Von Willebrand's disease in children
Last reviewed: 23.04.2024
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Von Willebrand disease is a haemorrhagic disease transmitted usually in an autosomal dominant type, characterized by increased bleeding in combination with an increase in the duration of bleeding, a low level of vWF in the blood or a qualitative defect in it, a decrease in the coagulant activity of the VIII factor, low values of adhesiveness and ristocetin-aggregation of platelets. The gene of Willebrand disease is localized on the short arm of chromosome 12 (12pl2-ter).
The disease was first described by Eric von Willebrand (1926) in a girl residing on the Åland Islands, whose hemorrhage-type bleeding was combined with a low level in the blood of the VIII factor, a sharp lengthening of bleeding time and a dominant type of inheritance. Hence it follows that with the described disease, there is a coagulation defect (low level of factor VIII) and vascular-platelet abnormalities (an increase in the duration of bleeding). The von Willebrand factor is a glycoprotein produced by the vascular endothelium and megakaryocytes. Being in the blood in its free form, it participates in the adhesion of platelets to the microfibrils of the vascular wall, being a "bridge" connecting the platelet receptors with subendothelium in damage to the endothelial layer. In addition, it is the carrier of the plasma component of factor VIII (VIII: PV). The bulk of the vWF is synthesized in the vascular endothelium, released into the bloodstream by thrombin, calcium ions, 1-desamino-8D-arginine vasopressin.
It has now been established that von Willebrand's disease is not one disease but a group of related hemorrhagic diathesis caused by a violation of synthesis or qualitative anomalies of the von Willebrand factor.
Symptoms of Willebrand's Disease
The disease is characterized by two types of hemorrhage: vascular-platelet (typical for thrombocytopathy and thrombocytopenia) and hematoma (typical for coagulation hemostasis defects).
With a severe course of the disease (the level of von Willebrand factor in the blood is less than 5%), the clinical picture is practically indistinguishable from hemophilia: delayed bleeding from the stump of the umbilical cord, venepuncture sites, cephalohematemata, hematomas at the site of injuries, intracranial hemorrhages. With a higher level of von Willebrand factor, the vascular-platelet type of increased bleeding comes to the fore: spontaneously arising ecchymoses, petechiae.
Hereditary disease of von Willebrand
The cause of hereditary von Willebrand disease is the polymorphism of the gene coding for the synthesis of von Willebrand factor. Hereditary disease of von Willebrand is the most common hemorrhagic disease. The frequency of carriage of the defective gene of von Willebrand factor in the population reaches 1 per 100 people, but only 10-30% of them have clinical manifestations. Transmitted by autosomal dominant or recessive type and occurs in both girls and boys.
Diagnosis of von Willebrand disease
In the diagnosis of von Willebrand disease, a careful examination of the anamnesis, in particular the identification of individuals with increased bleeding in the parents. Also note a sharp increase in the duration of Duke bleeding, a low aggregation of platelets of the patient with ristocetin (with a normal aggregation of platelets with ADP, adrenaline and collagen), a reduced level of factor VIII and von Willebrand factor in the patient's blood plasma. Often to establish a diagnosis, repeated studies are necessary. The most informative method is DNA-diagnostics using a polymerase chain reaction (the diagnostic value of this method is almost 100%).
Diagnosis of von Willebrand disease
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Treatment of von Willebrand disease
In most cases, effectively transfusion of antihemophilic plasma at a dose of 15 ml / kg or other preparations of the coagulation factor VIII factor at the same dose as in hemophilia A.
Treatment of von Willebrand disease
With mild forms of bleeding, you can appoint aminocaproic acid, etamzilate, intravenous or oral preparations of arginine-vasopressin.
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