Search

Introduction: The prophylactic administration of clotting factor concentrate is currently the most effective strategy for the prevention of joint bleeding. As new agents with different mechanisms of action and administration schedules are developed, it will be important to study them in relevant preclinical models., Aim: The aim of this study was the standardization of a mouse haemarthrosis model in a haemophilia mouse and the development and validation of a comprehensive bleeding assessment system, the Bleeding Severity Score (BSS)., Methods and Results: Four outcome measurements were assessed, two of which, the extra-articular bleeding score and intra-articular bleeding score, were determined to be the most reliable and were summarized into a BSS which was validated using a mouse haemarthrosis variability model., Conclusion: Using this model, the haemostatic effect of prospective drugs can be assessed in a clinically relevant joint bleeding model and will significantly increase the value of preclinical studies., (© 2016 John Wiley & Sons Ltd.)

Repeated haemarthroses and the consequences of blood in the joint contribute to blood induced joint disease (BIJD) in people with haemophilia (PWH). Prevention of bleeding, through medical management, is the standard of care in developed countries, but is not universally available due to financial and other barriers. Ice application, as part of R.I.C.E. (Rest, Ice, Compression, Elevation) or alone, is commonly recommended as an adjunct treatment to decrease bleeding, pain, tissue metabolism, oedema, and inflammation. This article will review evidence regarding local cooling by commonly used ice application methods, to decrease the temperature of the skin and intra-articular (IA) joint space and the resultant effects on haemostasis and coagulation. The general literature was reviewed for articles in English describing temperatures achievable in the skin and IA space using clinically relevant ice protocols, and the effect of cooling on haemostasis and coagulation. The literature demonstrates that typical methods of ice application can cool both the skin and IA space. Published, general literature studies have also consistently demonstrated that experimental cooling of blood and/or tissue, both in vitro and in vivo in humans and in animal models, can significantly impair coagulation and prolong bleeding. In PWH with acute haemarthrosis, ice application has potential to increase haemorrhage morbidity by further impairing coagulation and haemostasis. Ice has not been shown to improve overall outcome, stop bleeding nor swelling from haemarthrosis. Although ice can help manage acute, haemarthrosis-related pain, there are other available interventions that will not impair coagulation and haemostasis., (© 2012 Blackwell Publishing Ltd.)

Blood in the joint causes a number of physiological and pathological events that eventually lead to haemophilic arthropathy. Animal models show that blood in the joint induces inflammation that continues long after blood has been cleared. TNF-alpha, IL-1 beta and IL-6 are inflammatory mediators that increase following haemarthrosis in haemophilic mice. Conventional anti-inflammatory drugs have failed to demonstrate a lasting effect in preventing haemophilic arthropathy. A new TNF-alpha antagonist has shown promising results in haemophilic mice. Similarly, the use of cyclo-oxygenase-2 inhibitors may reduce angiogenesis associated with the healing process following bleeding and the associated tissue damage. Animal models are useful for studying the pathophysiology of haemarthropathy, however, when applying results from animals to humans, the differences in matrix turnover rate, thickness of cartilage and joint biomechanics must be kept in mind. In people with haemophilia, there is a variable response to haemarthrosis as demonstrated by magnetic resonance imaging (MRI). Up to 30% of subjects have normal MRI despite having three or more haemarthroses into the same joint. Once bone damage is present, little can be done to restore anatomic integrity. Several molecules, including members of the bone morphogenic protein subfamily, have been injected into bone defects in non-haemophilic subjects with some evidence of benefit. To achieve the primary goal of reducing blood in the joint and the negative sequelae, it is questionable to use ice to treat haemarthrosis. Indeed low temperature is associated with impairment of coagulation enzyme activity and platelet function., (© 2012 Blackwell Publishing Ltd.)

