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Key Clinical Questions Thrombocytopenia
Does the patient have true thrombocytopenia or pseudothrombocytopenia?
What is the timing of onset, progression, and severity of the thrombocytopenia?
Is the thrombocytopenia isolated, or is there concomitant anemia, leukopenia, or both?
What are the findings of the peripheral blood film?
What tests and studies are useful to evaluate each etiology?
What is the frequency of specific causes of thrombocytopenia in defined clinical circumstances?
Is the thrombocytopenia a marker of bleeding risk, thrombosis risk, or adverse prognosis?
What treatments are available for each etiology?
Thrombocytosis Is the thrombocytosis newly acquired during the hospitalization?
Is there concomitant splenomegaly and/or abnormalities in hemoglobin or white blood cell levels?
Does the thrombocytosis predate the hospitalization?
Is the red cell size (mean corpuscular volume) increased or decreased?
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The normal platelet count range is approximately 150 to 400 × 109/L (150,000-400,000/mm3). An individual’s platelet count usually remains relatively constant during life. The platelet count decreases normally during pregnancy (gestational thrombocytopenia). The platelet count increases to above the usual value following an acute self-limited thrombocytopenia. For example, after major surgery, an early postoperative platelet count nadir is observed; subsequently, thrombocytosis occurs, with the peak platelet count reached approximately 2-week postsurgery, with a late postoperative platelet count nadir occurring 2 weeks later (ie, approximately 1-month postsurgery) (Figure 171-1). As discussed later in this chapter, these postsurgery platelet count changes are expected, and reflect physiological consequences of changes in thrombopoietin-induced (TPO-induced) platelet production triggered by the initial acute surgery-associated platelet count fall.
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