Patient Information Resource:
Benign Hematologic (Blood) DisordersA collaborative project of the Arizona Telemedicine Program, the Arizona Health Sciences Library and the Arizona Cancer Center.
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Thrombocytosis
A. What Is Thrombocytosis?
Thrombocytosis is defined as an elevated level of platelets in the blood. Platelets are an integral part of the blood’s clotting mechanism, enabling the body to control bleeding at the site of injury. When a wound occurs, several changes take place to minimize blood loss. First, the blood vessel slows the flow of blood past the wound site. Next, platelets collect at the wound site to form a plug, which is replaced by a clot until the wound heals.
Platelets are produced in the bone marrow and are removed from the blood by the spleen. Therefore, these two organs work together to regulate platelet levels in the blood. Platelet levels can increase because of increased bone marrow production or decreased spleen removal.
B. Causes
Three basic causes may be responsible for thrombocytosis: it may be a temporary response to a change in the body’s chemistry; it may a reaction to a disorder or disease in another part of the body; or it may be a symptom of an underlying disease in the bone marrow.
Temporary thrombocytosis may occur in response to exercise, pregnancy and delivery, or other factors causing elevated blood levels of the hormone epinephrine. The spleen releases stored platelets in response to temporary elevations in epinephrine.
Thrombocytosis as a reaction to another disorder in the body results from increased production of platelets in the marrow and increased release of stored platelets from the spleen. Problems which may cause reactive thrombocytosis include infection (such as tuberculosis, osteomyelitis), surgical operation, inflammatory diseases (such as rheumatoid arthritis), cancer, iron deficiency, and blood loss or blood cell destruction (hemolysis).
If thrombocytosis occurs on its own, it is classified as primary thrombocytosis. It is due to disease causing increased platelet production in the bone marrow. Such diseases include essential thrombocythemia, polycythemia vera, agnogenic myelofibrosis and myeloid metaplasia, chronic myelogenous leukemia, or refractory anemia. Please see Myeloproliferative Disorders and Leukemia.
C. Symptoms
Some patients with thrombocytosis do not experience symptoms with the condition. If they occur, symptoms may include enlarged spleen, a feeling of fullness in the abdomen, blood in the stool, or warmth, pain, and redness of the skin. If thrombocytosis is a reaction to another disorder, the patient will note symptoms of that disorder.
D. Diagnosis
Thrombocytosis is diagnosed by patient history, physical examination for signs of disease, and laboratory testing. Detection of the cause of the platelet elevation is the chief concern.
E. Treatment
Treatment of thrombocytosis involves addressing the underlying disease if possible. If the platelet count remains high, medications to reduce platelet levels, such as anagrelide and alpha interferons, may be used.
GENERAL DISCLAIMER: This web site and its contents are designed for educational purposes only. This web site does not render medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, you should consult your health care provider.
Updated: October 30, 2000