Abstract:
Immune thrombocytopenic purpura (ITP) is an autoimmune disease presents with isolated thrombocytopenia (thrombocyte count < 100.000/mm3) and develops due to increased thrombocyte destruction by autoantibodies. ITP is the most common cause of pediatric thrombocytopenia. Usually a self-limiting disease with an acute course of 70% - 80%. However, 20% - 25% cases are chronical. These cases are follow-up and management difficult and expensive. It is important to distinguish events that may become chronic at the time of initial diagnosis. In this study, we sought clues to be able to choose, which the patient will be chronicle?
Background: Immune thrombocytopenic purpura (ITP) is an autoimmune disease present with isolated thrombocytopenia and develops due to increased thrombocyte destruction by autoantibodies.(1, 2) ITP is the most common cause of pediatric thrombocytopenia. Usually a self-limiting disease with an acute course of 70% - 80%. However, 20-30% of cases become chronic. ITP most commonly seen between 2 and 5 years of age but occurs in all pediatric age groups. (2, 3)
In this study, we aimed to investigate the main characteristics (features) and outcomes of our pediatric ITP cases and whether there are any factors affecting chronicity.
Procedure: We analyzed retrospectively our 184 newly diagnosed pediatric ITP cases. In this study, a history of viral infections and vaccination, physical examination, laboratory findings, treatment modality, and efficacy in children under 18-years old with ITP were recorded. Thrombocytopenia persisting beyond 12 months was defined as ”chronic ITP” whereas resolved thrombocytopenia within 12 months of diagnosis was defined as ”acute ITP”. The patients were divided into three age groups. Group 1 include the patients younger (smaller) than 2 years of age (57 patients), group 2 include the patients between 2 and 6 years of age (73 patients), and group 3 include the patients older (greater) than 6 years of age (54 patients). We evaluated the role of clinical and laboratory findings and treatment modalities in the chronicity of ITP.
As first-line treatment, 87 (47.3%) of patients were given Intravenous Immune Globulin ( IVIG, 1 g/kg, 1 or 2 days), 65 (35.3%) were given methylprednisolone (20 mg/kg/day for three days, and 10 mg/kg/day for four days), and 32 (17.4%) of patients were followed without any medication.
Results: One hundred four patients were male (56.5%) and 80 (45.5%) were female. The mean age of patients was 5.4 ± 4.75 years at diagnosis. The most common bleeding site was skin in 83,7% of patients and none of the patients had central nervous system bleeding. In 92 patients (50%) no triggering cause could be identified. The most common triggering factor was upper respiratory tract infection (in 34,2 % of patients).
Thirty-nine patients (21.1%) who had persistent thrombocytopenia after 12 months of follow-up were accepted as chronic ITP. The ratio of acute/chronic ITP cases was 83/21 in males, and 62/18 in females (p=0.7). The treatment modality at first admission did not affect the development of chronic ITP (p=0.61). The most important factor in the development of chronic ITP was the age at diagnosis. The mean age at diagnosis was 4.54±4.18 years in acute ITP and 8.62±5.39 years in chronic ITP (p<0.0001) Acute and chronic ITP ratio were 53/4 for patients less than 2 years of age, 60/13 for patients between 2 and 6 years of age, and 31/23 for over than 6 years of age (p<0.0001). The thrombocyte counts and mean platelet volume (MPV) at diagnosis did not affect chronicity. Total leukocyte count at diagnosis had also no effect on chronicity, but mean absolute neutrophil count (ANC) was significantly higher (p=0.007) and mean absolute lymphocyte count (ALC) was significantly lower (p<0.0001) in chronic ITP patients. But when these findings were re-evaluated according to each age group, we did not find any important differences between acute and chronic cases for mean ANC and ALC, except ALC levels had only a small effect on the 2nd (2-6 years) group (p:0.048).
Conclusions: Although ITP has a good prognosis in most of the patient in childhood, it may become chronic in about 20 % of patients. Our results support that, high age most important factor for ITP’s chronicity. Infantile ITP prognosis better than older children, and watch-and-wait strategy could be a safe treatment choice.