From the Guidelines
The diagnostic workup for Immune Thrombocytopenic Purpura (ITP) involves a complete blood count showing isolated thrombocytopenia (platelet count <100,000/μL), peripheral blood smear examination to rule out pseudothrombocytopenia, and exclusion of other causes through tests like HIV, hepatitis C, H. pylori, and bone marrow examination in selected patients, as recommended by the American Society of Hematology 2019 guidelines for immune thrombocytopenia 1.
Diagnostic Approach
The initial diagnosis of ITP is made by exclusion of secondary causes of thrombocytopenia, with no diagnostic tests to confirm ITP, as stated in the American Society of Hematology 2011 evidence-based practice guideline for immune thrombocytopenia 1. The diagnostic workup should include:
- Complete blood count to confirm isolated thrombocytopenia
- Peripheral blood smear examination to rule out pseudothrombocytopenia
- Tests to exclude other causes of thrombocytopenia, such as:
- HIV
- Hepatitis C
- H. pylori
- Bone marrow examination in selected patients
Treatment Approach
Treatment depends on bleeding risk and platelet count. For newly diagnosed ITP with significant bleeding or platelet counts <30,000/μL, first-line therapy includes corticosteroids (prednisone 1 mg/kg/day for 2-4 weeks followed by tapering) or intravenous immunoglobulin (IVIG 1 g/kg/day for 1-2 days) for rapid response, as suggested by the international consensus report on the investigation and management of primary immune thrombocytopenia 1. In severe bleeding, combination therapy with both agents plus platelet transfusions may be necessary. For persistent or chronic ITP not responding to first-line therapy, second-line options include thrombopoietin receptor agonists (eltrombopag 25-75 mg daily or romiplostim 1-10 μg/kg weekly), rituximab (375 mg/m² weekly for 4 weeks), or splenectomy, as discussed in the American Journal of Hematology article on transitioning patients with immune thrombocytopenia to second-line therapy 1.
Key Considerations
Treatment decisions should be individualized based on:
- Bleeding symptoms
- Platelet count
- Comorbidities
- Medication side effects
- Patient preferences The pathophysiology of ITP involves autoantibodies against platelet antigens leading to premature platelet destruction by macrophages in the spleen and impaired platelet production, which explains why therapies target either reducing antibody production, blocking platelet destruction, or enhancing platelet production, as described in the Blood Reviews article on tapering and discontinuation of thrombopoietin receptor agonists in immune thrombocytopenia 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Diagnostic Workup of ITP
- The diagnosis of ITP requires excluding secondary causes of thrombocytopenia 2, 3, 4, 5, 6.
- The bare minimum workup for ITP includes a complete blood count and a peripheral blood smear 2.
- The peripheral blood smear should show a small number of large platelets with normal morphology, and there should not be an increased number of schistocytes 2.
- A thorough and timely workup of thrombocytopenia is imperative to rule out other differentials of ITP as it is considered a diagnosis of exclusion 6.
Treatment of ITP
- Many patients with ITP require no emergent treatment 2.
- For patients with suspected ITP presenting with critical hemorrhage, treatment with a platelet transfusion, corticosteroids, and intravenous immune globulin (IVIG) should be initiated as soon as possible 2.
- For less severe bleeding, platelet transfusions are not recommended, and the treatment consists of corticosteroids by themselves or in conjunction with IVIG 2.
- Initial treatment of adult ITP is with corticosteroids, intravenous immunoglobulin, or intravenous anti-RhD immune globulin 3.
- Subsequent treatment of adult ITP is typically with thrombopoietin receptor agonists (TPO-RAs; romiplostim or eltrombopag), rituximab, or splenectomy 3, 4.
- The choice between therapy options is highly dependent upon patient values and preferences 4.