delivery, type and severity of haemophilia, onset and timing of haemorrhages, site(s) of bleeding, provision of prophylaxis with coagulation factor replacement therapy, and the role played by the federally funded Haemophilia Treatment Centers (HTC) in the management of these infants with haemophilia were evaluated. Seventy-five per cent of haemophilic infants were diagnosed early, in the first month of life, especially those with a family history or whose mothers were known carriers; infants of maternal carriers were more likely to be delivered by C-section. Involvement of an HTC prior to delivery resulted in avoidance of the use of assisted deliveries with vacuum and forceps. Bleeding from the circumcision site was the most common haemorrhagic complication, followed by intra- and extra-cranial haemorrhages and bleeding from heel stick blood sampling. Eight per cent of the infants were administered factor concentrate within 24 h of birth; more than half were treated to prevent bleeding. This study highlights the significant rate and the sites of initial bleeding unique to very young children with haemophilia and underscores the need for research to identify optimal evidence-based recommendations for their management.
[Show abstract][Hide abstract] ABSTRACT: Haemophilia is an inherited, x-linked bleeding disorder. Patients with haemophilia lack clotting factor VIII (FVIII) or factor IX (FIX) causing spontaneous or prolonged bleeding. The hallmark of severe haemophilia is recurrent joint bleeding, eventually leading to severe crippling arthropathy. Functional limitations and the need for lifelong treatment have a large impact on a patient’s daily life. Classification of haemophilia Haemophilia is classified into the types and quantity of clotting factor deficiency. Haemophilia A patients lack FVIII and haemophilia B patients lack FIX. In 1958 haemophilia was classified in three severities based on clinical observations; <1 IU/dl FVIII/FIX (<1% of normal activity levels) was classified as severe haemophilia, 1-5 IU/dl FVIII/FIX (1-5% of normal activity levels) as moderate haemophilia and 6-40 IU/dl FVIII/FIX (6-40 % of normal activity levels) as mild haemophilia. In 2001 this classification has been adopted by the International Society of Thrombosis and Haemostasis as standard. However since 1958 this classification has remained unchallenged; does it still stand? This thesis showed that, without fancy laboratory work or statistical tools, Biggs and MacFarlane designed a very robust classification of haemophilia. The association between annual number of joint bleeds and factor activity level confirmed the current classification. This association was asymptotic: The classification of haemophilia was also confirmed by the association between the milestones of haemophilia; age at diagnosis, age at first treatment and age at onset of bleeding and factor activity levels. When comparing the two types of haemophilia (A and B) this asymptotic relation was also observed in both haemophilia types. Outcome in moderate haemophilia Moderate haemophilia is the rarest and least studied form of haemophilia, only 20% of haemophilia patients have 1-5 IU/dl FVIII/FIX. Since the introduction of prophylaxis at the end of the 1960s, physicians have been trying to convert the bleeding pattern of severe haemophilia into the milder bleeding pattern of moderate haemophilia. It appeared that patients with baseline factor activity levels of >3 IU/dl had less complications of haemophilia than patients with baseline levels <3 IU/dl. Bleeding occurred more frequently and joint function was more reduced in patients with severe haemophilia on long-term prophylaxis than in patients with moderate haemophilia. Magnetic Resonance Imaging (MRI) can detect early signs of joint deterioration. In some joints abnormalities were detected by MRI, without prior joint bleeding. These abnormalities may have been caused by sports-injuries rather than haemophilia related. Haemosiderin on MRI was associated with the time between assessment, suggesting regeneration of the joint after a bleed, provided sufficient time to recuperate in the absence of bleeding.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this paper is to describe the current state of
avalanche transistor-based Pockels cell driver development at LLNL and
to provide the reader with a set of useful design guidelines. A general
description of the units is followed by a short section on the circuit
design of avalanche transistor pulsers. Techniques for delivering either
¼ or ½ wave voltages to a Pockels cell are covered.
Recently these units have been modified for use at repetition rates up
to 10 kHz. Operating at high repetition rates presents problems for both
the driver and the Pockels cell. Design solutions for the pulser are
presented as well as a discussion of Pockels cell acoustic resonance
Pulsed Power Conference, 1997. Digest of Technical Papers. 1997 11th IEEE International; 01/1997
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