Long-term steroids are avoided if possible because of potential side-effects that include osteoporosis, diabetes and cataracts. Anti-D
Another option, suitable for Rh-positive patients with functional spleens is intravenous administration of Rho(D) immune globulin [Human; Anti-D]. The mechanism of action of anti-D is not fully understood. However, following administration, anti-D-coated red blood cell complexes saturate Fcγ receptor sites on macrophages, resulting in preferential destruction of red blood cells (RBCs), therefore sparing antibody-coated platelets. There are two anti-D products indicated for use in patients with ITP: WinRho SDF and Rhophylac. The most common adverse reactions are headache (15%), nausea/vomiting (12%) chills (<2%) and fever (1%). Steroid-sparing agents
There is increasing use of immunosuppressants such as mycophenolate mofetil and azathioprine because of their effectiveness. In chronic refractory cases, where immune pathogenesis has been confirmed, the off-label use of the vinca alkaloid and chemotherapy agent vincristine may be attempted. However, vincristine has significant side effects and its use in treating ITP must be approached with caution, especially in children. Intravenous immunoglobulin
Intravenous immunoglobulin (IVIg) may be infused in some cases in order to decrease the rate at which macrophages consume antibody-tagged platelets. However, while sometimes effective, it is costly and produces improvement that generally lasts less than a month. Nevertheless, in the case of an ITP patient already scheduled for surgery who has a dangerously low platelet count and has experienced a poor response to other treatments, IVIg can rapidly increase platelet counts, and can also help reduce the risk of major bleeding by transiently increasing platelet counts.
Recent research now indicates that impaired production of the glycoprotein hormone, thrombopoietin, which is the stimulant for platelet production, may be a contributing factor to the reduction in circulating platelets. This observation has led to the development of a class of ITP-targeted medications referred to as thrombopoietin receptor agonists.The stimulus for auto-antibody production in ITP is probably abnormal T cell activity. Preliminary findings suggest that these T cells can be influenced by medications that target B cells, such as rituximab. Diagnosis
The diagnosis of ITP is a process of exclusion. First, it has to be determined that there are no blood abnormalities other than a low platelet count, and no physical signs other than bleeding. Then, secondary causes (5–10 percent of suspected ITP cases) should be excluded. Such secondary causes include leukemia, medications (e.g., quinine, heparin), lupus erythematosus, cirrhosis, HIV, hepatitis C, congenital causes, antiphospholipid syndrome, von Willebrand factor deficiency, onyalai and others. All patients with presumed ITP should be tested for HIV and hepatitis C virus, as platelet counts may be corrected by treating the underlying disease. In approximately 2.7 to 5 percent of cases, autoimmune hemolytic anemia and ITP coexist, a condition referred to as Evans syndrome.Despite the destruction of platelets by splenic macrophages, the spleen is normally not enlarged. In fact, an enlarged spleen should lead to a search for other possible causes for the thrombocytopenia. Bleeding time is usually prolonged in ITP patients.