Objective: to describe the characteristics and treatment response of immune thrombocytopenic purpura (ITP) who have platelet 20.000/mm3 at Children Hospital No.2 and compare characteristics, method of treatment and response between 4 weeks nonresponse and response group. Subjects and methods: prospective case series study through 52 new- diagnosed ITP who have platelet 20.000/mm3 at Children Hospital No.2 from 15-03-2011 to 15-08-2011. Results: 52 new- diagnosed ITP (29 boys, 23 girls) with the median age of 28,S (4-174) months, 77 percent less than 5 years, 37 percent infant
29 percent viral infection antecedent and 10 percent vaccination 2-4 weeks before ITP. Clinical subgroup: mild 12 percent, moderate 73 percent, severe 15 percent. Response of mild ITP: 1st week 83 percent, 2nd week 100 percent, 4th week 50 percent (lose 1/3 patients at 4th week). Response of moderate ITP: 1st week 79 percent, 2nd week 87 percent, 4th week 86 percent. Response of severe ITP: 1st week 50 percent, 2nd week 87 percent, 4th week 100 percent. Response of all group: 1st week 75 percent, 2nd week 88 percent, 4th week 85 percent. No difference in characteristics, method of treatment between 4 weeks non-response and 4 weeks response group. Difference in platelet between 2 group: platelet of 4 weeks response group is lower at admistration but higher at 2nd week and much higher at 4th week than platelet of 4 weeks non-response group.