Platelets Platelets The main components of blood include Plasma Red blood cells White blood cells Platelets read more 
(thrombocytes) are cell-like particles in the blood that help the body form blood clots. Platelets are normally produced in the bone marrow by cells called megakaryocytes. In thrombocythemia, the body produces too many platelets. Thrombocythemia can be
Primary (essential): Caused by a disorder of platelet-forming cells (see essential thrombocythemia Essential Thrombocythemia Essential thrombocythemia is a myeloproliferative neoplasm in which excess platelets are produced, leading to abnormal blood clotting or bleeding. The hands and feet may burn, turn red, and... read more )
Secondary: Caused by a disorder that triggers increased production by normal platelet-forming cells
When thrombocythemia is caused by such an underlying disorder, the thrombocythemia is called secondary thrombocythemia (or reactive thrombocytosis) and is not classified as a myeloproliferative neoplasm Overview of Myeloproliferative Neoplasms In myeloproliferative neoplasms (myelo = bone marrow; proliferative = rapid multiplication; and neoplasm = new abnormal growth, such as a precancer or cancer), the blood-producing cells in the... read more .
Causes of secondary thrombocythemia include
Bleeding
Removal of the spleen
Other surgical procedures
Trauma
Infections
Rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more
, inflammatory bowel disease Overview of Inflammatory Bowel Disease (IBD) In inflammatory bowel diseases, the intestine (bowel) becomes inflamed, often causing recurring abdominal pain and diarrhea. The 2 primary types of inflammatory bowel disease (IBD) are Crohn... read more , and other inflammatory disordersPremature destruction of red blood cells (hemolysis Anemia due to excessive red blood cell destruction Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more )
People with secondary thrombocythemia usually have no symptoms related to the high number of platelets (unlike people with primary thrombocythemia). Symptoms of the underlying condition usually dominate.
Although an increased number of platelets might be thought to cause excessive blood clotting, this rarely happens in secondary thrombocythemia unless people also have severe arterial disease or prolonged immobility. Although some people with essential thrombocythemia have an increased risk of bleeding, this is not a concern with secondary thrombocythemia.
Secondary thrombocythemia is diagnosed—and distinguished from primary thrombocythemia Essential Thrombocythemia Essential thrombocythemia is a myeloproliferative neoplasm in which excess platelets are produced, leading to abnormal blood clotting or bleeding. The hands and feet may burn, turn red, and... read more —when people with high platelet counts have a condition that readily accounts for the high number of platelets.
To identify possible causes, doctors do blood tests, sometimes including genetic testing, and occasionally a bone marrow biopsy Bone Marrow Examination Red blood cells, most white blood cells, and platelets are produced in the bone marrow, the soft fatty tissue inside bone cavities. Sometimes a sample of bone marrow must be examined to determine... read more . Other tests such as radiologic tests may be needed to ascertain the cause of the platelet elevation.
Treatment is aimed at the cause of the platelet elevation. If the treatment is successful, the platelet count will return to normal.
