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A Reason for Increased Platelet Size

The body produces disc-haped particles called platelets, or thrombocytes, in the bone marrow. The platelets enter the blood stream to seek out excessive bleeding. Platelets are essential for blood clotting, but excessive clotting can cause problems by narrowing arteries. Changes in the size and number of platelets usually indicates some type of disorder.

  1. Platelets

    • Large cells in the bone marrow, called megakaryocytes, produce platelets. At any given time a normal blood count should show between 150,000 and 400,000 platelets per microliter, according to the Mayo Clinic.

      Platelets have a short life span and new ones are constantly being produced. They move around in the blood waiting to be stimulated, or directed, to respond to a trauma in a blood vessel. The platelets form a plug to stop the bleeding.

    MDS

    • Under normal conditions, the bone marrow produces enough platelets to keep the active number within normal limits. Some disorders cause the marrow to produce too many platelets. Not only are there too many platelets, but some of the platelets are larger than normal.

      One such condition is MDS, or myelodysplastic syndrome, a group of disorders where the bone marrow malfunctions and fails to produce healthy cells. The cells it does produce are not the normal size and shape. An increase in platelet size indicates that there is a higher than normal rate of production, an abnormal growth rate or the platelets are leaving the bone marrow prematurely, according to the Aplastic Anemia & MDS International Foundation.

    Thrombocytosis

    • Thrombocytosis, or the production of too many platelets, leads to an excess of platelets in the blood stream. Even though the average platelet lives 10 days and many others are used for clotting, an overactive bone marrow can send numbers beyond 500,000.

      Causes of thrombocytosis include acute bleeding and blood loss, allergic reactions, heart attack, infections and exercise. These causes are classified as reactive thrombocytosis, indicating the body is producing large numbers of platelets as a reaction to a condition.

    Excessive Clotting

    • Too large or too many platelets lead to excessive clotting. Known as platelet aggregation, causes include a high-fat diet, stress and high cholesterol levels. Blood clotting is essential to stopping bleeding but clots can build up in arteries and slow blood flow. Large enough clots block the flow. A large blood clot can break free and move through the body, causing a blockage or stroke.

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