AIIMS PG Questions

Ref : Harrisons 17^th edition page no 724   Von Willebrand disease is characterized by prolonged bleeding time and a prolonged PTT. The prothrombin time is normal. In Hemophilia A (factor VIII deficiency) and B (factor IX deficiency) – bleeding time is normal, APTT is prolonged Glanzmann thrombasthenia is a genetic platelet disorder in which the platelet glycoprotein IIb/IIIa (GP IIb/IIIa) complex is either deficient or present but dysfunctional. Prothrombin time and PTT is normal with prolonged bleeding time     Von Willebrand disease It is an Autosomal dominant disease (most common inheritance)

It is the most common inherited bleeding disorder

Menorrhagea is a common manifestation of VWD.

 VWF serves two roles: (1) as the major adhesion molecule (large VWF multimers) that tethers

                                            the platelet to the exposed subendothelium

                                       (2) as the binding protein for FVIII, resulting in significant prolongation

                                            of the FVIII half-life in circulation.

VWD has been classified into three major types

                   Type 1 VWD –decrease in VWF protein, VWF function, and FVIII levels

                                              It is the most common type

                    Type 2 VWD -  have functional defects in VWF

                    Type 3 VWD or severe VWD - virtually no VWF protein and FVIII levels <10%

Investigations

Bleeding time is increased (normal in Hemophilia)

Clotting time is increased

Prolonged PTT

Normal Prothrombin time

Decreased factor VIII

Decreased Ristocetin cofactor ( normal in Hemophilia)

Treatment

1-deamino-8-d-arginine vasopressin (DDAVP, or desmopressin) - usual dose is 0.3 g/kg intravenously or 2 squirts (1 in each nostril) for patients >50 kg (1 squirt for those <50 kg).

VWF replacement in severe cases

Epsilon aminocaproic acid or tranexamic acid - for the prevention or treatment of mucosal bleeding.

Coagulation pathway