On peripheral blood smear, the morphology of red blood cells and leukocytes is normal. The morphology of platelets is typically normal, with varying numbers of large platelets. Some persons with acute ITP may have megathrombocytes or stress platelets, reflecting the early release of megakaryocytic fragments into the circulation. If most of the platelets are large, approximating the diameter of red blood cells, or if they lack granules or have an abnormal color, consider an inherited platelet disorder.
The hallmark of ITP is isolated thrombocytopenia; anemia and/or neutropenia may indicate other diseases. If anemia and thrombocytopenia are present, a positive direct antiglobulin (Coombs) test result may help establish a diagnosis of Evans syndrome.
Although CT scanning and MRI are relatively benign and useful noninvasive imaging studies that can be used to rule out other causes of thrombocytopenia, they are not part of the routine evaluation of suspected ITP patients of any age. However, when physical findings or the medical history suggest serious internal bleeding, prompt CT scanning or MRI is indicated.
Learn more about ITP workup.
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Cite this: Emmanuel C. Besa. Fast Five Quiz: Thrombocytopenia - Medscape - May 20, 2022.