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Thrombocythemia, Essential

Important
It is possible that the main title of the report Thrombocythemia, Essentialis not the name you expected.

Synonyms

Essential Hemorrhagic Thrombocythemia
Essential Thrombocytosis
ET
Idiopathic Thrombocythemia
Primary Thrombocythemia

Disorder Subdivisions

None

General Discussion

Essential thrombocythemia (ET) is one of four rare, myeloproliferative disorders (MPDs). Myeloproliferative means uncontrolled production of cells by the bone marrow. Each of the four myeloproliferative disorders is characterized by over-production of a different, but essential, type of blood cell resulting in a high concentration of these cells in the blood.

Essential thrombocythemia is characterized by overproduction of the precursor cells to blood platelets (megakaryocytes) which, in turn, leads to a vastly increased number of platelets in the blood. Platelets are specialized cells in blood essential for the normal process of clotting. In addition to over-production of platelets, other symptoms and signs of ET may include an enlarged spleen (splenomegaly); bleeding from the gut, gums and/or nose (hemorrhaging); and constricted or blocked arteries (thrombosis).

As many as two-thirds of patients are without symptoms (asymptomatic) upon initial examination. Most patients present with symptoms related to small or large vessel thrombosis or minor bleeding. Presentation with a major bleeding episode is very unusual. Clots may occur in the small arteries of the toes and fingers, leading to pain, warmth, tissue death (gangrene) and/or classic erythromelalgia. Erythromelalgia refers to a syndrome of redness and burning pain in the extremities. The incidence of the thrombotic and bleeding episodes is minimized, but not eliminated, with reduction of the platelet count to normal.

In some instances, this chronic disorder may be progressive, evolving in relatively rare cases into acute leukemia or myelofibrosis.

The three other myeloproliferative disorders are:

Polycythemia vera, in which blood contains abnormally high concentrations of red blood cells (erythrocytes).

Chronic myelogenous leukemia, which is characterized by abnormally high concentrations of white blood cells (neutrophils) or their precursor cells, granulocytes.

Agnogenic myeloid metaplasia, in which red blood cells have the shape of a teardrop rather than a disc. In this disorder, something goes wrong with the marrow microenvironment that affects the structure of the red blood cell.

These blood cells all arise from a common "ancestor", the stem cell, which in its undifferentiated form can become a red blood cell, a white blood cell, or a platelet.

The term secondary thrombocythemia is used to describe the problems involving persistent, high blood platelet counts associated with some underlying condition such as malignancy, infection, inflammatory disease, or iron deficiency.

Resources

NIH/National Heart, Lung and Blood Institute Information Center
P.O. Box 30105
Bethesda
MD
20824-0105
Tel: (301)592-8573
Fax: (301)251-1223
nhlbiinfo@rover.nhlbi.nih.govMyeloproliferative Mailing List (MPD-SUPPORT-L)
3706 North Roosevelt Blvd.
Key West
FL
44030
USA
Tel: (305)295-4444
Fax: (305)295-3335
lov2laf@bellsouth.net
http://www.mpdsupport.org

NIH/Hematology Branch, National Heart, Lung and Blood Institute (NHLBI)
10 Center Dr, Building 10-CRC
3-5140, MSC-1202
Bethesda
MD
20892-1202
Tel: (301)402-0764
Fax: (301)402-3088
zamaniw@nhlbi.nih.gov
http://dir.nhlbi.nih.gov/labs/hb/index.asp?

Platelet Disorder Support Association
135 Rollins Ave Suite 5
Rockville
MD
20852
USA
Tel: (301)770-6636
Fax: (301)770-6638
800: (877)528-3538
pdsa@pdsa.org
http://www.pdsa.org

CMPD Education Foundation
PO Box 4758
Scottsdale
AZ
85261
Tel: (480)443-1975
Fax: (480)443-1154
jniblack@mpdinfo.org
http://www.mpdinfo.org

Myeloproliferative Disease Support and Free Daily Email Digest
2011 Flagler Ave.
Key West
FL
33040
USA
Tel: (305)295-4444
roberttollen@gmail.com or mensabrain@aol.com
http://www.MPDSUPPORT.ORG

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

Last Updated: 4/25/2008
Copyright 1988, 1989, 1990, 1995, 1997, 1998, 2002, 2004, 2005, 2008 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization of Rare Disorders

Last Updated: April 25, 2008

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