What is thrombocytosis?

Thrombocytosis

Thrombocytosis is defined as a platelet count > 450,000/mm3 in the blood. With the increase in platelet counts, coagulation is facilitated in case of the slightest bleeding in the blood and anticoagulant thrombosis occurs in the veins. These blood clots are called “thrombus”.



The increase in the number of platelets may have been tried to ensure that the platelets, which were made defective, sometimes increased in number due to their poor functioning. Sometimes, rapid secretion of platelets, which are secreted immaturely in the early period, may occur. In this way, the risk of bleeding increases in cases where the number of immature or defective platelets increases.

Thrombocytosis can also be expressed by different names. If the cause of the increase in the platelet count is not known, it is expressed as “thrombocythemia”, if known, it is expressed as “thrombocytosis”. For example:

Primary thrombocythemia is also called:

• Essential thrombocythemia. This term is used if the high platelet count occurs alone (ie, there is no other blood cell disease).
• Idiopathic thrombocytopenia.
• Primary or essential thrombocytosis (these are less preferred terms)
• Secondary thrombocytosis is also given the following names (thrombocytosis, which is a symptom accompanying another disease):
• Reactive thrombocytosis.
• Secondary thrombocythemia (this is a less preferred term) .

Platelet elevation is usually seen together with changes in other blood cells. It can also be seen alone. Patients with high platelet count may experience weakness, headache, occasional bleeding, and numbness in the hands and feet. Blood clots can form due to increased clotting. Depending on where these blood clots form, their symptoms may vary. In patients with blood clots, symptoms such as confusion, hand and back pain, seizures, shortness of breath and nausea can be seen. If this clot forms in the placenta during pregnancy, it can cause miscarriage or stillbirth.



In patients with unknown (essential) thrombocytosis, an increase in later-developing cancer cases can be observed.

Determining the increase in platelet counts requires confirmation of the increase in the homogram with other tests. At the same time, conditions such as the patient’s medical treatment, blood transfusion, recent infection, vaccination, all drugs used, dietary habits, alcohol consumption, and family members with similar diseases are also investigated. Afterwards, the peripheral blood smear is counted again with a microscope and platelet counts and shapes are examined. Subsequently, platelet production can be examined by bone marrow biopsy. Other possible causes and conditions in the bone marrow are evaluated. Tests may also be done to look for genetic diseases.

The most common causes of increased platelet count:

• Primary essential thrombocytosis (increased platelet production from the bone marrow)
  • Familial (familial) thrombocytosis: Specific mutations in the thrombopoietin gene may cause familial thrombocytosis. It is usually autosomal dominant. It is quite rare. It is noteworthy that more than one individual in the family has thrombocytosis. Clinical findings are variable.
    • Linked to thrombopoietin gene mutation
    • Thrombopoietin receptor (MPL) linked to gene mutation
    • Familial thrombocytosis of unknown cause
  • Secondary thrombocytosis (Platelet count increased for other reasons. Platelet functions are normal.)
    • Reactive thrombocytosis
      • Acute blood loss
      • Acute infection
      • Acute or chronic inflammations (inflammatory bowel disease, tuberculosis, etc.)
      • Iron deficiency anemia
      • Folic acid deficiency
      • Collagen vascular diseases
      • Hemolytic anemia
      • Splenectomy
      • Malignancies
      • Recovery period of bone marrow depression due to chemotherapy or radiotherapy
      • Heavy exercise
      • Excessive alcohol use
      • Surgical intervention
      • Medicines
        • Vincristine
        • Adrenalin
        • Cytokines
      • Clonal thrombocytosis
        • Chronic myeloproliferative diseases
          • Chronic myeloid leukemias
          • Chronic neutrophilic leukemia
          • Polycythemia vera
          • Essential thrombocythemia
          • Idiopathic myelofibrosis
          • Other myeloid cancers
            • Refractory anemia with ring sideroblasts and thrombocytosis (RARS-T)
            • Myelodysplastic syndrome (MDS)