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)

Hypothyroidism

Hemolysis

Cancer

CML

Cirrhosis

Mutated TPO-R

Iron deficiency

Aortic stenosis

Bleeding

ET

Infection

Irritable bowel syndrome

Congestive heart failure

Inflammation

Guillain Barre syndrome

MDS/MPN-RS-T

PV

Surgery

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