Transfusion medicine handbook

7. Adverse Effects of Transfusion

7.10 Post-transfusion Purpura

Post-transfusion purpura (PTP) is a rare but potentially lethal complication of transfusion of red cells and platelets. It is characterised by the sudden onset of severe thrombocytopenia, typically 5 - 12 days following transfusion, often associated with haemorrhage. PTP is most often seen in females (90% of cases) and in particular those with a history of pregnancy.

Transfusion causes an anamnestic response boosting human platelet-specific antigen (HPA) antibodies previously stimulated by pregnancy or earlier transfusion. The resulting thrombocytopenia is due to alloantibody-mediated destruction of the transfused platelets as well as "bystander" destruction of the patient’s own platelets.

Treatment of choice is high dose intravenous immunoglobulin, 2 g/kg body weight, administered in divided doses over 2 - 5 consecutive days.

Plasma exchange and corticosteroids have been used in the past but an increase in platelet count is significantly delayed when compared to intravenous immunoglobulin. If platelet transfusion is unavoidable, platelets that are compatible with the patient's antibody should be used although survival of the platelets may be impaired during the acute phase of the syndrome. If future transfusions are planned, red cell or platelet components from donors negative for the implicated HPA antigen(s) should be selected wherever possible.

Expert advice from a NZBS Transfusion Medicine Specialist or specialist haematologist is needed when managing PTP.