Haemarthroses (intra-articular haemorrhages) are a frequent finding typically observed in patients with haemophilia. Diagnosis and treatment of these bleeding episodes must be delivered as early as possible. Additionally, treatment should ideally be administered intensively (enhanced on-demand treatment) until the resolution of symptoms. Joint aspiration plays an important role in acute and profuse haemarthroses as the presence of blood in the joint leads to chondrocyte apoptosis and chronic synovitis, which will eventually result in joint degeneration (haemophilic arthropathy). Ultrasonography (US) is an appropriate diagnostic technique to assess the evolution of acute haemarthrosis in haemophilia, although magnetic resonance imaging remains the gold standard as far as imaging techniques are concerned. Some patients experience subclinical haemarthroses, which eventually tend to result in some degree of arthropathy, especially in the ankles. Nowadays, the most effective way of protecting these patients is primary prophylaxis, which in practice changes severe haemophilia into moderate haemophilia, preventing or at least minimizing the occurrence of haemarthrosis. If primary prophylaxis is, for whatever reason not an option, secondary prophylaxis and enhanced on demand treatment should be considered. Two alternatives are available for inhibitor patients: (i) control of haemostasis using by-passing agents (rFVIIa or aPCCs) either as enhanced on demand treatment or secondary prophylaxis, as appropriate, following the same basic principles used for non-inhibitor patients and (ii) immune tolerance induction (ITI) to eradicate the inhibitor., (© 2011 Blackwell Publishing Ltd.)

Summary: Prophylaxis with concentrates of factor VIII has become the standard of care for patients with severe haemophilia A because of its ability to prevent joint and other bleeding events. Recent evidence suggests that the prophylactic use of bypassing therapy--activated prothrombin complex concentrate (aPCC) and recombinant activated factor VII (rFVIIa)--provides similar benefits to haemophilia patients with inhibitors. To assess the efficacy and safety of prophylaxis with the aPCC FEIBA, a meta-analysis was conducted of six studies and a total of 34 inhibitor patients. The mean prophylactic dose was 78.5 U kg(-1), typically infused three to four times weekly. A total of 31 of 33 patients (94%) for whom bleeding data were available prior to prophylaxis experienced a decrease in the rate of haemorrhage, albeit minor in some patients, and, regardless of the type of haemorrhage measured, had on average a 63.9% reduction in bleeding episodes during FEIBA prophylaxis. In the three studies that specifically assessed all joint bleeding, the 18 patients evaluated experienced an average reduction in annual joint bleeding of 74% while on prophylactic regimens. Among the four patients in this group who received concurrent immune tolerance induction and the 14 patients treated with prophylaxis only, annual joint bleeding decreased by an average of 79% and 78%, respectively. Anamnesis following FEIBA exposure was observed in some patients but had no impact on prophylactic efficacy. No thrombotic or other complications were reported. These results suggest that the prophylactic administration of FEIBA can be an effective and safe method for reducing bleeding events in patients with haemophilia A and inhibitors.

Prophylactic infusion of factor concentrates is a safe, effective intervention for preventing arthropathy in patients with haemophilia; on-demand treatment is insufficient to prevent the orthopaedic complications and subsequent haemophilic arthropathy that stem from recurrent joint haemorrhages. The usefulness of prophylaxis in haemophilia patients without inhibitors suggests that patients with haemophilia and inhibitors could derive similar benefits. In patients with haemophilia and high-titre (>5 BU mL(-1)) inhibitors, bleeding episodes are treated with bypassing agents such as activated prothrombin complex concentrates (APCCs) and recombinant activated factor VII (rFVIIa, NovoSeven; Novo Nordisk A/S, Bagsvaerd, Denmark). It is possible to administer bypassing therapy regularly to prevent haemorrhages, with the goal of limiting arthropathy and serious life- and limb-threatening bleeding. The data evaluating the efficacy and safety of this approach in patients with inhibitors are limited, consisting of results from one prospective trial and retrospective case reports. This report describes our experience with the prophylactic use of the APCC Factor Eight Inhibitor Bypassing Activity, Anti-Inhibitor Coagulant Complex, Vapor Heated (FEIBA; Baxter AG, Vienna, Austria). Data from patients at one treatment centre were retrospectively evaluated. Case records of six patients with haemophilia A or B and high-titre inhibitors were identified. When APCC was administered regularly, most patients exhibited a reduction in the numbers of haemorrhages, an improvement in orthopaedic status, and an improvement in quality of life. Prophylaxis with APCC can reduce haemorrhages and halt further joint deterioration in patients with haemophilia and inhibitors.

