The platelet count is reduced in thrombocytopaenia. The common causes involve the following mechanisms:
Reduced production of platelets (eg, marrow failure, post-chemotherapy)
Increased destruction or loss of platelets (eg, ITP, TTP, DIC, sepsis, drug-induced, dilution in massive transfusion)
- Sequestration of platelets (eg, splenomegaly)
In general, platelet transfusion is considered when platelet production is reduced, to support the platelet count while waiting for bone marrow recovery.
Platelet transfusion is contraindicated in some cases of thrombocytopaenia (eg, TTP and HIT).
Treatment is directed at the underlying cause for immune aetiologies.
Splenomegaly presents a particular problem and the response to platelet transfusion is often markedly reduced if this is not corrected.
The threshold for platelet transfusion is subject to the advice of guidelines and the decision to give platelets also depends on the patient's clinical status.
Transfusion is given more readily in the face of bleeding, coagulopathy, or planned surgery or invasive procedures (eg, central line insertion or lumbar puncture).