Bleeding disorders often arise when there is a problem with the clotting process. Hemostasis is the process by which the body arrests bleeding via the damaged blood vessels and it involves three major steps: vasoconstriction, formation of a temporary blockage (platelet plug), and blood coagulation. When injury causes a blood vessel to bleed, vascular constriction limits the flow of blood to the injured area. The vessel wall injury, via a series of reactions, triggers the attachment and activation of platelets which aggregates at the site of injury. Platelets adhere to collagen which becomes exposed in the endothelial cell lining of blood vessels at the site of injury creating the platelet plug. Initial platelet adhesion is to von Willebrand factor, a major component in the blood coagulation process. Coagulation factor VIII circulates in the blood stream in an inactive form when bound to von Willebrand factor.
当发生血管损伤时，VIII因子被激活并与von Willebrand因子分离，并与另一个凝血因子IX相互作用。这种相互作用引发了一系列其他化学反应的链blood clot。Activation of a sequence of blood clotting factors generates thrombin which converts fibrinogen to fibrin. Fibrin mesh is then produced around the hemostatic plug in turn strengthening the clot.
von Willebrand disease is the most common type of bleeding disorder and is通常不那么严重in comparison to other bleeding disorders. It occurs due to decrease in or malfunctioning von Willebrand factor activity which ultimately affects the hemostasis process and slows the formation of blood clots resulting in prolonged bleeding episodes. It is estimated that around 1% of the world’s population is affected by von Willebrand disease.
血友病是一种出血障碍，血液无法正确地凝结。它可能导致受伤或手术后自发出血和出血。那些患有血友病的人会比平常流血更长，尽管not faster。有两种主要类型的血友病是血友病A和血友病B，前者是两者中最常见的。尽管它是最常见的血友病类型，但它是一种罕见的疾病，会影响每10000个男人而血友病B会影响每50,000名男性中有一个。当突变或变化发生在其中一个基因中，该基因提供了使凝血因子蛋白形成血块所需的指令之一，从而导致相应凝血因子的产生或缺乏，从而导致凝血因子蛋白。均位于X染色体上的F8基因和F9基因分别提供了产生凝血因子VIII和IX的指令。F8基因中的A突变会导致血友病A，而F9基因中的A突变导致血友病B。因此，受苦的凝血因子VIII或IX水平较低，并且严重程度取决于血液中因子的水平。
由于该疾病的性别联系，突出在男性中，男性比女性大。尽管该疾病主要影响男性，但女性可以是受影响基因的携带者，并经历了症状。血友病是一种遗传性出血障碍。但是，已经发现大约第三of new diagnoses there is no previous family history. This could be due to新的或自发的基因突变。It is estimated that worldwide, around 400,000 people are living with hemophilia with 20,000 of these cases present in theUnited States大约有6,000个United Kingdom。主要症状可能包括割伤长期出血，尤其是在幼儿时期容易瘀伤的趋势，并流血成关节和肌肉，导致疼痛，肿胀和僵硬，如果未经治疗，则可能导致关节畸形和运动的限制。妇女可以经历长时间或沉重的月经出血（月经）和失血过多会导致贫血导致无力和疲劳。通常，在排卵过程中，女性可以发展出很小且通常不会有问题的简单/功能性卵巢囊肿。但是，已经发现，血友病的携带者更有可能在排卵过程中出现明显的出血，并且有更大的风险出血到这些简单的囊肿中，然后变成hemorrhagic ovarian cyststhat can cause considerable pain and may require urgent medical intervention. Women with hemophilia are also more likely to have postpartum bleeding following分娩。
It has been reported that of the 400,000 people living with hemophilia worldwide, only around25%receive adequate treatment. The recommended treatment plan for hemophilia depends on the severity of the condition. The main treatment for hemophilia isreplacement therapy因此，丢失的凝血因子被缓慢滴入或注入静脉。CDC赞助随机临床试验发现定期治疗以防止出血（用重组因子VIII进行预防）有效预防关节损伤并降低了严重血友病男孩的关节频率和其他出血的频率。经过定期接受治疗的儿童也比6岁以下的共同损害的证据要少于出血后接受治疗的孩子。
However, factor replacement therapy has its limitations as it has been found that approximately25–30％of people with severe hemophilia A and1-5％of people with severe hemophilia B develop an antibody (inhibitor) to the treatment which causes major complications.
There are a number of new therapies under development which include gene therapy where researchers are investigating means by which the faulty genes that cause bleeding disorders such as hemophilia can be corrected.Researchis also being conducted to design and implement interventions that will help combat complications. Although there is no cure for hemophilia, with the right treatment, care, and lifestyle changes, those who suffer from hemophilia can lead fulfilled lives.
如果您有兴趣阅读有关此主题的更多信息，请访问BMC血液学website. The journal welcomes submissions on non-malignant and malignant hematological diseases, hemostasis and thrombosis, hematopoiesis, stem cells and transplantation. Related papers which detail basic, experimental and clinical research can be submitted to the journal这里。
以下是涵盖血友病区域的杂志上的一些有趣的选择和最新出版物：
Generic and disease-specific quality of life among youth and young men with Hemophilia in Canada
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