Preservation of normal joint function in patients with haemophilia is a goal of modern therapy. Regular injections of anti-haemophilic factor concentrate reduce the risk of joint bleeding, the optimal regimen for which remains under investigation. The goals of the experiment described here are: (i) to assess the capacity of a murine model of severe haemophilic arthropathy to predict the likelihood of success of a test product to prevent joint bleeding and the complications that follow and (ii) to compare the effectiveness of recombinant human activated factor VII (rFVIIa) to recombinant human factor VIII (rFVIII) to prevent acute joint bleeding in the mouse model of haemarthrosis. Mice lacking expression of FVIII received a single intravenous injection of human rFVIII (280 U kg(-1)), rFVIIa (10 mg kg(-1)) or vehicle prior to blunt trauma injury to the knee joint. Mice receiving rFVIII and rFVIIa developed less injury-induced joint bleeding, swelling and loss of range of motion compared to mice pretreated with vehicle. Despite the reduction in clinical symptoms, synovial hyperplasia was evident in all groups after 7 days although less pronounced in mice receiving rFVIII and rFVIIa. The data under these experimental conditions demonstrate: (i) that this model can be used to evaluate novel therapies designed to prevent joint bleeding (prophylaxis) and (ii) both rFVIII and rFVIIa reduced acute haemarthrosis but did not completely prevent synovitis, the sequelae of blood induced joint injury.

Haemophilic arthropathy, which shares some clinical and biological injury characteristics with rheumatoid arthritis, is characterized by two main features: chronic proliferative synovitis and cartilage destruction. It is the consequence of repeated extravasation of blood into joint cavities, but its exact pathogenesis, particularly with regard to early changes in the joint, is still incompletely understood. This review presents recent findings obtained in experiments performed in vitro and using animal models, which have improved our knowledge of the pathogenesis of haemophilic arthropathy. These experimental studies show that haemophilic arthropathy is a multifactorial event in which the deposit of iron in the joints appears to exert a central role. First, iron may promote the apoptosis of chondrocytes by catalysing the formation of oxygen metabolites; this may explain the fact that intra-articular blood exerts a directly harmful effect on cartilage before, and independent of synovial changes. Secondly, iron may also act on the synovial membrane by favouring its proliferation through the induction of proto-oncogenes involved in cellular proliferation and stimulation of inflammatory cytokines as well as abrogation of apoptosis. These two processes, one degenerative and cartilage-mediated, the other inflammatory and synovium-mediated could occur in parallel or sequentially. Overall, it may be expected that these experimental results will yield new therapeutic strategies capable of effectively preventing the occurrence of this still serious and common complication in patients with severe haemophilia.

Recurrent haemarthrosis results in chronic synovitis and destructive arthropathy. The long-term effect of a single haemorrhage is not known. To investigate the histopathological changes following a single, but major joint haemorrhage, an animal model of massive haemarthrosis without mechanical trauma was developed and is described in this manuscript. The knee joint capsule of mice deficient in coagulation factor VIII or IX and non-haemophilic wild type mice was punctured to induce a one time, but massive haemorrhage. The single joint puncture resulted in acute haemarthrosis in both types of haemophilic mice but not in wild type mice. Subsequent to injury, the changes in the knee joints were analysed using gross, histological and radiographic assessments and compared with the uninjured knee. In addition, a novel imaging modality, micro-computed tomography, was used to document the structural damage to the joint. Our results indicate that the long-term changes classically observed in patients with advanced haemophilic arthropathy are evident following a single massive haemarthrosis. This model will allow a thorough investigation of the pathobiology of blood-induced joint disease and will be useful to test the efficacy of innovative therapeutic strategies to prevent haemophilic synovitis and arthropathy.

