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Diagnosis of immune thrombocytopenic purpura in children
Amy E Geddis1, Carlo L Balduini
1Department of Pediatrics, University of California, San Diego, California 92107, USA. ageddis@ucsd.edu
Insights
Diagnosing immune thrombocytopenic purpura (ITP) involves ruling out other causes of low platelets. Bone marrow aspiration is key for confirmation if initial tests are inconclusive or treatment fails, especially in children.
Area of Science:
- Hematology
- Pediatric Hematology
- Immunology
Background:
- Immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by low platelet counts.
- Distinguishing ITP from other causes of thrombocytopenia is crucial for effective management.
Purpose of the Study:
- To update the differential diagnosis of inherited versus acquired immune thrombocytopenic purpura.
- To review clinical practices for the initial diagnosis of ITP in children.
Main Methods:
- Clinical history and physical examination (petechiae, bruising, bleeding).
- Peripheral blood smear analysis (platelet size and morphology).
- Blood counts and recently developed assays for platelet-bound antibodies.
Main Results:
- Platelet-bound antibody assays have suboptimal sensitivity (80-83% positive predictive value).
- Diagnosis relies on exclusion of other thrombocytopenic causes.
- Bone marrow aspiration and biopsy are indicated for atypical cases or non-response to therapy.
Conclusions:
- ITP diagnosis is a process of elimination.
- Bone marrow aspiration is required for confirmation if diagnostic criteria are inconclusive or if the patient does not respond to therapy within 6-12 months.
- Confirmation is especially important before initiating corticosteroid therapy in children.
Purpose Of Review:
This review updates the differential diagnosis between inherited and acquired immune thrombocytopenic purpura as well as clinical practice on the initial diagnosis of children with the disease.
Recent Findings:
A diagnosis of immune thrombocytopenic purpura may be based on an evaluation of the history, physical findings such as petechiae, bruising and mucous membrane bleeding, examination of peripheral blood films stained with Wright's or May-Grünwald-Giemsa, determination of blood counts, platelet size and appearance. Recently, diagnostic assays have been developed to detect platelet-bound antibodies. The sensitivity of these assays, however, is suboptimal, with a positive predictive value of 80-83%. If the diagnosis of immune thrombocytopenic purpura is in question due to the presence of atypical features, or if a patient with findings typical of the disease does not respond to therapy, bone marrow aspiration and biopsy are indicated to confirm the diagnosis.
Summary:
The diagnosis of immune thrombocytopenic purpura is a process of elimination of other sources of thrombocytopenia. If the criteria discussed above are inconclusive and if the patient does not respond to therapy in 6-12 months (this is especially true in children) then a bone marrow aspiration is required to confirm the diagnosis, especially before initiating corticosteroid therapy.