The etiology is still unknown and the pathogenesis is complex and possibly depends on disturbed antigen presentation, T cell activation and signaling, disregulated B cell stimulation and antibodies, unbalanced activation / suppression of complement.
Secondary forms of the disease occur in association with SLE, the antiphospholipid syndrome, immunodeficiency states (IgA deficiency and common variable hypogammaglobulinemia), Lymphoproliferative disorders (CLL, Large granular lymphocytic leukemia, and lymphoma), infection with HIV and hepatitis c virus, and therapy with drugs such as heparin and quinidine.
The guidelines of the American Society of Hematology state that a bone marrow examination is not required in adults younger than 60 yrs of age if the presentation is typical but is appropriate before splenectomy is performed.
Marrow examination is necessary in the presence of atypical features (e.g., those with additional cytopenias, protracted fever, bone or joint pain, unexplained macrocytosis ), or in patients who do not have a brisk or robust response to therapy.
ITP in many children – certainly those without hemorrhage –is managed on an outpatient basis with minimal investigation, short-term therapy in select cases, and the avoidance of activities that predispose the patient to trauma and of medications that impair platelet function.
Achallenge is posed by the occasional symptomatic child in whom splenectomy fails or is containdicated and in whom the platelet count cannot be sustained with acceptable doses of corticosteroids, anti-D immune globulin.
The following intervals since the last administration of therapy for ITP were required : 2 weeks for IVIG , 8 weeks for alkylating agents , 16 weeks for rituximab , and 4 weeks for all other treatments.
AMG 531 does not appear to affect the ongoing rate of platelet destruction; in all patients receiving the drug, the platelet count returned to the baseline value after the discontinuation of short term treatment.