Background: Hemophilia A is the most common serious bleeding disorder, and the hallmark of this disease is joint bleeding episodes. These result in hemophilic synovitis, an inflammatory and proliferative condition of the joint, which progresses into a chronic degenerative arthritis, hemophilic arthropathy., Methods: In this paper, we describe the effect of recombinant factor VIIa (rFVIIa), and an analogue NN1731 as well as rFVIII on needle-induced bleeding in hemophilia A mice., Conclusions: Here we show a reducing effect of rFVIIa and NN1731 on bleeding induced in hemophilic mice, and we show that preventive treatment with rFVIII normalizes bleeding.

Haemophilia is a congenital disorder that commonly results in musculoskeletal bleeding and orthopaedic complications. After an acute joint haemorrhage, an increase in intra-articular pressure and inflammation cause pain, swelling and limited motion. Blood in the joint space provokes a proliferative disorder known as haemophilic synovitis. Overgrowth of the synovial membrane causes mechanical dysfunction. Eventually, there is destruction of the articular surface and underlying bone. The aim of this project was to test the hypothesis that a minimum number of haemarthroses negatively impacts on joint function and that this would be reflected by decreased physical performance of experimental animals. Mice deficient in factor VIII coagulant activity were trained to ambulate on a rotating rod then injured three times at weekly intervals. Their ability to walk was then compared to a group of uninjured mice. Cohorts of mice were killed after 1, 2 or 3 months and the knee joints examined by gross and histological methods. The results supported the following conclusions: (i) haemophilic mice can be trained to ambulate on a rotating rod; (ii) acute hemarthrosis temporarily impairs their ability to ambulate and (iii) following recovery from acute injury, mice developing synovitis demonstrated inferior physical ability compared to mice not developing synovitis. This is the first description of a quantitative assay to monitor joint function in experimental animals and should be useful to evaluate the efficacy of new therapies developed to prevent and treat bleeding and to test strategies to counter the devastating effects of synovitis.

Recurrent spontaneous haemarthrosis are commonly seen in patients affected by haemophilia. The knee and the elbow are most commonly affected and both are amenable to arthroscopic treatment. Arthroscopic synovectomy is indicated after failure of appropriate medical management with recurrent bleeding. Many patients also demonstrate motion loss and functional deterioration. The benefits of arthroscopic synovectomy include the ability to perform adequate synovial debridement, but also concomitant lysis of adhesion and capsular release to regain range of motion. Results of arthroscopic synovectomy demonstrate a significant decrease in episodes of haemarthrosis, and significant improvement in pain, range of motion and function. The primary predictor of outcome is degree of pre-existing degenerative changes within the joint. In more severe cases, the results of arthroscopic synovectomy are unpredictable and serious consideration should be given to primary arthroplasty.

Arthropathy remains a major cause of morbidity in patients with haemophilia. Frequent bleeding into the joints leads to joint damage with resultant contractures, joint deformities and arthritis. This in turn leads to muscle atrophy, limited physical activity, osteoporosis and disability. Even though several studies of prophylactic factor replacement for persons with severe haemophilia demonstrate improved joint function, this therapy is still not readily available to most people with haemophilia around the world and a universal treatment protocol has not been used. In this article, we discuss key issues in the treatment of severe haemophilia: the optimal timing of initiation and termination of therapy, dosing options and goals of therapy. The options for countries where prophylaxis is not readily available are also discussed. Most studies are small and not randomized making consensus treatment recommendations difficult to formulate. Randomized, clinical trials are needed to provide the answers regarding the optimal treatment of patients with severe haemophilia.

