الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Background: Immune thrombocytopenia (ITP) is one of the most common bleeding disorders in children. It is not easy to predict the course of the disease at the time of initial diagnosis. Measurement of thrombopoietin levels may help distinguish between various causes of thrombocytopenia and predict treatment response to thrombopoietin receptor agonists. Some studies investigated predictors of outcome in ITP but these were retrospective studies and to our knowledge, no prospective studies in children with ITP. Aim: This prospective study aimed to investigate the clinical features of immune thrombocytopenia in children and adolescents and predictors of outcome including the diagnostic potential of thrombopoietin levels as well as role in predicting response to therapy. Methods: Seventy pediatric patients with ITP; 25 were newly diagnosed patients, 45 had chronic ITP. They were compared with 20 age- and sex-matched healthy controls. Patients were studied stressing on bleeding manifestations, organomegaly/lymphadenopathy and therapy. Bleeding score was calculated to each patient according to the ITP Bleeding Scale (IBLS). Complete blood count was done serum levels of thrombopoietin were assessed by enzyme linked immunosorbent assay. The 25 patients with newly diagnosed ITP were followed-up for 3 months. The response after each line of treatment was recorded. Results: The incidence of epistaxis and bleeding with hypotension were higher in chronic ITP patients than newly diagnosed ITP patients. Initial platelets count at diagnosis was significantly higher in chronic ITP than newly diagnosed ITP patients. Age of onset > 5 years as well as the incidence of no recovery after 4 weeks of diagnosis and menorrhagia was significantly higher in active ITP patients than those in complete remission. It was found that 9 out of 25 (36.0%) patients had persistent ITP after 3 months follow-up and all were in active condition compared with those who entered in remission. Comparison between newly diagnosed patients who entered in complete remission and who became persistent after 3 months follow-up showed that age of onset > 5 years old was associated with progression to persistent ITP. Intake of IVIG was more frequent among newly diagnosed ITP patients who entered in complete remission although the difference did not reach a significant level. Initial platelet count at diagnosis was significantly higher in persistent ITP than those who had remission while platelets count 4 weeks after diagnosis was significantly lower. As regards thrombopoietin levels, no significant difference was found between all ITP patients and controls or between newly diagnosed and chronic ITP patients. High thrombopoietin levels have been noticed among those in active ITP. Thrombopoietin levels were significantly higher among patients with persistent ITP than those who had complete remission. Thrombopoietin level was significantly different in relation to initial response where highest levels were found among patients who had no response. ITP patients who experienced loss of response (relapse) had higher thrombopoietin levels. Thrombopoietin levels were inversely related to platelets count. Conclusions: The predictors of progression to persistent ITP and chronicity among our pediatric patients with ITP were age of onset > 5 years old, high initial platelet count, low platelets count 4 weeks after diagnosis and high baseline thrombopietin levels. High baseline thrombopoietin levels were also associated with absence of initial response as well as loss of response (relapse) denoting a poor clinical outcome. Therefore, it is important to be incorporated in routine practice for ITP patients to predict therapeutic response and modify treatment regimen, accordingly. Further prospective studies with longer follow-up including larger number of newly diagnosed ITP patients to verify our results and investigate predictors of chronicity in childhood ITP.