Thrombocytopenia is a reduction in the platelet count. The common causes are usually considered in terms of the mechanism involved either as:
- Reduced production of platelets eg marrow failure, post-chemotherapy,
- Increased destruction or loss of platelets eg immune (ITP) or drug induced causes, sepsis, TTP, DIC, dilution in massive transfusion
- Sequestration of platelets eg in an enlarged spleen.
In general platelet transfusion is considered when platelet production is reduced to support the count while bone marrow recovery is awaited. Treatment is directed at the underlying cause for immune aetiologies. Splenomegaly presents a particular problem and if it cannot be corrected the response to platelet transfusion is often markedly reduced.
The threshold for platelet transfusion is subject to the advice of guidelines (REF NHMRC The decision to give platelets is also affected by the clinical status with transfusion given more readily in the face of bleeding or coagulopathy or when surgery or invasive procedures eg central line insertion or lumbar puncture are planned.
Further discussion of the choice of platelets in particular circumstances can be found in the product sections of this website for leucodepletion, platelets pools, apheresis platelets, CMV negative products, irradiation, HLA matched platelets, platelets for NAIT and paediatric split platelets. Discussion of the use of IVIG for ITP is also covered.