Idiopathic Thrombocytopenic Purpura
- Idiopathic or immune thrombocytopenic purpura (ITP) is an autoimmune syndrome characterized by the following:
- Isolated thrombocytopenia (platelet count formally <100,000/mm3, typically <20,000/mm3)
- Shortened platelet survival
- Platelet autoantibodies
- Increased number of megakaryocytes in the bone marrow
- Primary ITP implies absence of other causes for thrombocytopenia; secondary ITP indicates another diagnosis associated with autoimmune thrombocytopenia.
- Phases of ITP
- Newly diagnosed (acute) ITP: within 3 months of initial diagnosis
- Persistent ITP: transient improvement or continued thrombocytopenia for 3–12 months
- Chronic ITP: persistent thrombocytopenia >12 months after initial presentation
- Most common acquired platelet disorder in childhood
- Often follows viral syndrome by a few weeks; this may be associated with higher likelihood of spontaneous recovery.
- Males and females are equally affected in childhood ITP (mild male predominance in younger children; female-to-male ratio is 3:1 in adult and chronic ITP).
- Median age at diagnosis is 4 years. Children <1 year or >10 years are more likely to develop chronic ITP.
- >70% of childhood ITP resolves within 6–12 months.
- Risk of severe bleeding is <5% and of intracranial bleeding is ∼0.5%.
Incidence is 1–10/100,000 children per year (<15 years of age).
- Thrombocytopenia due to increased destruction of antibody-coated platelets in the reticuloendothelial system, particularly the spleen
- Hypothesized that antibodies generated in response to foreign antigen or drug cross-react with platelet membrane glycoproteins (most commonly IIb/IIIa and Ib/IX)
- Other mechanisms of immune dysregulation have been implicated, including possible inhibition of thrombocytopoiesis, limiting ability to compensate for destruction.
- Typical bone marrow aspirate shows increased numbers of immature megakaryocytes.
Commonly Associated Conditions
- In younger children, primary ITP is the most common presentation of ITP.
- Secondary ITP is seen with autoimmune disorders (e.g., systemic lupus erythematosus [SLE], autoimmune lymphoproliferative syndrome [ALPS]).
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Cabana, Michael D., editor. "Idiopathic Thrombocytopenic Purpura." Select 5-Minute Pediatrics Topics, 7th ed., Wolters Kluwer Health, 2015. Medicine Central, im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14046/2.0.0/Idiopathic_Thrombocytopenic_Purpura.
Idiopathic Thrombocytopenic Purpura. In: Cabana MDM, ed. Select 5-Minute Pediatrics Topics. Wolters Kluwer Health; 2015. https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14046/2.0.0/Idiopathic_Thrombocytopenic_Purpura. Accessed June 5, 2023.
Idiopathic Thrombocytopenic Purpura. (2015). In Cabana, M. D. (Ed.), Select 5-Minute Pediatrics Topics (7th ed.). Wolters Kluwer Health. https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14046/2.0.0/Idiopathic_Thrombocytopenic_Purpura
Idiopathic Thrombocytopenic Purpura [Internet]. In: Cabana MDM, editors. Select 5-Minute Pediatrics Topics. Wolters Kluwer Health; 2015. [cited 2023 June 05]. Available from: https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14046/2.0.0/Idiopathic_Thrombocytopenic_Purpura.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Idiopathic Thrombocytopenic Purpura ID - 14046 ED - Cabana,Michael D, BT - Select 5-Minute Pediatrics Topics UR - https://im.unboundmedicine.com/medicine/view/Select-5-Minute-Pediatric-Consult/14046/2.0.0/Idiopathic_Thrombocytopenic_Purpura PB - Wolters Kluwer Health ET - 7 DB - Medicine Central DP - Unbound Medicine ER -