Idiopathic Thrombocytopenic Purpura

Abstract

1. Yu-Waye Chu, MD* 2. James Korb, MD† 3. Kathleen M. Sakamoto, MD* 1. 2. *Division of Hematology-Oncology, Department of Pediatrics. 3. 4. †Division of General Pediatrics, Department of Pediatrics, UCLA School of Medicine, Los Angeles, CA. This work was supported by a Resident Research Grant from the American Academy of Pediatrics (Y-WC). KMS is a Scholar of the Leukemia Society of America. After completing this article, readers should be able to: 1. Describe the clinical and laboratory features of idiopathic thrombocytopenic purpura (ITP) and explain how they differ in acute and chronic ITP. 2. List the features of ITP that distinguish it from other causes of thrombocytopenia. 3. Explain the role of bone marrow examination in the diagnosis of ITP. 4. Describe the advantages and disadvantages of the primary therapies for ITP. 5. Delineate the differences in therapeutic strategies for ITP and neonatal alloimmune thrombocytopenia. 6. Describe the role of splenectomy in the treatment of ITP. Idiopathic thrombocytopenic purpura (ITP) is an acquired hemorrhagic disorder characterized by: 1) thrombocytopenia that is defined as a platelet count less than 150 × 109/L ( 150,000/mcL), 2) a purpuric rash, 3) normal bone marrow, and 4) the absence of signs of other identifiable causes of thrombocytopenia. ITP is classified as acute or chronic, with the latter defined as the persistence of thrombocytopenia for more than 6 months from the initial presentation of signs and symptoms. ITP is estimated to be one of the most common acquired bleeding disorders encountered by pediatricians, with the incidence of symptomatic disease being approximately 3 to 8 per 100,000 children per year. Acute ITP is more prevalent among children younger than 10 years of age, affects males and females equally, and is more prevalent during the late winter and spring. Chronic ITP affects adolescents more often than younger children, with females being affected more frequently than males. Unlike acute ITP, it does not show a seasonal predilection. Patients who have chronic ITP are more likely to exhibit an underlying autoimmune disorder, with up to one third having clinical and laboratory manifestations of collagen-vascular disease. Although the focus of this article is on the clinical presentation, diagnosis, and management of ITP, the pathophysiology of this …