Idiopathic thrombocytopenic purpura (ITP)

• Abs are against platelet membrane glycoproteins; their binding encourages phagocytic destruction

• Spleen is thought to make Abs and be place where the platelets are destroyed, but splenomegaly and lymphadeopathy are rarely seen

• In the marrow, megakaryocytic hyperplasia is seen, and this is reflected in the blood by larger than normal platelets

• Bleeding tendency and prolongation of bleeding time <> (platelet count usually < 5,000/mm³)

• Acute: self-limited, abrupt onset in kids following viral infections (give steroids in severe cases)

• Chronic

  • Thrombocytopenia there for > 6 months

  • Platelet-bound Ig (direct anti-platelet Ab) present in 90% of patients

  • Mostly seen in adults (mostly repro age women; babies born to a woman with ITP will be transiently thrombocytopenic)

  • May occur with another autoimmune d/o or lymphoproliferative syndrome (such as lymphocytic leukemias or lymphomas)

  • Treatment includes immunosuppression, plasmapheresis, and splenectomy if refractory

Category: Medical Subject Notes , Pathology Notes