Immune thrombocytopenic purpura (ITP), also called primary immune thrombocytopenia or idiopathic thrombocytopenic purpura, is an autoimmune disease affecting thrombocytes.
The most common presentations observed are bleeding and prolonged bleeding time leading to thrombocytopenia and anemia. Common signs are bleeding spots (purpura) and petechiae mostly on extremities, bleeding gums, epistaxis and menorrhagia. Complications occur due to extremely low blood cell counts (< 5,000 per ul). These include subarachnoid hemorrhage hematomas and lower gastrointestinal bleeding. Care should be taken as ITP patients are at a risk for internal bleeding with slightest trauma. This is unlikely if the platelet count is more than 20,000 per ul. .
Diagnosis is partly made through a careful history and nature of symptoms. A complete blood count shows thrombocytopenia and low hemoglobin suggests anemia due to blood loss. Blood smear is mandatory to evaluate and rule out other causes of thrombocytopenia.
Congenital thrombocytopenia shows abnormal morphology in leucocytes and erythrocytes as well, suggesting an underlying bone marrow disease. A blood smear shows large number of schistocytes suggesting thrombocytopenia due to thrombotic purpura or hemolytic uremic syndrome.
A bone marrow examination is done in cases who do not respond to the primary treatment. The bone marrow biopsy may show reduced counts of megakaryocytes that help in diagnosis of ITP. Also, leukemia is ruled out. In cases where splenectomy is done, bone marrow examination is done to evaluate for fibrosis.
Treatment aims at increasing the platelet level to a safe value of more than 30x 109/L and maintaining the count thereafter till remission. Corticosteroids comprise the first line of treatment that includes prednisone, dexamethasone and methylprednisolone. In case of bleeding tendencies, along with corticosteroids anti-RhD injections are also given to stimulate the platelet count. Studies show that the platelet value increases by > 50 × 109/L in a few days to several weeks after giving prednisolone. Patients requiring anti–RhD treatment are first screened direct antiglobulin test and the Rh type is determined before initiating the treatment. The standard dose is 50 nanogms/kg. The response is seen after 48- 72 hrs.
Splenectomy is the most commonly done as a part of treatment especially in chronic ITPs. The procedure has been curative to majority of patient, as it lowers the rate of relapse .
Prognosis of acute ITP in children is good. Studies showed that about 80% of children recovered completely. There might be a relapse after 6 weeks and only about a small percentage of children develop a chronic disease. Chronic disease is usually seen in adults. Patients gain a normal platelet count with prednisone treatment. If the prednisone is reduced chances of platelet reducing further increases.
The exact cause of the immune mediated antibodies that cause platelet destruction is unknown, however it is postulated that a reduction in suppressor T regulatory cells and increase in B cell activating factor may be responsible for the generation of these autoantibodies. Certain theories relate activation of self-reactive platelet antibodies after infections such as HIV, H pylori and hepatitis C. Here the antibodies cross reacts with the platelets leading to immune thrombocytopenic purpura .
The incidence of ITP is estimated to be 50-100 cases per million per year . It is accounted that most of the adult age group is affected with this disease, children being concerned 50% off the adult ratio. The mortality rate is higher in adults. It was concluded that over 90% deaths occurred in the age group of individuals over 45 years .
Dr. William Harrington had first experimented on himself, along with his other colleagues by injecting with the blood of patients with ITP. The experiment resulted into severe thrombocytopenia in their blood sample lasting for several days. Immune thrombocytopenic purpura involves both cellular and humoral immunity. There are certain autoantibodies found which are directed against the platelet surface glycoprotein (GP) complexes gp IIb-IIIa  .
The autoantibodies are mostly of IgG subtype and they attach to the targeted platelets on their surfaces. It was found that in ITP patients who were injected with in-labeled autologous platelets, the uptake is primarily from the spleen and liver. After platelets are attached to the antibodies’ surface, there is degradation and macrophages secrete cytokines that stimulate CD4 T cell clones. These CD4 T cells identifies distinct epitopes on gp IIb-IIIa, leading to a general autoimmune response and massive platelet destruction. The trigger for such a response is not known. Studies show that platelet associated auto antibodies are found in about 50-70% affected individuals.
B cells in ITP produce antibodies directed against the normal platelet antigens thereby initiating response from the CD4 T cells. A potent immunosuppressive cytokine called beta 1, is found to be elevated in patients with ITP in remission as compared to those with active ITP. The autoreactive T cells are found in healthy individuals, but the active form is only found in patients with autoimmune diseases. Also, along with destruction of platelets there is suppression of production of megakaryocytes leading to thrombocytopenia.
Immune thrombocytopenic purpura (ITP) is an autoimmune disorder also referred to as primary immune thrombocytopenia or idiopathic thrombocytopenic purpura, characterized by destruction of platelets and impairment of platelet production (thrombopoeisis) leading to a tendency to prolonged bleeding .
Immune thrombocytopenic purpura (ITP), also called primary immune thrombocytopenia or idiopathic thrombocytopenic purpura, is an autoimmune mediated disorder wherein antibodies are directed to destroy or kill normal platelets leading to bleeding disorders. The cause is not known. Certain drugs and infections such as HIV and Helicobacter pylori infections are thought to be some of the causes for this disease. Signs and symptoms include bleeding from gums, nostrils, bruises on extremities, easy bleeding to slightest injury and there is a increased risk of intracranial hemorrhage which may prove fatal. Treatment is aimed in restoring the platelet values to normal levels by treating with corticosteroids. Chronic long standing patients are advised spleen removal (splenectomy) that has shown considerable results.