Thrombocythemia
| Thrombocythemia | |
|---|---|
| Other names | Thrombocytosis |
 | |
| 3D rendering of four inactivated and three activated platelets | |
| Specialty | Hematology  |
In hematology, thrombocythemia is a condition of high platelet (thrombocyte) count in the blood. Normal count is in the range of 150×109 to 450×109 platelets per liter of blood,[1] but investigation is typically only considered if the upper limit exceeds 750×109/L.
When the cause is unknown, the term thrombocythemia is used, as either primary thrombocythemia or essential thrombocythemia. The condition arises from a fault in the bone marrow cells leading to over-production of platelets but the cause of the fault is unknown, and this type is not common.[2]
When the cause is known such as another disorder or disease, the term thrombocytosis is preferred, as either secondary or reactive thrombocytosis. Reactive thrombocytosis is the most common type and though it can often have no symptoms it can sometimes predispose to thrombosis. In contrast, thrombocytopenia refers to abnormally low blood platelet numbers in the blood.[2]
Signs and symptoms
High platelet counts do not necessarily signal any clinical problems, and can be picked up on a routine
A very small number of people report symptoms of erythromelalgia, a burning sensation and redness of the extremities that resolves with cooling, or aspirin or both.[3]
Scientific literature sometimes excludes thrombocytosis from the scope of
Causes
Reactive thrombocythemia is the most common cause of a high platelet count. It accounts for 88% to 97% of thrombocythemia cases in adults, and near 100% in children. In adults, acute infection, tissue damage, chronic
The SARS disease caused thrombocytosis.[10]
Once the reactive causes of thrombocythemia are ruled out, clonal thrombocythemia should be considered. The most common cause of clonal thrombocythemia is a
Extremely rare causes of thrombocythemia are spurious causes. This is due to the presence of structures resembling platelets in the blood such as needle-like cryoglobulin crystals, cytoplasmic fragments of circulating leukemic cells, bacteria, and red blood cell microvesicles. These structures are counted as platelets by the automated machine counter; therefore, causing the platelet number to be falsely elevated. However, such error can be avoided by doing a
Diagnosis
Laboratory tests might include:
If the cause for the high platelet count remains unclear, bone marrow biopsy is often undertaken, to differentiate whether the high platelet count is reactive or essential.[citation needed]
Treatment
Often, no treatment is required or necessary for reactive thrombocytosis. In cases of reactive thrombocytosis of more than 1,000x109/L, it may be considered to administer daily
However, in essential thrombocythemia where platelet counts are over 750x109/L or 1,000x109/L, especially if there are other risk factors for thrombosis, treatment may be needed. Selective use of
In Janus kinase 2 positive disorders, ruxolitinib (Jakafi) can be effective.[citation needed]
References
- ISBN 0-7020-2763-4.
- ^ a b "Thrombocythemia and Thrombocytosis | National Heart, Lung, and Blood Institute (NHLBI)". www.nhlbi.nih.gov. Archived from the original on 14 June 2019. Retrieved 20 December 2019.
- ^ S2CID 19341388.
- S2CID 44647401.
- ISBN 978-1-4160-2973-1.
- PMID 18024620.
- ^ Pediatric Thrombocytosis at eMedicine
- ^ PMID 22084665.
- PMID 26557653.
- ^ Low D (2004). Learning from SARS: Preparing for the Next Disease Outbreak: Workshop Summary. National Academies Press (US). pp. 63–71. Archived from the original on 2020-02-24. Retrieved 2021-01-18.
- ^ Secondary Thrombocytosis~treatment at eMedicine
- PMID 16000354.
Further reading
- Schafer AI (March 2004). "Thrombocytosis". The New England Journal of Medicine. 350 (12): 1211–1219. PMID 15028825.