title: Duration and morbidity of newly diagnosed idiopathic thrombocytopenic purpura in children: A prospective Nordic study of an unselected cohort.
abstract: OBJECTIVE
  To determine the duration of the risk period with platelet counts <20 x 10(9)/L and the frequency of bleeding episodes in unselected children with idiopathic thrombocytopenic purpura (ITP).
  
  
  METHODS
  We established a registry for patients with newly diagnosed ITP in the five Nordic countries, enrolling children aged 0 to 14 years with platelet counts <30 x 10(9)/L. Treatment centers prospectively reported presenting features, management details, and disease-related events during the first six months after diagnosis.
  
  
  RESULTS
  At presentation (n=501), more than half of the children had a platelet count <10 x 10(9)/L, but only 15 (3.0%) had a hemorrhage requiring blood transfusion. During follow-up of 409 patients, thrombocytopenia resolved uneventfully in 277. A risk period was present in 376 cases. Among 283 with self-limiting ITP, 26 were at risk >1 month and 25 had 30 events. Among 93 patients with chronic ITP, 73 were at risk >1 month and 44 had 111 events. Events occurred with an average frequency of 0.39 per month at risk. Life-threatening hemorrhages did not occur in the first six months after diagnosis.
  
  
  CONCLUSIONS
  Most children with ITP are at risk for serious bleeding for less than one month. Continuing severe thrombocytopenia is associated with little morbidity, bleeding episodes being infrequent and very rarely serious.
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006470:Hemorrhage / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010976:Platelet Count; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy; D018570:Risk Assessment; D012537:Scandinavian and Nordic Countries; D012720:Severity of Illness Index; D013997:Time Factors