Hemarthrosis is a common manifestation of haemophilia, and joint arthropathy remains a frequent complication. Even though the exact mechanisms related to blood-induced joint disease have not yet been fully elucidated, it is likely that iron deposition in the synovium induces an inflammatory response that causes not only immune system activation but also stimulates angiogenesis. This process ultimately results in cartilage and bone destruction. Investigating the processes that occur in the early stages of blood-induced joint disease in humans has been very limited. Therefore, the use of haemophilic animal models is critical to augment the understanding of this phenomenon. This article discusses three cellular regulators (p53, p21 and TRAIL) induced in synovial tissue that are important for iron metabolism. A cartilage remodelling programme induced by the release of cytokines and growth factors that result in articular damage is also discussed. Full elucidation of the pathogenesis of haemophilic joint disease is required to identify new avenues for prevention and therapy.

Orthopaedic complications are among the most disabling sequelae occurring in patients with haemophilia and inhibitors. Recurrent or refractory joint bleeds can lead to joint damage, limiting mobility and causing permanent disability. Activated prothrombin complex concentrates (aPCCs) are effective in controlling acute, intraoperative and postoperative bleeding in patients with haemophilia and inhibitors. The relatively long, dosing interval and safety profile distinguish aPCCs as a well-suited option for prophylaxis. Therefore, it is postulated that long-term routine aPCC administration will decrease the frequency of recurrent bleeds, prevent damage to normal joints, and slow the progression of existing joint disease in patients with inhibitors. To test this hypothesis, a retrospective chart audit was performed. In four treatment centres, five patients were identified who received aPCC [Factor Eight Inhibitor Bypassing Activity, Anti-Inhibitor Coagulant Complex (FEIBA); Baxter AG, Vienna, Austria] prophylactically for > or = 6 months to prevent or reduce further joint deterioration, reduce bleeding and prevent postsurgical bleeding. Median treatment duration was 15 months and included administration of >1300 doses of aPCC. Dosages ranged from 50 to 75 U kg(-1) three times per week in four patients; one patient received 100 U kg(-1) daily. Orthopaedic status was maintained in four patients and improved in one; the frequency of bleeding episodes was reduced in all patients. No adverse events or thrombotic complications were reported. This case series demonstrates that routine aPCC administration may be used safely and effectively to reduce the occurrence of bleeding episodes and to maintain or improve clinical joint status in some patients.

BeneFix, the only recombinant factor IX (FIX), has been reformulated. The reformulation involves a change in diluent and allows for more concentrated infusions of recombinant FIX. A double-blind, randomized, pharmacokinetic (PK) crossover study demonstrated that reformulated BeneFix was bioequivalent to original BeneFix and follow-up PK evaluation after 6 months of treatment demonstrated the PK stability of reformulated BeneFix after multiple exposures. Favourable efficacy and safety profiles, consistent with those already well-established for original BeneFix, were observed: 81.1% of haemorrhages resolved with only a single infusion; 85.3% of initial treatment response ratings were Excellent or Good; more than half of the subjects using reformulated BeneFix for routine prophylaxis (11 of 17, 64.7%) had no spontaneous haemorrhages during their 6-12 month course of prophylactic treatment, with an overall spontaneous bleeding rate of 0.72 year(-1); and for the single surgical procedure (knee washing), treatment was rated Useful. In addition, there was no FIX inhibitor development, allergic-type manifestations, or thrombogenic complications with more than 1100 infusions (nearly 5.2 million IUs) administered in this trial. All efficacy and safety outcomes from this study were achieved with more concentrated recombinant protein infusions than that possible with original BeneFix, and utilization of the 2000 IU per vial dosage strength, newly introduced with the reformulated product, was high (>62%). The reformulation of BeneFix allows smaller delivery volumes and an increased choice of dosage strengths without altering the PK properties (including incremental recovery and half-life) or the established efficacy and safety profile of recombinant FIX.

