Idiopathic thrombocytopenic purpura: a 10-year natural history study at the childrens hospital of alabama

Abstract

Childhood idiopathic thrombocytopenic purpura (ITP) is a common disorder. However, single-institution, long-term, natural history data are limited. The objective of this paper is to review presenting features, response to therapy, and natural history of ITP treated at a single pediatric academic medical center. A retrospective chart review was made for all children (ages birth-18 years) diagnosed with ITP (ICD 287.3) and treated at the Childrens Hospital of Alabama/University of Alabama at Birmingham between 1993 and 2003. Four hundred nine patients were identified (49% male, 51% female; mean age: 5.85 years; range: 1 month-17 years). There was no seasonal variation of presentation. The mean platelet count was 19k (0-120k). Bone marrow aspiration (BMA) was performed in 72% but altered the diagnosis or therapy in no patient. Treatment consisted of corticosteroids in 256 (92% response), intravenous immunoglobulin (IVIG) in 125 (87% response), Win-Rho D in 58 (91% response), and no therapy in 71 (100% response). Response was defined as increase in platelet count to > 50k. There was no difference in response to any therapy. No patients died. One patient presented with a CNS hemorrhage at presentation, responded to therapy, and survived. Twenty-three of 409 patients (6%) experienced clinical bleeding requiring hospitalization or blood transfusion. Chronic ITP (persistence > 6 months) was noted in 99 patients (24%). Chronic patients presented at an older age (7.8 vs 5.2 years for acute only, p<0.001), and with higher platelet counts (27k vs 17k, p<0.001). The risk of chronic ITP was partially predicted by presenting platelet count > 50k and age > 10 years, or both; 50% of patients presenting with these features developed chronic ITP vs 24% overall rate. Splenectomy was curative in 30/31 (97%) patients. There was no postsplenectomy sepsis. Of 99 patients with chronic ITP, 25 responded to splenectomy, 37 resolved at a mean of 20.3 months after diagnosis (7-96 months), 36 had persistent mild thrombocytopenia (50k-125k), and 1 failed to respond to any treatment including splenectomy. Overall, 91% of cases resolved with therapy or observation. ITP is a common pediatric disease presenting at any age with low morbidity and mortality. Most cases can be managed by pediatricians without hematology referral. Several equally successful therapeutic options exist. Chronic cases present at an older age with higher platelet counts. Up to 50% of cases of chronic ITP will resolve with ongoing follow-up. The overall prognosis in childhood ITP is excellent.