Haemorrhagic Diatheses Caused by a Genetic Disorder, Part One and Two

Definition
Bleeding in any part of the body that sustains trauma is prohibited by the process of haemostasis. During the first phase of haemostasis thrombocytes, vessel wall and the von Willebrand factor interact in the formation of a platelet plug. Fibrin polymers are the end products of activation of the second phase of the coagulation cascade and reinforce the platelet plug. The differential diagnosis of hemorrhagic diathesis consists of both hereditary and acquired diseases. The combination of information from the history and the physical examination points the clinician to the most likely localisation of the defect in the pathway of haemo- stasis, and reveals if a congenital coagulation factor deficiency is likely.

Haemostasis
Problems in the first phase of haemostasis mostly cause mucocutaneous bleeding. The bleedings are usually small and can be stopped by local pressure. Clinical signs differ depending on the pathogenesis of bleeding. Problems in the second phase of haemostasis often lead to larger more difficult to control bleedings, such as haematomas, haemothorax or haemoabdomen. In these cases systemic therapy that substitutes absent or dysfunctional coagulation factors is often necessary.
In case of a hereditary disease the hemorrhagic diathesis is congenital and therefore bleeding usually, but not exclusively, occurs at a young age.

Anamnesis
In the history attention should be given to details concerning excessive bleeding after vaccination, chipping, shedding of the teeth, and bleeding problems during or after minor or major surgeries (castration, ovariectomy). If the defect is expected in the primary phase of haemostasis additional diagnostics such as buccal mucosal bleeding time, thrombocyte count, thrombocyte aggregation or determination of von Willebrand’s disease antigen concentration are helpful. In case of suspected problems within the secondary phase of haemostasis, the combination of prothrombin time, activated partial prothrombin time, and thrombin time is helpful in determining the location of the defect within the intrinsic, extrinsic or common pathway. Additional measurement of the functional activity of individual coagulation factors that reside within the dysfunctional pathway confirms the diagnosis. For an individual patient this diagnostic pathway is usually sufficient to make a diagnosis. [...]