Immune Thrombocytopenic Purpura (ITP)

Immune Thrombocytopenic Purpura (ITP)

Immune thrombocytopenic purpura (ITP) is an acquired disorder that affects both children and adults, characterized by a decrease in the number of platelets in the blood. The bone marrow of patients functions normally, and ITP is not associated with any other medical conditions.

In clinical practice, ITP is the most common cause of thrombocytopenia. The clinical presentation of ITP in children and adults differs:

• Children (CH): ITP usually presents acutely and resolves spontaneously within 6 months.

• Adults (AD): ITP onset is insidious and rarely resolves spontaneously.

Werhof was the first to describe ITP in adults in 1735.

Pathogenesis of ITP:

• The key organ in the pathogenesis of ITP is the spleen.

• The spleen is the site of production of anti-platelet antibodies, mainly IgG, with a smaller amount of IgM.

• These antibodies bind to platelet membrane antigens, including GP IIb/IIIa and GP Ib/IX, leading to platelet destruction.

• Higher levels of IgG anti-platelet antibodies correlate with lower platelet counts.

• The body responds by increasing platelet production 5-fold to compensate for low platelet counts, resulting in increased platelet precursors in the bone marrow.

• Splenectomy is a crucial piece of evidence demonstrating the role of the spleen in the pathogenesis of ITP because the condition quickly improves after splenectomy.

Clinical manifestations:

• Adults:

• Ecchymosis (asymmetrical), mucosal bleeding.

• Rare cases of cerebral or internal bleeding.

• Overall health is usually normal.

• Children:

• May occur after a viral infection or immunization.

• Petechiae and purpura.

Blood count:

• Platelets are decreased.

• Red blood cells and white blood cells are normal.

• No anemia unless there is significant bleeding.

Bone marrow biopsy:

• Platelet precursors are normal or increased.

• Red blood cell and white blood cell lines are normal.

Coagulation tests:

• Normal except for prolonged partial thromboplastin time (PTT).

Immunologic tests:

• IgG and/or IgM antibodies against platelet GP complexes.

Differential diagnosis:

• Familial thrombocytopenia.

• Drug-induced thrombocytopenia.

• Thrombocytopenia in pregnancy.

• Pseudothrombocytopenia due to EDTA in vitro.

• Hypersplenism.

• Lupus.

• HIV.

Treatment:

• No treatment required when the platelet count > 30,000/mm3 and there are no signs of bleeding.

• Treatment required when the platelet count < 20,000/mm3 or there is significant bleeding.

Treatment modalities:

• Medication:

• Corticosteroids.

• Immunoglobulin.

• Anti-D.

• Danazol.

• Vinca alkaloids.

• Immunosuppressive drugs.

• Surgery: Splenectomy.

Note:

• Avoid intramuscular injections and do not use drugs that decrease platelet function such as Aspirin, NSAIDs when platelets are low.

• Closely monitor young individuals using cyclophosphamide due to the risk of cancer and infertility.

Prognosis:

• Most children spontaneously recover within 6 months.

• Adults rarely recover spontaneously.

• Splenectomy may help improve the condition in 2/3 of patients.

Conclusion:

ITP is a complex disorder that requires appropriate monitoring and treatment. Timely diagnosis and treatment help patients control the disease and improve their quality of life.