Summary. Background: Inhibitors are rare in boys with mild hemophilia A (MHA; factor (F)VIII:C >5%) but may arise following intense FVIII exposure, e.g. continuous infusion (CI). Objectives: To determine the impact of intense FVIII exposure in inhibitor formation in MHA at our institution and to compare this with previous reports. Patients and methods: We reviewed FVIII exposure and inhibitor development in boys (ages 0-18 years) with MHA followed at our institution from 1996 to 2001 and conducted a Medline search on the experience of inhibitor development following intensive/CI exposure to FVIII. Results: We identified 54 boys with MHA. Twenty-nine (54%) had been exposed to FVIII. Seven had received FVIII by CI. Four developedinhibitors;threehightiter(atages10 years,16 yearsand 17 years) and one low titer (at 1 month old). All four had received a CI of recombinant (r) FVIII of at least 6 days within 6 weeks of developing inhibitors. Baseline FVIII levels fell to <1% in all cases and the three with high-titer inhibitors developed severe bleeding. Immune tolerance therapy (ITT) was attempted in two boys and was successful in one. Our literature search identified 35 cases (only four children) with MHA developing inhibitors following intense FVIII exposure often in the context of surgery. Conclusions: The incidence of inhibitors in our MHA population was 7.4%. If expressed according to exposure the incidence was significantly higher: 14% (4/29) for any exposure to FVIII and 57% (4/7) for exposure by CI. A prospective study to address whether CI is associated with an increased incidence of inhibitor development in MHA is warranted.
Radiological imaging of joints in children with haemophilia is important to detect abnormalities, grade their severity and monitor the effects of treatment. Scoring systems for staging haemophilic arthropathy have been developed based on plain film or magnetic resonance imaging (MRI) findings. Radiographs alone may be inadequate for evaluating joint disease in children with haemophilia on prophylaxis while MRI may be difficult to access and require the child to be sedated. Sonography can be a useful complementary modality in the evaluation of haemophilic arthropathy that is readily available and does not require the child to be sedated. In this paper, we briefly review the current imaging scales available for the assessment of haemophilic arthropathy and present a systematic protocol for sonographic assessment of the knee and ankle in haemophilic children along with examples of findings in joint effusion/hemarthrosis, synovial hypertrophy and cartilage loss. Also, we correlate the ultrasound findings with the corresponding MRI images demonstrating the anatomic planes used for imaging acquisition. Sonography is a promising technique for the assessment of soft tissue changes which are the earliest findings in haemophilic arthropathy. Further investigation is required for evaluation of osteochondral changes given limitations of sonography in this regard and in minimizing operator dependency, especially if applied in multicentric clinical trials.
Summary. The PFA-100® system provides an in-vitro method of assessing primary platelet-related haemostasis by measuring the time (the closure time, or CT) taken for a platelet plug to occlude a microscopic aperture cut into a membrane coated with collagen and either epinephrine or ADP. We used the system to establish normal ranges for CTs in healthy children, adults and neonates. Mean CTs of healthy children were independent of the needle gauge used (21G or 23G) for blood sampling; they were very similar to the mean CTs of healthy adults, but longer than mean CTs of healthy neonates. Although children with haemophilia had normal CTs, the PFA-100 system was found to be potentially useful in screening for von Willebrand disease in children.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.