For patients affected by severe inherited platelet dysfunctions, e.g.
Glanzmann thrombasthenia (GT) or
Bernard-Soulier syndrome (BSS),
platelet transfusion is frequently needed for controlling spontaneous
bleeding, and is always needed when
trauma occurs or surgery is performed. For the mild-to-moderate
bleeding entities, e.g. storage pool disease, thrombaxane A2 receptor defect,
platelet transfusion is usually unnecessary. Transfusion of platelets should be used selectively and sparingly because of the substantial risk of alloimmunization against
HLA antigens and/or
platelet glycoproteins (GP) αIIb, β(3), or αIIbβ(3) in GT, and GPI-IX-V in BSS, which may lead to refractoriness to
therapy. To reduce the risk, HLA-matched single donors of platelets should be used. If such donors are unavailable, leucocyte-depleted blood components should be used.
Therapy other than
platelet transfusion includes: (i) Prevention (vaccination against
hepatitis B, avoidance of non-steroidal anti-inflammatory drugs, preservation of
dental hygiene, correction of
iron deficiency and prenatal diagnosis). (ii) Topical measures (compression with gauze soaked with
tranexamic acid,
fibrin sealants,
splints for dental extractions and packing for
nose bleeds). (iii)
Antifibrinolytic agents that are useful for
minor surgery and as adjuncts for other treatment modalities. (iv)
Desmopressin that increases plasma levels of
von Willebrand factor and
factor VIII giving rise to increased platelet adhesiveness and aggregation associated with shortened bleeding time. (v)
Recombinant factor VIIa (
rFVIIa). GT patients have been treated for
bleeding episodes by
rFVIIa with partial success. The mechanism by which
rFVIIa arrests
bleeding is probably related to increased
thrombin generation by a
tissue factor-independent process, enhanced platelet adhesion and restoration of platelet aggregation. (vi) Female
hormones. Excessive
bleeding during menarche in patients with GT or BSS can be controlled by high doses of oestrogen followed by high doses of oral oestrogen-
progestin.
Menorrhagia later in life can be managed by continuous
oral contraceptives.
Depo-medroxyprogesterone acetate administered every 3 months is an alternative when
combined oral contraceptives are contraindicated.