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Abstract
von Willebrand disease (VWD) is the most common autosomally inherited bleeding disorder caused by a quantitative (VWD types 1 and 3) or qualitative(VWD type 2) defect of von Willebrand factor (VWF). VWF is a multimeric adhesive protein which plays an important role in primary hemostasis. It is also the carrier of factor VIII , thus indirectly contributing to the coagulation process. VWD has a prevalence of about 1% in the general population. . Bleeding manifestations are heterogeneous but mucosal bleeding is typical of all VWD types. (80)
Due to the large heterogeneity of VWF defects and to the external variables (blood groups and other physiological modifiers) influencing VWF levels in the circulation, VWD diagnosis can be difficult especially in relatively mild forms.
An assessment of VWD requires attention to three clinical and laboratory components: a personal history of excessive mucocutaneous bleeding, a family history of excessive bleeding and a laboratory evaluation consistent with a defect in VWF.(80)
This study aims to detect von Willebrand disease among cases of bleeding in children.
To achieve this goal the study was carried out on twenty five subjects presenting with various bleeding manifestations to Alexandria university children’s hospital at Shatby compared to 20 control subjects of equivalent age and sex.
All subjects were subjected to thorough history taking including personnal and family history of bleeding mainefestations , complete clinical examination especially bleeding manifestations, routine laboratory investigations including: complete blood count(CBC), bleeding time, activated partial thromoplastin time , prothrombin time, blood grouping, factor VIII assay, von Willebrand factor antigen assay by ELISA and determination of ristocetin cofactor activity using agglutination method.
In our study 40% of bleeding patients were diagnosed as VWD, ,suggested type 3 was the most predominant type(50%), 80% were females, positive family history was reported in 70% of VWD positive cases, consanguinity was found among 30% of the patients ,mucocutaneous bleeding was the most predominant symptom and 70% of VWD patients were of blood group O.
The screening panel alone for VWD is not efficient to diagnose VWD in chronic bleeders as it has a sensitivity of 70% and specificity of 80%. On applying the diagnostic panel, VWF:RCo was the most sensitive test for detection of VWD, irrespective of whether VWD is due to a quantitative or qualitative deficiency showing a sensitivity of 100% and a specificity of 100%. we consider that the low levels of VWF:RCo and personal bleeding history are of prime importance in the diagnosis of VWD.
The high prevalence of type 3 and a low prevalence of type 1 VWD which is in contrast to the western reports, suggests the low awareness of the disease as also the underdiagnosis of the mild cases in our country.