abnormally low number of platelets (platelet) (thrombocytes) in the circulation. Thrombocytopenia may occur as a result of decreased platelet production, when the bone marrow is malfunctioning or not functioning (e.g., in leukemia, from an excess of certain drugs or radiation, in certain anemias (anemia), or from a congenital lack of megakaryocytes, cells in the bone marrow that give rise to platelets), or as a result of increased platelet destruction (e.g., from a malfunctioning spleen, congestive heart failure, blood transfusion after hemorrhage, or incompatible blood transfusion). Symptoms of thrombocytopenia include small hemorrhages into the skin, nosebleeds, and easy bruising; sometimes gastrointestinal bleeding, excess menstrual bleeding, or other hemorrhage is observed. Treatment includes rest, protection from injury, and sometimes platelet transfusion.