Haemophilia is a congenital disorder that results in frequent bleeding into joints, in which a chronic and debilitating arthritis develops. The presence of blood evokes an inflammatory and proliferative synovial reaction. Although the molecular mechanisms and biochemical pathways which underlie this disorder are not known, significant advances have been made by studying a murine model of human haemophilic synovitis. In order to better understand and correlate the pathological, molecular and biochemical changes, it has become necessary to grade the histological changes observed. Despite a search of the literature and review of relevant publications, none of the currently utilized schemes were appropriate, and therefore a novel grading scheme was developed. After review of over 1000 histological sections, six characteristic changes were identified: (i) synovial hyperplasia; (ii) vascularity; (iii) discolouration by haemosiderin; (iv) the presence of blood (erythrocytes); (v) villus formation; and (vi) cartilage erosion. Synovial hyperplasia and vascularity were present in variable amounts and were quantitatively scored (0-3), while the other changes were qualitatively scored as absent or present (0 or 1). Application of the grading scheme was tested and a high interobserver correlation (greater than 80%) was found. The scheme was easy to learn even by novices, with no prior experience. The availability of the histological grading scheme for murine synovitis will allow for precise evaluation of the pathological changes following joint bleeding, and facilitate correlations with molecular and biochemical changes that lead to these changes.

Haemophilia is a genetic disease as a result of the deficiency of blood coagulation factor VIII or IX. Bleeding is common, especially into joints where an inflammatory, proliferative synovitis develops resulting in a debilitating arthritis, haemophilic arthropathy. The pathogenesis of blood-induced haemophilic synovitis (HS) is poorly understood. The gross, microscopic and ultrastructural changes that occur in the synovial membrane following human and experimental hemarthrosis have been described. Repeated episodes of bleeding induce synoviocyte hypertrophy and hyperplasia, an intense neovascular response and inflammation of the synovial membrane. The component(s) in blood that initiates these changes is(are) not known, although iron is often proposed as one possibility. Here, we describe a novel murine model of human haemophilia A, which facilitates the examination of large number of animals and tissue specimens. The effects of hemarthrosis on the physical, gross and microscopic changes evoked following joint bleeding are described. Controlled, blunt trauma to the knee joint consistently resulted in joint swelling because of a combination of bleeding and inflammation. Hemosiderin was found in the synovial membrane. Similar to hemarthrosis in human haemophilia, joint bleeding resulted in acute morbidity evidenced by inactivity, weight loss and immobility. With time the animals recovered. The model of experimental murine HS described here has utility in the study of the pathogenesis of HS. This is the first of a series of articles, which will discuss the pathophysiology and characterize the model, with comparison of his model to others which have been published previously. It should provide a useful model to test potential therapeutic interventions.

Prophylaxis is widely recommended for the management of severe haemophilia A. Adoption of this approach has varied from country to country, and notably in the US prophylaxis is currently administered in fewer than one-half of severe cases. One implication is that a substantial segment of the severe haemophilia. A population will only be able to reap the potential benefits of prophylaxis if administered in the form of secondary prophylaxis. This therapeutic alternative has been less extensively investigated than primary prophylaxis, but nevertheless sufficient evidence has been reported to allow an assessment of the benefits and limitations of secondary prophylaxis. This evidence addresses the use of secondary prophylaxis in three contexts: (i). early secondary prophylaxis; (ii). delayed secondary prophylaxis and (iii). secondary prophylaxis in adults. In patients receiving early secondary prophylaxis studies in Sweden, the Netherlands, the UK and the US have demonstrated a reduction in the frequency of bleeding episodes and a subsequent low incidence of arthropathy. Additional reported benefits consist of reduced emergency room visits and hospitalizations. However, secondary prophylaxis is associated with an increased risk of the eventual development of arthropathy compared with primary prophylaxis. When delayed until school age or adolescence or until the development of frequent bleeding episodes under on-demand treatment, secondary prophylaxis generally appears to be unable to reverse all existing or developing joint damage. Nevertheless, multiple studies have shown that this therapy can retard further joint deterioration, reduce the frequency of haemorrhage, hospitalization and missed school days, improve physical function and capacity for self care, lessen restrictions on activities, reduce pain and enhance quality of life. Secondary prophylaxis in adults has been shown effective in reducing bleeding episodes. Adults under secondary prophylaxis can also experience improvements in joint condition, functional capacity and quality of life and a reduction in pain. Irrespective of age at initiation, long-term secondary prophylaxis appears to reduce the frequency of bleeding episodes even in patients with existing target joints whose bleeding diathesis persists during the early phases of secondary prophylactic therapy. In light of its potential benefits for substantial numbers of patients with severe haemophilia A, secondary prophylaxis should be considered to as a therapeutic option for patients not receiving primary prophylaxis.

