New Developments in ITP
by Maria A Pelidis MD, Division of Pediatric Hematology/OncologyFloating Hospital for Children
Immune thrombocytopenic purpura (ITP) is the most common acquired bleeding disorder in children. It usually occurs one-to-two months after a viral infection and is thought to be due to an inappropriate immune response. It has a benign natural history in most children and within six months of diagnosis 85 percent of affected youngsters have a normal platelet count. Yet despite tremendous experience treating this disease and the development of new efficacious therapies, the management of ITP remains quite controversial.
In the presence of life-threatening bleeding, all pediatricians and hematologists would immediately initiate therapy; however, patients with petechiae (small reddish or purplish spots containing blood in skin or mucous membranes), bruises and platelet counts of less than 20,000/cu mm generate treatment dilemmas. Some hematologists believe that children with acute ITP but without severe bleeding should be observed rather than treated, regardless of the platelet count. Most hematologists, however, are inclined to initiate treatment in patients with platelet counts less than 20,000/cu mm to rapidly bring the platelet count to a "safe" range. In 1996, a panel established by the American Society of Hematology recommended treatment for children with platelet counts less than 20,000/cu mm and significant mucous membrane bleeding, and those with platelet counts less than 10,000/cu mm and minor purpura. Practically, the decision to treat is individualized for each patient based on the severity of bleeding, the activity level of the child and careful consideration of the potential side effects of the various therapies.
The mainstay of therapy for ITP until 1981 was corticosteroids. Intravenous immune globulin (IVIG) then became the mainstay of treatment until a decade ago, when anti-D was added to the armamentarium. This agent has the benefit of ease of administration, since it can be given as an injection or short infusion, rather than the cumbersome prolonged infusion of IVIG. The severity of infusion-related side effects such as fevers, nausea and headaches is lessened, although its administration is associated with a predictable, mild hemolytic anemia. Some hematologists are also using shorter pulses of high dose steroids and combining agents, in an attempt to rapidly increase the platelet counts and decrease adverse reactions. There are numerous studies that have demonstrated that treatment of ITP patients with oral corticosteroids, IVIG or anti-D results in a more rapid elevation of the platelet count. However, none of the studies have enough statistical power to determine the ability of treatment to eliminate severe bleeding episodes, such as the rare but much feared intracranial hemorrhage.
A minority of patients (10-20 percent) do not achieve a normal platelet count six months after their diagnosis. These patients are said to have chronic ITP and are more commonly older children, especially adolescent females. However, most of these patients will also achieve a remission within months. It is important to work closely with chronic ITP patients and their families to help them to learn how to live with their disease and maintain their quality of life. Traditionally, splenectomy was thought to be the cure for these patients, but it is currently only considered for those with significant bleeding and failure to respond to less invasive treatment, since the failure rate for splenectomy is 25-30 percent, and is probably higher with longer follow-up. Splenectomy is also associated with a small but lifelong increased risk of sepsis.
A new treatment for chronic ITP called Rituximab has been established for adults and is now beginning to be used in children. Rituximab is a chimeric monoclonal antibody directed against the CD-20 antigen found on B lymphocytes. Infusion of this agent results in depletion of B-cells and subsequently leads to reduction in antibody production and interruption of the immune mediated decrease in platelets usually associated with conditions like ITP. The complete response rate in adults who are resistant to various other treatment regimens including splenectomy is approximately 40 percent. There are numerous reports of Rituximab's successful use in children who have failed other immunosuppressive regimens for the treatment of chronic ITP and a controlled study is underway to determine the exact response rate for this population. There is concern that depletion of B cells might transiently leave children susceptible to infections, although this does not appear to be a problem for adult patients receiving this treatment.
About Tufts-New England Medical Center
Founded in 1796 as the Boston Dispensary to care for sick and needy Bostonians, Tufts-New England Medical Center is the oldest health care facility in New England. It serves as the primary clinical and teaching affiliate of Tufts University School of Medicine. Tufts-NEMC is a world-class, academic medical institution that is home to both a full-service hospital for adults and the Floating Hospital for Children and has long been recognized as a leader in cancer care, cardiology, organ transplantation and pediatrics. Rituximab treatmens for ITP is available at the Floating Hospital. For more information on Tufts-NEMC, access our web site, https://www.tuftsmedicalcenter.org/
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Never take any herb identity for granted. The best way to be sure that you are using the right kind of herb is by buying it.
