Immune Thrombocytopenia (ITP)

Although often asymptomatic and identified only by a low platelet count on a routine assay, when present the symptoms and signs of immune thrombocytopenia are

Gross gastrointestinal (GI) bleeding and hematuria are less common. The spleen is of normal size unless it is enlarged by a coexisting viral infection or autoimmune hemolytic anemia Autoimmune Hemolytic Anemia Autoimmune hemolytic anemia is caused by autoantibodies that react with red blood cells at temperatures ≥ 37° C (warm antibody hemolytic anemia) or < 37° C (cold agglutinin disease). Hemolysis... read more (Evans syndrome). Like the other disorders of increased platelet destruction, ITP is also associated with an increased risk of thrombosis.

Immune thrombocytopenia is suspected in patients with isolated thrombocytopenia (ie, otherwise normal CBC and peripheral blood smear). Because manifestations of immune thrombocytopenia (ITP) are nonspecific, other reversible causes of isolated thrombocytopenia Thrombocytopenia Platelets are circulating cell fragments that function in the clotting system. Thrombopoietin helps control the number of circulating platelets by stimulating the bone marrow to produce megakaryocytes... read more (eg, drugs, alcohol, lymphoproliferative disorders, other autoimmune diseases, viral infections) need to be excluded by clinical evaluation and appropriate testing. Typically, patients have coagulation studies, liver tests, and tests for infection with hepatitis C and HIV. Peripheral blood smear must be reviewed to assess platelet size and granularity and to help exclude other major causes of thrombocytopenia such as thrombotic thrombocytopenic purpura Thrombotic Thrombocytopenic Purpura (TTP) Thrombotic thrombocytopenic purpura (TTP) is an acute, fulminant disorder characterized by thrombocytopenia and microangiopathic hemolytic anemia. Other manifestations may include alterations... read more (TTP), inherited thrombocytopenia, and leukemia Overview of Leukemia Leukemia is a malignant condition involving the excess production of immature or abnormal leukocytes, which eventually suppresses the production of normal blood cells and results in symptoms... read more . Testing for antiplatelet antibodies may aid the diagnosis in some cases (1) Diagnosis reference Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more . The immature platelet fraction may be elevated in ITP when the platelet count is < 50,000/mcL (< 50 × 10⁹/L).

Bone marrow examination is not required to make the diagnosis but is done if blood counts or blood smear reveals abnormalities in addition to thrombocytopenia, when clinical features are not typical, or if patients fail to respond to standard therapies (eg, corticosteroids). In patients with ITP, bone marrow examination reveals normal or possibly increased numbers of megakaryocytes in an otherwise normal bone marrow sample.

Children typically recover spontaneously, even from severe thrombocytopenia, in several weeks to months.

In adults, spontaneous remission occurs in under 10%. With completion of initial treatment, about one-third of patients undergo remission. Up to 75% of patients improve within 5 years (1 Prognosis reference Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more ). However, many patients have mild and stable disease (ie, platelet counts > 30,000/mcL [> 30 × 10⁹/L]) with minimal or no bleeding; they are often discovered by the automated platelet counting now routinely done with complete blood count.

2019 guidelines are now available (1,2) Treatment references Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more . Asymptomatic patients with a platelet count > 30,000/mcL (> 30 × 10⁹/L) and no bleeding do not require treatment and can monitored.

Adults with newly diagnosed ITP with bleeding and a platelet count < 30,000/mcL (< 30 × 10⁹/L) are usually given an oral corticosteroid (eg, prednisone 1 mg/kg orally once a day) initially. An alternative, probably equally effective, corticosteroid regimen is dexamethasone 40 mg orally once a day for 4 days. In most patients, the platelet count increases within 2 to 5 days. However, in some patients, a response may take 2 to 4 weeks. When the corticosteroid is tapered after response, most adult patients relapse. Repeated corticosteroid treatments may be effective but increase the risk of adverse effects. Corticosteroids should not usually be continued beyond the first several months; other drugs may be tried in an attempt to avoid splenectomy. If medical therapy is effective, most guidelines recommend continuing it for at least one year before considering splenectomy.

Oral corticosteroids, IVIG, or IV anti-D immune globulin may also be given when a transient increase of the platelet count is required for tooth extractions, childbirth, surgery, or other invasive procedures. Thrombopoietin receptor agonists (TPO-RA, eg, romiplostim, eltrombopag, avatrombopag) can also be used before invasive procedures but should not be used for childbirth. IVIG and IV anti-D immune globulin are also useful for life-threatening bleeding in immune thrombocytopenia Life-threatening bleeding in ITP Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more (ITP) but are rarely used for chronic treatment because their response may last for only a few days to weeks.

Splenectomy can achieve a complete remission in about two thirds of patients who relapse after initial corticosteroid therapy. Splenectomy is usually reserved for patients with severe thrombocytopenia (eg, < 15,000/mcL [< 15 × 10⁹/L]) in whom bleeding risk cannot be controlled with medical therapy or those whose disease persists after 12 months. If thrombocytopenia can be controlled with second-line medical therapies, splenectomy is often not necessary (1, 2 Treatment references Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more ). Splenectomy results in an increased risk of thrombosis and infection (particularly with encapsulated bacteria such as pneumococcus); patients require vaccination against Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis (ideally > 2 weeks before the procedure).