CAMLPR Evaluation And Interpretation Competency Practice Test

Late-onset thrombocytopenia after a transfusion with mucosal bleeding points to post-transfusion purpura. This condition usually occurs about a week after transfusion and is driven by alloantibodies against platelet antigens (often HPA-1a) that cause the rapid destruction of platelets by the spleen and other reticuloendothelial tissues. The key clinical clue is a sudden, severe drop in platelets with mucous membrane bleeding, while coagulation tests remain normal, since the problem is platelet destruction rather than a coagulation factor defect. The treatment aims to stop the immune-mediated platelet destruction. High-dose corticosteroids or intravenous immunoglobulin (IVIG) are effective options: steroids suppress the immune response, and IVIG saturates Fc receptors on macrophages, reducing clearance of platelets. Platelet transfusions are often not helpful on their own because the transfused platelets can be destroyed by the same alloantibodies.