7.2.2.-7.2.3. Coagulopathy (coagulation disorders). Von Willebrand’s disease (VWD). Acquired coagulopathy
von Willebrand’s disease

von Willebrand’s disease
(syn: angiohemophilia, athrombocytopenic purpura) is a severe bleeding disorder due to qualitative or quantitative defect in von Willebrand’s factor (vWF). This defect may be impaired synthesis of vWF or decreased sensitivity of receptors to vWF.

The gene for vWF is located at chromosome 12. vWD is thus inherited as an autosomal dominant trait, which may occur in either sex. This factor comprises the larger fraction of factor VIII-vWF complex. This complex circulates in the blood and facilitates platelet adhesion to subendothelial collagen. The capillaries lose their ability to constrict vessels after injections in vWF deficiency. 

Clinical features

• Profuse bleeding from the nose and uterus;
• Bleeding from cuts and possible hemarthrosis.

Investigations

Diagnosis is based on clinical features and Duke method (bleeding time more than 5 minutes) with normal platelet count and normal retraction time of blood clot; reduced adhesion of thrombocytes. Diagnosis is confirmed only in specialized hematological centers.

Management

1. Cryoprecipitate (greater risk of infections) or FFP;

2. vWF concentrates;

3. In mild cases – DDAVP®;

4. oral ε-aminocaproic acid – 40mg/kg ;

5. Bleeding from the uterus – hormonal contraception. 

Acquired coagulopathy

1. Hypoprothrombinemia – prothrombin consists of vitamin K and globin. The intestine aided by bile acid absorbs Vitamin K. Deficiency of vitamin K and reduced prothrombin production is observed in patients with persistent cholestatic jaundice. Globin is a protein synthesized in the liver. Prothrombin production is reduced in its pathology (hepatitis and cirrhosis). Differential diagnosis is done by administration of vikasol (vitamin K) intravenously for few days. If prothrombin level is raised, it means hypoprothrombinemia and is caused by hypovitaminosis; if the prothrombin level remains unchanged, it is caused by decreased liver function.

2. Hypoprothrombinemia develops after administration of anticoagulants – antagonists of vitamin K (warfarin, neodicumarin and others). Vikasol is administered in anticoagulant overdose and sharp decrease of prothrombin. 

3. Elevated antithrombin activity – as a result of heparin introduction or treatment by leech (hirudin – antithrombin). Protamine sulfate is administered in prolonged coagulation time. 

4. Elevated fibrinolytic activity – after administration of activator of fibrinolytic system or in DIC. Contrycal, ε-aminocaproic acid and FFP are used in these cases.