Essential thrombocytosis

Last reviewed: March 2019

Last updated: May 2018

Summary

Essential thrombocytosis (primary thrombocythemia) is a myeloproliferative disorder associated with an increase in number and size of circulating platelets.

Half of all patients are asymptomatic, but clinical presentations include thrombosis and bleeding. There are no pathognomonic features and it is a diagnosis of exclusion.

Low-risk asymptomatic patients do not need treatment. High-risk patients (e.g., those who are >60 years old, or those with a history of thrombosis or major bleeding) should be treated with aspirin and cytoreductive drugs. Treatment approach should be individualized based on risk factors.

Hydroxyurea is the preferred cytoreductive agent in most people with the disease. Interferon alfa-2b and busulfan are alternative treatments.

The life expectancy for people with essential thrombocytosis is usually similar to that for people without the disease. Patients need CBCs on a regular follow-up basis.

Definition

Essential thrombocytosis is also known as primary thrombocythemia. It is a chronic myeloproliferative disorder associated with sustained dysregulated megakaryocyte proliferation, increasing the number of circulating platelets. It is associated with thrombosis and bleeding.

History and exam

Key diagnostic factors

erythromelalgia
splenomegaly
arterial and venous thrombosis
bleeding
livedo reticularis

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Other diagnostic factors

age 50 to 70 years
female gender
no symptoms
headache
dizziness, lightheadedness, and paresthesias
syncope and seizures
transient visual disturbances
hepatomegaly
priapism

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Risk factors

Unknown risk factors
Genetic mutations (e.g., Janus kinase 2 [JAK2], calreticulin [CALR], or myeloproliferative leukemia virus oncogene [MPL])

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Diagnostic investigations

1st investigations to order

CBC with peripheral smear
iron panel

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Investigations to consider

CRP
ESR
fibrinogen
bone marrow biopsy and histopathology
Janus kinase 2 (JAK2) mutation testing of peripheral blood
myeloproliferative leukemia virus oncogene (MPL) mutation testing of peripheral blood
calreticulin (CALR) mutation testing of peripheral blood
BCR-ABL fluorescent in situ hybridization (FISH) of bone marrow

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Treatment algorithm

ACUTE

Contributors

Authors VIEW ALL 

Debabrata Mukherjee, MD, FACC

Chairman, Department of Internal Medicine

Chief, Cardiovascular Medicine

Professor of Internal Medicine

Texas Tech University

El Paso

Disclosures

DM declares that he has no competing interests.

Peer reviewers VIEW ALL 

Tony Kan, MD

Senior Staff Physician

Henry Ford Medical Center

Sterling Heights

Disclosures

TK declares that he has no competing interests.

Uri Rozovski, MD

Department of Cardiology

Tel Aviv Sourasky Medical Center

Tel Aviv

Israel

Disclosures

UR declares that he has no competing interests.

David A. Garcia, MD

Professor

Division of Hematology

University of Washington Seattle

Disclosures

DAG declares that he has no competing interests.

Bethany Samuelson, MD

Fellow

Division of Hematology

University of Washington

Seattle

Disclosures

BS declares that she has no competing interests.

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Essential thrombocytosis

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

thrombosis or bleeding

nonpregnant: low or intermediate risk

nonpregnant: high risk

pregnant: low or intermediate risk

pregnant: high risk

Contributors

Authors VIEW ALL 

Debabrata Mukherjee, MD, FACC

Disclosures

Peer reviewers VIEW ALL 

Tony Kan, MD

Disclosures

Uri Rozovski, MD

Disclosures

David A. Garcia, MD

Disclosures

Bethany Samuelson, MD

Disclosures

Differentials

Guidelines

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