Knowledge Check • The Blood Project

What is the definition of thrombocytosis?

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Platelet count > 450 x 10⁹/L

What does the word “primary” refer to in primary thrombocytosis?

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To the fact that the cause is intrinsic to the platelet

What is a “platelet millionaire”?

a

A case in which the patient won the lottery

b

A case in which one million platelets are being produced every second

c

A case in which the platelet count is > million x 10^9/L

d

A case in which the platelet count is > million/microliter

Yes! We now routinely talk about platelet counts as 10/L. The millionaire refers to a time when the platelet count was expressed per microliter.

The original description of platelet millionaire:

Sort conditions (on top) to appropriate buckets (on bottom)

MDS/MPN-RS-T

Cirrhosis

Congestive heart failure

Hypothyroidism

Mutated TPO-R

Cancer

PV

Aortic stenosis

Surgery

ET

Infection

Iron deficiency

Hemolysis

Inflammation

CML

Guillain Barre syndrome

Irritable bowel syndrome

Bleeding

Primary thrombocytosis

Secondary thrombocytosis

No link to thrombocytosis

Abbreviations, ET, essential thrombocythemia; PV, polycythemia vera; CML, chronic myelogenous leukemia; MDS/MPN-RS-T, myelodysplastic syndrome/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis; TPO-R, thrombopoietin receptor.

What is the most important cytokine causing reactive thrombocytosis?

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Interleukin (IL)-6