Awareness of Mild Bleeding Disorders
Awareness of Mild Bleeding Disorders
Inherited bleeding disorders are rare in the general population. Nevertheless, the most common bleeding disorders, haemophilia and von Willebrand disease (VWD), occur in one in 5,000 males and 1% of the general population.1 Since fibrin formation or platelet aggregation in these patients is insufficient, prophylaxis with clotting factor concentrate or desmopressin (DDAVP) prevents severe bleeding complications in situations where optimal haemostasis is crucial, such as surgery. Most patients with either haemophilia or VWD have a relatively mild phenotype, and their disease may well become apparent only after abnormal bleeding post operatively.
In addition, many patients may not be aware of having a bleeding abnormality, since relatives may have the same symptoms. Therefore, it is of the utmost importance to identify patients with underlying bleeding disorders before they undergo surgery. In particular, dentists, gynaecologists and paediatricians should investigate patients for potential bleeding abnormalities.
In general, patients with haemophilia can be distinguished from those with VWD by the difference in bleeding symptoms. VWD is caused by a deficiency in or a dysfunction of von Willebrand factor (VWF). VWF is a multimeric protein synthesised in megakaryocytes and endothelial cells. It has two main haemostatic functions. In primary haemostasis at the site of injured vessel walls, it facilitates platelet adhesion to subendothelial structures, such as exposed collagen fibres, and supports platelet aggregation and thrombus formation. As part of secondary haemostasis, VWF acts as a carrier protein for coagulation factor VIII, stabilising and protecting factor VIII pro-coagulant activity. Since VWD has an autosomal dominant inheritance pattern, both men and women can be affected. Individuals with VWD are at increased risk of mucocutaneous bleeding including epistaxis, easy bruising, prolonged bleeding after trivial cuts and dental procedures and reproductive tract bleeding, notably menorrhagia.1,3 Haemophilia is an X-linked recessive disorder caused by a partial or complete deficiency of clotting factor VIII (haemophilia A) or factor IX (haemophilia B). Males are typically affected, and bleeding mostly occurs in joints and muscles.
Table 1: What Questions Should Be Asked to Investigate a Bleeding Diathesis?
How Can Patients with Mild Bleeding Disorders Be Detected?
First, one has to be certain that bleeding manifestations are due to an abnormal bleeding diathesis. This is not simple, since the discrimination between patients with mild bleeding disorders and normal subjects is often unclear. In the case of evaluation of a bleeding disorder, patients can be referred because of abnormal bleeding or physicians can actively screen patients pre-operatively for a defect in haemostasis. In the first instance, patients themselves may have suffered from excessive bleeding after trauma or surgery or have spontaneous bleeding or a family history of increased bleeding tendency. One should remember that most of the time, bleeding symptoms are not caused by a specific bleeding disorder.4
References:
1. Rodeghiero F, Blood, 1987;69:454–9. 2. Rodeghiero F, Castaman G, Tosetto A, et al., J Thromb Haemost, 2005;3:2619–26. 3. Tosetto A, Rodeghiero F, Castaman G, et al., J Thromb Haemost, 2006;4:766–73. 4. Greaves M, Watson HG, J Thromb Haemost, 2007;5(Suppl. 1): 167–74. 5. Kadir RA, Economides DL, Sabin CA, et al., Lancet, 1998;351:485–9. 6. Chee YL, Crawford JC, Watson HG, Greaves M, Br J Haematol, 2008;140:496–504. 7. Kadir RA, Economides DL, Sabin CA, et al., Haemophilia, 1999;5:40–48. 8. Sramek A, Eikenboom JC, Briet E, et al., Arch Intern Med, 1995;155:1409–15. 9. Tosetto A, Castaman G, Rodeghiero F, Blood, 2008;111:3998–4003.
