16. Thrombocytosis

Question 1

what is reactive (secondary) thrombocytosis?

Answer 1

caused by processes that are extrinsic to the megakaryocyte:

• anemia/blood loss (↑ cellular proliferation)
• infection and non-infectious inflammation (effects of cytokines)
• post-splenectomy (↓ platelet sequestration)

Question 2

what is autonomous (primary) thrombocytosis?

Answer 2

caused by cell-intrinsic mechanisms:

• essential thrombocytopenia
• polycythemia vera
• primary myelofibrosis
• CML

Question 3

how does primary thrombocytosis present?

Answer 3

increased risk of thrombotic events (DVT/PE, MI, stroke), bleeding (PLT>1.5 million)
pruritus
splenomegaly
migraine

Question 4

when is Aspirin (100mg) indicated in patients with thrombocytosis?

Answer 4

platelet counts> 1 million/µL