Prophylaxis prevents joint and other bleeding episodes in patients with haemophilia A. Development of new factor concentrates with longer circulating half-lives may encourage patients to start, continue or resume prophylaxis. The aim of this study was to compare the pharmacodynamic effect of a PEGylated full-length recombinant factor VIII ( rFVIII) concentrate with that of an unmodified rFVIII concentrate with respect to the duration of prophylactic efficacy in a murine model of haemophilic joint bleeding. Mice were pretreated with BAX 855 or unmodified rFVIII at specified times before right knee puncture to induce haemarthrosis; left knee joints served as controls. Joint bleeding was evaluated using a combination of visual and histological assessments. Administration of a single dose of unmodified rFVIII before joint puncture prevented haemarthrosis in mice up to 24 h, whereas pretreatment with BAX 855 protected the joint from bleeding up to 48 h. This pharmacodynamic study showed prolonged efficacy of BAX 855 compared to ADVATE in a haemophilia A mouse joint bleeding model. This finding supports the possibility of using BAX 855 to increase FVIII trough levels and/or extend the dosing interval in patients with haemophilia A on prophylaxis, which may potentially improve prophylactic efficacy and long-term adherence. [ABSTRACT FROM AUTHOR]

The phenotypic variability in haemophilia is well documented; however, the biological basis beyond factor VIII and IX activities to explain the differing clinical pictures of the disease remains unclear. It has therefore been of interest to explore other modulators of the disease's variability. Furthermore, a scoring system that reflects the multiple facets of haemophilia symptoms would be useful to compare patients via a comprehensive assessment tool. To this end, Schulman et al., created a measure known as the Haemophilia Severity Score ( HSS) as one way to compare phenotypic severity. The aim of this study was to document the differing symptomatology of haemophilia patients using the HSS. Clinical data for 178 haemophilia patients without inhibitors were reviewed and annual incidence of haemarthrosis, orthopaedic joint scores and annual factor usage calculated. Each parameter was then entered into the formula to create the HSS for haemophilia A and B patients with mild, moderate and severe factor deficiencies. Variability in the HSS for patients with the same baseline level of factor was observed for all three deficiency levels and both haemophilia types. In addition, we found that moderate and severe haemophilic B patients tended to have more morbidity based on the above calculations than the haemophilic A counterparts. The HSS is a comprehensive tool that allows for easy numerical comparison of haemophilic patients and elucidates the variable clinical presentation of the disease. The HSS could be used to stratify patients via other possible modulators of haemophilia and discover other aetiologies of the disease. [ABSTRACT FROM AUTHOR]

Prophylaxis with clotting factor concentrates has been shown to prevent bleeding episodes and improve quality of life in patients with severe haemophilia A or B. The benefits of long-term prophylaxis may also extend to patients with high-titre factor VIII or IX inhibitors who have failed or are not candidates for immune tolerance. Because the presence of an alloantibody makes it difficult to achieve haemostasis during a bleeding event, inhibitor patients are at increased risk for life-threatening haemorrhage and the development of arthropathy. Accumulating evidence suggests that prophylactic therapy with the bypassing agent FEIBA reduces bleeding episodes, including haemarthrosis, and maintains normal joints, although it does not halt established joint disease. Infections associated with central venous access devices are a frequent complication of prophylaxis in young children with haemophilia. [ABSTRACT FROM AUTHOR]