From the Guidelines
The correct answer is (a) idiopathic thrombocytopenic purpura is caused by antiplatelet immunoglobulin G originating in the spleen. ITP is an autoimmune disorder characterized by the production of autoantibodies, primarily IgG, against platelet surface antigens, as stated in the 2019 guidelines by the American Society of Hematology 1. These antibodies are produced by B cells in the spleen and cause premature destruction of platelets by macrophages in the reticuloendothelial system, particularly in the spleen. The other options are incorrect:
- ITP typically does not cause significant splenomegaly (b), which is not a common finding in ITP patients 1.
- It affects platelet count but not coagulation factors, so prothrombin time remains normal (c), as ITP primarily affects platelet production and destruction, not the coagulation cascade 1.
- Splenectomy is reserved for refractory cases in adults and is rarely needed in children, who often experience spontaneous remission (d), with 1-year remission rates of 74% in children <1 year of age, 67% in those between 1 and 6 years of age, and 62% in those 10 to 20 years of age 1.
- And ITP actually has a female predominance, although the exact female to male ratio is not specified in the provided evidence, it is not 3:1 in favor of males (e). First-line treatment typically involves corticosteroids like prednisone or intravenous immunoglobulin for acute cases with significant bleeding or very low platelet counts, with the goal of minimizing bleeding events and improving quality of life 1.
From the Research
Idiopathic Thrombocytopenic Purpura (ITP) Characteristics
- ITP is characterized by a low platelet count due to increased platelet destruction and insufficient platelet production 2
- The development of autoantibodies against platelet glycoproteins is central to the pathophysiology of ITP 2, 3
Treatment Options for ITP
- Conventional treatments for ITP aim to reduce platelet destruction through immunosuppression or splenectomy 2, 4
- First-line therapies for ITP include corticosteroids, intravenous immunoglobulin, and anti-RhD immune globulin 4, 5
- Second-line treatments for ITP include immunosuppressive therapy, such as rituximab, and thrombopoietin receptor agonists 3, 6
- Splenectomy is a treatment option for patients who do not respond to first-line therapies, but it is an invasive procedure with potential risks 4, 5
ITP Diagnosis and Classification
- A platelet count in peripheral blood <100 × 10(9)/L is a key criterion for the diagnosis of ITP 3
- ITP can be classified into three types: acute, subchronic, and persistent, based on disease duration 3
Gender Ratio and Splenomegaly
- There is no information in the provided studies about the male to female ratio of ITP or the association with splenomegaly
- Prolonged prothrombin time is not mentioned as a characteristic of ITP in the provided studies
Pediatric Cases
- There is no information in the provided studies about the requirement for splenectomy in most pediatric cases of ITP