A 17-year-old boy with chronic immune thrombocytopenia (ITP) comes to the clinic for follow-up. The patient was initially diagnosed with ITP over a year ago when he developed prolonged epistaxis after colliding with another player during a soccer game. This past school year the patient has been unable to participate in sports due to frequent episodes of mucosal bleeding after mild trauma warranting pharmacologic intervention. He has received treatment with multiple medications, including intravenous immunoglobulin and prednisone. His response to treatment has been transient, with platelet counts that have decreased rapidly to the 10,000/mm³ range at follow-up visits. Physical examination shows diffuse petechiae and a few areas of ecchymosis along the thighs but is otherwise normal. Laboratory results are as follows: Workup for autoimmune disorders and chronic viral infections is negative. Bone marrow evaluation reveals a normocellular marrow with slightly increased megakaryocytes. Which of the following is the best next step in management of this patient?

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11ec25c8_d6a6_6aaa_bc81_e1d34737c70e_MD0003_00 Immune thrombocytopenia (ITP) is an autoimmune disorder in which IgG antibodies form against platelet membrane proteins, resulting in isolated thrombocytopenia. Most cases of ITP self-resolve within 3 months; however, some patients continue to have platelets <100,000/mm³ for >1 year, which is known as chronic ITP. Adolescents with mild initial presentation and no preceding viral trigger are more likely to develop chronic ITP. Chronic ITP evaluation includes bone marrow examination and blood tests for infection (eg, HIV, hepatitis C, cytomegalovirus) and autoimmune disorders (eg, systemic lupus erythematosus, thyroid disease). If laboratory evaluation is negative, management is similar to acute ITP. This includes observation alone if asymptomatic, or a combination of glucocorticoids, anti-D immune globulin (if Rh-positive and Coombs-negative), and/or intravenous immunoglobulin for bleeding episodes. This patient has bleeding and thrombocytopenia requiring repeated pharmacologic interventions and should be considered for second-line therapies (eg, rituximab, thrombopoietin receptor agonists) or splenectomy. Although not without risk (eg, sepsis, thrombosis), splenectomy removes the source of platelet destruction and is often curative in patients with ITP. (Choice A) Anti-D immune globulin is a potential first-line therapy for ITP in patients with the Rh antigen. Anti-D binding to Rh(D)-positive erythrocytes is thought to saturate Fc receptors on macrophages within the reticuloendothelial system (RES), thereby limiting the ability of the RES to clear platelets. This patient is Rh(D) negative. (Choice B) Desmopressin promotes release of von Willebrand factor and is used for the treatment of von Willebrand disease (vWD); it is not helpful in patients with ITP. VWD does not typically cause significant thrombocytopenia. (Choice C) Epoetin alfa stimulates red blood cell production for patients with anemia, not thrombocytopenia. (Choice D) Granulocyte colony-stimulating factor increases granulocyte production and is used to treat neutropenia, not seen in this patient. (Choice E) Platelet transfusions are reserved for life-threatening hemorrhage in patients with ITP because antibody production destroys the transfused platelets. In contrast, this patient's bleeding is limited to mucocutaneous. Educational objective: Patients with chronic immune thrombocytopenia have platelets <100,000/mm³ for >1 year. Splenectomy is an option for those with persistent bleeding and thrombocytopenia despite repeated pharmacologic interventions (eg, glucocorticoids, anti-D, intravenous immunoglobulin). References: Bleeding manifestations and management of children with persistent and chronic immune thrombocytopenia: data from the Intercontinental Cooperative ITP Study Group (ICIS). (http://www.ncbi.nlm.nih.gov/pubmed/23550040) Reemergence of splenectomy for ITP second-line treatment? (http://www.ncbi.nlm.nih.gov/pubmed/27741009) Chronic immune thrombocytopenia in children: who needs splenectomy? (http://www.ncbi.nlm.nih.gov/pubmed/23664519)

A 17-Year-Old Boy with Chronic Immune Thrombocytopenia (ITP) Comes to the Clinic