Platelets are blood cells that are essential for blood clotting. Platelet disorders can involve an inappropriate number (too many or too few) or improper functioning of the platelets. Any platelet disorder affects blood clotting. Disorders of platelet function can be caused by congenital (present at birth) diseases or acquired conditions. Acquired platelet function disorders involve improper platelet function. They develop as a result of another disease or condition (acquired). In many cases, the platelet count may be normal or even elevated, but evidence of a bleeding disorder will be present. Myeloproliferative disorders such as primary thrombocytopenia, polycythemia vera, chronic myelogenous leukemia, and myelofibrosis can produce abnormalities in platelet function. Other causes include renal failure, multiple myeloma, and medications such as aspirin and other anti-inflammatory medications, penicillins, phenothiazines, and prednisone (prolonged use).
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